New Tech question of the Week

[PaulProe]

Mark,
Looking for the next challenge

this is fun

Paul

[Purple Venom]

How long are the axles (each side, not flange to flange) in the 8.8 Ford rear end and how many different spline configurations are there?:p

[Purple Venom]

Oh, and it's Tim btw. :D http://i137.photobucket.com/albums/q234/Hawgwild06/grape.gif

[Matthew 10:16]

Oh, and it's Tim btw. :D http://i137.photobucket.com/albums/q234/Hawgwild06/grape.gifHey Mark, Timbo or whatever the heck UR name is I have the correct answer from Funk & Wagnal's Mayonaise Jar which has been kept hermetically sealed for mellineniams(never could spell). Drum roll please. SHE has 2 very long Foxie axles, anchoring her rear, which sway side 2 side as she moves her spline in different configurations! :eek: :eek:* Dave/Shrewd Snake

[STL-Scott]

Tim,

Let's start with the spline configurations:
28 spline were offered up until '93 and then 31 spline was used from '94-'04(which was the stronger unit). An aftermarket search turns up 30, 33, and 35 spline as alternates.

Now for the axles lengths - that is tougher to find: 29.16" long. (Found on Ford Racing Parts 2008 performace Catalog)

I can already taste the Ice Cream!

Scotty

[Matthew 10:16]

Hey Scotty: what flavor R U ordering? Will it come w/Whipped cream, a cherry & pecans? Or is Timbo a cheap weesie weasel? Throw it back @ em cubbie style if doesn't include the goodies. :eek: Dave/Shrewd Snake

[STL-Scott]

I'm a sucker for anything with chocolate and peanut butter.

[Purple Venom]

still looking for the correct answer, Scott you are partially correct (again, this is by my information - however, I can be proven wrong and the whole purpose of me starting this thread was so everyone could learn something or share their knowledge with all) :D That being said, by my info, you have it partially right. Not exactly a trick question, but.....

[STL-Scott]

I guess if I'm adventurous I can tear apart my axle when it gets here...and measure it!

Curious to see what the full answer is!

Hints for those still guessing here is what I couldn't find out. Early fox mustangs had 4 lug set up with drum brakes. Switched to 5 lug disc brake rotors in '94(?) I think...same year as switch from 28 spline to 31 spline...I'm sure they were different lenghts.

[Matthew 10:16]

still looking for the correct answer, Scott you are partially correct (again, this is by my information - however, I can be proven wrong and the whole purpose of me starting this thread was so everyone could learn something or share their knowledge with all) :D* That being said, by my info, you have it partially right.* Not exactly a trick question, but.....Scotty Says: Gadzooks Batman. Ya mean I could be wrong. What now? Geewillikers. Back 2 the books w/even more zeal. Onward I go 4 the quest of knowledge of truth, justice & the American way. After all I do luv chocalate milk shakes w/peanut butter. Dave :D

[Purple Venom]

Ok, so this was kind of a trick question. The Ford 8.8 was not JUST used in the Mustang. It is also used in the Ford Bronco, Econoline, T-Bird, Explorer, Ranger, Lincoln, and Mustang. There are numerous axle lengths that range from 27 5/16" to 35 5/8". As for splines - 28 & 31 are all I could find on FORD axles. I'm sure the aftermarket has tons more, but the question was on Ford 8.8's. Make sure before you order new axles you check the plate on the differential or to be positive, measure the axle. So, no real winner this week, but Scott should get a can of whip cream or something. :D

[Purple Venom]

A bit more of a history question this time and kind of a lob for everyone to hit a homerun with:

What do the letters AC stand for in terms of the AC Shelby Cobra? And, what was the 1953 AC 2 seater model called?:rolleyes:

[STL-Scott]

I thought in your original question you said "fox" axles...therefore Fox Bodied Mustang is what I immediately thought.

Whip cream is good, I'll buy my own ice cream to put it on!

[STL Mark]

Auto Carriers, Ltd.

The complete story: http://en.wikipedia.org/wiki/AC_Cars

[Purple Venom]

Auto Carriers, Ltd.

The complete story: http://en.wikipedia.org/wiki/AC_Cars

Peaky peaky, no shaky shaky ;) Just kidding. Ok, need the 2nd part of the question answered.:p

[STL Mark]

AC Ace - which was inspired (copied) from the Ferrari Barchetta.
Extra Credit - right?
Anyway - a softball - and a little spare time tonight.
I like those fancy sundae shakes at Sonic! :D

[STL-Scott]

How long are the axles (each side, not flange to flange) in the 8.8 Ford rear end and how many different spline configurations are there?:p

Tim - when you change the question after the post you are changing the rules...now you are starting to sound like my wife...LOL! Oops didn't mean it that way Michelle!

I was probably still wrong on the axle lengths...

[Purple Venom]

You know I was just kidding right? :D Anyway, as my ORIGINAL question suggested, I was asking about the Fox axles, which DO come in one length, 29 3/4" by my info. I will by the shake as I'm not 100% sure about the length, anyone? Bueller? Bueller? :):D

[STL-Scott]

You know I was just kidding right? :D Anyway, as my ORIGINAL question suggested, I was asking about the Fox axles, which DO come in one length, 29 3/4" by my info. I will by the shake as I'm not 100% sure about the length, anyone? Bueller? Bueller? :):D

Tim - I know you were kidding - I could see it in your eyes Sunday when I said that to you:confused:

I was also kidding...gotta have some fun man. My wife does that to me all the time (change the rules)! I'm used to it.

See ya' Thurs.

[Purple Venom]

1 - What is the width of a DOHC 4.6 and a SOHC 4.6?

2 - What was the most HP produced by the SOHC 4.6 1991 to present and the DOHC 4.6 1993 - present?

Hint - DON'T look at wikipedia:D

[STL-Scott]

1 - What is the width of a DOHC 4.6 and a SOHC 4.6?

2 - What was the most HP produced by the SOHC 4.6 1991 to present and the DOHC 4.6 1993 - present?

Hint - DON'T look at wikipedia:D

1. Dimensions:
Engine - Height Depth Width
4.6L SOHC 26" 23 5/8" 26 5/8"
4.6L DOHC 27 1/8" 23 5/8" 26 5/8"

2. I have to condition my answer to your question - in their stock from the factory form, without new injectors, re-chipping, or re-programming the computer:
SOHC – 2004 Mustang GT (with the PI Heads): 4.6L 2v SOHC = 260 hp
SOHC - Current Mustang GT ('05-'08) model: 4.6L 3v SOHC = 300 hp
DOHC - 2003-2004 Mustang SVT Cobra 4.6L 4v DOHC (supercharged) = 390 hp

[STL-Scott]

Correction on the width. The information I posted earlier was from a thread on the ffcobra.com forum.

I read the Ford Racing Performance Parts Catalog tonight...page 94:

4.6L Modular Engine
SOHC Width = 25 5/8" Height = 26"
DOHC Width = 30" Height = 29 7/8"

Interesting comparison:

302W Engine Width = 18 3/4" Height = 20 3/4"
351W Engine Width = 21" Height = 23 3/4"
460 Engine Width = 26" Height = 26"

[Purple Venom]

Well, since no one else answered last weeks, Scott is the default winner. His first answer was incorrect, but his revised answer was correct. I had found that interesting as well that the 4.6 dohc was 4" WIDER than my 460! :eek: This week is for the carb guys.

When sizing a carb for your engine, what does CFM stand for and what is the calculation based on?

[STL-Scott]

Well, since no one else answered last weeks, Scott is the default winner. His first answer was incorrect, but his revised answer was correct. I had found that interesting as well that the 4.6 dohc was 4" WIDER than my 460! :eek: This week is for the carb guys.

When sizing a carb for your engine, what does CFM stand for and what is the calculation based on?

CFM = "Cubic Feet per Minute". It is a standard measure of how much air and/or fuel volume can be passed through an orafice in a measured period of time.

(And I'm not even a carb guy...just know this from being an architect!)

[Purple Venom]

Kind of right, but not entirely.

[Kerry & Kathy]

CFM = "Cubic Feet per Minute". It is a standard measure of how much air and/or fuel volume can be passed through an orifice in a measured period of time.


Scott is very close....just substitute venturi for "orifice", minute for "measured period of time" and add "at WOT"...

CFM is the measurement of airflow that indicates how many cubic feet of air pass by a stationary point in one minute. In the case of a carburator...it is the airflow measured at the carb venturi at WOT (wide open throttle).

There are two different formulas for determining a specific engines CFM requirement that takes into consideration engine displacement, maximum engine RPM, volumetric efficiency and whether we are considering a 4 stroke or 2 stroke engine.

For 4 strokes the formula is:

C.F.M. = C.I.D. x R.P.M. x Vol. Eff. divided by 3456

Factors are assigned for Volumetric efficiency depending on if the engine is naturally aspirated, turbocharged / supercharged, diesel, etc..
and no...I do not have them committed to memory.

K&K

[STL-Scott]

He says and I quote:



For 4 strokes the formula is:

C.F.M. = C.I.D. x R.P.M. x Vol. Eff. divided by 3456

Factors are assigned for Volumetric efficiency depending on if the engine is naturally aspirated, turbocharged / supercharged, diesel, etc..
and no...I do not have them committed to memory.

K&K

Wow Kerry...I'm sure you have forgotten more about engines than I will ever know ;)

I bow down to your surpreme knowledge..We're not worthy, we're not worthy...Wayne's world! Wayne's world!

[Purple Venom]

Kerry is the winner for this week. I have nothing to add as he covered it all.
http://i137.photobucket.com/albums/q234/Hawgwild06/milkshake.jpg

[Purple Venom]

Compression ratio - how is it figured? What are typical ratios for the 4.6, 302, 351, 390, 427 and 460?

[Kerry & Kathy]

Compression ratio - how is it figured? What are typical ratios for the 4.6, 302, 351, 390, 427 and 460?


Are you asking for "static" compression ratio...or "dynamic" compression ratio...?

There is a measurable difference...


Dynamic compression ratio is dependent on intake valve closing in relationship to the piston location in the cylinder. On engines with fixed valve timing the dynamic compression ratio remains unchanged. However on engines like the Honda VTec which has variable valve timing...the dynamic compression ratio actually changes as the engine speed increases...

Static compression ratio is what most people refer to... and assumes that there is no valve timing overlap between intake and exhaust valves...which on modern automotive engines...ALWAYS takes place.

K&K

[Kerry & Kathy]

Both static and dynamic compression ratios are determined by calculations or measurements based on actual dimensions of a specific engine.

These dimensions will be dependant on bore and stroke, combustion chamber volume, intake valve relief in the piston dome, head gasket inside diameter and compressed thickness, piston deck height, piston ring land location and crown undercut, and presence of a piston dome or dish. ALL of these variables have to be measured or calculated to achieve an accurate compression ratio and there are specific tools and methods to achieve this.

In basic form, the Static Compression Ratio (SCR) of an engine is the ratio of the cylinder volume compared to the combustion chamber volume. A cylinder with 20 units of volume (usually referred to as the swept volume), and a chamber with a volume of 2 units has a 10:1 compression ratio.

Static Compression Ratio (SCR) is the compression ratio most people and manufacturers specification sheets refer to. It is determined by measuring or calculating the volume of the cylinder at BDC and comparing that to the volume at TDC.

The simple formula is: Swept Volume divided by Combustion Chamber volume = SCR

The tricky part is measuring all the engine variables such as valve relief and compressed gasket thickness in order to determine the true values for combustion chamber volume and swept volume. For example, some pistons have zero deck height, which means the piston top is flush with the engine block at TDC. Other engines have .005” deck clearance where the piston is below the block surface .005” to provide additional piston to head clearance to compensate for rod stretch at high RPM. The volume of this .005” height must be deducted from the calculated cylinder volume. If you fail to do this…your SCR will be WRONG. Other easy to miss variables include compressed head gasket thickness. A standard automotive head gasket may measure .042” thick…but after being installed and having the heads torqued… will measure .037” thick. If you don’t take this .005” variable into account your calculation of SCR…will be WRONG.

Dynamic Compression Ratio, on the other hand, uses EXACTLY the same methods to measure engine variables but adds one very important variable measurement. It takes into account the location of the piston when the intake valve closes to determine the swept volume of the cylinder.

The difference between static compression ratio and dynamic compression ratio can be substantial. For example with a radical cam that closes the intake valve at 65º after bottom dead center, the piston may have risen nearly an inch from BDC once the intake valve closes. This decreases effective volume of the cylinder considerably. It effectively has reduced the stroke length by almost an inch. This in turn reduces the compression ratio. As a result, the dynamic CR is ALWAYS lower than the static CR. The same cylinder that had a 10:1 static compression ratio might now have an 8:1 dynamic compression ratio.

The dynamic compression ratio and static compression ratio will always remain unchanged once an engine is assembled… UNLESS the engine has variable cam timing such as the previously mentioned Honda VTec engine.

In the case of variable cam timing, the piston position as the intake valve closes… will change. This in turn effectively reduces the calculated stroke. That change in stroke results in a change in dynamic compression ratio.

Static compression ratio remains unchanged in a variable valve timing engine as static compression ratio is not dependent on valve timing.

Of the two methods of measuring compression ratio, the dynamic compression ratio is far more important as it is a much better indicator of engine output and octane sensitivity.

It is one of two often overlooked reasons why a short overlap cam engine with 9:1 static compression ratio will knock under load using 87 octane gas while a 10:1 static compression engine with long overlap cams will run fine with no detonation on the same 87 octane fuel.

Professional engine modeling software will take these variables into account when calculating engine power output and HP / torque curves and provide BOTH an engine’s static and dynamic compression ratios.

As far as specific compression ratios for each of the engines mentioned…I’ll leave that to someone else to answer…since by now most should agree the static compression ratio's advertised, really are not very important.

K&K

[Purple Venom]

Ok, you caught the "trick" part of my question - :( Now, the ratios of the engines? Where's Pepe Lepeau - a.k.a. Paul?

[PaulProe]

Kerry gave you a very good explanation. But most people only refer to static. Take a brown paper bag and measure the amount of air inside it. Crumple it up and measure the air inside it then. The first number to the second gives you the compression ratio.

Depending on engine design and use, the ratio varied - generally between 8.5 and 12.1. As an example, the 390 FE motor used 10 different compression ratio's, all directly related to performance. The higher the ratio, the higher the performance. Some of the high end motors got to 12 but that was back in the 60's/70's when leaded fuel was available.

With today's pump gas (hi Octane is only 93 :mad:) it is almost impossible to run over 9:1 unless you have aluminum heads, you then can approach 10:1. Unless you go to racing fuel, as a rough rule of thumb, you can't run over 10:1 on the street. If you think Hi-test is expensive, try pricing 104 octane race fuel. :eek:

This is a link to the wikipedia page http://en.wikipedia.org/wiki/Ford_FE_engineon FE motors. You'll see the compression ratio is posted and various low to high based on performance.

One exception: supercharged motors use a lower compression ratio because the blower pushes extra air into the chamber before it goes into the compression cycle. Typical ratio for that style motor is 6/7:1

That enough? Need more? pretty hard to give you exact compression ratio based on just cubic inch displacement of a motor.

Paul :)

[Purple Venom]

Hmm, this might have to be a shared prize. Kerry was correct on the compression ratio, I did intend that part of the question to be a 'trick' part with Static and Dynamic. As for Paul's point, he is absolutely correct, however, I was looking for typical factory rated ratios as PUBLISHED (static) by Ford.

So,here ya go - one for each of ya
http://i137.photobucket.com/albums/q234/Hawgwild06/milkshake.jpg

http://i137.photobucket.com/albums/q234/Hawgwild06/milkshake.jpg

[Purple Venom]

Ok, new question - this one has to do with hardware, you know, the nuts and bolts you are using to put your rides together. There are different grades, and each grade has a head marking on it.
No markings on head is what grade?
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt1.gif

Three radial lines is what grade?
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt2.gif

Six radial lines is what grade?
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt3.gif

2nd part of the question - What are the tensile strengths of each?

[STL-Scott]

My answers (mostly a joke from me) are below in the quote


Ok, new question - this one has to do with hardware, you know, the nuts and bolts you are using to put your rides together. There are different grades, and each grade has a head marking on it.
No markings on head is what grade?
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt1.gif

Grade 5

Three radial lines is what grade?
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt2.gif

Grade 8

Six radial lines is what grade?
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt3.gif

NASA Grade - capable of space travel!

2nd part of the question - What are the tensile strengths of each?

[Kerry & Kathy]

Uh.....Scotty...Don't change your day job....NASA is not hiring...
Ok, new question - this one has to do with hardware, you know, the nuts and bolts you are using to put your rides together. There are different grades, and each grade has a head marking on it.

First..The head designation identifies all bolts as SAE Inch dimension bolts as opposed to an ISO Metric designation.

No markings on head is what grade?

Grade 2

Minimum Tensile Strength of 74K PSI for bolt diameters of 1/4"-3/4" and 60K PSI for bolts larger than 3/4 to 1 1/2" diameter.

http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt1.gif

Three radial lines is what grade?

Grade 5

Minimum Tensile strength of 120K PSI for diameters 1/4-3/4" and 105K PSI for larger than 3/4 to 1 1/2" diameter.

http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt2.gif

Six radial lines is what grade?

Grade 8

Minimum Tensile strength for all bolt sizes of 150K PSI
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Bolt3.gif

2nd part of the question - What are the tensile strengths of each?

See above....although some might argue that minimum yield strength is more important than tensile strength.

K&K

[STL-Scott]

Uh.....Scotty...Don't change your day job....NASA is not hiring...


K&K

That's why I went into architecture...I hire consulants that spec. these sorts of things.

I remember the quote about architects "Jack of all trades, master of none."

[Purple Venom]

Winner winner chicken dinner! Kerry - good job!
http://i137.photobucket.com/albums/q234/Hawgwild06/milkshake.jpg

This isn't the new tech question, rather a "i'm curious" question - Where should/can each grade be used? In some cases, I would think you would want the bolt to break rather than damage something else (grade 5 rather than grade 8), anybody know this?

[PaulProe]

, rather a "i'm curious" question - Where should/can each grade be used? In some cases, I would think you would want the bolt to break rather than damage something else (grade 5 rather than grade 8), anybody know this?

Typically, the design of the bolted joint dictates the type of fastener to be used. To function properly, the joint requires a certain clamp load. To get that load, the fastener has to produce a certain amount of force. In the majority of cases, grade 2 or 5 is adequate. But certain applications require higher forces or the size of the bolt is limited and to get a proper force, a higher grade bolt is necessary. prime example is a rod bolt - limited space available and a bigger bolt would adversely affect the rotating weight. Using Gr 8 rod bolt allows a higher clamp force with a smaller bolt which also makes for lower weight.

The only place I can think of that uses a general bolt to shear off are the break away signposts installed in concrete. When a joint is designed to fail at a specific point, relying on the very wide/liberal specifications of a bolt makes for a difficult design. Better to design a piece that will fail at the given point or load.

Paul

[Purple Venom]

Well it's been a while, so here goes - any guesses as to what size/type engine this is? Or, is it car "porn"? http://i137.photobucket.com/albums/q234/Hawgwild06/DSC02230.jpg

[STL-Scott]

Well it's been a while, so here goes - any guesses as to what size/type engine this is? Or, is it car "porn"? http://i137.photobucket.com/albums/q234/Hawgwild06/DSC02230.jpg

Sorry, but I already saw this on the ffc forum...

http://i318.photobucket.com/albums/mm414/wereglsfly/6154/DSC02234.jpg

It's a Roush built, Shelby Aluminum FE big block, 468 cubes, 480 HP, 538 lb/ft. of torque.


http://www.ffcobra.com/forums/showthread.php?t=189527

Come on timbo, running out of orginal questions???????

[Purple Venom]

Well if you saw it (cheater) you should have opted out of the answer :D Man, milkshakes are really important around here.

[Kerry & Kathy]

Our "Engine and Tech Area" thread has turned into a trivia thread...not a "Technical" thread.

Where are the questions like:

Name the three methods of lubricating a wrist pin and why is one method preferred over the other two? What is the most common method used by OEM's ?

What is positive, zero and negative deck height? Why is one preferable to OEM manufacturers and the other two preferable to maximum engine efficiency? Why is it important to control this dimension closely?

With a .010" negative deck height and a .043" uncompressed head gasket thickness what is your minimum piston to head clearance on an assembled engine using a flat top piston?

What is a squish band? What negative event does it help control? How does it affect an engine's octane requirement?

What engine component and it's construction material dictates a greater piston to head clearance than another?

What is the difference between camshaft lobe angle and camshaft lobe separation angle?

How do you calculate camshaft duration?

How do you calculate camshaft overlap?

What is a camshaft "acceleration ramp"?

Name three reasons why four valves per cylinder are preferable to two valves per cylinder?

What is the primary shortcoming of a SOHC engine to a DOHC engine as it pertains to camshaft operation?

Why is a "checking clearance" important when degreeing a camshaft? What is the industry accepted "standard" checking clearance?

What is the difference between a hyper-eutectic piston and a hypo-eutectic piston?

What is the most important surface on piston ring or piston to insure good ring sealing? and no...it isn't the cylinder bore.

Why are most engine built with three rings and how does the purpose of each differ?

What is ring stagger?

What is the best piston ring groove configuration to insure good oil drain from the cylinder wall?

Given a 10.5 to one static compression ratio, 93 octane fuel and equal cam timing... will spark knock occur first in an aluminum headed engine or a cast iron headed engine?

These are all rhetorical questions...but they illustrate what I would consider legitimate "Engine and Tech area questions.

Let's focus on legitimate technical questions.

Feel free to select from the list above as a starter...

Just my $.02...

K&K

[Purple Venom]

Point taken, but I ain't smart enough to answer these. Let's start with the wrist pin. For the benefit of those that don't know, this is the connecting pin on the piston to piston rod. So, I know it is lubricated via splash and pressure. Not sure of a third. Depends if you are talking 2 stroke or 4 stroke engine? Am I close?

I now dub Kerry as tech question of the week forum moderator :D Suggestion though, only ask one question a week, not sure if my fingers will last that long. :D

[Kerry & Kathy]

I know it is lubricated via splash and pressure. Not sure of a third. Depends if you are talking 2 stroke or 4 stroke engine? Am I close?

I now dub Kerry as tech question of the week forum moderator :D

Hmmmm...I'm not sure thats a good thing... :eek:...but I made the suggestion so I'll get the ball rolling.

Tim, were talking four stroke engines and you are correct that the three methods are comprised of one pressure lubrication and two splash lubrication.

The question is how is each accomplished...or

1. what is different in how the piston is machined to accomplish each method... ?

2. which method is most common to OEM manufacture... and why...?

3. which method is preferred for high performance applications... ?

4. which method, often employed by aftermarket piston manufacturers can actually weaken a piston resulting in catastrophic failure...and why does this occur?

That should be enough to get started.

Let the competition begin.....:D

Kerry

[Purple Venom]

Ok, one question at a time.

Types of lubrication for the wrist pin - Correct statement of splash and pressure or is there another or two types of one of these?

[Kerry & Kathy]

Ok, one question at a time.

Types of lubrication for the wrist pin - Correct statement of splash and pressure or is there another or two types of one of these?

One method for pressure lubrication and two methods for splash lubrication. Actually there are more than two methods for splash...I just selected the two most often seen today. In older engines splash was commonly used but was simpler and less sophisticated. But then the engines didn't rev to the RPM levels of todays modern engines.

I am also referring to the lubrication in the piston wrist pin bore...not the rod small end bore. Rod wrist pin lubrication is another subject all to itself with three variations for splash and one variation for pressure feed.

K&K

[Purple Venom]

Well, I found a lot of different answers than what you are stating above. I know of only one wrist (grudgeon) pin in the connecting rod, if there is another, I don't know the answer to this question or I don't understand your terminology. I've included a photo of what my descriptions would be of a piston and supporting parts.
http://i137.photobucket.com/albums/q234/Hawgwild06/Tech%20Question%20Pics/Piston.jpg

[Purple Venom]

So, if I read correctly, you are wanting to know how the surface between the wrist/gudgeon pin and the piston itself get's it's lubrication. If that is the case:

1 - Splash - As the crankshaft spins through the crankcase oil, it is splashed on to the bottom of the piston skirt and pin. OR some hot rodders drilled holes in the piston above the pin and as the oil get's pumped in to the cylinder, the rings scrape it off on the down stroke, it then drips down on to the pin or "splashes" it with oil.

2 - Pumped - In my search endeavors, I found a few different ways to pump oil to this area. Commonly used seems to be using the oil pickup/pump, oil get's pumped through the oil passage to the cylinder wall and is pumped onto the pin. OR, a pump jet is installed at the bottom of the cylinder and is shot at the piston skirt/pin.

As for piston design - I can see that the piston skirts are getting shorter for weight considerations and the pin guides are being re-designed in many different shapes (we are talking hundreds of thousandths of an inch). Also, it appears the location of the pin relative to the piston dome makes a difference in torque, bore and stroke. So, there's my answer to the first question. I can't find (3) methods, only two. I found what I believe is the common method. I can't seem to find what is preferred - too many opinions from Smokey Y. to Edelbrock to whoever.

Stay tuned for next week's question - What is positive, zero and negative deck height, why is one preferable to OEM and the other two preferable to maximum engine efficiency, I guess. :rolleyes:

[Kerry & Kathy]

You are very close...but pressure fed oil does not mean a need for an actual oil "pump". Oil can be pressurized by other means as described below.

There is only one wrist pin per rod and piston assembly, but because this wrist pin requires lubrication on both the surface that fits inside the rod small end bore, as well as the piston pin bore there is a need to have lubrication in both the piston as well as the rod small end.

The method most used by OEM car manufacturers to lubricate the piston pin bore in the piston is a pair of broached grooves that run parallel with the piston pin centerline. These grooves rely on oil splash from the rotating assembly to insure oil can migrate down these grooves to keep the wrist pin lubricated. This method is fine for most production engine applications but not ideal for racing use. It is used because it is relatively easy and cheap to produce in a production environment where a broach can produce both grooves in a single stroke during the manufacture of the piston.

The second method relying on splash lubrication and employed by many aftermarket automotive piston manufacturers is one or two chamfered holes drilled on the bottom of the piston pin boss that allow oil splash to enter the holes and migrate to the wrist pin bore. It is done in this fashion because it is easy and quick to produce these holes using very simple drill fixtures. The problem with this method is that it weakens a highly stressed area of the piston that often already has a marginally thin cross-section between the wrist pin bore and the bottom of the piston pin bosses. Adding a hole in this thin area often produces a stress riser and at high RPM and heavy tension loads the piston boss cracks resulting in the wrist pin pulling right through the bottom of the piston bosses.

The third method and the one preferred for high performance applications is one which is pressure fed by the oil ring. The oil ring is designed to remove excess oil from the cylinder wall and force it through the holes or milled slots located at the back of the oil ring groove in the piston. This oil is actually pressurized as it is scraped off the cylinder walls faster than it can be drained through the oil ring drain back holes. What is done is a small 1/16" diameter hole is drilled at a 45 deg angle to the wrist pin centerline in the top of each wrist pin boss approximately 1/2" deep toward the piston dome. Then an intersecting hole is drilled from the back of the oil ring groove drilled parallel to the wrist pin centerline which joins this previously drilled hole. In this manner oil under pressure is constantly being fed to the top of the wrist pin bore...lubricating the wrist pin. Because the top of the piston pin boss is in compressive stress it not as highly loaded as the bottom of the pin boss which is stressed in tension...it results in better lubrication for the wrist pin without weakening the integrity of the piston. This method is preferred for high output high RPM applications.

K&K

[Purple Venom]

What is positive, zero and negative deck height? Why is one preferable to OEM manufacturers and the other two preferable to maximum engine efficiency? Why is it important to control this dimension closely?

This question is confusing to me as well. If I know and understand this correctly, deck height is defined as the distance from the top of the piston at TDC to the head mounting surface or piston deck. The way I see it, you will always have a positive deck height. In other words, there will always be some distance (1mm say) between the top of the piston to the bottom of your straight edge layed across the cylinder. The smaller the measurement, the more compression/torque you get. OEM prefers nothing less than 1.5 mm deck height. Hot rodders would try to get as close to 1mm as possible. If you COULD achieve negative deck height, the piston would be slightly ABOVE the piston deck height. This would require some milling or a thicker head gasket I guess. So, it's important to control this measurement to not overstress the engine, piston, and rod as well as prevent any interference between the piston and the heads.

How'd I do? :D

[Kerry & Kathy]

If I know and understand this correctly, deck height is defined as the distance from the top of the piston at TDC to the head mounting surface or piston deck.


Actually deck height is the distance from the crank centerline to the block deck surface.

NEGATIVE deck height (or piston deck clearance) is when the piston top surface is below the block deck.

A ZERO deck height is when the piston top is flush with the block deck at TDC.

A POSITIVE deck height (or piston deck clearance) is when the piston top sticks above the block deck.


The way I see it, you will always have a positive deck height.

You meant Negative deck height...but neither is true...

In other words, there will always be some distance (1mm say) between the top of the piston to the bottom of your straight edge layed across the cylinder.

True for an unmodified OEM block but not true for a racing engine. Most blueprinted racing engines will have from .010" negative deck clearance to zero deck clearance. However, some supercharged or turbocharged engines using .060" think soft copper head gaskets will have a POSITIVE deck clearance of as much as .015" to offset the thicker copper gasket and still maintain a desirable squish band clearance.

The OEM manufacturers intentionally build negative deck clearance into their engines to allow for multiple engine rebuilds where the block deck surface will be machined. An excessive amount of clearance adds longevity to the block by allowing it to be rebuilt several times without the pistons hitting the heads.

The smaller the measurement, the more compression/torque you get. OEM prefers nothing less than 1.5 mm deck height.

Generally true... but reducing deck height is not done for added torque. It is done for two distinct reasons.

One is to control the squish band clearance to approximately .035-.050" between the piston top (disregarding any dome or dish) and cylinder head. (This is based on a steel rod. Aluminum rods require more clearance due to added rod stretch.) The "squish band" is that portion of the cylinder head and that portion of the piston top surface that come in very close proximity to each other at TDC. The fuel air charge cannot ignite when this clearance is less than .060". Keeping the squish band clearance below this dimension prevents the flame front from igniting in this tight area. Effectively reducing the width of the combustion chamber where fuel burning can occur effectively limits an engines tendency to "spark knock" under load. It limits the distance the flame front can travel across the cylinder bore to just the combustion chamber.

The second benefit of controlling the squish band to this tight .035-.050" clearance is that in nearly all combustion chambers a narrow squish band increases the turbulence inside the cylinder allowing the fuel and air to mix in a more homogeneous manner resulting in more complete burning of the intake charge. This increases the engines fuel efficiency and increases power.

There is an added benefit as BOTH of these results reduces an engines octane sensitivity. An engine with a factory .060" negative deck height plus a .043" or thicker head gasket results in a squish band clearance of over .100". With this much clearance the engine may knock under load running 87 octane fuel. However, the same engine machined to a ZERO deck height with a common .043" thick head gasket (.038" compressed) results in a nearly ideal .038" squish band clearance. This is sufficient clearance to prevent the piston from hitting the head at TDC even with normal rod stretch, however the clearance is too tight to allow combustion to occur in the squish area... so no spark knock occurs with the same 87 octane fuel.

Hot rodders would try to get as close to 1mm as possible.

Not true...most try to get from zero deck height to a negative .010" based on the current offerings of head gasket thicknesses.


If you COULD achieve negative deck height, the piston would be slightly ABOVE the piston deck height. This would require some milling or a thicker head gasket I guess.

You meant POSITIVE deck height...and it can easily be obtained by simply machining the block deck below the piston top surface. The situation where you will see a positive deck height is the scenario described above using gaskets made from solid copper sheet.

So, it's important to control this measurement to not overstress the engine, piston, and rod as well as prevent any interference between the piston and the heads.

Very true...but for different reasons than you might have thought.

How'd I do? :D



Hmmmm... C-


K&K

[Purple Venom]

Awwww, thought I would get an A for effort. Where's the rest of the crowd?:D

[STL-Scott]

Way above my level of knowledge when it comes to engines...I know where to put the oil and gas, and enjoy driving them...

Not being in this industry, I will probably never know more than I do...what brain cells I have for storing info like this is dedicated to building code related data...life safety...phone numbers for structural, mechanical, electrical, civil engineers, etc...

[Mike DeGuire]

Deck height = how many steps below the back door you want your patio furniture.

See what happens when there isn't anyone on the forum to play with.

[Kerry & Kathy]

Deck height = how many steps below the back door you want your patio furniture.



Right.......

And "Squish Band" is that area of the deck where you are most likely to step on an insect... :D

K&K

[STL-Scott]

Right.......

And "Squish Band" is that area of the deck where you are most likely to step on an insect... :D

K&K

Oh, I thought that was a the name of new progressive rock band playing down in Soulard this weekend?

[Purple Venom]

http://i137.photobucket.com/albums/q234/Hawgwild06/Smilies/thhijack.gifhttp://i137.photobucket.com/albums/q234/Hawgwild06/Smilies/ot.gifhttp://i137.photobucket.com/albums/q234/Hawgwild06/Smilies/nono-1.gif
Whatsa matter, can't answer the questions? :D

[Purple Venom]

Reviving this thread a bit will see who responds and if worth carrying on. Kerry was right, the technical section was becoming a trivia section. My questions won't be as technical, but here goes:
What are the bore and strokes of the following engines?

280
302
351
390
427
460

Stock dimensions, not like Marks 588 from a 460 block. And, which one above is also referred to as a 4.6L?

[TOM KEISER]

280 (4.6l) 3.551 3.543

302 4.000 3.000

351 4.000 3.500

390 Fe 4.050 3.780

427 4.232 3.784

460 4.362 3.850

[STL Mark]

Not to be left out -

588 = Bore is 4.560, Stroke is 4.500

[6stringcobra]

Show off !!! :D:D

[Purple Venom]

Reviving the thread

How many and what types of engines are there, and what are the differences/unique features of each?

[PaulProe]

How many and what types of engines are there, and what are the differences/unique features of each?

Tim
Can you clarify your question. Isn't asking how many and what type kind of asking how many and what type of insects are there? or why is the sky blue?

Do we nee to specify whether they're mopar, ford, gm, volvo, yugo, el-car, etc?

Or are you asking, in-line, opposed, v, radial, wankel, sterling, etc?

Paul

[Purple Venom]

Ok, here's a hint - Fuel type and heads have a factor in the answer.

[Purple Venom]

TTT, thought maybe Kerry wants to give this a shot.

[Kerry & Kathy]

I'm with Paul on this one.

Too broad a question.

Kerry

[Purple Venom]

alright, alright. Apply to gas engines only as there are many different types of engines and fuel types, which by the way motor and engine are widely misused.

[Purple Venom]

Uh.....Scotty...Don't change your day job....NASA is not hiring...


K&K

I double check above with the sheet you gave me and it matches. The only difference is there are some additional grades

0 & 1 - have no radial lines either
3 - has two radial lines
6 - has (4) radial lines
7 - has (5) radial lines

Mike thought the information about the bolt heads may not have had all the information.

[Purple Venom]

So, working on my brakes I've learned a lot. So, thought I would quiz you guys on something.

- Two fitting types used for carrying fluids, that I know of. NPT and AN, what do these designations stand for?
- Can one be interchanged with the other?
- What AN fitting = a 3/8" NPT?
- What NPT fitting = a -6 AN?

I have a document to post, will do that after a few guesses.

[Kerry & Kathy]

NPT stands for "National Pipe Thread". It is a tapered thread with .75" taper per foot used for its self sealing qualities as a result of the taper.

AN is a term used for a variety of Military specification hardware. It simply stands for 'Army-Navy". It is NOT a tapered thread. As a result it is a thread that relies on an additional flared surface of some type to provide sealing.

NPT and AN fittings are NOT interchangeable in any size.

Kerry

[Purple Venom]

Kerry, thanks for the answer. I will tell you from personal experience that a -8 AN WILL screw in AND seal in a 3/8" NPT inverter flair hole. Now, not saying that it was right, but that's what I had without ANY leaks, until I removed the fitting. :rolleyes:

[Purple Venom]

This question pertains to brake fluid. What are the differences in DOT 3, 4, and 5 brake fluid and what are the temp ranges of each? I have a story associated with this one that I will tell after the answers.