Need technical info on 3.2

[zak]

If you are trying to move a Windstar, increasing DCR is probably not the right direction, unless you are going to significantly decrease weight. Also the tune for a high DCR engine is less fault tolerant.

To bound you, most that have gone beyond 10.5:1 static on these engines, even with the longest duration cams currently avialable (SHOnut +40's or SHOshop Stage 2) have not been able to run pump gas. Not sure how many have payed attention to quench distances and those sorts of things.

IIRC, the 3.0 SHO was either .007 above, or .007 below on piston to deck, sorry I can not remember which direction.

As to strokers, the welded up and reground journal/reuse stock rod approach used by the SHOshop did not work well, possibly because most ran with a type of crank underdrive pulley that had no rubber (or any other sort of) dampener to them (crank vibrations can be bad for fatigue). Those that have gone to the Honda 48 mm rod journal diameter, so far so good but no high rpm work yet.

Much of the Performance sections of this site recently got scrambled, the owners are still trying to unscramble, until then mining for the types of data you'll be looking for will be difficult.

Hope ths helps - zak

 

[hawkeye18]

I guess not many people know about Dynamic Compression Ratio. It is a completely different number than SCR. I think the SHO engine can benefit from someone doing the math and building it to run on 93 octane with a DCR of 8.5:1.

This is, IMHO, much akin to measuring stroke length in Cubits and becoming agitated when nobody knows what you're talking about.

I read the article, and I understand what you're talking about now, but honestly... unless one is changing both the stroke length and the valve duration at the same time, the ratio between DCR and SCR is going to be the same.

Why don't we mess with the internals? Unlike 350s or 427s, you cannot get 35hp from a K&N, and you cannot get 50hp from a cam. This engine is, honest to God, about as good as it's gonna be inside. Lengthening the stroke will very quickly turn it into an oversquare engine, and that will hurt redline dramatically - and the redline is one of the best things about this motor. The SHO motor, and especially the 3.2, is a very undersquare design... yes, this hurts torque down low but does it matter when you're at 8000-8500 rpm?

Many people have bored the cylinders out - 3.6L is about as far as you can go without violating intercylindrical integrity. This works very well and gives you gobs of torque down low without hurting redline too much.

Everybody I know of that has messed with the crank has ended up with a two piece crank at one point or another. They just don't like to be messed with.

Look, we're not saying don't do it... by all means, if you have the money and the desire, and the money, go for it! But don't be surprised when your engine blows up. This engine is not American Muscle, with its loose tolerances and inefficient factory design. This engine is a tightly wound watch, with very tight tolerances, and very efficient design. Engines designed to max out at 5500 RPM tend to be very forgiving with internal intrusions. Engines designed to max out at 10,000 RPM are somewhat less so...

 

[<SLV>]

If you are trying to move a Windstar, increasing DCR is probably not the right direction, unless you are going to significantly decrease weight. Also the tune for a high DCR engine is less fault tolerant.

To bound you, most that have gone beyond 10.5:1 static on these engines, even with the longest duration cams currently avialable (SHOnut +40's or SHOshop Stage 2) have not been able to run pump gas. Not sure how many have payed attention to quench distances and those sorts of things.

IIRC, the 3.0 SHO was either .007 above, or .007 below on piston to deck, sorry I can not remember which direction.

As to strokers, the welded up and reground journal/reuse stock rod approach used by the SHOshop did not work well, possibly because most ran with a type of crank underdrive pulley that had no rubber (or any other sort of) dampener to them (crank vibrations can be bad for fatigue). Those that have gone to the Honda 48 mm rod journal diameter, so far so good but no high rpm work yet.

Much of the Performance sections of this site recently got scrambled, the owners are still trying to unscramble, until then mining for the types of data you'll be looking for will be difficult.

Hope ths helps - zak

That is GREAT help. I haven't seen anything out there to say yet what the piston to deck clearance is, but I just read that the head gasket thickness is .002". I think ideal quench is in the .003-.004 range. I also read that the SHO heads are hemis. Are they symetrical? Does anyone have a photo of a SHO compustion chamber? Are the 3.0 and 3.2 heads identical?

As far as the weight goes, the difference between the factory Windstar and the factory SHO was only about 400 pounds. Once I remove the rear seats and spare tire and replace the carpet with a rubber mat I'll be close in weight to a factory SHO. Any other suggestions on shaving weight are appreciated!

 

[<SLV>]

BTW... I'm reading through the SHO Engine Book and a drawing of the pistons showed they were cut for valve relief. I thought the SHO was a non-interference engine... is it?

 

[Sho Amo]

it isnt in stock form, higher compression would change that though

 

[<SLV>]

This is, IMHO, much akin to measuring stroke length in Cubits and becoming agitated when nobody knows what you're talking about.

I read the article, and I understand what you're talking about now, but honestly... unless one is changing both the stroke length and the valve duration at the same time, the ratio between DCR and SCR is going to be the same.

Why don't we mess with the internals? Unlike 350s or 427s, you cannot get 35hp from a K&N, and you cannot get 50hp from a cam. This engine is, honest to God, about as good as it's gonna be inside. Lengthening the stroke will very quickly turn it into an oversquare engine, and that will hurt redline dramatically - and the redline is one of the best things about this motor. The SHO motor, and especially the 3.2, is a very undersquare design... yes, this hurts torque down low but does it matter when you're at 8000-8500 rpm?

Many people have bored the cylinders out - 3.6L is about as far as you can go without violating intercylindrical integrity. This works very well and gives you gobs of torque down low without hurting redline too much.

Everybody I know of that has messed with the crank has ended up with a two piece crank at one point or another. They just don't like to be messed with.

Look, we're not saying don't do it... by all means, if you have the money and the desire, and the money, go for it! But don't be surprised when your engine blows up. This engine is not American Muscle, with its loose tolerances and inefficient factory design. This engine is a tightly wound watch, with very tight tolerances, and very efficient design. Engines designed to max out at 5500 RPM tend to be very forgiving with internal intrusions. Engines designed to max out at 10,000 RPM are somewhat less so...

I think I'm going to shy away from the OC grinding. I appreciate all of the cautions metioned out there. I wasn't really after the additional displacement as much as I was after the additional torque, but I think the gains don't justify the risk.

DCR matters so much to me because I'm planning on camming it. DCR is the "magic" number. I'll still probably get custom con-rods and forged pistons to give me perfect quench and the right volume at TDC for running 93 octane at 8.5:1 DCR.

 

[hawkeye18]

The SHO engine is very much a non-interference motor. IIRC, +40 cams are where it becomes an interference motor. The heads are of a Pent-roof design... straight out of F1 cars of the time (86-88).

If they were hemis, everybody would be making "That thing got a hemi in it?" jokes... lol

 

[<SLV>]

The SHO engine is very much a non-interference motor. IIRC, +40 cams are where it becomes an interference motor. The heads are of a Pent-roof design... straight out of F1 cars of the time (86-88).

If they were hemis, everybody would be making "That thing got a hemi in it?" jokes... lol

... I wonder why they cut valve reliefs in the pistons... maybe because the original 300hp design from Yamaha was an interference design.

I got the hemispherical heads information from a Ford publication entitled "Engine Operations: 1989" (page 53), "The platinum spark plugs are centrally mounted in the hemispheric combustion chambers..."

 

[pjtoledo]

That is GREAT help. I haven't seen anything out there to say yet what the piston to deck clearance is, but I just read that the head gasket thickness is .002". I think ideal quench is in the .003-.004 range. I also read that the SHO heads are hemis. Are they symetrical? Does anyone have a photo of a SHO compustion chamber? Are the 3.0 and 3.2 heads identical?

As far as the weight goes, the difference between the factory Windstar and the factory SHO was only about 400 pounds. Once I remove the rear seats and spare tire and replace the carpet with a rubber mat I'll be close in weight to a factory SHO. Any other suggestions on shaving weight are appreciated!

I piece of paper is thicker than .002", so are SHO V6 head gaskets.

 

[<SLV>]

I piece of paper is thicker than .002", so are SHO V6 head gaskets.

Maybe I'm not reading the manual correctly (I too was thinking that the number should be .030-.050). Here is a screen shot of the specs.

Maybe "flatness" refers to tolerable variation rather than "thickness".

 

[jelloslug]

Maybe I'm not reading the manual correctly (I too was thinking that the number should be .030-.050). Here is a screen shot of the specs.

Maybe "flatness" refers to tolerable variation rather than "thickness".

That is the tolerance of the surface, not the thickness of the gaskets. As for the mythical 300HP SHO engine, there is no real evidence that the 3.0 (or the 3.2) version of this engine was ever tuned to 300 HP by Yamaha.

 

[Phoenix]

Damn that 300hp (by Yam) myth is still alive?

Die already

 

[ManySHOs]

Keep in mind that the SHO engine book was published around 88 or 89 before the 3.2 was out. Some minor things may have changed.

Jason - the +20 cams reportedly make the SHO engine an interference engine with the stock pistons.

Ian

 

[<SLV>]

That is the tolerance of the surface, not the thickness of the gaskets. As for the mythical 300HP SHO engine, there is no real evidence that the 3.0 (or the 3.2) version of this engine was ever tuned to 300 HP by Yamaha.

I can appreciate that the 300hp myth is just that.

However, the fact that it cam with valve reliefs cut into the piston indicates to me that it had a stronger initial build. Unless... they cut the reliefs just in case the timing belt broke loose.

 

[Sho Amo]

However, the fact that it cam with valve reliefs cut into the piston indicates to me that it had a stronger initial build. Unless... they cut the reliefs just in case the timing belt broke loose.

for a motor to be 'freewheeling a.k.a. a non interference engine, it must not slap valves to pistons under any circumstance ( broken timing belt, extremely advanced or ******** timing etc.) so having the valve releifs was the main idea i beleive because any drastic change iin duration causes the motor to be an interference.

 

[hawkeye18]

for a motor to be 'freewheeling a.k.a. a non interference engine, it must not slap valves to pistons under any circumstance ( broken timing belt, extremely advanced or ******** timing etc.) so having the valve releifs was the main idea i beleive because any drastic change iin duration causes the motor to be an interference.

Not true. You can drop all the valves to max lift, leave them there, and run the engine and nothing will touch. Only increasing the lift will make it an interference engine.

 

[Sho Amo]

im sorry i contradicted myself. what i meant was lift. or raising the compression

 

[zak]

<SLV>, are you any relation to redwraith?

Anyhow, I am having some trouble locating my engine notes, but did recall one spec that is not in any of the Ford literature. Compression height (pin centerline to piston top) is 1.315 on both 3.0 and 3.2 (field verified on some 3.0 pistons I had kicking around, as well as measured by a company that makes pistons for engine rebuilders).

More when I find my notes.

zak

 

[<SLV>]

<SLV>, are you any relation to redwraith?

Anyhow, I am having some trouble locating my engine notes, but did recall one spec that is not in any of the Ford literature. Compression height (pin centerline to piston top) is 1.315 on both 3.0 and 3.2 (field verified on some 3.0 pistons I had kicking around, as well as measured by a company that makes pistons for engine rebuilders).

More when I find my notes.

zak

No relation that I know. :wave:

Thanks for that number. I'm looking for more like that. If I could get piston to deck clearance nailed down that would be great! Also, any cam information would be appreciated. Especially if someone knew the factory LSA (if this is possible on a DOHC engine).

 

[Sho Amo]

are you any relation to redwraith?

is he on this forum?