I have a Gen IV block at RED to be sleeved. The sleeves Steve are using have a 4.110" bore so I am going with 4.125" bore. After kicking it around I am thinking of a 400 CI displacement but I am not finding any off the shelf pistons for a 3.75" stroke. 3.622" and 4.00" all day long but not 3.75".

My goal is whatever I can make with E85 and an upgraded Ti, 800 to 1000 WHP. Anyone know of 11 or so CR, off the shelf pistons that will work for that?

Thanks!

 

Not a Typically used stroke so it's More than Likely Custom you could as KSC once said do the Math on

Deck Height
Rod length
Crank stroke
Piston pin Height

And see if there's a Rod combination that works with Any Aftermarket OTB piston and a Given Set deck Height.

Rules of math possibly can work without the Use of A Custom piston.

Longer Rods 👍 do the math with a Piston height using a 4.125 or 4.100 - 4.00 stroke Then adjust available Rod Lengths to get Close to your Deck height
Example of 9.225 to 9.235 are common Deck height numbers.

If you Know your Deck height do the Math 😏


Off the Shelf piston not intended for ...may work
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@Corona Thanks!

I got a reply from JE Pistons;"We can make the piston close to what you are asking based on the shelf ULTRA piston. Closest configuration is a flat top which should put you right at 11- 1 if you use 68 cc heads and a 0.040” gasket and zero deck.

I would use 361713 as reference and make a new set based on your pin height you need (1.240” ) . Cost is $1273.19 / set, rings (jg31f8-4125-2) are $225.86. You will get all features same as the part number. I assumed a 6.125” connecting rod with 0.927” pin diameter.

All parts are FOB Mentor OH, freight and taxes are not included.

Lead time for this project at current state is 4-5 weeks."

I can measure the deck height when I get the block and go from there but it looks as though JE has a solution.

Molnar makes Power Adder rods in 6.125", 6.2" and 6.3".

There are a couple of ways to go. One way or another I can get there.

Are there other off the shelf pistons that have a similar (or better) feature set as the JE Pistons Ultra's?

 

Go find other Pistons and there pin Height with the rods listed....6.300 sounds like it will eat up some of the space...👍

http://www.wallaceracing.com/Calc-Deck-Height.php

 

That's a **** ton of money for pistons and rings just to make a oddball combo IMO

 

I've Learned let a person do there thing shut up and help if one can ....Everyone's Different...

🤫 Me Personally I Luv's me some Stroker...

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Best. Post. Ever…

 

Only reason I'll agree is I was @ Work when written😂🤣👍

 

I guess I'm one of those people that make an 'oddball combo". I doing a "COPO 396" (3.825 stroke with a 4.065 bore) for a 67 Chevelle. JE says that 3.90 stroke is better than a 4.00 stroke due to the sleeve length in the LS block so 3.825 has to be even better.. Also, I like the idea of being able to honestly say it has a "396" in it.

 

What the BS Guy Didn't tell is that a 4 inch Crank isn't a Problem when Using a Experienced Builder... 🤫

 

FWIW - Here's their article on the topic. I'd think a company like JE knows a smidge about engines.

https://auto.jepistons.com/blog/diff...nk-for-your-ls

 

I've read that and Have Heard this Yrs ago

On just the 4 inch crank 😂🤣

I bypass that Notion as When and if one Has A Correctly Made Piston with a good tapered bottom of the Sleeve cylinder I hear and Know of Guys getting Many Miles. Old Interweb Truth's and MF'ers not Knowing how to do a Bore correctly.

Also know and Hear if one goes Larger on stroke such as 4.100 to 4.125 in a Factory Block it may have a Little consumption but a Great Piston design HELPS. Don't forget someone Who Knows what there doing. KCS went with a 4.25 stroke Lq4 Lmao. .just don't spin it All crazy keeping the RINGS IN THE PISTONS @ THE bottom of the bore along with Piston Speed.

Quote In my own Words from knowing and Reading
Erik K.

 

I'm laughing @ the thought of you getting a Internet post ....And there's Nothing I haven't Typical seen nor Read or haven't asked myself...

Ask that guy in the post What's the availability of Pistons @ Various Compressions using a 3.90 crank better Said:

a on the shelf Piston from Various Manufacturers


Dude tries to get me with some old Non being able to build or Machine a block Correctly 🐂💩

😏

 

I get it man. I work in manufacturing and we look at a lot of risk vs. reward scenarios so when I see things I look at it that way generally. Different strokes for different folks obviously, I mean I'm building a 400+ci cathedral port engine lol

 

I get it. ...trust me I do. It's cool to be different and knowing what to expect is cool also 😉


But what I said is A Known......
Given the question of Asking how Many 383/402/408/416/418's using any of the Various factory blocks combinations listed Above that use a 4 in arm/Crank having Problems with Pistons with a Good/Knowledgeable Finished cylinder Bore. 👍

Piston design and Ring Technology has made the Old Wives tail of Oil consumption and it's Associated problems using a 4 inch crank Irrelevant.
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JE can only say that about their pistons. Companies like Wiseco had it figured out well before that article was written, and actually came out with even better designs since then.

 

We are going to state this without trying to be harsh but Amen and actually “getting it right” started as early as 2002. We have not met a sub 4” stroke person who could mathematically give us a reason why 3.900 or shorter is better because they are not intimate with skirt taper and ring stack design. If someone wants to run 3.900 or shorter because they “enjoy” rpm or something, that’s fine, but accept higher prices for one-off parts if they enjoy being different. The reason the entire piston and rotating assembly component industry settled in on 4” is because it works. Sub 4” stroke people of today are the same as the long rod folks from the ‘80’s. There are just so many more important variables to consider such as rings, windage and breathing.

 

truth!

 

Custom pistons? Call Ross.

 

They can do well. As do some others, but the key is finding someone in sales that asks the right questions. If they don’t ask your cylinder length, you can probably assume they are going to go with defaults. Just because they work there doesn’t automatically make them an expert with years of experience of crossing the t’s and doting the i’s.