DJ's 02' Z28

iTrader: (2)

Where can I find this info?

Stang's Bane

iTrader: (22)

Are you sure he should take a ls7 block to 4.250?? Not much sleeve left....

ramairws6

iTrader: (33)

^^^He's talking about stroke there Stang's Bane. Your motor fixed yet? How come your master engine builder didn't know how to set things up? Not bashing, just trying to understand what went on?? Traver

Tom@SpeedInc

iTrader: (5)

4.250" stroke leaves you at .990" CD

That is almost impossible to build, ask any piston expert. The rings are all bunched together at that point.

The LS7 block does have longer sleeves then the LSX block mind you

I would stay with a 4.100/4.125" crankshaft as being max stroke, but nothing wrong with 4.000" stroke setup.

07BlueDevilZ06

iTrader: (8)

4.145 is the max bore of a ls7 and 4.145 is a piston available as a overbore from gm. And max stroke is 4.125 recamended. So biggest ls7 is 445ci which is what I have. if you go 4.250 stroke the pistons wont be very stable and the ring stack will be very high this can be a n/a only motor and not reved high due to high piston speed id say 65-6800 rev limit big bore motor is the way to go with a short stroke.

George

Tom@SpeedInc

iTrader: (5)

We have a machinist who builds engines.

hope that helps?

07BlueDevilZ06

iTrader: (8)

can be build and right are 2 different things

Stang's Bane

iTrader: (22)

I read that wrong, my fault

The mess up came from another shop, not the good guy

HKE has it now, no mess ups there. He ordered a new set of pistons, so we should be good to go by the end of next month

07BlueDevilZ06

iTrader: (8)

I dont need to speak to anyone. I build my own stuff and I correct alot of other peoples stuff also. currently have one of the fastest Z06's in the country built buy me. Im in to longivity the piston in a 4.250 stroke motor is way less stable then a 4.125 stroke. On the 4.250 stroke the compressed height is very short and does not give a very good ring stack and the skirt needs to be short to clear on the bottom which makes the piston less stable. Im sure it can be built but it will not live as lone as a shorter stroke motor. also with a comprimized ring stack power adders are out of the question.

George

07BlueDevilZ06

iTrader: (8)

"We can make a pistons for the 4.250 stroke and the 6.200 rod but, it will get you only a .915 compression height. Which is very small for a street car. We can make piston with .750 compression heights but, it is not something that we do everyday. Just wanted to clear that up, we can make the piston I just would not advise it for street use.

Thanks,
Chris Gelineau
Diamond Pistons"

So diamond says not for street so that means no longivity

George

RAMPANT

iTrader: (17)

I am no expert, but a stock LS7 block has shorter sleeves than my RED's Darton sleeved block.

Here is a picture of the bottom of the Darton sleeves in my new block.



The piston is from a 4" bore out of my old LS2.

I was told my sleeves are .350" longer than the stock LS7 sleeve. That is why it can handle a little extra stroke and keep the piston more stable at the bottom of the stroke.

Tom@SpeedInc

iTrader: (5)

I'll leave with this

07BlueDevilZ06

iTrader: (8)

my ls7 had sleeve extension that stuck out the bottom more then the block in your photo.

RAMPANT

iTrader: (17)

Actually I did a search and found the LS7 is 5.900 gray iron vs my 5.800 ductile iron sleeve. Mine is a 4.190" bore though

I will let you know how my custom Wiseco's turn out for my 4.125 stroke Callies. They should be here very soon.

Tom@SpeedInc

iTrader: (5)

I have no clue what your talking about

I've spoken with Erik in past on suppliers and small stuff, even built the motor for a buddy of mine, Mike Shellenbarger, of course when he informed me of this I told him hes making a sound decision to use Erik's services.

I don't think we're the only shop that can build a motor.

racer7088

The sleeve length and rod length and the ring stack determine how much skirt is left in the bore at the bottom. We don't use a 6.200 rod with the 4.250 stroke but rather a different rod. The rod length, stroke and deck height tell you how much CH and ring stack you can run.

The CH I use on that is .995 and it works great for NA motors and could certainly run some small NOS as well and has. We aren't using .078 rings so we have fairly normal NA ring lands and ring stack and plenty of skirt in the bore still at BDC as well as the correct skirt shape to make it work.

Also Chris Gelineau does not = Diamond Pistons and only worked there for a short time and was not a piston engineer but rather a salesman before he left and started ripping people off on this website and went bankrupt and got banned. 900 hp WOO engines use pistons this short and spin 8500 all night long.

racer7088

Blanco, don't be getting these guys mad at me!!!

The 4.250 deal is not anything easy for a reg shop to do as there are many things that can be done wrong but we do stuff like this pretty often.

racer7088

NO Darton sleeves I know of are any .350 longer than an LS7 or you couldn't even hone them! You have an older Darton with SHORTER sleeves than an LS7 probably, maybe the 5.675 long deals but they are still longer than the oem reg LSx stuff at least which is a good thing. The Darton stuff is all awesome and I had several talks with Steve at RED about making them even longer like they are now so they could offer more skirt support down there at BDC. We did this years ago and now the Dartons are 5.800 and 5.900 long so even lower break points can be used and/or more stroke.

racer7088

I don't do that combo either since the cylinders are just not long enough. The CH is not the issue but rather the problems at BDC. I don't even do many 4.125 deals in a reg length cylinder because of this but rather mostly 4.100s or my piston gets too cramped for rings.

I will say that what I told Blanco about the majority of piston people and reps being utterly clueless though is certainly true. We have crap right now in the shop from a very big name race engine builder that has only done a few LS1s and a huge piston outfit sold him the stuff in this engine and it was major money too. It burns a quart of oil per 100 miles and is new.

The block was done perfectly by this race engine builder and yet because of the asinine piston design used with this perfectly normal and expertly put together 6.125 rodded 4.000 stroke deal it was a giant smoking POS. The skirts had over .010 taper in them and were basically straight taper being biggest at the bottom. These had long "stable" skirts and with .0045 cold clearance still rocked .050 at the top and almost .150 at the bottom.

These pistons cost 1800.00 and were not expedited.

The rings cost 267.00 and had napier seconds.

That engine made 83 more rwhp when the correct 500.00 pistons and 75.00 rings were installed and no more smoke and no more excessive crankcase pressure.

A resident piston expert at this company said that they thought the cylinders were 6.000 long but still couldn't explain the nearly .011 total taper. Fortunately this company is one of the most popular piston companies for the american V8 market but is not a regular player on this bulletin board.

Stang's Bane

iTrader: (22)

Damn Erik, go to bed.