SStrokerAce

Diamond makes whatever you want.... actually those would be relatively cheap since they would just enlarge the OD of a off the shelf piston and it would only be a $30 charge on top of a regular set.

$550+ and it's a better piston than a speed pro, that should save you a whole ton of work on the block.

BTW why did they ever bore it out to .040" This just seems really odd to me.

If it's at .040" exactly now you should be able to get it to size in .003" I would hope.

Bret

blackztpi

this motor was built to the 4.040 bore. since then, it has had some problems with dirt scores and needs redone again. it isn't bad, but it could use a bore. the shop told me they could clean it up on a deep torque plate hone, but nobody makes pistons inbetween .040 and .060 unless you go custom. so i'm not sure what they could clean it up to, but it should be way under 4.060. BTW, what kind of machine work would have to be done??? bore/hone, clean and freeze plugs. align hone the mains, resurface the deck...what else? i'm coming up with about 400-500 worth of machining. this car is no race car as stock pistons do jsut fine for my app (11:1 ish and 420-440 hp flywheel using your cam, bret) btw, even if it cleans up at 4.045, is the extra .015" going to make that much of a difference in durability? i don't have any way to sonic check a block in my area so that is not an option. thanks

jerrysta

I have a .060 over block on Ebay. It's already been checked. I had it in the for sale section but no serious offers came for it. It came out of a '95.


http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMESE%3AIT

blackztpi

it checked out okay? people are too affraid to buy it at .060 probably

jerrysta

It checkout out fine. Up until a month ago it was going to be used for my 388, until I decided to go a different route on the motor altogether. (I won't mention that here bc I don't want to get flamed or hijack the thread)

It's a good, solid block. My builder told me the .060 bore was the absolute limit, but if done correctly is not a problem. So, I believe you are all correct in that there are problably some bad ones out there,
just not mine.

1racerdude

How much wall thickness did it have on the piston's thrust side?
If it had less than .200 it won't be good for even a N/A engine much less hose or blower.

RCF925

I agree, I wouldn't be afraid to go .060 over on a N/A motor. You probably don't want to go more than .040 on a blown application.

1racerdude

Ya gonna have to sonic check a truckload to find a LT1 that will go.060.

engineermike

Dude, I would not hesitate to go .060" over. I'm running .060" over at 20+ psi turbocharged with no problems.

The stock LT1 blocks have .250" wall thicknesses. Most agree that .200" is the minimum wall thickness, so you can go all the way to .100" overbore without thinning the cylinder walls too much. I've heard of people going the full .125" over, which brings the cylinder wall down to .188". Some say you can go all the way down to .125" wall thickness. Can you imagine a .250" over LT1? That'd be 454 cid with a 4" stroke! Of course, I don't advocate doing this, but it made me feel alot better about going .060" over with mine.

Also, I've never seen or heard of a Chevy V-8 block that split the cylinder wall. I've seen mains break, even main webbing crack and fall out, deck surface cracks, etc., but never a crack in the cylinder bore.

1racerdude

Ya want to see one? Got one here that is .060 and got a vertical crack half way up #5 cyl and a crack around the top of #6 cyl.
Just don't believe EVERY one will do it,so I don't go past .040 unless the customer wants to pay for a sonic check.

94Z396_0621

I have a 96 corvette block i bought from a race shop it was bored .30 at first had scratches in one of the cylinder walls that wouldnt come out. Went .10 over to try to clean it up but it didnt come out, went .005 more and it clean up. Its .45 over now. Order Custom JE .45 over pistons with like 5cc dish. But thats what you get when your doing a custom application.

MachinistOne

Those lt4 blocks are going for $700 on ebay. I have mine tucked away...

.200" min wall? Used to run 400 blocks at .090" wall...but those were one race only claimer motors lol. Weld the main caps to the block and go win the race, when someone claims your motor they get real pissed when the oil pan comes off.

engineermike

Do me a favor and check the wall thickness near the cracks. I'd be real interested to see if the block was thin there from core shift or something.

Sounds like something screwy went on, especially in #6. The radial hoop stress is double the axial stress. That's really strange for it to get a radial crack.

SStrokerAce

I love those stories. lol

Now everyone makes a 305 with a stroker crank in it that smokes a little and goes claimer racing.

Bret

blackztpi

lol. what was a killer in the races was the old rusty nova with the built 327-383. i never got the point of claimer races? whats the point and rules? anyways, i still have'nt got a good answer on the .060 over thing..... let the opinions roll!