piston issue

[englundjd]

I pulled the drivers side head today to put a new head gasket on and I found a problem with my #1 piston.
27593

right there at the edge of the piston between the valve reliefs there is a chunk of metal missing. What do you guys recommend? I want to hit this engine with a 175 shot so I'm thinking this piston needs to go?

[93camarolt1m6]

i would pull it replace it and triple check your ring gaps, it looks like either detonation damage or the rings were not properly gapped. i know because with my keith black 122 pistons i gapped my rings wrong and the damage from it looks just like your but now that is in my 383 sbc not my lt1.

[englundjd]

I had the engine built by a company ~25,000 miles ago, I know the pistons are sealed power hyper's its tuned by Bryan @ pcmforless and then the tune was tweaked once threw datalogs. It still looks like the car was running a bit rich tho.

[93camarolt1m6]

here is what mine looked like its a little worse than yours. http://i1071.photobucket.com/albums/u507/1984s10/mykeithblack.jpg

[noice]

Can you rotate the engine and see if there is any damage to the cylinder walls? Anything that you can get your fingernail caught in means it has to come apart and be bored/honed.

[englundjd]

i'll give it a spin next weekend and check but i will most likely be pulling it all the way apart just because that makes me nervous knowing i'm going to spray it. I'm going to get a set of forged pistons and have it redone again most likely.

Also on a side note I know a guy that parts these out, I maybe able to pick up a running stock long block and throw my cam and nitrous on that ... it'd probably be a lot cheaper that way.

[englundjd]

to get my car running (hopefully for the whole summer) I am planning on picking up a stock long block (115k and in good running condition) and pulling the heads off of it and putting mine on it along with the 231/239 from lloyd, then putting the nitrous kit on it. I'm going to have it pulled apart and checked out and i'm going to put arp bolts on the connecting rods. Whats my chances of this playing nice and hanging together for the summer while i fund a nice forged rod and piston 355?

[noice]

If you put arp bolts on the connecting rods, they need to be resized.

[DMBlack]

I would say it depends on what parts you have in your current lower end. If it has decent parts it may be cheaper to bore/hone your current block and buy some new forged pistons. Replacing the stock rod bolts will require resizing the rods so you will have some machine shop costs in that alone. Then you have the "snowball" effect set in and we all know how that goes.

[englundjd]

Well as my current engine sits it has stock rods and sealed power (speed pro) hypertunic pistons so its nothin fancy. going with forged pistons and rods but until that gets done I am going to use the new short block I found.

If you guys think I can get away with it I'll just leave the new block alone and slap it together with my heads and LE cam and let it eat. I'm just kinda worried about how this cam is gonna want 6500-6700rpm's on stock rod bolts that are 115k miles old...

[noice]

With the "quality" (or lack thereof) that I see in modern parts, you are just as likely to be replacing a part that has no problems with one that has.



In the last year or so of putting engines together, I spend more time getting new parts to fit than I should.

Example a 355 built about a year ago.

Edelbrock Performer Carb, had a burr blocking the step up piston from moving properly and was leaning out an entire engine bank.

New timing cover was so badly stamped that the old one was cleaned up an used instead.

New Felpro head bolts, broke before tightened 50% of the final torque value.

http://img202.imageshack.us/img202/7470/felprobolts.jpg

Bought some ARP head bolts instead, the washers that came with it were not fully ground on one of them in the picture below. If you installed that on a bolt and torqued it, it would cause a stress riser on the underside of the radius of the bolt head and would most likely fail the fastener at the head.

http://img411.imageshack.us/img411/2075/arpbolts.jpg

Comp cams camshaft had a burr on the first bearing lobe edge that scratched up a camshaft bearing that I had to reinstall.

http://img41.imageshack.us/img41/9148/compcams.jpg


I ordered a Stef's Custom oil pan that was good to 4" stroke. I got it and it wouldn't clear 3.875" stroke.

Don't count out factory stuff, I've been screwed by the aftermarket more than factory.


To sumarize, you have some bolts that have withstood the test of running in an engine easily, re-torque them if you want to and if they feel "spongy" or they don't all pull with the same feeling on the torque wrench, then replace them.

People run stock main bolts and rod bolts to rpms WAY above what you are trying to do.

[firebird_1995]

Well said and sorry about your luck. JEEZ!!

[DMBlack]

If I was in your situation, I would swap the heads and cam to the stock short block. I would run that while building a forged lower end that is ready and waiting when you need it.

[englundjd]

If I was in your situation, I would swap the heads and cam to the stock short block. I would run that while building a forged lower end that is ready and waiting when you need it.

this is my current plan. thank you for the opinions guys, it gives me some peace of mind. I know what i'm going to do.