Broken piston(s) SBC - Motorgen - Automotive Events, Meets, Cruises and Forums

enkeivette · 05-31-2009, 08:47 PM

I think Glenn guessed it, ring land broke. Another pitson took a bit of a beating but it's still intact. Since I'm poor, I think I'll stick with the SRPs this time around, and just buy 1 or 2 new ones, then upgrade the fuel pump and the rings.

I think I'll be able to reuse this block. What do you guys think? (Look at pic 2) The upper edge of the cylinder is a bit messed up, but it looks like it doesn't extend past the point where the ring slides, so I might just clean it up and run it. The cylinder heads will prob need a once over with the mill, the combustion chamber over each cylinder have evidence of abuse and some metal fragments lodged in the surface, but nothing detrimental. I'll prob get them magnafluxed to make sure there are no cracks.

Remember this before you give me advice. I have less money than you, and I am concerned only with what I NEED to do, not what I SHOULD do.

enkeivette · 05-31-2009, 08:49 PM

Vettezuki · 05-31-2009, 09:09 PM

How much are willing to spend? There's a a shop I like that's local to OC (Anaheim). I'm guessing, but a magnaflux, head touch up, and a couple piston replacements and rebalancing, assuming you do all the dissaseembly work, will be in the $500~ range.

94cobra69ss396 · 05-31-2009, 10:10 PM

Are those forged pistons? If so, that thing had to have been detonating horribly. That's exactly what happened to my stock hypereutectic pistons when I gave the car too much timing. If the mark in the bore isn’t protruding out you should be fine running it. If you can save up the money I would have it checked by a machine shop to see if you could get by with just a hone or if it should be bored but I understand the not having any money thing. You probably won’t need to mill the heads unless you got the car hot and they warped. Check them with a straight edge and see. If they’re not then just clean up the combustion chambers.

SeanPlunk · 05-31-2009, 10:38 PM

Quote:

Originally Posted by 94cobra69ss396

Are those forged pistons? If so, that thing had to have been detonating horribly. That's exactly what happened to my stock hypereutectic pistons when I gave the car too much timing. If the mark in the bore isn’t protruding out you should be fine running it. If you can save up the money I would have it checked by a machine shop to see if you could get by with just a hone or if it should be bored but I understand the not having any money thing. You probably won’t need to mill the heads unless you got the car hot and they warped. Check them with a straight edge and see. If they’re not then just clean up the combustion chambers.

The pistons are indeed forged.

enkeivette · 05-31-2009, 10:45 PM

Never ever heard detonation. Not saying it didn't denonate, but if it did it wasn't obvious. Timing was at 32 full, 36 is normal for a SBC. Guess I need to pull more. Heads never got hot.

Block is staying in the car, going to clean up the bores with hydrochloric acid to get the aluminum off. No boring, no honing, and possibly no milling. Going old skool. Where's Glenn at? I need some duct tape and some inspiration.

Ben, you want me to pay someone else to do the labor? Who did you think you were responding to?

Vettezuki · 05-31-2009, 11:21 PM

Quote:

Originally Posted by enkeivette

. . .Ben, you want me to pay someone else to do the labor? Who did you think you were responding to?

You gonna mill heads and rebalance the assembly in your garage? I'd like to see that.

big_G · 06-01-2009, 08:08 AM

If you get the same EXACT piston (part number) you don't need to re-balance..unless the tops or pads were milled. Also, if you expect the rings to seat you will need to hone the affected cylinders. BTW, I had to do what you're about to do, but only 1 cylinder. (some a-hole dropped a BB down my carb....jealous ex-employee).

BTW, if you're still not using an inter-cooler, detonation is likely the reason. I can't hear any on mine...but reading the spark plugs told me I had occurrences of detonation.

BRUTAL64 · 06-01-2009, 09:18 AM

Quote:

Originally Posted by enkeivette

Never ever heard detonation. Not saying it didn't denonate, but if it did it wasn't obvious. Timing was at 32 full, 36 is normal for a SBC. Guess I need to pull more. Heads never got hot.

Block is staying in the car, going to clean up the bores with hydrochloric acid to get the aluminum off. No boring, no honing, and possibly no milling. Going old skool. Where's Glenn at? I need some duct tape and some inspiration.

Ben, you want me to pay someone else to do the labor? Who did you think you were responding to?

I'm here now. The scratches don't seem deep. If you run your finger nail over them do you feel your finger nail pull at them. If so, then, they are maybe too deep. Just run your finger nail over the scratches and see if they pull. Let me know. Other wise you seem to have a handle on this. If you need me to to check it out, let me know.

I blew the ring lands out of 4 pistons and never heard a thing. Well, I did hear the engine run funny after that.

enkeivette · 06-01-2009, 01:43 PM

Quote:

Originally Posted by Vettezuki

You gonna mill heads and rebalance the assembly in your garage? I'd like to see that.

Like I said above I might not mill the heads, and hopefully if I can find the same piston I won't need to rebalance. If it's off, I will just grind on that piston. You can grind on the back of a piston can't you?

Big G, you've inspired me, looks like I need to sell the jet skiis and buy a damn intercooler. But I think I'll leave the boost at 10lbs for now.