Visit The Dirt Forum for More Information

Author Topic:   What Happened ?
Dirt Maniac

Total posts: 143
posted April 17, 2005 10:22 PM  

Last year we had our distributor springs come off and I guess we had detonation. When we tore down the engine this is what number 8 looked like. It is a J.E. forged piston. We also had a fire slot between #3 and #5 on the head. It didn't damage the block though. We honed out #8 and it seemed to clean up. Is this all from the springs? I question whether or not the driver put in racing gas or pump gas. What do you guys think? This is a 13.5:1 383 chevy.

[This message has been edited by crc1124 (edited April 17, 2005).]

Dirt Freak

Total posts: 402
posted April 18, 2005 08:02 AM  
They look more like scuff marks from tight cyl. wall clearances. Or it got hot a few times. A bent rod can do that as well. although a bent rod will leave marks off center axis of the pin.

Dirt Forum Champ
Total posts: 2007
posted April 18, 2005 08:57 AM  
Now you know the reason why you should lock up the mech advance....

Dirt Freak

Total posts: 217
posted April 18, 2005 09:44 AM  
this doesn't look like detonation to me.
damage would be on top of the pistion.

Dirt Forum Champ
Total posts: 968
posted April 18, 2005 01:51 PM  
I am in the "too tight" camp. All may have been well until you warmed her up to 250 degrees tho!

Dirt Freak

Total posts: 206
posted April 18, 2005 04:24 PM  
It's definitly too tight on piston to wall,wrist pins siezing or too tight will cause this also.

Dirt Maniac

Total posts: 167
posted April 19, 2005 12:31 PM  
definently check bore size and piston size along with the rest of the block and pistons may have got one oversized piston mixed in.

Back to the Archives