Notices

1 melted piston

Thread Tools
 
Old 10-11-2008 | 10:49 AM
  #1  
Thread Starter
Registered
 
Joined: Jul 2007
Posts: 335
Likes: 0
From: linwood, nj
Default 1 melted piston

I am in the process of rebuilding my port engine. Gen VI 502 carb motor.
Things are going well except I would like to be certain that I don't re-create the same issue that caused the need for the build.

The last cylinder on the port side had a melted piston. It was on the very edge as to where the ring was visible and a hot spot in the center of the same piston. All other holes looked fine.
Besides the obvious such as fuel pressure, the carb(which I've purchased a new 750 Dbl pmpr), is there something specific that I should pay attention too?
Everyone on here has been a great help, your thought are appreciated. Thanks,
Alex
86 apache 22 is offline  
Reply
Old 10-11-2008 | 01:45 PM
  #2  
johnny g's Avatar
Registered
 
Joined: May 2006
Posts: 372
Likes: 1
From: Baton Rouge, La.
Default

timing
johnny g is offline  
Reply
Old 10-11-2008 | 03:54 PM
  #3  
BY U BOY's Avatar
Registered
 
Joined: Aug 2005
Posts: 8,779
Likes: 1
From: HOUSTON ,TX
Default

good gaskets
BY U BOY is offline  
Reply
Old 10-11-2008 | 06:29 PM
  #4  
Banned
 
Joined: Oct 2006
Posts: 5,844
Likes: 0
From: Bradenton Florida
Default

Are the jets in the carb the right ones ?????
DareDevil is offline  
Reply
Old 10-11-2008 | 08:15 PM
  #5  
ChristianGott's Avatar
Platinum Member
25 Year Member
Platinum Member
 
Joined: Nov 2000
Posts: 1,420
Likes: 33
From: Connecticut
Default

Hi.
problem sounds familiar...
jets...timing...higher than stock octane in the gas.
sounds like it's leaning out/pre-igniting...plenty of high octane, well distributed should prevent problems (as well as well matched, application sensitive parts)
just some thoughts..
c
ChristianGott is offline  
Reply
Old 10-11-2008 | 08:56 PM
  #6  
Thread Starter
Registered
 
Joined: Jul 2007
Posts: 335
Likes: 0
From: linwood, nj
Default parts

So far my plans/parts aquired are: Pro-comp alum. heads 115cc, roller rockers, crane 168731 roller cam, new 750 Cfm, althogh that may change based on what I've heard on this forum. I've been told that my stock intake is sufficient for the mild build that I'm doing and Gil, Hp500 manifolds with 16 inch low risers.
All thoughts are much appreciated.
86 apache 22 is offline  
Reply
Old 10-12-2008 | 09:46 AM
  #7  
Rookie's Avatar
Registered
20 Year Member
 
Joined: Jan 2003
Posts: 6,017
Likes: 1,519
From: Grand Rapids, MI
Default

A 750 is a little on the small side for a 502, what was wrong with your old carb?
Rookie is offline  
Reply
Old 10-12-2008 | 05:01 PM
  #8  
blue thunder's Avatar
Registered
20 Year Member
 
Joined: Nov 2001
Posts: 3,393
Likes: 6
From: IBX
Default

If you are rebuilding the engine, make sure you set the quench to .037-.038". It will give you good insurance against problems caused from lean and timing issues. Combine that with alum heads, inconnel exhaust valves and cometic head gaskets and you should have the basis of a good running blower motor.

BT
blue thunder is offline  
Reply
Old 11-04-2008 | 08:44 PM
  #9  
Registered
 
Joined: Nov 2008
Posts: 7
Likes: 0
From: Glen Spey NY
Default

Last cylinder on port bank is #7. Probably had crossfire from the #5 plug wire, causing severe preignition. Make shure your wires are loomed so that #'s 5-7 and 4-8 on the other bank cant touch each other.
jw454 is offline  
Reply
Old 11-05-2008 | 07:57 AM
  #10  
Banned
 
Joined: Sep 2007
Posts: 12,849
Likes: 3
From: Frankfort,ill
Default

Meth injection call rudy @ ICE
302-367-4962
good luck
RunninHotRacing163.1 is offline  
Reply


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.