Turbo Buick Forums banner
1 - 6 of 6 Posts

·
Valve Monkey
Joined
·
574 Posts
Discussion Starter · #1 ·
Everytime I talk to the machine shop the news is worse! So far only my .030 over block checks out OK. Machinist says that 4 of the pistons are now .002 undersized and the other 2 are distorted. Presumably from overheating. Are they all junk now? He says they're SpeedPro pistons, some say they were junk from the beginning! If so, what pistons should I buy this time?

------------------
Richard Gautier
'87 GN, TE44 (was TE61), blue tops,IC and a half,Champion iron heads, Roller rockers,ported intake and plenum,70mm TB, Houston DP, no times yet!
 

·
Registered
Joined
·
102 Posts
When I bought my pistons I went with JE
They're almost to pretty to hide in the engine.I was told they might make some noise on cold start ups,but they haven't yet.Don't forget filefit rings.
Just my .02:Bildo

------------------
87 GN 3"ATR DP 2.5 ATR duals,7th injector,rebuilt turbo(stock)rebuilt injectors(stock).30 JE Pistons,accufab regulator,ATR super pump Hot wired,stainless driver side exhaust manifold.SOME ASSEMBLY STILL REQUIRED
 

·
Valve Monkey
Joined
·
574 Posts
Discussion Starter · #3 ·
Thanks Bill. It's become painfully obvious that the previous owner gave me the shaft on this thing. Lots of "go fast" parts on an "el cheapo" short block. No way to know w/o tearing it apart though, it ran fine for about 2 weeks. I saw what was left of the original engine. He is a member of the DOTC(drove over the crank) club for sure (and the oil pan and a couple of rods and...)
Anyone else care to chime in on the damage? Are the pistons junk now? Who's got the best prices on pistons?

------------------
Richard Gautier
'87 GN, TE44 (was TE61), blue tops,IC and a half,Champion iron heads, Roller rockers,ported intake and plenum,70mm TB, Houston DP, no times yet!
 

·
Premium Member
Joined
·
43,735 Posts
Pistons don't shrink....it means the bore was .002 big-in the machine shops mind anyway.

Properly, a block should not be bored/honed until pistons are on hand and then each bore should be based upon the dimensions to the piston going into that hole.

Machine shop will have to tell you if the pistons are reusable or not. We don't know if they are in or out of spec.

Nothing wrong with SP pistons tho they may not be the quality of JE, Wiseco, etc. Different price range (cheaper) but a good everday piston.
 

·
Valve Monkey
Joined
·
574 Posts
Discussion Starter · #5 ·
Steve,
The block checks out at .031 over bore. Not saying you're wrong (if I knew everything, I wouldn't ask you guys!) but the machinist is very knowledgable about turbo motors (that's what he races) and says that some shrinkage from overheating (which I did)is fairly common. Hell, I don't know, I'm learning a very painful lesson. I'm beginning to wish someone would steal this one too! (like my '86)
 

·
Registered
Joined
·
279 Posts
I doubt that .002 is out of spec for SpeedPro during the Quality Assurance checking.

.002 is thiner than a hair from my head. I just plucked one from my head and measured it (.003) with digital calipers..


BTW, pistons are not perfectly round.. but you may have already known that..

Kevin

------------------


87GN, 12.05 @ 111, SIXTY FOOT 1.60-LAUNCH 15#, BONE STOCK LONG BLOCK, STOCK I.C. (BELL MOUTHED), STOCK TRANS/CONV, Stock Turbo, 009'S, RED'S 107 CHIP. HOME MADE 3" DOWN PIPE. RUNS CONSISTANT 12.10'S-12.11'S.

http://www.geocities.com/kdslaby/solidworks.html

[This message has been edited by KEVINS (edited July 31, 2001).]
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top