TRW Piston identification..
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Pro
Joined: Feb 2005
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From: Hamilton New Jersey
TRW Piston identification..
Just picked up a spare 350 for $150 bucks. Trying to determine what components its made of and get a rough guestimate of the comp ratio.. I'm trying to avoid pulling the heads since I'm on a tight budget with this build and dont wish to replace the headgaskets.. The bottom of the pistons are marked TRW toward the cam, and toward the wall of the block D with 262-96 under them, is there anyway to determine what pistons these are with those markings? What I'm really interested in knowing are they flat tops, dished, or?
Last edited by 86GoldProject; Apr 19, 2008 at 02:58 PM.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
I do not have a TRW casting reference.
However, are you interested in trying a different approach to
identifying the compression ratio? If so, what are the casting numbers
on the heads and on the block?
As for the shape of the piston tops, you may be able to do a visual
through the plug hole & exhaust port. (A borescope like the ProVision
PV-636 would make determination a snap.)
.
However, are you interested in trying a different approach to
identifying the compression ratio? If so, what are the casting numbers
on the heads and on the block?
As for the shape of the piston tops, you may be able to do a visual
through the plug hole & exhaust port. (A borescope like the ProVision
PV-636 would make determination a snap.)
.
Thread Starter
Pro
Joined: Feb 2005
Posts: 560
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From: Hamilton New Jersey
Head casting #'s are 042770, they are world products S/R torquers which from what I found should have 76cc chambers unless they have been milled or something, the block is 14093638 which comes up at an 87-95 350, it has 4 bolt mains and some sort of roller cam in it. Unsure of deck height, there is nothing stamped on the pad in front of the pass side head where there is normally a partial vin and suffix code which could have been removed if it was decked at some point or there may have never been anything stamped there to begin with if it was a replacement engine.. I was told that it was a reman engine with a .030overbore so it most likely no longer has the stock pistons... so in other words the casting number is very little help. All I really know is that the heads should have 76cc chambers, don't know anything about the pistons and I'm not sure how thick the head gaskets are.. I'm really just trying to get an educated guess.. hopefully its over 8:1. The large chambers have me a little worried.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
There may be people who can determine the compression ratio of
an engine assembled from a collection of unknown part dimensions,
but I am not one of them.
If you wanted to amuse yourself for a while, you could play what-if
with one of the on-line calculators as below, but my vote is that
further physical investigation lies ahead.
Compression Calculator
Assume
4.034" x 3.48" (+0.30 & 0.004 piston clearance)
4.030" gasket bore
0.040" compressed gasket thickness
76 cc chamber volume
0.00" deck
Theoretical compression ratios:4.030" gasket bore
0.040" compressed gasket thickness
76 cc chamber volume
0.00" deck
_8.7:1 (-10 cc dome)
_9.6:1 (00 cc dome)
10.8:1 (+10 cc dome)
Edit: changed 2nd example from 10 cc to 00 cc_9.6:1 (00 cc dome)
10.8:1 (+10 cc dome)
.
Last edited by Slalom4me; Apr 19, 2008 at 06:18 PM.
Thread Starter
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From: Hamilton New Jersey
yeah way too many unknowns to come up with a solid figure, just hoping someone knows what those pistons are to get an educated guess.. it did sound pretty healthy before I pulled it.. didnt get a chance to see drive the truck it was in though due to a blown trans.. it supposedly only has 10k on it since the rebuild but you know how those things go.. from what I can see though its in extremely good shape, the bearings look new, no deflection in the timing chain, no oil build up to speak of, from what I can see of the cylinder walls they appear almost new, so I think I made out pretty good. I'm gonna throw some new gaskets on it, put it in a car n see how it does as is. Just hoping to get an idea of what it is comprised of for future parts selection if it proves to be a real dog.
Last edited by 86GoldProject; Apr 19, 2008 at 06:11 PM.
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From: Hamilton New Jersey
Not sure, heads are still on it. Already poped the intake on and put a coat of paint on it. Hopefully one of my friends has a bore scope they will lend me as suggested above. If not I'll just try running it as is and if it turns out to be a dog I'll find out after I tear the top end down.
Race Director
Joined: Sep 2003
Posts: 16,836
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From: Database Error Indiana
Not sure, heads are still on it. Already poped the intake on and put a coat of paint on it. Hopefully one of my friends has a bore scope they will lend me as suggested above. If not I'll just try running it as is and if it turns out to be a dog I'll find out after I tear the top end down.
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From: Hamilton New Jersey
