Anyone have an old trw catalog. I have a set of trw forged 400 sb chevy dished pistons. the pn on the piston is L2376, I called sealed power but that was useless.
Its amazing what you find when you reorganize the shelves LOL.
old trw piston help
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bill jones
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bill jones
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-I think I can find some info from some previous engines I've built.
-It seems to me like that has the deepest dish that was made for a 400, could be something like about a 28cc dish.
-I do know the clearances can be set up pretty tight like we used about a thou and a half at the pin C/L.
-Mostly what we did with those pistons is we cut .135 " off the top and ran'm with 5.7 rods.
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-Found a 89 spec book all it shows is a .185" dish.
-the L2352F has .083" dish which I know has a 12.5CC.s and weighs 606grams and the wrist pin is a normal weight 143 pin
-The L2410F has a .159" dish.
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-I do remember that either the 2376 and/or the 2410 had heavy wall pins something like 186 grams, and maybe the pistons were a little lighter was the reason.
-It seems to me like that has the deepest dish that was made for a 400, could be something like about a 28cc dish.
-I do know the clearances can be set up pretty tight like we used about a thou and a half at the pin C/L.
-Mostly what we did with those pistons is we cut .135 " off the top and ran'm with 5.7 rods.
----------------------------------
-Found a 89 spec book all it shows is a .185" dish.
-the L2352F has .083" dish which I know has a 12.5CC.s and weighs 606grams and the wrist pin is a normal weight 143 pin
-The L2410F has a .159" dish.
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-I do remember that either the 2376 and/or the 2410 had heavy wall pins something like 186 grams, and maybe the pistons were a little lighter was the reason.
Bill, thanks for answers. I was courious if the top could be cut down enough to be abol to run a 5.7 rod without hitting the head. When you were doing those mods how high of a compression ratio did it become? did you have to cut in any valve reliefs and most imortantly did the pistons hold up.
Thanks
Thanks
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bill jones
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- Posts: 2650
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
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-there's no problem taking .110" off the top if you don't intend to deck the block, or you could cut .135" of fthe tops if you have a decked block.
-Probably used a dozen sets of L2352's cut like that with no problems on oval track engines, but you end up with a flattop pistons
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-The only failure I ever had was I cut a set of 2352's and then cut nice deep eyebrows and machined a "D" shaped dish to get the 13 CC dish back and then I lightened the underside to where I had about .140" total max thickness of the flat areas, but I ended up with .100" thick spots in the valve notches.
-I drove this engine 10,000 miles on 88octane pump gas and I didn't let it rattle or ping.
-Then I sold the engine to a young kid and gave him the El Camino it was in and he rattled it to where it cracked the pistons.
-The pistons cracked from each end of the oil ring groove slot upwards and right into the bottom of the valve notchs.
-I had butchered those pistons from 606 grams or so down to 503 grams.
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-since I have a shotpeener I would still do the same thing but I would shotpeen the ends of the grooves and the underside of the valve notches and the top of the piston in the notch areas.
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-I'm at 4200 elevation and for daily driver engines (not race engines on the street) the most CR I'll let out of my shop is 9.77 and that requires an excellent tune-up.
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-I wouldn't cut the top to allow 5.7 rods and NOT put at the least some correct diameter small eyebrows that are based off the valve guide C/L.
-Probably used a dozen sets of L2352's cut like that with no problems on oval track engines, but you end up with a flattop pistons
--------------------------------------------------
-The only failure I ever had was I cut a set of 2352's and then cut nice deep eyebrows and machined a "D" shaped dish to get the 13 CC dish back and then I lightened the underside to where I had about .140" total max thickness of the flat areas, but I ended up with .100" thick spots in the valve notches.
-I drove this engine 10,000 miles on 88octane pump gas and I didn't let it rattle or ping.
-Then I sold the engine to a young kid and gave him the El Camino it was in and he rattled it to where it cracked the pistons.
-The pistons cracked from each end of the oil ring groove slot upwards and right into the bottom of the valve notchs.
-I had butchered those pistons from 606 grams or so down to 503 grams.
------------------------------------------------
-since I have a shotpeener I would still do the same thing but I would shotpeen the ends of the grooves and the underside of the valve notches and the top of the piston in the notch areas.
--------------------------------------------------
-I'm at 4200 elevation and for daily driver engines (not race engines on the street) the most CR I'll let out of my shop is 9.77 and that requires an excellent tune-up.
-----------------------------------------------
-I wouldn't cut the top to allow 5.7 rods and NOT put at the least some correct diameter small eyebrows that are based off the valve guide C/L.