Getting a new piston. What engine do I have?
Thread Starter
Intermediate
Joined: Feb 2017
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Getting a new piston. What engine do I have?
I have a '76 L48 that does not have the original engine. A few days ago, a piston broke between the rings. I am wanting to locate a new piston, but not for sure which engine I have. The last owner told me it was a 1969 327. The engine was bored .030 over.
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
OP is not looking for a machine shop. He wants somebody to read the block code numbers for identification. You will need the numbers off of the front pad also. If somebody finds your ID, you should also check the dia of the piston with a Mic.
Then go to Summit Racing > Engine & componets > Pistons, enter yr, make, model, 30 over.
Then go to Summit Racing > Engine & componets > Pistons, enter yr, make, model, 30 over.
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
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OP is not looking for a machine shop. He wants somebody to read the block code numbers for identification. You will need the numbers off of the front pad also. If somebody finds your ID, you should also check the dia of the piston with a Mic.
Then go to Summit Racing > Engine & componets > Pistons, enter yr, make, model, 30 over.
Then go to Summit Racing > Engine & componets > Pistons, enter yr, make, model, 30 over.
If that casting number is 3914678, that block is 1968 model year casting, and could be a 302, 327, or 350. The stamp pad on the right front will define that.
Last edited by TimAT; Jan 23, 2018 at 08:17 PM.
Burning Brakes
Joined: Sep 2009
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From: Western New York
Therefore, you need to go to a NAPA store where they will fix you up with a piston pressed on your rod and also the rings on the piston. I went through this a few years back and NAPA supplied everything I needed at an unbelievably affordable price. Give them a try. Don't order what you need for one piston replacement online. If something's not right, you'll have to wait for delivery and return to correct it. Good luck.
Duane
Duane
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St. Jude Donor '22
wow.
defective part or what?
I think I would find the numbers and maker of the piston, located somewhere on it and get at least hyperutetic ones that match the broken one. change the all.
defective part or what?
I think I would find the numbers and maker of the piston, located somewhere on it and get at least hyperutetic ones that match the broken one. change the all.
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Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
Block casting number 3914678 was used on the following engines only in 1968:
1968 302 290hp
1968 327 210hp
1968 350 295hp
All three engines had the same 4" bore, so the only way to tell them apart is to check the stroke:
302: 3" stroke
327: 3.25" stroke
350: 3.48" stroke
If you check the ID pad on the forward passenger side of the engine and post the numbers, I can tell you exactly what the engine is.
Lars
1968 302 290hp
1968 327 210hp
1968 350 295hp
All three engines had the same 4" bore, so the only way to tell them apart is to check the stroke:
302: 3" stroke
327: 3.25" stroke
350: 3.48" stroke
If you check the ID pad on the forward passenger side of the engine and post the numbers, I can tell you exactly what the engine is.
Lars
Last edited by lars; Jan 23, 2018 at 08:37 PM.
Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
It was probably broken upon engine assembly: The ring compressor was not correctly installed, and the ring broke the ring lands when the piston was pounded into the hole. That piston looks like it has less than 1000 miles on it, so it was broken at assembly.
Lars
Lars
Last edited by lars; Jan 23, 2018 at 10:12 PM.
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I think you need to look for more problems other which piston to buy. That looks like some detonation issues maybe (is it a hypereutectic?) Have you checked all the others??
JIM
JIM
Last edited by 427Hotrod; Jan 23, 2018 at 10:12 PM.
Team Owner
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St. Jude Donor '22
Gotta be.
Race Director
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From: SW Florida.
Find a piston that is all the way down. Stick a ruler in it and see if it's three in three and a quarter or three and a half inch down. I'll tell you whether it's a 302, 327, or 350. Post a picture of the top of the piston. Or the top of an intact one and post a picture of the bore this piston came out of several pictures of the bore.
Race Director
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From: SW Florida.
You must be sure one piston or actually two Pistons are all the way up flush with the deck. And then two will be all the way down and four will be at the halfway point. Minus of course the one that is not installed.