Getting a new piston. What engine do I have?
Thread Starter
Intermediate
Joined: Feb 2017
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I checked compressions. They were 180-190. except that one. It was 60. That is a strange situation. Walls look really good. Journals look good. Go figure. Lot of work for a simple mistake.
Thread Starter
Intermediate
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No damage to the walls. When I pulled the piston out, it didn't look damaged. When I was checking out the rings, The broken pieces fell out. The engine started smoking. I checked compressions and found this to be low.
Thread Starter
Intermediate
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Up date. I went to my local machine shop and he looked around for a few seconds. Reached down and handed me a piston exactly like the old one. Good call on the advise to go to a shop. I will have it together this weekend. Thank you guys for the help.
Race Director
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From: SW Florida.
So, do you know what engine it is yet? Because the difference between a 327 and a 350 piston is 1/8 of an inch of piston pin height. Take a look at this picture and see how close the Piston is to the oil ring. This is the 350. Which is far more common and more likely to be found in an automotive machine shop than a 327 piston.
Last edited by derekderek; Jan 25, 2018 at 06:52 PM.
Race Director
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From: SW Florida.
Okay, the more I look at these two pictures the more it looks like the pin height is the same. A little bit less than the width of the oil ring itself distance between the top of the pin and the bottom of the oil ring. I 327 would be an eighth of an inch lower than a 350. Which is about the width of the oil ring. But you really need to measure the stroke to be sure what engine you have. And it's quite easy to do. I might as well measure the bore to any cheapie dial Caliper from the auto parts store will tell you whether it's a 4in or 4.030 or 4.040. They can't measure tenths but they can measure ten-thousandths pretty well
Race Director
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From: SW Florida.
Because you can put a 350 piston into a 327. And it'll run. But the Piston will stop the an eighth of an inch before it gets to the top of the bore. And have a very little compression.
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Le Mans Master
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From: Cool Northern Michigan
I wonder if . . . thats . . . . naw.
Thread Starter
Intermediate
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Thank you.
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
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From: SW Florida.
Now measure the bore and look for anything like .030 or 040 on top of any pistons in the engine and the new one. Compare pin heights side by side and see how piston fits the bore without any rings. Did shop hand you a piston-rod combo, or just a piston? What are you doing for a rod bearing?
Last edited by derekderek; Jan 26, 2018 at 08:46 PM.
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The "V" indicates that the engine was assembled in Flint MI, and "1205" is the assembly date, December 5th, 1967.
Le Mans Master
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From: Cool Northern Michigan
"Here, let me grab a 4" piston out of the back room, it SHOULD be exactly the same".
After all, a small blocks a small block right?
Oooops, didn't see that comin' about the pin location. (post 28)
After all, a small blocks a small block right?
Oooops, didn't see that comin' about the pin location. (post 28)
Thread Starter
Intermediate
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The guy that handed me the piston is a 30 year veteran machine shop guy. He gave me the .030 over piston that I needed. It's in the engine. Thanks for the responses everyone.
Race Director
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From: SW Florida.
Was it a piston and rod, or did he install the piston on your rod? What did you do for a rod bearing? Did you get a new one? Did you check the bearing you took out for size? Because if you put a standard bearing on an .010 crank journal, the engine will have a very short life.
Thread Starter
Intermediate
Joined: Feb 2017
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Was it a piston and rod, or did he install the piston on your rod? What did you do for a rod bearing? Did you get a new one? Did you check the bearing you took out for size? Because if you put a standard bearing on an .010 crank journal, the engine will have a very short life.
Le Mans Master
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From: Tampa Bay FL
For good measure, I would pull all of the pistons... where there is one...