Rebuilt SBC 350

Donagain

Not-quite-so-new-guy
Dec 3, 2017
37
18
Just a shot in the dark here . I had the same issue on a 350 crate . Smoke like crazy on the passenger side . Turns out there is a hole for a plug on the passenger side. It's built that way in case you need the dipstick on the passenger side . It's hard to see and it didn't drip it just burned off when l drove and it looked like it was coming out of the exhaust.
 
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Bigtexs

Apprentice
Thread starter
Mar 30, 2017
56
18
Oak Cliff, Tx
Is your trans fluid level any lower? If you suspect it’s the rebuild causing the problem, do a compression test.
First off guys thanks for all your comments on what to test. After reading what range compression numbers should be within each cylinder no more than 10 to 15% drop in difference I started the compression test on the suspect passenger side of the motor. Cylinder 2 is 120 psi. Cylinder 4 is 90 psi. If I'm correct my rebuilt bottom end is NO good right?
 

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pontiac guy

Master Mechanic
Oct 28, 2016
493
93
Royse City, TX
You have a problem for sure but it could be a valve problem. The only way to know for sure is a leak down test. You can sort of cheat by putting some oil in the cylinder and redoing the compression test. If your numbers go up, it's likely ring seal. Its not a replacement for a leak down test but it's an old school trick that can help be diagnostic.

Didn't the guy who did the bottom end do the heads? If so who cares where the problem is. Take it to him and tell him what you found. He's on the hook to fix it no matter what
 

Bigtexs

Apprentice
Thread starter
Mar 30, 2017
56
18
Oak Cliff, Tx
You have a problem for sure but it could be a valve problem. The only way to know for sure is a leak down test. You can sort of cheat by putting some oil in the cylinder and redoing the compression test. If your numbers go up, it's likely ring seal. Its not a replacement for a leak down test but it's an old school trick that can help be diagnostic.

Didn't the guy who did the bottom end do the heads? If so who cares where the problem is. Take it to him and tell him what you found. He's on the hook to fix it no matter
You have a problem for sure but it could be a valve problem. The only way to know for sure is a leak down test. You can sort of cheat by putting some oil in the cylinder and redoing the compression test. If your numbers go up, it's likely ring seal. Its not a replacement for a leak down test but it's an old school trick that can help be diagnostic.

Didn't the guy who did the bottom end do the heads? If so who cares where the problem is. Take it to him and tell him what you found. He's on the hook to fix it no matter what
The motor was a complete rebuild from the heads to the bottom end. They even sent pictures of the progress but did a terrible job putting it back together. After talking to the owner he agreed to take a look at it and like you said the valves may need adjusting. Hopefully this will fix it once and for all.
 

pontiac guy

Master Mechanic
Oct 28, 2016
493
93
Royse City, TX
The motor was a complete rebuild from the heads to the bottom end. They even sent pictures of the progress but did a terrible job putting it back together. After talking to the owner he agreed to take a look at it and like you said the valves may need adjusting. Hopefully this will fix it once and for all.
Valve seats and guides is not an adjustment. That the sign of a messed up valve job. Who did the motor?
 

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