Engine Problems
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Freshman User
Joined: Jul 2003
Posts: 37
Likes: 0
From: Bloomfield New Mexico
Engine Problems
I recently rebuilt my 360 engine (1975 F-250 4x4). During the rebuild, I converted it to a 390 by replacing the pistons and crank. I had it bored .030 and installed a 4 bbl edelbrock manifold and Carb. In addition to having the heads reworked, I installed a new Cam, Oil pump, lifters etc.
Problem: Engine uses a quart of oil every 500-600 miles. I also have weak oil pressure and when the engine idles, it exhausts what appears to be carbon (black splatter).
Diagnosis: I have good compression on all cylinders. No fouled plugs and the engine otherwise runs and sounds good.
Any ideas on what to check/test?
Thanks
Custom 1975
Problem: Engine uses a quart of oil every 500-600 miles. I also have weak oil pressure and when the engine idles, it exhausts what appears to be carbon (black splatter).
Diagnosis: I have good compression on all cylinders. No fouled plugs and the engine otherwise runs and sounds good.
Any ideas on what to check/test?
Thanks
Custom 1975
Elder User
Joined: Jul 2003
Posts: 870
Likes: 1
From: Upstate NY Rochester
Engine Problems
How's the viscocity of the oil you are using? 10w-40w? 20w-30w?
I'm currently using 20w-50w and 1 bottle of Lucas Oil Suppliment. Mine shot from 0 to 45psi and Ive got 181k miles on it. No smoke! Really! Good luck.... Talk with you guys later....
I'm currently using 20w-50w and 1 bottle of Lucas Oil Suppliment. Mine shot from 0 to 45psi and Ive got 181k miles on it. No smoke! Really! Good luck.... Talk with you guys later....
Elder User
Joined: Jan 2003
Posts: 539
Likes: 0
Engine Problems
Sounds like you need to tear down the engine again
.
Something is not assembled right if you just rebuilt the engine.
If you do this, check all your clearances. Plastigage all the bearings and mic your cam bearings.
Check all your rings and make sure that you did not bust one putting it in the bore. Sounds like oil is getting past the rings (black splatter) and partially burning.
Good Luck!
.Something is not assembled right if you just rebuilt the engine.
If you do this, check all your clearances. Plastigage all the bearings and mic your cam bearings.
Check all your rings and make sure that you did not bust one putting it in the bore. Sounds like oil is getting past the rings (black splatter) and partially burning.
Good Luck!
Logistics Pro
Joined: Jan 2002
Posts: 4,907
Likes: 39
From: suburban atlanta
Engine Problems
If the smoke out the exhaust is black, you are fueling too much.. rich. If it were blue, I'd expect it is oil related. A qt in 5-600... give it some more time to break in and seat the rings. You DID follow the break in procedure provided with the ring install sheet, didn't you...
Pressure.. yeh, I thin you messed somethin up if it really is that low. Use a mechanical gauge to check the real pressure to make sure before doing any more work..
My free advice... and worth every penny... tom
Pressure.. yeh, I thin you messed somethin up if it really is that low. Use a mechanical gauge to check the real pressure to make sure before doing any more work..
My free advice... and worth every penny... tom
Thread Starter
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Freshman User
Joined: Jul 2003
Posts: 37
Likes: 0
From: Bloomfield New Mexico
Engine Problems
I decided to tear back into the engine and have a look around.
I am going to check all bearing clearances and look at the condition of the cylinder walls. If I broke a ring on installation, how would be the best way to tell outside of removing the pistons, or do you think I should just pull them and inspect?
Thanks
Custom 1975
I am going to check all bearing clearances and look at the condition of the cylinder walls. If I broke a ring on installation, how would be the best way to tell outside of removing the pistons, or do you think I should just pull them and inspect?
Thanks
Custom 1975
Elder User
Joined: Jul 2003
Posts: 870
Likes: 1
From: Upstate NY Rochester
Engine Problems
Hey Custom 1975! tomw has soom good advise. May as well check what you can on the exterior of the engine before tearing it down. You didn't mention if you kept the compression tester on long enough to establish a leak down on each cylinder. If you have a broken ring, at least you'll know which cylinder you need to yank the piston out to have a closer look. Let us know how things go. Talk with you guys later....
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