1989 4.3 - Looses oil pressure, oil smoke in valve covers and clacking above 2K rpm

[moparron]

Still chasing demons in this boat... whoever 'rebuilt' the motor deserves to be throat punched. Got all my leaks chased down and repaired. along with about 100 other little demons. Fresh oil change, new plugs, new wires, cap, rotor and gas. Compression still 140-160 all cylinders. took it out for yet another shake down. Idled fine, headed out of the marina - no issues. Got into the ICW - throttled up. Oil pressure about 40 PSI. Get up to about 2K RPM - slick clacking noise? oil pressure good, throttle down - noise goes away. Throttle back up... clacking comes back above 2K, clacks more with higher RPMs. Then oil pressure dropped to 5. Shut it down, pulled engine cover and heavy smoke coming out of valve covers (not steam). Temp never went over 175. Start it back up - no oil pressure. Thew anchor called for a tow. 45 minutes later restart for giggles... 20psi oil pressure at 2000RPM, Clacking while not in gear.
Get it home ... starts up on muffs - 40PSI oil pressure, clacking above 2K rpms, sounds fine at idle??

I am open to guesses?? I have a few ideas, but want to know what y'all think.

 

[nola mike]

What's it look like when you pull the valve covers?

 

[Bondo]

but want to know what y'all think.

Ayuh,...... Find another long block to swap into it,.....

 

[moparron]

pull the valve covers and it all looks normal.

Bondo.... that's sort of what I have been thinking.

 

[biggjimm]

Sounds like it might have been run low on oil or just not "rebuilt" correctly. Could have been run extremely hot before the rebuild & not had everything replaced that should have been replaced. I know guys who have not replaced things like cam & lifters & even cam bearings because they looked "ok" only to end up losing oil pressure & blowing their supposed rebuilt motor up.

 

[Bonus Check]

Before you swap blocks, try draining about 2 quarts of oil from the pan and adding 2 quarts of diesel. run it for about 30 minutes in the lake at about 1800 RPMs. It could be something simply stopped up. If you are going to consider getting a new long block then you have nothing to loose and everything to gain if it works.I did that to a Pontiac back in 76 with a 400 ci engine. Pushrod was stopped up.

 

[moparron]

HOLY CRAP! I looked into longblocks - okay $1600-$2000 seems to be about average.
Then I figured I would look into rebuilding - you have got be kidding!
4.3 rebuild kit w/forged pistons and high volume oil pump - $510
4.3 heads -$550 exchange
Required marine gaskets - $60
Cam for MY motor with shipping $350
=$1470 total.
Now if I went cast pistons and standard volume pump - I save $200. And I haven't even machined the block yet. Figured I wouldn't even call around for that.... unless someone can do it for $125? Longblock even comes with a warranty and they do the labor.

Thank you Bondo for not even suggesting I rebuild!

Now accepting donations towards my longblock fund

 

[Bondo]

Bondo.... that's sort of what I have been thinking.

Ayuh,.... A Runnin' motor outa a '96, 'n Up, pickup is a great up-grade, 'n potential cheap, quick way back onto the water,.....

There'd be abit of swappin', 'n up-gradin', like goin' electric fuel pump, but all very doable,....
We'll walk ya through it if need be,.....

 

[moparron]

Swappin... no problem. What sort of upgrading - outside of fuel pump? Might think about this route

 

[81 Checkmate]

Bondo's talking about swappin over the marine parts. Exhaust, dist, carb, starter, alt ect.

 

[moparron]

Ahhhh... so no like going toEFI or anything. Intake won't work from mine... mine is a 12 bolt.

 

[Bondo]

Ahhhh... so no like going toEFI or anything. Intake won't work from mine... mine is a 12 bolt.

Ayuh,.... So ya up-grade to a Vortec manifold, 'n new 4bbl. carb,.... 1409 Edlebrock is a Great choice,....