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Noisy valve train intermittent oil pressure

Rico

Rico

New member
2000 GP GT 190K miles
Original oil pump, valve train, main bearings and heads.
Synthetic oil only with Mobil 1 filter.

I recently noticed the oil pressure light coming on sometimes at idle. The bottom end was getting noisy as hell. After pulling the oil pan I gauged the rod bearings. None were less than 0.005" clearance but the journals were all 2.250" and nice and smooth (yea for synthetic oil!). Some of the bearings were worn through to the backing. I replaced the rod bearings and put everything back together. I thought this would take care of my oil pressure problem. The bottom end is now as quiet as a church mouse. It runs like a bat outa hell!

Now, after 3500 miles of driving since replacing the rod bearings, I've noticed a tremendous amount of noise coming from the valve train at idle and the oil light still comes on.

Question
Could the valve train be starved for oil due to the oil pump or maybe loose main bearings? Maybe the lifters aren't pumping up; dropping the oil pressure? I haven't checked the oil pressure yet. Where should I start?
 


You need to get a real pressure gauge on it first and see what it's at. Could just be a stuck lifter.

I know this sounds dumb but what brand of oil filter are you running? Did you clean the pickup screen off when you were doing the rod bearings?
 
Filter is Mobil 1 as mentioned. Oil is 10W30 Mobil 1 synthetic as always.
Tube and screen were cleaned with new gasket.

Thanx for the reply.
 
Most guys replace bearings and are lucky to get 500 miles out of it. Has a lot to do with putting the engine back together and how things distort when being torqued. Reptile gave me some info at one time about how it happens. You might be losiing your bottom end.
 
Are the rod bolts TTY like the rest of the motor is? Could be an issue as well.

And yea, I have a feeling that bottom end is about to make another appearance, into the pan :th_sick2:

Best bet is to get a jy motor and swap it in.
 
The bolts are TTY but I was able to get a solid 50 ft-lbs out of them. The motor is very rarely run past 5K rpm. I figured 50 ft-lbs even on a reused TTY bolt should hold up. I wouldn't do this on a racing motor-imminent failure.

The bottom end is still very quiet...all the noise is coming from the top of the motor under the intake. It sound like some lifters are relatively quiet while 1 or 2 are very noisy. How many miles are these lifters good for. These have 190K on them.

Thanx again.
 


I've seen lifters exceed 300K miles. And I've seen them need to be replaced by 100K... Wehn they go, they go. At 190K it's odd that all of a sudden they made noise.
 
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