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Dick, thanks. A follow up question re engine noises, when warm, the 289 has a
'tock' sound from the drivers side near the rear? hard to tellwher from. seems to get quiter a higher rpm's. Someone told it could be from a bad fuel pump and not a bearing. Any thoughts on your experience?
thanks again
keith h
AnswerNoises are really hard to describe to another person.
My first thought is that if it seems to be from the rear of the engine, I always suspect the clutch/transmission on a manual shift car. Try having someone operate the clutch while you listen, and have them put it in a gear while the clutch is held down. This will stop everything moving in the transmission, while idling in neutral will have some items rotating in the transmission. Of course if stepping on the clutch affects the noise, it could still be in the engine, as the pressure on the crankshaft thrust bearing is affected by the clutch.
The fuel pump is toward the front of the engine, so that doesn't seem likely to me. But you can eliminate that possiblity by removing the fuel pump and then starting the engine after first getting it up to full warm. The engine will idle for perhaps 5 minutes without the fuel pump, using the fuel in the carburetor.
Localize the sound by using a stethoscope, or a piece of garden hose - one end in your ear, the other in contact with the engine in various places. If it is coming from under the valve cover, you can remove the valve cover and look further - it could be a slightly bent push rod, or a wobbly rocker arm etc.
If the noise is coming from lower down in the block, it is likely a bearing noise or a piston slap, however piston slap is usually worse when the engine is cold.
If a hydraulic valve lifter is failing, these will often make less noise at higher RPM. If the noise seems to be coming from under the carburetor area, try adding a can of "CD-2" additive to the engine oil. While I never advise using "mechanic in a bottle" type cures, this is one exception. CD-2 is magic at cleaning out sticky valve lifters. I've many times used it on this problem, and typically the noise goes away as you are pouring the stuff in! This is a very powerful detergent booster - works magic on areas of tight passages, typical of valve lifters.
Make sure you are not being fooled by accessory noises. This is less likely since it appears to be from the rear of the engine, but to make sure, you can take all the belts off the engine and run it long enough to see if the noise is gone - it won't hurt it for a minute or so to do this.
That's all I can think of off hand.
Dick
