1978 FI Engine noises


Craig Smith

New member
Hello,
I have been dinking around with my 1978 2.0 fi. It had issues. Anyway, I.ve gotten to the point where it starts right up, idles fine, decent acceleration, goes up to 70 mph with no problems. So what is the problem - it's the tap-tap-tap-tap noises or loud ticking coming out of the engine compartment that concern me. I am guessing it has something to do with the mechanicals inside the engine, but I'm wondering if there could be something in the fi system that could cause it. If not I'll head to the engine forum.

Thanks all responders,
Craig
 

scotsborn

New member
Hi Craig, the tapping is probably related to your hydraulic lifters. I cannot think of any issues with your FI system that would cause this so it is definitely inside your engine case. If it is a 'light' tapping then it will (probably) be related to your valve train and should be constant but increase with engine speed. If it is crank / piston related then it will be a 'heavier' knock and more prevalent either hot or cold. It will also be more prevalent when accelerating and get quieter when cruising with less load.
 
I

Impeplevap

Guest
1978 FI Engine noises

The timing chain and guides are designed to last the life of the engine. How long is that? Ask FoMoCo.
I cant listen on this computer as its too old, so can only comment about noises.
A thud is a sound created by crankshaft main bearings.
A rap or knock is created by rod bearings, and other things.

A failing timing chain would generally be of two sorts: slap or slop due to worn guides or rattle and chunk if it is REALLY loose and trying to walk off the sprocket teeth. Take a look at images on the web, and youll see looooong chain guides, which should spread any load over a pretty big surface, giving good life.
Unless the engine was run without oil, or low on oil, the chain should have been lubed properly, guides too, and it should last.
You also have hydraulic valve adjusters that could be causing intermittent tapping noise. A bit louder than clicking, but not as loud as a rod knock, which would be continuous. The lifters/supports can make noises that come and go as the lifter gets filled with oil under pressure, and leaks out if theres a speck of something that keeps the check valve open. If the flow is low, or the check valve leaky, it will / may tap more often. If the noise goes away is not hidden when rpms increase, it may be increased oil volume from the increased rpms is keeping the lifter clearance close and thus quiet.
tom
 

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