450 engine noise

Chester5731 · Oct 20, 2009

I have a 450 gasser that has a noise in the engine. When I first start it, it sounds like a light knock or kind of like the higher compression from a diesel. It is towards the front on the right side. It seems worse when it is colder out but quiets down some as the engine warms up. It always starts and runs good. Any thoughts on what to check or where to start looking?

Bob M · Oct 20, 2009

A failing cam drive gear is a prime suspect. The noise location (front right side of engine) is consistent. Also the Super M/400/450 engines with live hydraulics are prone to cam gear failures. (I've had had to replace cam gears on two of my tractors...)

A quick check is to apply a load to the hydraulics with the engine idling. If the knocking sound changes (or disappears) with the pump loaded it's likely the cam gear hub has failed. Or you can pull the hydraulic pump then reach inside the timing gear case and feel if the cam gear is loose.

A new cam gear runs about $140 or so. Replacing the gear is not difficult, although some large and heavy parts (the front bolster assembly) must be removed to get at it.

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Another possibility is the nut holding the crankshaft pulley has worked loose. Can test by grabbing the pulley (engine stopped of course!) and trying to wiggle it.

Good luck!

Chester5731 · Oct 20, 2009

Thanks Bob M!!

mhmalcolm · Oct 20, 2009

I"m just going to throw this out there because it happened to me once. Check the generator for a front bearing or rear bushing. I had a 400 that was making that exact type of noise under the same conditions that you describe, and I thought it was coming from the right front of the engine, but it was driving me nuts trying to pin point it. I took the hoods off and realized it was coming from the generator. It had a reman generator on it and the rear bushing had never been drilled for the oil wick, so no oil was getting to it. The bushing had worn to the point that the armature had started to drop into the field, making a tic-tic-tic sound on every revolution. Something about the the sheet metal being on made it echo and sound louder on the right than on the left, even though the generator is on the left up under the hood. This may not be your problem, but it is worth checking out.

450 engine noise

Chester5731

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Bob M

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Chester5731

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mhmalcolm

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