Oliver 70 engine knock cont.

KenL

Member
I checked and rechecked everything and could find no reason for an engine knock. A couple of you said
it could be the timing gears. I also checked them and found very little wear. I decided that very
little wear might be too much. I called my dealer who is a very old Oliver dealership. I will be
replacing all three timing gears with brand new ones. Hopefully no more engine knocking.
 
what do mean by engine knock? what is very little wear? need something to go on. how much backlash is there on the gears? get a dial indicator on them and measure the backlash. sure dont see how a gear can make a knock. can you actually see any gear wear on the teeth?
 
Excessive end float can give rise to a knock as the drive is taken up on helical gears. I have an oli pump which was still being driven, even though the woodruff key slot was about as wide as it could get without failing. Not a 70, mind.

I found a previous thread, on pan removal, but nowt about any knock. Regular? ?Screwdriver? location of sound? Governor?
 
The knock sounded like a rod bearing. The very little wear, I didn't measure backlash but you could just barely feel a little movement in the gears. In the previous post, couple days ago, there where two other guys with the same problem. They changed the gears and the knock went away. I talked to an old Oliver mechanic and he said that was not a common problem but it did happen. I will be finding out if that's the cure. I have three NOS gears coming.
 
Those timing gears especially the cast cam gear will not have an even wear pattern. The knock is probably at one of the points where the greatest amount of wear is. Get a dial indicator and check the backlash in at least a half dozen places.
 
Ken, please keep us updated on how this works out... sounds like you are a step or two ahead of me, so I'm quite interested.

I'm in the middle of tearing down the front end on mine. I have quite a bit of backlash at the governor gear (I don't have a dial indicator, but by using feeler gave with front governor housing removed I believe it to be greater than 0.020"). I've also noticed that the front end of the governor shaft which rides in a bushing in the governor housing appears to be somewhat worn - particularly on the side away from the timing marks on the gear (worn more on one side of rotation than the other - at smallest point the shaft measures about 0.359" compared to 0372" on unworn area - enough to easily detect with fingernail). I've also noted that the governor shaft assembly has a notable amount of endplay (~0.030") in the magneto coupler housing as it sets on the bench, but maybe this is normal. I plan to disassemble further to review bearing/seal/etc, but first need to find/borrow a puller to remove impulse drive. I don't yet have the timing cover removed, but there is barely any perceptible lash between cam and crank gears when I try to rotate cam gear with governor housing removed.
 
Here's something that I've seen more than once with the olivers. If someone installed too long of bolt in the front crank shaft pulley, every revolution of the crank shaft, the bolt would touch the domed front of the governor housing, and jerk the crank shaft(end play)forward. It sounds exactly like a real bad engine knock. Check it out. Make sure all the bolts in the crank shaft fan belt tensioning pulley are short.
 
(quoted from post at 17:13:49 03/23/18) I checked and rechecked everything and could find no reason for an engine knock. A couple of you said
it could be the timing gears. I also checked them and found very little wear. I decided that very
little wear might be too much. I called my dealer who is a very old Oliver dealership. I will be
replacing all three timing gears with brand new ones. Hopefully no more engine knocking.

Hey KenL - just checking back in to see if the NOS timing gears fixed your problem, or if you've found something else...
 

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