1966 122
New fiber timing gear installed Thursday. Car runs great. Big pool of oil under car though. So much for hours of cleaning while rebushing the control arms last week. Apparently the front part of the oil pan gasket flaked off when the timing gear cover was removed.

Gasket goop was borrowed from the nice kid next door with the 400 Hp Firebird. The timing gear cover was removed for a quick cleaning and gasket goop application. I then noticed that top edged of the teeth on the new fiber timing gear were pretty chewed up. The oil leak is fixed now and the car runs excellent with no unusual noise from the timing gear area.

Should I be alarmed at the condition of the edges of the fiber timing gear teeth? The damage seems to be limited to roughly 1/32" of the outermost part of the teeth but almost all of the teeth are chipped. The old gear had separated from the hub but its teeth were not chipped at all.

Thanks,

Joe M in WV

If the car runs and sounds good I'm not sure I'd worry too much about it. When my regular 'driver' was a 122s I had the fiber gear go out on me when I was out of town. Just made that awful knocking sound. I ordered the new gear set and only replaced the fiber gear in a friends back yard. I proceeded to drive it another 12+ years. These engines are pretty indestructable.

You might check it in a few thousand miles (or hundred thousand miles).
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Carter

Be alarmed. The gear must be scraping itself apart against the timing cover. The only ways it can contact the timing cover is if 1) you didn't get it fully seated on the cam, or 2) the cam retaining plate is worn on the back side, allowing the cam to slip forward.

So here's a new rule for everyone: Never change a timing gear without pulling the cam retaining plate off and inspecting it. It must be absolutely flat on both sides. If there is any sort of ridge in it, the cam endplay (supposed to be only .003") is excessive.

As long as I'm here being snotty, let me add that it makes me cringe whenever someone recommends freeing the old gear by hammering the cam into the retaining plate -- I've seen several of them break apart in use, and the results are expensive. If you must extract a separated gear hub that way because there's nothing for a puller to grab onto, replace the plate -- they're only $20 or so.

.003" doesn't give you a lot of leeway...

Just as a note (I had to pull my timing gear and cam in advance of a rebuild), I picked up a nice 4pc set of three-arm gear pullers on eBay. An import no doubt, but the smallest pulled took my timing gear off easily. I paid $2.00 for the set, plus $20.00 shipping and had it in two days.

I would never dream of hammering the cam to get the gear off. Steering Wheel...maybe....
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You mean Volvo makes cars that are *NOT* Wagons?!?

I dunno who was hammering on their cam. The fiber gear had completely disassociated itself from the metal hub. The "stars" sticking out of the hub gave enough purchase to gently tap the hub forward from the back side until it moved enough to walk the hub off the cam by (gently) prying against the block.

If the hammering described above is the cause of dire warnings to others, then I am guilty of abuse and have learned a lesson in tolerance (pun intended).

Joe M

Joe,

Sometimes ya gotta do what ya gotta do -- my comments were not directed at you.

Quite a few times I've seen people say that the way to take a timing gear off is to tap the cam into the block (being careful not to pop out the plug at the rear, of course). I suggest this is a really bad idea. Use a puller if you possibly can.

I've also seen people say that you can recycle a worn retaining plate by flipping it front to back. This is absolutely incorrect -- both sides are thrust bearing surfaces, and the plate must be .003" thinner than the spacer ring on the nose of the cam.

I once gave up on a motor that was making a banging sound under the timing gear cover. The fiber gear was indeed separating from its hub, and I replaced it. The banging sound continued, and I only got as far as finding bits of brass in the pan before opting to swap engines and not deal with the repair.

Later I realized that all that was needed was a new retaining plate as well as the new gear. I think when the gears start to fail, they cause the cam to eat into the plate. That was the source of the brass and the banging. It never occured to me to pull it off for a look at the back side.

Now we have your gear chipping teeth, and another guy getting a new whirring noise after a gear replacement...

I suspect that you are correct that my fiber gear chipping is caused by the teeth touching the timing gear cover. The helical mesh between the crank gear and fiber gear would not allow any interference between them unless the timing gear was just manufactured incorrectly - not likely. The whirring sound could very well have been the fiber gear spinning against the timing cover. IIRC, the tooth damage was most pronounced near the small end of the timing gear.

What confuses me is why my gear stopped whirring and Tom's did not. Perhaps Tom has a little more end play in his cam than mine.

Thanks for helping,

Joe M

Joe;

If there has been contact with the cover, I would expect you would see unmistakable signs of it...otherwise, if there is gear wear, it had to come from an interference with something...if you still have the cover off, I'd look around and inspect until I convinced myself nothing serious was happening...

I still don't fully understand exactly where the wear occured...please explain: "tooth damage was most pronounced near the small end of the timing gear". Or maybe post a pic...

Phil;

If a timing gear hub is stubborn to "dissassociate" (great term!) itself from the cam, I have suggested gentle tapping on the end of cam with a soft hammer (while supporting the hub). That has always worked for me (and I've never damaged a thrust plate or popped out a freeze plug)...since the hub is not an interference fit, it will likely "dissassociate" itself, with the slightest impact force...but it is a technique which must be employed with a measure of judgement...hamfisted Chevy mechanics with three-pound hammers need not apply...

Cheers

Ron:

I'll take some pics when a newer timing gear arrives and is installed.

Only the outer edge of the teeth on the timing gear were chipped. I didn't notice any damage in the valley between the teeth on the fiber gear.

If there is no marks on the timing cover, then perhaps the installed fiber gear was an inferior composite or part of a bad manufacturing run. I spent a lot of time trying to line up the teeth and index marks before tapping the gear on the cam until enough threads were exposed to get the retaining nut started. Once the nut was started I used a socket to turn the nut and push the fiber gear the rest of the way home.

Best regards,

Joe M

Ahh - the tips of the teeth? That doesn't sound good at all. I think the only damage you could expect from hitting the timing cover is a little rubbing on the front side of the gear. Yours must be arguing with the steel crank gear somehow.

If you are curious as to whether or not the oil sprayer is spraying, you can pull the plugs and crank it around with the cover off - and see if oil comes out. It won't make too much of a mess. I could see a gear doing what you describe fairly quickly if not properly lubed.
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I'm JohnMc, and I approved this message.

Yeah, that was my bad for not checking the oiler. The manual says to check the oiler. Many here in previous posts said to check too. Mabye that's why the old gear went bad in the first place.

If the oiler does not discharge a healthy spray of lubricant, do you just unscrew it from the block and run an old guitar wire through it?

Thanks,

Joe M

;)
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Mike!

There is nothing snotty about sharing good information. Some lessons are learned by making mistakes. The second time the timing gear is replaced will hopefully be a better installation and last a few hundred thousand miles longer than the last.

Best regards,

Joe M