Sheared distributor gear.

Old June 24th, 2019, 08:04 PM
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Sheared distributor gear.

Hi guys been a long time since my last confession,

So my 68 442 400ci crapped out last weekend and I found that I sheared the distributor gear. Any Idea why this happened? I probably need to pull the engine for at least metal in the engine, right?
The engine was fully rebuilt about 3 years ago and only has about 8000 miles on it.

Thanks in advance!

Craig
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Old June 24th, 2019, 09:32 PM
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Are all the teeth chewed up like that or just those ?
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Old June 24th, 2019, 10:30 PM
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Too much oil pump load? Lack of lubrication?
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Old June 24th, 2019, 10:37 PM
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May want to add an oil galley plug with a distributor gear oiler hole if not already installed.

Good luck!!!
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Old June 25th, 2019, 03:59 AM
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I’d take a good look at the camshaft. I’d have a hard time believe the distributor gear is torn up that bad with no damage to the cam gear.

Are the teeth sheared off, or worn away? Even wear all around? If the teeth are sheared off in one place only, unless the distributor shaft locked up in the housing I don’t know what could cause that if the oil pump locked up, I would think the driveshaft would twist and break before ripping off the teeth. If the wear is even all around, I’d look at the oil plug. I’m guessing someone installed a solid plug with no oil hole to lube the gears
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Old June 25th, 2019, 01:15 PM
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The gear is sheared on that side, fine the rest of the way around. This is as far as I've gotten. I frankly was surprised to find it, thought it was a bad coil when it died on the freeway. Trying to get a few opinions before tearing into it. I think I need to pull the cam or
maybe a camera down the distributor hole. I did notice the distributor shaft had some up and down play in it. Cant remember it that is normal, moves about an 1/8 of an inch.

Thanks guys!

Craig
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Old June 25th, 2019, 01:40 PM
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Oil pump locked up?
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Old June 25th, 2019, 01:56 PM
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Originally Posted by allyolds68
Oil pump locked up?
I'm gonna have to look into that!
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Old June 25th, 2019, 01:57 PM
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Originally Posted by 442craig
I'm gonna have to look into that!
I know someone that it happened to that had the exact same damage as you do
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Old June 25th, 2019, 02:09 PM
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Any idea why it failed? How much of a tear down did he do?

Thanks!
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Old June 25th, 2019, 02:31 PM
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Originally Posted by 442craig
Any idea why it failed? How much of a tear down did he do?

Thanks!
Complete tear down. I think the same pistons and rings but he had it honed, block flushed, and installed all new bearings.

it was an older motor so I think the pump was probably just due. I can find out for sure
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Old June 25th, 2019, 09:30 PM
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Had same issue two years ago with mine. Debris jammed up oil pump. Twisted the shaft that drives the pump. Teeth on cam and distributor were destroyed. Complete teardown and rebuild after that. Found a piece of metal in oil pump at teardown inside the pump. Car just made an awful racket and died.
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Old June 26th, 2019, 04:10 AM
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Originally Posted by hawks70
Had same issue two years ago with mine. Debris jammed up oil pump. Twisted the shaft that drives the pump. Teeth on cam and distributor were destroyed. Complete teardown and rebuild after that. Found a piece of metal in oil pump at teardown inside the pump. Car just made an awful racket and died.
Thanks for jumping in Jim. I knew you went through the same thing.
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Old June 26th, 2019, 07:56 AM
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Were any valve lifter retaining clips broken/missing when you pulled the intake manifold ? Another member on here reported finding one of the "paper clip" retainers stuck in the oil pump screen.
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Old June 26th, 2019, 08:16 AM
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So, looked down the dist hole. Cam gear looked good, pump shaft spun freely. Maybe the shaft broke? I did notice some wear where the distributor seats on the block, is that normal? The Distributor shaft has about a 1/16" vertical play. Is that normal?
The engine was totally rebuilt about 4 years ago and only has about 8000 miles on it. I really don't want to tear it down. I will probably pull the pan and inspect the pump. Maybe something lodged in it then freed itself. Nothing is easy!!

Thanks all!

Craig
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Old June 26th, 2019, 08:55 AM
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Something probably got sucked into the oil pump and jammed it. If the pump shaft had simply broken, the distributor would have continued to spin and not chew off one area. The engine would have continued to run, but your oil pressure would have dropped to ZERO. You definitely have to pull the oil pan to check the oil pump and see what pieces are in the oil pan.
.......Just my two cents worth.
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Old June 26th, 2019, 09:16 AM
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Originally Posted by OLDSter Ralph
Something probably got sucked into the oil pump and jammed it. If the pump shaft had simply broken, the distributor would have continued to spin and not chew off one area. The engine would have continued to run, but your oil pressure would have dropped to ZERO. You definitely have to pull the oil pan to check the oil pump and see what pieces are in the oil pan.
.......Just my two cents worth.
I think you are right, and going to be my next step.

Thanks!
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Old July 24th, 2019, 08:33 AM
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Update...

Pulled the motor and began disassembly. Pulled pan and found a few metal shavings. Cylinders looked good. Pump was good, I think I dodged a bullet! Was told the proper distributor gear should
be bronze by Comp Cams. Seems to have worn the dist gear and ultimately caused the failure. The puzzling thing is the distributor shaft has about a 1/8" vertical play. I don't remember that being the case when I originally
installed it.

Onward and upward I go!

Thanks Guys!

Craig
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Old July 24th, 2019, 10:19 AM
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What brand camshaft ? What brand distributor ? Did you find an oil hole to lubricate the distributor gear ?
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Old July 24th, 2019, 10:40 AM
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Originally Posted by OLDSter Ralph
What brand camshaft ? What brand distributor ? Did you find an oil hole to lubricate the distributor gear ?
The Cam is a Comp Cam Roller.(Bernard Mondello grind.) Distributor is stock, rebuilt with engine builder specs at a Carb shop. Not familiar with an "oil hole"
Gears are in the block and exposed to internal block oil. Am I missing something?

Thanks!

Craig
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Old July 24th, 2019, 12:34 PM
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Hello 442craig,

The proper gear to use with the camshaft you have is a Melonite gear as explained to Ollie originally... But the gear that's on your distributor looks stock?

There must be a .040 oil hole in the inside oil galley plug just in front of the distributor gear, you will need to use a mirror and light to see if it's there...

Thank you in advance,
Bernard Mondello Racing Enterprises
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Old July 24th, 2019, 11:41 PM
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I had that happen to my first 350 when I was 17. All of the teeth on the cam were pointy. I had a shop replace the distributor (I didn't know any better at the time) and sent me on my way. I drove that until it developed a rod knock and replaced the engine.
With that damage I would seriously suggest a tear down and complete inspection because I'd lay odds, at the very least, the cam is wiped. You very well could be looking at bearing damage and all sorts of other hidden issues.

My $0.02
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