Camshaft damaged by Distributor

[wavegobbler]

The Distributor seized, the Camshaft lost some teeth. The Driven Gear on the Distributor is a tough, little brute! I have a few questions beyond the remove/ replace steps spelled out in the manual.

What should I do about the metal tooth chunks? Drop the pan for a scrubbing? The engine is a quality rebuild with about 20,000m on it.

I have another Distributor in my parts cave, should I remove the gear and grease the Governor Shaft? I really want to scream; why me, van Gods?! But don’t really want an answer to that question.

Any advice will be much appreciated!

[wavegobbler]

Here is a photo of the mangled Camshaft and the Distributor Shaft bound to what seems to be a housing part pressed into Distributor body64426443

Im planning to flood the damage area, try and flush the shrapnel into the pan, pull the pan.
I’m also thinking of pulling the cap off the Distributor every other oil change and flooding the area with a thin lubricant. I don’t know how uncommon this failure is.

The manual description of the removal is good.
Removing the plate behind the fuel filter for finger access worked well.

My ‘quality’ rebuild is looking suspect.
Check out the firsts cam bearing.
6444

It looks damaged and the marks don’t look very fresh.

Any thoughts on:
getting the loose metal shrapnel out of engine?
keeeping the Distributor from failing?
suspect cam bearings?
other thing I’m missing?

[originalkwyjibo]

Have you read Tim's posts regarding aftermarket cam gear clearance issues? Is there any signs of rubbing or damage to the backside of the cam gear or the cam retainer bolts?

[wavegobbler]

Thanks for reminding me about that great write up by Tim. I put a new toyota timing kit in this motor after reading the post. I think there was no interference in this location. I'll pay attention to the camshaft end play during installation. Parts should be arriving over the next week.
I can't find another mention of this issue (camshaft wreaked by distributor). I hope its rare.

[timsrv]

It's definitely rare. Was the distributor shaft seized to the distributor housing? Don't forget the oil pump is driven by the distributor shaft too, so use a long slot tip screwdriver to make sure it spins freely. If the oil pump was sucking up/ingesting foreign material it would have put a tremendous load on the shaft and the gears. However, the distributor shaft gear has a sheer pin, so even if the pump or the distributor seized it should have sheered off and saved the cam gear. Perhaps there was a quality issue with that cam and the gear just fell apart? Tim

[wavegobbler]

Thanks for the reply Tim. If you examine the photo of the Distributor shaft, where the pen is pointing, you can see a part that I think should be part of the housing. Maybe pressed in? That part is bound to the shaft.

I think this experiment (disaster) shows that the pin in the Distributor shaft might not shear if the shaft binds. However, my Distributor was rebuilt, and the pin was not original. Maybe the original pin would shear. My camshaft lost most of its teeth in the ring.

I have an extra oil pump from the rebuild kit, I think I'll swap it out, thanks.

[timsrv]

That is certainly an unfortunate failure. I've never seen a cam gear fail like that on a 4Y. Of course I'm talking OE Toyota here and we're just getting started with the need for rebuilds using AM parts. It's odd the sheer pin didn't sheer, but I'm guessing none of that would have happened if the shaft of the distributor didn't bind up. I think you're going about it the right way. The gear pieces would most likely harmlessly fall into the pan and stay there, but if it were mine, I'd want to be thorough and get them out of there. Putting a new oil pump on probably isn't necessary either, but considering the type failure you had, I'd want that changed too (just in case). Please keep us posted as to how it all works out. Tim

[wavegobbler]

The new camshaft is installed, plenty of clearance with the radiator removed to slide it in.

My current issue is lack of end-play. The timing gear is on, no interference with the thrust washer bolts (like Tim had with the aftermarket sprocket) but no end play. The cam spins freely, its not bound up but I don't read any end play.

I went to the Rockauto parts site and noticed a 'thrust washer' listed for our engine. They sell what appears to be shims. Maybe they are shims for the camshaft? There are two, two piece, shims in the kit. They don't say how thick they are.

The Part is: Sealed Power 67277BF
Does anyone know what these shims are for? Crankshaft? Camshaft? other?

The camshaft I installed is: Sealed Power CS875

Has anyone shimmed their timing sprocket/camshaft? Or machined their Thrust Washer?

[timsrv]

It sounds like you're describing the thrust bearing for the crank shaft. The camshaft thrust surface is that plate that holds it in right behind the gear. If there's not enough play, and you've ruled out interference, then you can adjust it by removing material from that plate. Machining is best, but you can do it in other ways. I've done it by taping a piece of sand paper to a flat surface, then pushing it back & forth with firm/even pressure.

[wavegobbler]

The sandpaper on flat surface works for me, thanks Tim.
I wish I’d payed more attention to the Manual, it’s clearly spelled out how to check the end play on the bench.

[wavegobbler]

The Camshaft is replaced and I’m on the road again. It took me about 40hrs over two weeks to disassemble, receive parts and install.

What I would do differently: Bench test the Camshaft end play as discribed by the Manual.
I also would have changed out the lifters. My lifters had around 20,000m on them so I figured they were ok but it’s too easy and relatively inexpensive to swap them.

Why did it happen? There was probably no oil getting to the top bushing of the Distributor. I’ve been adding an ‘engine break-in product to my oil. It’s thick and must increase the oil viscosity. Maybe it blocked the transfer of oil up the Distributor Shaft to the top bearing?

What I would watch out for: My Distributor was rebuilt. It had a different pin in the gear. Maybe the original would have sheared before wrecking the Camshaft.
Here is a photo of the stock Straight Pin.
6499
The pin looks the same on both ends

I hope this doesn’t happen to anyone else and thanks to this forum for all the help!

[timsrv]

I'm happy to hear you got it all put behind you. FWIW, I used to work for Toyota and in addition I've personally put around 1/2 million miles on 4y engines. I've also read most of the posts here and on TVP for ~13 years. With all that exposure, I have never seen a problem like that, so I'd say your chances are excellent you'll never see that particular one again. Strange failures can happen on old things. I doubt it had anything to do with your oil additive...........some things just happen. Tim