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Got my motor tore apart & it looks pretty good except for a broken cam shaft. Do 4bt's usually bend the valves when the camshaft stops turning? I can't visually see that they are bent with them still in the head.
 

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Where did the cam break? I have heard of them breaking off near the gear when the "killer dowel pin" falls out and get's caught in the front gearing.
 

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The head is off & the valves don't look bent. One tooth is missing on the crank gear & the camshaft is broken behind 1st cam journal. Could this be from that "killer dowel pin"? Where is this thing anyway?
 

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The "killer dowel pin" is an issue as well as the case bolts inside that cover. Many, many people have reported hand tight or loose case bolts, however you want to describe it. Not a bad idea to get a gasket and front crank seal and check the bolts and tab the dowel pin. If you are a victim of the KDP it could cost you as much as you have in buying your donor vehicle... Cam, gears, front cover and the list could be longer...
 

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Got my motor tore apart & it looks pretty good except for a broken cam shaft. Do 4bt's usually bend the valves when the camshaft stops turning? I can't visually see that they are bent with them still in the head.
I would bet they are. Pull it apart and check them.
 

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The only easy way to tell for sure on those valves is to set up a magnetic base dial indicator and check runout, or check them in a vee-block.

Note: all 4BT's had a dowel pin, so if your engine has a vacant hole instead of a dowel pin you know what happened. Bad news and sorry it happened to you.
 

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I think a close examination of the piston tops would give an indication as to whether there was any interference between the valves and pistons. Jimmie's method with the dial indicator will give a very accurate reading. An old timers method is to simply roll them on a smooth flat surface and look for a wobble when they roll. If you also find bent push rods there is a good chance the valves contacted the pistons.
 

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Discussion Starter #10
I found out what caused it, like SDSTRIPER said it was a case bolt and it is in the bottom of the pan along with one crank gear tooth. the kdp is still in place. I have another old engine that I should be able to get the cam & crank gear from.
 

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You may also want to take a real close look at the oil pump gear. That sudden stop with the pump spinning can sometimes crack a tooth.
 

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Really interesting info, guys!

How often should we pull the front acc cover off and inspect this stuff?

Is there a sticky/FAQ anywhere that shows you what you should be looking for?
 

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Really interesting info, guys!

How often should we pull the front acc cover off and inspect this stuff?

Is there a sticky/FAQ anywhere that shows you what you should be looking for?
One time is better than none. I personally would make a tab for the dowel pin and loctite red the bolts and sleep better having done it.
 

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Is it as simple as pulling the front cover off and making sure everything is good?
Shouldn't take more than a few hours?
 

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Is it as simple as pulling the front cover off and making sure everything is good?
Shouldn't take more than a few hours?
No, you need to do what SDSTRIPER mentions on post #13 above yours. I even locktite my oil pump bolts. Remember there is a hidden bolt under the cam gear that also needs locktite. You need to bar the engine to get to a opening in the cam gear to see it.

I too sleep well knowing i have done all possible to avert a diaster.

Paul
 

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No, you need to do what SDSTRIPER mentions on post #13 above yours.
Thanks, yeah....I knew I would be securing fasteners once inside,
I was just looking for other info,
like: "the cam gear needs to come off" or something along those lines.

If all I need to do is unbolt the cover, remove every bolt I see and clean them (more or less!) and then re-install with loctite, it will be cheap insurance for sure.
 

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Thanks, yeah....I knew I would be securing fasteners once inside,
I was just looking for other info,
like: "the cam gear needs to come off" or something along those lines.

If all I need to do is unbolt the cover, remove every bolt I see and clean them (more or less!) and then re-install with loctite, it will be cheap insurance for sure.
Yup, thats it. Just rotate engine to get cam gear to openings to get bolt under gear. Also dont forget to do the KDP mod. Tab works well and is quick and forever with red thread locker.

Paul
 
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