440 problems ,new motor

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superbirdrag

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I ran my rebuilt 440 up last night . all was good. shut it down and then restarted it . We heard a pop and then shut the motor off . Tried to restart it we had no spark. Turned out that the cam was not turning . We removed the timing cover and found the cam bolt broke off and the dowel pin sheared off as well.
The motor is .30 over ,440 source heads. Cam is a comp cam .460 intake lift almost stock.we did the pre oil and had oil running out the rockers both sides. oil pressure was 50 on my gauge.

whats your thoughts ? cam seized ? bad cam bearings ? or just bad cam bolt ?
whats next ? new cam and bearings ?can i get the dowel pin out that broke ?

Thanks
 
superbirdrag said:
I ran my rebuilt 440 up last night . all was good. shut it down and then restarted it . We heard a pop and then shut the motor off . Tried to restart it we had no spark. Turned out that the cam was not turning . We removed the timing cover and found the cam bolt broke off and the dowel pin sheared off as well.
The motor is .30 over ,440 source heads. Cam is a comp cam .460 intake lift almost stock.we did the pre oil and had oil running out the rockers both sides. oil pressure was 50 on my gauge.

whats your thoughts ? cam seized ? bad cam bearings ? or just bad cam bolt ?
whats next ? new cam and bearings ?can i get the dowel pin out that broke ?

Thanks
Click to expand...
I always go with a 3 bolt cam. U might not have had it tightened up right--------------
 
we torqued it to the book specs , i always do a second check . The bolt didn't come loose it broke off. wonder if it was abad bolt or if the cam could have seized ?
 
is the cam seized now? I think at this point a total disassembly would be in order. cam not turning might equal bent valves and pushrods. plus any metal in the oil that got to the bearings in the engine.

Just my 2 cents
 
superbirdrag said:
we torqued it to the book specs , i always do a second check . The bolt didn't come loose it broke off. wonder if it was abad bolt or if the cam could have seized ?
Click to expand...
if the cam turned OK when u put it in, it probly didn`t seize, sounds like a 'luck of the draw" bad bolt !?!
Would the cam turn by hand after you tore it down ?
 
I would remove the rockers and see if the cam turns . After that I would remove the heads to see if the valves hit the pistons . If the cam is stuck the motor has to come out . Sorry
 
Pictures of the bolt? A difference in color from an open defect prior to installation may offer you a clue on it.
 
Follow the suggestions above. I would start with the belief it was a bad bolt, but do your inspections. I don't believe in torque specs here, I use an impact gun.
 
Was it a new bolt or the original one? Sometimes you're better off with the original. I had a bolt come loose once on a Mushroom lifter cam. Went to a 3 bolt after that. You want a hi grade bolt, 6 or 8, torqued to 40 ft lbs and use loc tite. Mine bent 6 valves. Had to pull the heads and change some valves.
 
I checked the bolt it was a fresh break through . nothing showing previous damage.it was a original bolt from the old cam. I was also told that the stock cam bolt can be bottomed out on some aftermarket cams. Then your torque is just twisting the bolt.
the plan sounds like a tear down, pull the heads look for damaged valves , valves hitting the pistons. see if the cam turns freely , pull it check for wear. I have the engine on my run stand so the process is easier, hope its not expensive . I will be pulling it apart tonight
 
Here's the thing: I don't think there's enough room to get the sprocket substantially off the cam IF THE BOLT WAS GONE!!! And you say the bolt is sheared, as well as the woodruff key. That indicates A LOT of force. I'm thinking you had a LOT of force there somewhere. Something I'd look into is problems in the OIL PUMP and the intermediate shaft bushing. Something, foreign, in the gear teeth? Bad/ seized bushing? Look that whole drive over. Pull the pump off and tear it down and inspect it carefully.

Obviously inspect the cam bearings and journals. Check them carefully (run a rod down through the head oil holes) for displacement in the block
 
post some pics up when you can,
 
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The friction of the load from the bolt squeezing the gear onto the cam is what turns the cam.
The dowel pin is soft and is just there to align the gear to the cam.
If the bolt gets loose, the dowel will just shear right off.

One important component in the single bolt cam set up is the washer.
It needs to be a thick hardened washer that can transfer the load from the bolt stretch into the gear to create the proper amount of clamping/friction.

Imo, it’s one of a few things:
-bolt had been previously over torqued
-bolt had insufficient torque
-substandard washer
-cam was stuck/seized in bearings when you went to refire the motor.

“What I would do” is, remove rocker gear, remove timing cover, see how easily the cam turns.
If questionable, remove it and look for signs of heat in the journals.
If it seems fine, I’d tend to think it was a bolt/washer problem.
If it doesn’t have the OE washer, I’d see if I could find one.
Use a grade 8 bolt, torqued to 50ft/lbs and I put red loc-tite on them.

Leak test all cylinders to check for bent valves.
 
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the result: the cam was siezed. we had to remove the block plug and hammer it out . The journals on the cam were clean but the cam bearings are scored up. Two of them started to push out as we took out the cam. One exhaust and one intake valve touched the piston on #2 and #8. I filled the ports with fluid and there was no leaks . no bent push rods.
still dont know if the cam siezed then the bolt broke or the bolt broke first .
thoughts ?
 
Sounds like insufficient oiling to the cam bearings. Perhaps the oiling hole didnt line up perfectly or something plugged the oiling to the cam bearings. The fact 2 bearings came out with the cam sounds like the culprits. Any sign of excessive heat on the bearings?
 
I couldn't tell if the cam bearings were over heated , will have to get a better look . I know that i had good oiling . we did a preoil and had plenty oil out both sides of the rockers, but maybe not enough to run it ? I will check the bearing hole to see if it has any debris in it from the block bore and clean. I will have to also check see if the bearings hole is lined up even though it has pushed forward. Would like to know why the bolt broke and the cam siezed .Its a $800 repair plus time.Would not want to do it a second time.
 
Garys72Duster said:
Was it a new bolt or the original one? Sometimes you're better off with the original. I had a bolt come loose once on a Mushroom lifter cam. Went to a 3 bolt after that. You want a hi grade bolt, 6 or 8, torqued to 40 ft lbs and use loc tite. Mine bent 6 valves. Had to pull the heads and change some valves.
Click to expand...

An old trick on three bolt cams is to use locktite on them, I always have andused the factory tightening specs---------hemi`s, sbc and 505 stroker--------
 
superbirdrag said:
the result: the cam was siezed. we had to remove the block plug and hammer it out . The journals on the cam were clean but the cam bearings are scored up. Two of them started to push out as we took out the cam. One exhaust and one intake valve touched the piston on #2 and #8. I filled the ports with fluid and there was no leaks . no bent push rods.
still dont know if the cam siezed then the bolt broke or the bolt broke first .
thoughts ?
Click to expand...
I'm sure the cam seized, then the bolt broke. I've never seen a cam bolt break on its own. May want to run the oil pump a minute, and see if the cam journals all have oil coming out. Hard to say why a cam journal would seize to the bearing.
 
May want to inspect cam lobes closely for any damage. I guess a valve could seize, and cause the cam to stop, but that would bend a push rod. Did you prime the oil system before first start up? Most likely cause, is a seized cam bearing. Cam seizes, dowel pin bends over, and pushes the cam gear out, breaking the bolt.
 
Daves69 said:
Possible scenario? Cam locks up, crank pulls timing chain, chain pulls cam gear, shears timing gear pin, and gear drags and rotates bolt till breaking point?
Click to expand...

My thoughts exactly.

As for why it seized......only two possibilities imo.
Lack of oil, or lack of adequate bearing clearance.

My experience with BB mopars is replacement cam bearings often require fitting/scraping to achieve a decent fit.
And, in the last several years I’ve seen a few instances where the journals on the cam core were not within spec(too big).
I’d measure the journal sizing as the first step in troubleshooting.
 
i think Dave69 is correct or closest i can figure as long as his scenario can happen after i shut the motor off.
The engine was running , we heard a small pop, it was still running for about 15 seconds after that with no charge in sound or idle. I shut it down to determine what the pop was . we didn't find any obvious damage. we tried to restart it and it did not fire. this is when we found the cam not turning, so the cam seized after the engine stopped, when we tried to restart it the dowel pin broke ,then the bolt broke. I guess this sounds like the story .I think its a good idea to pre oil with out the cam in to make sure the oil is coming through the journals ?? Any thing else to watch for going forward next week
 
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