[TXsilverado]

ok, so im driving down the road and the truck just took a shit. it was like i just turned off the key. luckily i was about 2 miles from home and a wrecker had me home in no time. i was thinking best case scenario and figured my crank sensor went bad or i melted one of the wires. a visual check and scan showed no problems. pulled the valve cover and turned the motor and rockers did nothing. SWEET!

next step was to pull the front cover. i totally expected a broken timing chain but it wasnt the case. when the cover came off, the cam gear fell out and hit the ground. all 3 bolts sheered off. i figured the cam locked up and spun the gear off with but the cam spins free and feels completely normal. i was actually logging the VE table when this happened and nothing looked out of the ordinary in the log. just all the sudden the rpm just dumped. motor still has oil pressure when trying to crank it over.

really dumb question but what are some possible causes other than the bolts backing out and giving the gear enough wiggle room to sheer off (had this happen with converter bolts before. i also considered them possibly being over torqued. you can see on the cam retainer plate that the cam gear was rubbing.

and just for fun, does anyone have experience with how weisco pistons hold up to ferrea valves? what are the odds that a valve bent a callies rod? this motor has less than 1,200 miles on it!

 

[shadys281]

I've seen it happen on cam bolts that didn't get locktite on them.. It appeared the bolts backed out and gave the gear slack to work away and eventually broke the bolts..

 

[jon6.0]

Damn dude. Hopefully it's not to jacked up.

 

[blackonblacksls]

Is there rub marks on the cam sensor?

 

[BillyBob750]

Id say your cam bolts backed off, which allowed the cam gear to start dancing around. It wouldnt take long before those bolts would shear off. Im with blackonblack, there are probabaly some wear marks from the cam gear coming loose. How recently have you been inside the timing cover?

 

[TXsilverado]

the motor was built with this cam. not even 1,200 miles on the entire new combo.

 

[TXsilverado]

Damn dude. Hopefully it's not to jacked up.

i know there are a ton of bent valves in my expensive hand ported heads no telling what the pistons look like. bent rods? crushed lifters? who really know until we gut it.

 

[LosLS2]

Look sorta like this?

Dowel broke also and was stuck to the magnet on the oil drain bolt.

Those are ARP bolts by the way.

We suspect that what happened was that they backed out and walked, then sheared off on a hard launch but it really is unclear.. They are now Loctited drilled and wired. They were Loctited before.

 

[TXsilverado]

looks identical lol. how tore up was the rest of that combo?

 

[gray86hatch]

Comp has a bolt retainer out now.

Like a SBC.

Tim

 

[ShiznityZ28]

2 issues. 1 not tq'd and/or locktight and or too long of a bolt. The cam bolts are a few threads shorter than the regular bolts for everything else. same with the cam retainer plate. We recieved a few cams where the holes were not tapped as deep as others and the stock short bolts work fine but the bolts for the cover and oil pump etc that are a few threads longer do not. they would feel tq'd but the gear has 1/8" or so play in and out. it will cause heat and eventually fail.

 

[GKsGS400]

Were you trying to clear the converter when this happened?
Posted via Mobile Device

 

[TXsilverado]

so for the engine builders out on this board....if a customer of yours brought this motor back to you after less than 1,200 miles what would you do about it? should i eat a $6,000+ longblock?

im sure a few guys have experienced a situation like this. what was the outcome? if it was a broken timing chain or locked up cam i would sum it up to the "pay to play" scenario...it's hard to swallow sheered off cam bolts though.

 

[TXsilverado]

Were you trying to clear the converter when this happened?
Posted via Mobile Device

nope. driving down the road.

 

[Collinsautomotive]

so for the engine builders out on this board....if a customer of yours brought this motor back to you after less than 1,200 miles what would you do about it? should i eat a $6,000+ longblock?

im sure a few guys have experienced a situation like this. what was the outcome? if it was a broken timing chain or locked up cam i would sum it up to the "pay to play" scenario...it's hard to swallow sheered off cam bolts though.

Typically I warranty against fialures like that. Most builder will work with ya. I doubt its more then 2-3 bent int/exh valves anyways. so it should be easy to fix.

That cam retaining plate being all rubbed up, suggests something was not happy.

 

[TXsilverado]

only 2 or 3 would make me happy. rpm was up there when it came loose.

 

[Collinsautomotive]

only 2 or 3 would make me happy. rpm was up there when it came loose.

Theres only so many cylinders that can be up at a given time. If the pistons have generous reliefs you should be ok IMHO. Might not have bent any valves at all.

 

[TXsilverado]

there are definately some bent valves. a few of the springs didnt retrun all of the way to the top when i removed the rockers. i didnt count how many looked funny. the pistons have 8cc reliefs.

 

[Collinsautomotive]

there are definately some bent valves. a few of the springs didnt retrun all of the way to the top when i removed the rockers. i didnt count how many looked funny. the pistons have 8cc reliefs.

ekkk, yeah your gonna have a few bent valve, but its not insurmountable to fix.

 

[TXsilverado]

that makes me feel a little better. hopefully my engine builder has the same type of warranty that you guys over there do. it's tough to not rip a head off to see the damage but ill hold off on it until i get it over to them.