SC Tear down pics, some Scarry!!

[dc914guy]

Well I started tearing down the 911sc engine this afternoon. I removed the CIS, Fan, Exhaust, etc. The Damage to the engine started to become apparent after removing the CIS. All of the damage seems to be on #5, but I will know for sure after I pull the heads off.

Has anyone seen damage like this before? The consensus seems to be that the engine was over revved however the PO's son (who was driving the car at the time the engine blew) swears that he was around 4K when it blew.

I have a couple of the pictures posted below, to see the rest check out:
http://www.itvl.com/eric/_cars/teardown/

#5 looking into the intake port:


Same as above, but a better angle:


Broken Rocker (JB Weld?? )


Intake:


Exhaust:


Sloppy Work:


Thanks,
~Eric

[AirCooledExcellence]

Ouch, that looks nasty! Good luck with the rebuild!

Cheers,

Tim.

[Scott Clarke]

Tensioner failure?

[dc914guy]

This does have the oil fed chain tensioners. Is it comon to see those fail, and what should I look for? I am going to pull the chain covers off later on today.

[Scott Clarke]

It should be obvious when you get the cain covers off. It is not common for the oil-fed tensioners to fail, but it could happen. I was just trying to figure out why you have a broken rocker arm. The cams and pistons getting out of sync would certainly do that!

[emcon5]

As could a mechanical overrev.

Tom

[nostatic]

Originally posted by emcon5
As could a mechanical overrev.

Tom

as in, "gee, I was looking for 4th but found 2nd"?

[Halm]

Originally posted by Scott Clarke
It is not common for the oil-fed tensioners to fail, but it could happen.

Actually, they may be more common than you think. Otto does not use them because of bad experiences and I have heard "rumors" that Jerry Woods also does not use them for the same reasons.

[Mike Kast]

Damn! had the oil in that thing ever been changed? Maybe the kid wasn't sure where the oil fill was so he just dumped it on top.

[Wayne 962]

Originally posted by Halm
I have heard "rumors" that Jerry Woods also does not use them for the same reasons.

Completely untrue. Jerry Woods uses them all the time on street performance engines. I believe for engines that will be run for "hours" only, he uses the mechanical chain tensioner with an adjustment screw.

He also has a unique technique for placing "safety collars" on the tensioners. I was going to write a tech article on this, but I haven't gotten around to it quite yet...

-Wayne

[Halm]

Thanks Wayne. The safety collar trick is exactly what I had heard he used on street engines. A little truth sometimes goes too far.