Broken Crankshaft

[twinockchef]

Well 'Hairball' has struck again with a broken crankshaft. It happened last month. I have been very busy with school so I have only been able only able to devote eight hours each weekend. Metric Motors provided me with a new crankshaft (plus flywheel, balancer, a seal kit, and bearings) at a very reasonable cost.


During the proccess I decided to replace all of the oil, transmission, power stearing, and fuel line hoses. There is a local shop which was able to replace all the hoses and still keep the orininal fittings, at a very reasonable cost. All of the metal oil and transmission lines were also looking ragged. So I sand blasted them and spray painted them. All of the rubber parts on the clamps were replaced.



The engine is back in and I should have Hairball running Sunday afternoon.
There was just one problem I have three things left over and I can not figuire out where they go.
The person who correctly identifies them will get the booby prize.

[68_280SE]

I don't recognize the first bolt. But the second one is the cap that goes on the end of the timing chain tensioner. The third bolt looks like a cylinder head bolt.

Hope that helps,
John Heller

[JMela]

Guessing 1st bolt is an engine accessory mounting bolt.

How did that crankshaft sound when it went? Any other damage?

[twinockchef]

I did not have any left over parts. The parts pictured are a flex disk bolt, timming tensioner nut/cap, and a head bolt. I did this because everyone hears of the stories about finishing a project and having extra parts which did not happen to me. So I picked a few extremely important parts to have fun with. (68_280SE was correct on two of them. "Two out of three ain't bad.")

The crazy thing about the crankshaft was at first I believed it had just a big crack, on one of the counter weights, because the car worked but with a loud noise from the engine until I parked it in my shop.
Metric Motors informed me, from just a photo of the the crackshaft through the oil pan, that the engine was running very rich and was the probably of the shaft failure. I was lucky with other damage. It was only a broken shaft and a very small amount of wear on the bearing in front of the break which had a small amount of shavings.
Surprisingly replacing the crank shaft is not as difficult as you might think. As long as you have a engine hoist and stand it can be done.

[vandor]

Any idea of why it broke? Is this a weak point in those engines?
It's pretty uncommon for a crank to break.

Csaba

[Tony H]

Had the crank been magnifluxed before it went into the engine? I know straight 6's have harmonics and the long crank can be a problem but one would think a 7 bearing engine would be very strong. Sounds like you recovered pretty well though.

[Benz Dr.]

This head bolt is the one used for the cam bearings - the shorter one holds the cam cover brackets in place.
Chain tensioner cap and flex disc screw which is the longer one used to fix the cross joint in place.