Dennis Wilson

I used the universal type (?Prestone?) when I changed it in 2006. The old water pump wasn't frozen or leaking. All of the water ports I can see are clear and not scaled. The break was no where near a water port and everything wlse was in good shape, so I can't see how that would really contribute.

Dennis

AaronSweat

I think he was kidding. Half the people I know with 928's are running M1, I doubt that could have contributed, but what do I know. Sucks either way. I hope you get everything straightened out.

Dennis Wilson

You never can tell with the FBIII. I do know there is a lot of concern in some circles about the reduction of zinc in the oils. That's as far as my knowledge goes. Where is Doug Hillary when you need him?

Dennis

FBIII

I think Aaron's explanation makes the most sense.

Shark Attack

why did i read this....it never fails, reading it somehow always makes me next

Lizard928

Shark you have a 32V car which is not prone to this failure.

Warren928

Oil? Baaa--humbug. Why not just because it's old? 1991 isn't exactly new, and maybe the "crate" got dropped off the back of the truck, causing a fracture that would later bloom into a full blown pain in the ****.

LT Texan

thought I'd add to this tread.....

My left side cam broke nice and clean at the nose. It also slipped in timing (crazy!) and bent a couple exhaust valves

The cam was an '86 Euro S in same year carriers and atop same year heads.

Block is early 4.5L manual.

Was using 5W50 Castrol synthetic for older flat tappet cars (more zinc)

Nice hot day in August (died in W Virginia).

Zerex G05 coolant.

whatudrivin

The same thing happened to RKD's GTS last year on the way to the monthly in the Dallas area. It even stayed on and would still spin when the motor cranked. You couldn't tell it was broken just by looking through the peep holes and even after it was torn apart it took a few to see it.

Mrmerlin

it would be good to know what the tension was on a Kempf tool for the older cars it should be set to the low side of the gauge for the later cars S4 to the top edge

Dave928S

It would also be good to know if routine re-torquing of the cam bolt had been carried out at intervals. Torquing of these bolts is critical, and they should be checked at intervals, because they do come loose.

Because of the narrow land on the cam and the little frictional resistance to rotation that this provides, all it takes is a little bolt stretch and rotational movement can start, which can quickly progress to hammering which fractures the cam.

RKD in OKC

On my GTS it appeared the 3 pronged hub behind the cam the key actually goes in broke causing the keyway to wear and break the cam off at the back end of the keyway. There was a lot of dirt and corrosion on the hub where it had broken so looked like it was at least cracked for some time. All the mechanics I talked to said it looked like the hub was the point of failure and probably a defective part to start with. The timing belt light had been coming on only when decelerating from speed over 130 mph. Checking found nothing wrong, but nobody pulled cam gear to check the hub.