How to bend 4 valves without a snapped t-belt and proper timing
 

Story time....

I recently managed to bend 4 valves just 30 miles after picking up my 944 mechanic. Timing belt is intact and timing marks are dead-on. How did I do it?

I recently dropped off my car at the mechanic due to a popped coolant expansion tank hose. Mechanic calls me up and says he thought he had it fixed but it is now spurting out oil on the exhaust side between the head and the cam tower. This is not a small leak but one which will drain a quart of oil every 10 minutes. He suggests we tear down the cam tower to check the head and see what happened. He asks me how hot the car got...I told him it didn't even get to the red and I didn't drive more than 1/4 mile with it at elevated temps.

I get a call 2 days later. Car is ready! (w00t!) Head was fine....threads in the head holding cam tower bolts....not so much. He time-serted 6 threads for cam tower bolts. A moderate size bill and I'm back in business...for 30 miles.

I'm literally a mile from home, accelerating normally at about 3500 rpm when I hear a pop, metallic bang, and then a sound I can only describe as "expensive." I didn't even try and restart it, figuring I had just popped the timing belt. Looking under the hood through the distributor housing inspection hole and the timing belt had proper position and still looked to have perfect tooth engagement. I had the car towed back to the mechanic and he called me later that day saying he was puzzled. The belt had not snapped and the timing marks were all correct, yet I had no compression on 3 cylinders. His theory was that a valve seat may have dropped into one cylinder, had fragments break apart, and been sucked into the other cylinders causing damage. The head needed to come off and he told me not to worry about the cost for that.

Fast-forward 2 days and he calls me. He says he needs some time and I thought he was talking about the tear-down. He was talking about the repair and issued his profuse apologies as he had solved the mysterious failure. It turns out he had forgotten to torque one of the interior cam tower bolts. It backed out and managed to lodge itself into a cam lobe. Here's the tricky part, it didn't stay lodged in there. It wedged into the cam lobe just long enough to result in 4 bent valves but not long enough to overstretch and snap the belt. So basically the head needs to be redone, the cam tower has a chunk taken out of it, and the cam is toast. Mechanic is covering everything.

That's some bad luck.
I'm glad to hear he's covering it. Would have been easy for him to try to blame something else.
Will he clean out the oil pan of metal fragments and change the oil too?

Yea that sucks, but, any good honest mechanic will cover his mistakes and come clean about it.......
Imo mistakes do happen, it's at those times you find out what people are made of.......
I'd give him reasonable time to correct his mistake, he probably still needs to do some paying jobs to put food on the table......

If my mechanic forgets to torque a very important internal engine bolt, I will not trust any engine work from him. I will be worried whenever I take my car out for a drive. :D

Man, rough to make a mistake in that line of work!

I'm not mad and I've used this mechanic for over a decade and never had anything which required a repeat visit. Last time I was in his shop he had a 250,000 mile 944 in there. If anything, I'm just frustrated because I seem very unlucky with cars lately. In the last 4 months I've been towed 6 times between both cars. So I'm just getting tired of what seems like horrible luck with both cars.

+1 bell I think LAdy Luck is on your side. An honest mechanic is golden IMO. I work on my car in company of The German from ******** and he's a detail freak so he watches me like a hawk whenever we wrench. Sounds like you'll be alright other than the no P-car situation for awhile. Good luck getting this sorted out!:)

Wrenching on your own stuff is therapeutic. It's not hard.

he probably torqued the cam tower with the cam in the wrong position and the engine on tdc.

The gig is that you need to be at least + or - 45 degrees (90 would be the safest) from TDC on the crank, if you are bolting on the tower or moving the cam around. Once the cam is aligned, THEN bring the crank in to TDC.

Everyone makes mistakes. This guy's honest enough to admit it and man enough to cover all of it at his own expense. You know how rare that is?