My engine runs rough since I had timing belt pulley failure. I was getting misfire error codes, but after I replaced thermostat and temp. sensor (It was a separate problem with constantly running fan) the CEL and error codes mysteriously disappeared and never came back. However, misfire-like behavior still remains, as it was since the day the car came back from the shop, after timing belt job. The engine performance is fine, I would not bother with it, but I my gas mileage deteriorated tremendously since the timing belt failure happened. I am getting 15 – 17 miles per gallon of premium gasoline. I was getting 28 – 30 miles before it happened. So I think I have bent valve(s) and think to swap the engine head. My car is 98 S70 with T5 engine. The head came from 1995 850 turbo. Would this head fit to my engine block? In a separate question, has anyone replaced valves? What kind of special tools do you need? Thanks a lot!

 

Did the timing belt break before gong to the shop? These engines are no-tolerance and will grenade if the timing belt breaks.

 

No, it did not break. But it apparently jumped over few teeth off camshaft pulleys. The marks on camshaft sprockets were off when I took off plastic cover. The cover was ripped from inside.

 

Just did a t5 that jumped a couple teeth. I pulled the head off and took it to my machine shop and let them go through it. When the car jumped time, it slapped all the intake valves against the pistons. they slapped to hard they gouged valve marks in the top of the pistons. Pretty straight forward job, biggest problem I had was the head bolts were seized in the block (steel w/aluminum and no anti-seize...) I broke 3 craftsman 14's and one impact socket getting the damn things out. Once I got through that I was ok.
The other problem I had was once I got the head off, I found every last vacuum line and piece of rubber in the engine bay was complete garbage. Some of that stuff would have been nearly impossible to see or fix with the intake and head on.
Price wise I spent $500 redoing the head with 10 new valves, and another 500 on hoses, lines, motor mounts, etc. First time doing the job, it took a day to take it apart and a day to put it back together.
That was my experience with it, I think the best thing you could do for yourself is run a compression check and see what you get from that first.
P