M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: KenC on October 25, 2007, 09:46:36 PM
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So evidently hot carbon build up got onto my valve seats on the exhaust side and bonded to them when it cooled, thus not allowing the exhaust valves to seat properly - compression not high enough for combustion.
So the valve seats on the exhaust side need to be reground.
A local shop wants $350 to regrind the exhaust seats, install new valve guides, and new seals. Is this a fair price? Seems pretty steep for one side...
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If you're doing the R&R on the head, I'd just go ahead and do the valves myself. If this is the only thing wrong, that would be a real low cost repair. The carbon is softer than the valves and can be cleaned with chemicals or a soft wire brush. Use a wooden stick with suction cup and valve grinding compound to reseat the valves. New seals, gaskets, etc. I learned how to do this in high school shop class - yes, it's true. I was a "hood" (short for hoodlum) in high school in the late 50's. Chicago Box Car haircut, Levis with a four inch cuff, and white cotton t-shirts with a pack of regular Camels rolled up in the sleeve.
But I digress.
It depends on the overall condition of the engine and the source of the carbon buildup. If it's from a lot of short trips at low RPM that's one thing. If it's from excessive blow by past the rings that's another....
The price sounds high by about $100 but if it's new valves with the guides it's OK. realoem says the guides are discontinued. They may be upgraded to the smaller later model valves.