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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
Posts: 3,776
Originally Posted by hoyabear View Post

I seem to have a similar build to you, and I believe I also have a similar problem

I see that your car is also running hot. Mine runs about 8:30 cruising on a cool day, 9:00 if caught in traffic on a cool day, and will easily get up to 10:00+ if it is hot out and I'm in traffic.

This is definitely running WAY hot for a 930 and needs to be dealt with. I also had a previous problem with oil going past the turbo seals (Bruin had PM'd me discussing a similar problem the PO of his car had with turbos), in the end I found out that it wasn't the turbo's fault. The issue was, the car was running so damn hot that the oil would hit the turbo and coke up into little bits. These bits would then get stuck in the scavenge line right before the pump, blocking the return of the oil. The oil would then back up in the turbo and go through the seals causing a huge amount of smoke.

I've solved the first problem by implementing a service regimen that involves checking the return line for blockage every 500 miles. Now, to get at the root cause of the problem, high operating temps, I have to do some more work:

My car is an 86 and didn't come with a fan for the right front oil cooler, with the modifications that have been done, I don't think the stock cooling system can keep up. I think that adding a fan may be enough to do the trick. If not, I will look to put on a big center mount oil cooler ($$$) in addition to this and if that doesn't solve the problem, there are some other places to look (although I will be fiddling with some of these variables as well over the summer).

Another angle to consider is ignition timing, if it isn't set right the car can run hot. I just put in a programmable MSD, so screwing around with timing is on the agenda anyway.

AFRs (to a lesser degree) are also a concern, do you know where your car stands in this respect? Right now I have my car running on the rich side to be safe (running lean car cause a car to run on the hot side), but I am going to tune this so that it is optimum, along with the ignition, as soon as I get a chance.

Hope this helps, if anyone else has some thoughts, please chime in!
Timing...yes, too retarded will heat things up. Do you know for sure that your timing is advancing when the vacuum to the distributor goes away as the throttle opens...and that your mechanical advance is working?

I don't hear (and not sure I ever have heard) my oil cooler fan turn on (will have to check that it's functioning some day). I run about 14.2 AFR at cruise and about 12 degrees more advanced timing than stock, and usually don't get much hotter than 8:00 or maybe 160-170 degrees.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 05-28-2010, 04:04 PM
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