Is this even possible?????
 

I’ve narrowed down my overheating problem in my 85 Euro 930 to timing.

I checked my timing today after the car was running hot. This is what my timing light read:

1000 RPM 7 degrees BTDC
2000 RPM 0 degrees BTDC
3000 RPM 6 degrees BTDC
4000 RPM 5 degrees BTDC

Is this even possible? Isn’t timing supposed to increase with RPM’s? Apparently I have a very serious problem at hand. Is this an issue with the distributor-timing curve?

Any help would be greatly appreciated.

:rolleyes:

This is why your engine is heating up. You need to check out your advancement mechanism or you could burn a hole in the top of your pistons.

Steve

Actually Turboruf doesn't have enough timing, it's too much timing that causes pistons to burn. However this is most likely the reason for the overheating problem because as rpms increase the engine is firing late and therefore allowing excess heat into the exhaust port, manifolds, etc. Late firring ignition overheats the exhaust side of the head first and eventually the rest of the engine through conduction of heat.

I would remove the distributer cap an check to see if the mechanical advance is frozen, you should be able to move the rotor 10-15 degrees with relative ease, if it can be rotated or is very hard to rotate then it is stuck.

How about putting the unit in a distributor machine and checking it out at the various RPM's? Sure makes it a lot easier to do then you can stick it back in the motor and be positive of the advance curve.

Joe

Thanks for the information everybody.

This is a used twin-plug distributor that I picked up a while back but I never had it fully tested. I will pull the cap to see if I can manually advance the rotor. If it's stuck, how easily can it be repaired? Would a dealer have a distributor machine to check for proper advance?

If it isn't stuck, what else could be wrong?

SmileWavy

Usually the older shops have the distributor machines. Most dealers are parts changers and would not have one. Call around to the older performance shops and see if you can find one.

Joe

I pulled off the distributor cap today and checked to see if I could manually advance the rotor. I was able to rotate it counter-clockwise roughly a quarter inch. When I let go of the rotor it would spring back into place. Does this indicate my mechanical advance is working correctly? The rotor will not move clockwise.

I decided to test my retard and advance vacuum canister ports with a mity-vac. What I discovered is that my advance port works when I apply vacuum. I can visually watch the internal parts rotate (sorry, can’t be more specific).

When I apply vacuum to the retard port, it does nothing. Nothing moves, it just holds vacuum. Would this cause the engine to overheat?

Try putting pressure in the dist. pot. See if the mechanisum moves with pressure. Do you have the factory timing spec.? If so follow the manual for setting the timing. The factory manual tells you how to check the dist.

Blown,

It was set to 25 degrees at 4000RPM. This was after the engine was warm with both vac lines plugged.

Is that the spec.? I thought it was 29 degs. at 4000. Do you have the manual? You can check out the workings of the dist. on the car without a dist. mach. if you read the manual.

I think you total timing is retarded a little

>Is that the spec.? I thought it was 29 degs. at 4000. Do you >have the manual?

The 25 degree at 4000RPM spec. was recommended by a few turbo experts due to my engine modifications.

>You can check out the workings of the dist. on the car without a >dist. mach. if you read >the manual.

Can you elaborate on this?

Is the retard pot supposed to operate on pressure or vacuum?

Thanks

Okay, confusion lies here. Do you have a twin plug setup, or not? You said you did, but the photo shows a single plug system.

Total advance should be reduced with a twin-plug setup...

-Wayne

Sorry Wayne... the photo was for illustration purposes only. :rolleyes:

This is a picture of my distributor:

I don't know about your year but to check out the dist. You need the manual and a timing light and a vacume gauge. Follow the procedure in the factory manual.

The pot on my 75 930 has only one port and it is a vacume retard. I read that some 930 retard on boost as well as vacume.

I don't think timing is the cause of your overheating problem. Have you checked your mixture?

CO was set to 3.5%, so I don't believe it’s a mixture issue.

The distributor is a used unit and I never had it fully tested. The seller insisted it was in perfect working order. When I received the distributor it looked almost new. So I never had it tested, something I should have done.

Does anybody have an 85 930 workshop manual?

I have the factory manual. I think it covers your year.

Blown,

Can you scan and email the timing section for my year? I would greatly appreciate it.

I can't scan but I could fax the pages. What do you want? E-mail me with your fax #