Engine died after speed run - TROUBLE?
06-24-2001, 01:15 PM
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Engine died after speed run - TROUBLE?
1979 SC - 82K - top end rebuild 3K miles ago and it runs great.
I did a 120mph speed run and when I slowed to a stop sign, the engine died. I pulled over and did a visual check. Things looked o.k. and restarted the car. A lot of smoke out the exhaust for 5 seconds. When the smoke cleared (literally) the car ran normal again.
What happened and what should I be checking?
Any feedback would be greatly appreciated!!
I did a 120mph speed run and when I slowed to a stop sign, the engine died. I pulled over and did a visual check. Things looked o.k. and restarted the car. A lot of smoke out the exhaust for 5 seconds. When the smoke cleared (literally) the car ran normal again.
What happened and what should I be checking?
Any feedback would be greatly appreciated!!
06-25-2001, 10:21 PM
#2
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Brink,
As I was reading your note, I was thinking it sounded like a problem that occurred in early 1978 911SC's, with the engine under load at higher RPM's, where the oil end up all in the sump, the engine would lose power and die. A few minutes later everything was OK. Porsche fixed that problem starting with engine 6282539 and 6581060, both of which were in 1978 model year by fixing the pressure relief valve. Another change was in 1980, where a new sump screen was introduced, to help picking up the oil. This was also to help prevent sudden loss of pressure under high speed driving. This is a recommended upgrade for pre-1980 911SC's, in addition to the pressure relief valve update in late 1978. This is pretty well documented in the Up-Fixin' series and the Dec 1999 Panorama.
Did you happen to notice what, if anything, your oil pressure was doing towards the end of your run? Know what your engine number is? (on a vertical bar to the right of the fan on the engine)
As I was reading your note, I was thinking it sounded like a problem that occurred in early 1978 911SC's, with the engine under load at higher RPM's, where the oil end up all in the sump, the engine would lose power and die. A few minutes later everything was OK. Porsche fixed that problem starting with engine 6282539 and 6581060, both of which were in 1978 model year by fixing the pressure relief valve. Another change was in 1980, where a new sump screen was introduced, to help picking up the oil. This was also to help prevent sudden loss of pressure under high speed driving. This is a recommended upgrade for pre-1980 911SC's, in addition to the pressure relief valve update in late 1978. This is pretty well documented in the Up-Fixin' series and the Dec 1999 Panorama.
Did you happen to notice what, if anything, your oil pressure was doing towards the end of your run? Know what your engine number is? (on a vertical bar to the right of the fan on the engine)
06-27-2001, 01:15 PM
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Bill:
Yes, the oil pressure dropped to 1 (bar?) when the engine was around 2500 RPM. At this RPM, the engine is usually at 5+ (bars).
The engine number is 6290763
Thanks for the information in your reply, it gave me a lot to go on.
Brian
Yes, the oil pressure dropped to 1 (bar?) when the engine was around 2500 RPM. At this RPM, the engine is usually at 5+ (bars).
The engine number is 6290763
Thanks for the information in your reply, it gave me a lot to go on.
Brian
06-28-2001, 12:49 AM
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Brian,
I ran across another reference. It's a Bruce Anderson answer in Up-Fixin Vol 9 regarding sudden oil pressure drops in a 1978 SC.
In it he says: "There was a technical bulletin concerning this problem over ten years ago, July 12, 1979. The fix was a venturi-like sump pickup around the oil scavenge pump pickup, part number 930.107.314.00. In 1980 they introduced a fix in conjunction with the new model using this new venturi sump pickup. You should be sure that your car has this fix." He also describes the oil bypass piston upgrade to 1978 SC's.
Then he says "My opinion is that the venturi pickup is the solution for the oil pick-up problem, but it won't hurt to change both the bypass pistons as well." (Based on your engine serial number, your engine already has the bypass piston update) and "Since you did mention a recent oil change, there is another possibility. It is possible to get the oil sump cover on incorrectly and the drain plug can obstruct the oil pick up tube, creating similar problems".
I ran across another reference. It's a Bruce Anderson answer in Up-Fixin Vol 9 regarding sudden oil pressure drops in a 1978 SC.
In it he says: "There was a technical bulletin concerning this problem over ten years ago, July 12, 1979. The fix was a venturi-like sump pickup around the oil scavenge pump pickup, part number 930.107.314.00. In 1980 they introduced a fix in conjunction with the new model using this new venturi sump pickup. You should be sure that your car has this fix." He also describes the oil bypass piston upgrade to 1978 SC's.
Then he says "My opinion is that the venturi pickup is the solution for the oil pick-up problem, but it won't hurt to change both the bypass pistons as well." (Based on your engine serial number, your engine already has the bypass piston update) and "Since you did mention a recent oil change, there is another possibility. It is possible to get the oil sump cover on incorrectly and the drain plug can obstruct the oil pick up tube, creating similar problems".