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Running out of options: Rebuilt engine-no oil pressure :(
Last night I was finally ready to start my rebuilt engine after 7 months of almost constant work. In order to build some oil pressure I ran the engine on the starter with no DME relay and no spark plugs for a few revolutions. Shock of all shocks: no oil pressure. I pulled the filter and found the filter housing dry. No oil at all.
I have 7.5 liters of oil in the engine and I have checked the crank shaft bolt. I tried to prime the oil pump by pouring oil down the centre hole in the filter housing and manually turning the engine counter-clockwise. The oil was sucked back down but it still does not build presure. I then pulled the OPRV which was dry as a bone. I tried to turn the engine over with no OPRV, but no oil came out. What now? I am out of Ideas and do not dear to try to crank it over to build pressure. Do I have to pull the engine again? I hope not as I'm running out of time, money, friends and patience
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1990 944 T: 100 000 km/63K miles, 1997 986 2.5L: 95 000 km/60K miles, Living in the trackless land of plenty! |
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What did you do during the Rebuild? Did you put the gasket/o-ring for the pickup tube in? How many cranks did you give it? SOme times it takes a while to build pressure on a totally dry rebuilt system
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1986 951, Stock for now. ]87 924S Gaurds red- SOLD after 11 years of ownership |
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Toofah King Bad
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+1, keep cranking, you'll get it. You packed the pump with assembly lube, yes?
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» 1987 924S Turbo - Got Boost? « "DETERMINATION. Sometimes cars test us to make sure we're worthy. Fix it." - alfadoc |
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I vaguely recall another thread, same problem where the crank-cam gear was installed backwards and caused the problem?
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Architect / Car Guy
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Start the car.
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Looking Forward to getting my First "car" Porsche 951 |
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Thanks for your suggestions.
@fast924S: How long do you suggest to keep cranking? I didn't time it but I would guess the longest try must have been around 20 seconds. Yes I put the gasket on the brand new pickup tube. @mikepellegrini: Crank sleeve is in the right way. I distinctly remember putting it in and taking care not to damage the seal. @Rasta Monsta: No I did not pack the pump with assembly lube. This is not a complete rebuild, more like a major overhaul. I did not open the pump. I simply took it off the engine and put it in a plastic bag. Then cleaned the surfaces to be glued and stuck it back on. I think I've seen somewhere that one can prime the pump by using compressed air to pressurize the crankcase through the dipstick tube. Is this possible? Is there any way I can provide some more lubrication to the journals and cam before i continue cranking it? I'm worried that the assembly lube will wear off if I continue cranking.
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1990 944 T: 100 000 km/63K miles, 1997 986 2.5L: 95 000 km/60K miles, Living in the trackless land of plenty! Last edited by bebbetufs; 06-26-2010 at 02:12 PM.. |
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Quote:
Trouble getting oil pressure on new motor - Rennlist Discussion Forums 10psi to dipstick while cranking to get oilpressure
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Looking Forward to getting my First "car" Porsche 951 |
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On my S2, it took me 10x removing the oil filter and filling up the center hole with oil and manually turning the crank CCW to get oil pressure with the DME relay out and no spark plugs.
I had to recharge my battery once. You will get oil pressure, just keep priming. If you put assembly lube on the bearings, you are good. Just keep on priming.
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1993 964 C2 still makes me smile Retired and work as needed as a pain in the **s. |
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Quote:
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Looking Forward to getting my First "car" Porsche 951 |
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Quote:
On a newly rebuilt engine with the oil passages empty, it will take a while to prime it. You have to remove oil filter, put a funnel on the center hole, pour oil, manually turn the crank CCW until it stops sucking oil, put the oil filter back in, then start the car with no DME relay and no spark plugs. If you don't get oil pressure after 3 starts, repeat the manual priming. I had to do this for like 10x before oil pressure registered on the oil pressure gauge.
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1993 964 C2 still makes me smile Retired and work as needed as a pain in the **s. |
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I have trouble seeing how putting pressure down the dip stick tube can do anything. The air simply escapes through the crank case breather hose.
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1990 944 T: 100 000 km/63K miles, 1997 986 2.5L: 95 000 km/60K miles, Living in the trackless land of plenty! |
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You def need to do it longer then 20 sec, if you put assembley lube on everything youll be fine since it wont wash away till the fresh oil cleans it off, it took me about 5min of crankin to get pressure and I never used the air pressure trick or filled the center tube.
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It takes a long time to build pressure. But no, don't start it till you do.
Just keep cranking, and boosting that battery.
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Vaughan Scott http://www.vaughanscott.com http://www.924.org |
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Keep cranking - on my recent rebuild it took quite a bit of cranking to build oil pressure the first time.
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Some time ago I replaced the rod bearings. I decided to build up the oil pressure by cranking the engine with dme out and spark plugs out so it would crank faster. I cranked for what seemed an eternity with the oil pressure never coming up. Finally, I said to myself, "---- it" and replaced the dme and spark plugs. I turned the key. It started immediately, and the oil pressure came up very quickly. Maybe I was lucky. That was 9 years ago. Obviously there was no harm done. "Your results may vary."
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Lawrence 1986 951 2002 SLK32 AMG 1987 328GTS 2011 528i |
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Thanks guys. I finally got pressure after priming the pump several times with 50W oil. I opened the plugs on the cam tower and squirted lots of 50w oil directly onto the cam lobes and lifters. After all the priming it didn't take much cranking. I'm really happy about it and everything seems smooth and quiet.
Only problem now is I can't get her to start up. I'll do some searches and see what I come up with. Just a quick question first, will swapping the speed and reference sensors prevent the fuel pump from working? Looking forward to going for that first summer drive.
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1990 944 T: 100 000 km/63K miles, 1997 986 2.5L: 95 000 km/60K miles, Living in the trackless land of plenty! Last edited by bebbetufs; 06-27-2010 at 10:28 AM.. |
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[QUOTE=bebbetufs;5426236]
Only problem now is I can't get her to start up. I'll do some searches and see what I come up with. Just a quick question first, will swapping the speed and reference sensors prevent the fuel pump from working? QUOTE] Swapping sensors has no effect of the fuel pump. You must connect the sensor cables correctly. You have to connect the correct sensor to the correct plug at the top rear of the engine.. Speed and Reference Sensors - Checking, Replacement, and Adjustment Have you tried a new DME/fuel pump relay or jumper to ge the fuel pump working? DME Relay Information and Testing Does the tach bounce at all when you grind/starter engaged the engine? GL John
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1988 924S, 85,750K ..+ 1987 924S, 154K DD (+15K est. bad odo) Last edited by John_AZ; 06-27-2010 at 01:34 PM.. |
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Thanks John.
Fuel pump runs when jumpered but not when cranking on starter. I swapped the speed and reference sensors (labels on cables unreadable). I had tach bounce the way they were before swapping, but I cannot get tach bounce after swapping them back again. I suspect that the dried up cable has broken when I moved them around. (I have already bought one new sensor because of a broken cable). I will get a reading with an oscilloscope tomorrow.
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1990 944 T: 100 000 km/63K miles, 1997 986 2.5L: 95 000 km/60K miles, Living in the trackless land of plenty! |
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I rebuilt my engine; primed the system; and it ran for several minutes. Like 5 minutes. Oil pressure excellent. I sprung a leak on the edge of the oil pan. I lost oil pressure again. What's happening??? I'm going to try removing the plugs and cranking..... What else can i DO???
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