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-   -   rebuild cunundrum (http://forums.pelicanparts.com/911-engine-rebuilding-forum/1166743-rebuild-cunundrum.html)

jello67 09-07-2024 03:28 PM

rebuild cunundrum
 
I rebuilt my engine, installed it, and had some real big unanticipated issues. The bottom line issue is that I have too much oil in the block, and not enough in the tank. Oil pressure is ok, but it's so much oil in the case that oil is getting pushed into the exhaust. I have a 7R case stamped with 76 28. I believe the oil bypass was done at the factory, as I don't have a hole or plug internal to the case. I have the right pressure relief springs and pistons (no holes in the body of them). The oil pump is new, and is a 83 and up pump. The oil tank is a newer tank (post 74). I also have the external oil cooler up front with a thermostat to send oil there when needed (not that I think this is an issue). I assumed one of the oil pump mating "o-rings" was missing, but I opened the case back up and all was good. Any ideas of what to look for would be helpful - I'm at my wits end trying to find the problem.

Flat6pac 09-07-2024 03:58 PM

I would have gone with the oil pump on the scavenge side seal being off location
What happens as you come up on the RPMs. Does oil move to the tank? Pull the oil filter to see if you have flow there off idle.
Bruce

'78 SC 09-08-2024 02:09 AM

Sounds like an obstruction in the oil scavenging circuit. Do you have the sump plate installed correctly (drain plug on driver's side, not on centerline)? What oil strainer and sump plate are you using?

+1 on Bruce's suggestion to run at different steady RPMs and note oil level at each.

stownsen914 09-08-2024 04:59 AM

When are you checking the oil level? If it's after the car has been sitting, it is normal for oil to migrate from the tank to the engine, as Flat6pac mentions. If you check while running and warmed up, oil level should be normal of course.

jello67 09-08-2024 06:15 AM

Oil does move to the tank, but not enough of it does. There's still a lot of oil in the case/block. I know the procedure to check oil hot at idle, but it doesn't really get hot. I think there's so much oil it can't get hot. I also have the oil level gauge. It always indicates low, even though I drained it and had 14 qts.....because I had kept adding to bring the level up. As far as oil strainer, the pump has a strainer, and I have an aluminum billet oil pump plate - with a drain plug.

stownsen914 09-08-2024 10:16 AM

It sounds like you may have multiple things going on. It's possible there is some kind of restriction in the scavenge side. I also think too much oil may have complicated the situation (and the troubleshooting).

How sure are you that you don't have a rag or other blockage in an oil line?

I like Bruce's idea to check the scavenge flow at idle. It should be healthy. I'd even go a step further and say you can pull the sparkplugs and use the starter to turn over the motor. This should be plenty of oomph to check for flow at the filter at the tank (which is in the scavenge circuit).

What is the longest you have run the engine? The oil has to get hot eventually. Just don't top off until it's warm. And check level at the tank (not the gauge). 14 qts is way too much.

I might check a few things like the above before starting it again.

mepstein 09-08-2024 11:52 AM

I might be reading this wrong but with 14 quarts of oil, it sounds like its been overfilled. Unless you check it hot, you won’t get a good reading in the oil level. I would drain the oil, fill it up to spec, minus about 1 quart since oil will still be in the lines and cooler, drive it until it’s hot and then check oil level at the tank. Don’t even look at the oil gauge until you know it’s correct at the tank.

Flat6pac 09-08-2024 12:58 PM

Wow, 14 quarts, no place for it to go, ‘10 qts to start, warm and top warm to mid way on stick.
Bruce

jello67 09-09-2024 05:14 AM

I 100% agree that 14 quarts is too much. My system will hold 14 if it is working properly - though - 9 for the engine and tank, 2 for the cooler lines and 3 for the front spoiler mounted Billy Boat cooler. One problem is that the thermostat to the front cooler never opened. Another problem was that after 40 minutes of sitting running to warm up (oil should be checked hot at idle - I know that), the oil was not hot. So I see the real problem as not the quantity of oil but the location of the oil. Even at 40 minutes to heat up, my tank level (at the tank dipstick) was low.

I think the blockage comment is most likely the issue - I just don't know where to look for the blockage. Oil lines were clean. Oil drained out of both engine and tank with no problem.

Flat6pac 09-09-2024 04:36 PM

But your oil lines forward of the thermostat don’t drain on engine removal

Bruce

jello67 09-09-2024 07:41 PM

The car has been down a while, and I did drain the cooler at the front - BUT - I do understand your point, and will retry with a lower level of oil, and increase as it warms up. It only makes sense.

What I still don't understand is that I tried starting with 7qts, and adding after the lower (S) hose was warm, and it still never reached a good level on the dipstick.

stownsen914 09-10-2024 03:49 AM

If you want to verify no blockage in the scavenge system, Bruce’s test to remove the filter and check for flow. He mentioned doing that at idle, but even cranking the starter should create detectable flow.

gsxrken 09-10-2024 04:47 AM

Are you using the victor reinz o rings for the oil pump? Wrightwood gaskets are highly recommended by most builders these days.


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