no oil pressure
10-22-2013, 05:55 AM
#16
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William, I checked the crank bolt and it was tight. Just to be safe, I loosened it and retorqued it to 155 lb-ft.
Kev, how are you? I never took the oil pump off. This is a used motor straight from a wrecked car. I only touched the top-end. I don't know if it needs to be primed or not.
Kev, how are you? I never took the oil pump off. This is a used motor straight from a wrecked car. I only touched the top-end. I don't know if it needs to be primed or not.
10-27-2013, 07:23 AM
#17
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I think the pump is primed, and the pickup is OK.
I tried some priming methods tonight. I made a "fitting" made of silicone and vinyl hose that fits into the hole at the filter stand that comes from the oil cooler (coming from the pump), and pulled a vacuum on it to try to get any air out. It began to pull oil. And when there was oil in my tube, I tried turning the crank clockwise and the oil level went up momentarily. I turned counterclockwise and the level in my tube went down momentarily. Seems like the pump is working (?).
I tried pouring oil into the center hole of the filter stand (going to the crank) and turned the crank (CW, then CCW).
Cranked it over again, with oil filter off... no oil flow at all.
I figured, WTF, so I took off the oil pan. Only took me about 3-4 hours. The pickup tube looks fine, but it's covered in dark residue so I'm going to clean it tomorrow and inspect it closely. The o-ring looked ok but had some flaky black residue on it - maybe it was leaking. There was some milkshake in the pickup screen and at the bottom of the oil pan...
I don't know what else it could be... I'm going to try using a clear jug as an oil sump, and cranking it with the starter to see if oil gets sucked up at all. Could it be a failed oil pump? I don't think I've ever heard of a bad 944 oil pump.
I tried some priming methods tonight. I made a "fitting" made of silicone and vinyl hose that fits into the hole at the filter stand that comes from the oil cooler (coming from the pump), and pulled a vacuum on it to try to get any air out. It began to pull oil. And when there was oil in my tube, I tried turning the crank clockwise and the oil level went up momentarily. I turned counterclockwise and the level in my tube went down momentarily. Seems like the pump is working (?).
I tried pouring oil into the center hole of the filter stand (going to the crank) and turned the crank (CW, then CCW).
Cranked it over again, with oil filter off... no oil flow at all.
I figured, WTF, so I took off the oil pan. Only took me about 3-4 hours. The pickup tube looks fine, but it's covered in dark residue so I'm going to clean it tomorrow and inspect it closely. The o-ring looked ok but had some flaky black residue on it - maybe it was leaking. There was some milkshake in the pickup screen and at the bottom of the oil pan...
I don't know what else it could be... I'm going to try using a clear jug as an oil sump, and cranking it with the starter to see if oil gets sucked up at all. Could it be a failed oil pump? I don't think I've ever heard of a bad 944 oil pump.
10-27-2013, 08:49 AM
#19
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Yes, I'm pretty sure. The oil goes from the pump, to the OPRV, to the cooler/thermostat for the external cooler, outside of the oil filter, inside of the oil filter, oil pressure sending unit, into the block.
10-27-2013, 09:23 AM
#20
Proprietoristicly Refined
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10-29-2013, 04:09 AM
#21
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I took off the oil pan and removed the pickup tube. It looks OK, but I'm going to vacuum test it. If it's bad, I have a couple of used spares.
The pickup tube seal looked bad. I'll replace the seal and put the pan on with a few bolts, fill with oil, and fast crank with the filter off to see what happens.
The pickup tube seal looked bad. I'll replace the seal and put the pan on with a few bolts, fill with oil, and fast crank with the filter off to see what happens.
10-29-2013, 10:45 AM
#23
... so we took the (951) engine out, and we thought we'd put in an NA engine meanwhile, just so we could drive the car.
I did some stuff to the NA engine before putting it in - head gasket, oil cooler seals, belts and rollers.
I got it started today, and there's no oil pressure.
I did some stuff to the NA engine before putting it in - head gasket, oil cooler seals, belts and rollers.
I got it started today, and there's no oil pressure.
10-30-2013, 08:03 AM
#24
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Coming in late here. Counter intuitive to me at least but on my last failure to prime situation on a 84 944 N/A engine, I found that that oil does not come out of the center post of the the oil filter mount, rather it comes out of what looks like the oval "drain" outside of the center post. I was sorta shocked to see this so it has stuck in my memory.
I will try and verify this fact this coming weekend, when I am back in my shop.
So if this is indeed the case (and I can't be sure all engines are the same but suspect so) then when we prime the oil pump we need to be pouring the oil down into the oval opening.
Your plan to put a clear jar of oil over the pickup and rotate the crankshaft (by hand I presume?) sounds like a good test. Rotate the crank clockwise, looking at the front of the engine towards the rear.
I will try and verify this fact this coming weekend, when I am back in my shop.
So if this is indeed the case (and I can't be sure all engines are the same but suspect so) then when we prime the oil pump we need to be pouring the oil down into the oval opening.
Your plan to put a clear jar of oil over the pickup and rotate the crankshaft (by hand I presume?) sounds like a good test. Rotate the crank clockwise, looking at the front of the engine towards the rear.
10-30-2013, 01:33 PM
#25
" I found that that oil does not come out of the center post of the the oil filter mount, rather it comes out of what looks like the oval "drain" outside of the center post. I was sorta shocked to see this so it has stuck in my memory". - Harvey
This is why it is important that we use a quality oil filter with a good check valve. Otherwise the oil that is above that point will drain back into the sump over a period of time (as in overnight). I think the resulting consequences of this is worth the few extra bucks.
This is why it is important that we use a quality oil filter with a good check valve. Otherwise the oil that is above that point will drain back into the sump over a period of time (as in overnight). I think the resulting consequences of this is worth the few extra bucks.
10-30-2013, 03:04 PM
#26
Burning Brakes
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I am going through this for a second time with my S2. I believe in my case the problem is the oil pump is not properly sealed to the block as the system was always loosing its prime and would take 30 seconds or more to build oil pressure on cold start up and then as it got to a higher operating temp the oil pressure would drop to 1 bar at idle.
If the oil pump is not properly sealed to the block with Loctite 574 it will suck air and not circulate the oil and possibly never prime. Resealing the pump may be something else to consider especially if you already have the oil pan off.
If the oil pump is not properly sealed to the block with Loctite 574 it will suck air and not circulate the oil and possibly never prime. Resealing the pump may be something else to consider especially if you already have the oil pan off.
10-30-2013, 08:56 PM
#27
Burning Brakes
+1^
Also, the seal on the cradle / girdle ( oil pressure side) can cause the same problem if there is no more loctite left to seal ..... very rare to find though.
Also, the seal on the cradle / girdle ( oil pressure side) can cause the same problem if there is no more loctite left to seal ..... very rare to find though.
10-31-2013, 10:27 AM
#28
Drifting
I found out the hard way that they changed oil pumps throughout the years.
If there was a rebuild AND they used a pump from a different year -- then the
mating surfaces don't match against the block and no matter what you
do you will not get primed/suction.
Note there is no way to tell from the outside -- they look the same -- you have
to pull the pump and compare to one that is the same year
or look at the surfaces and see that they match.
M
If there was a rebuild AND they used a pump from a different year -- then the
mating surfaces don't match against the block and no matter what you
do you will not get primed/suction.
Note there is no way to tell from the outside -- they look the same -- you have
to pull the pump and compare to one that is the same year
or look at the surfaces and see that they match.
M
10-31-2013, 02:12 PM
#29
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Referring to the Tech Sheet for Locktite 546 here:
http://www.loctite.sg/sea/content_data/93789_574EN.pdf
"The product is designed for close fitting flanged parts with
gaps up to 0.25 mm."
That works out to 0.010". Take away message is that all the sealing surfaces need to be pretty much spot on. Which brings to mind one engine rebuild where couldn't get a prime and found that the front edge of the girdle was sitting proud of the front edge of the block. The oil pump seats over this interface. The difference in the 2 surfaces was easily felt with my finger and I suspect if was beyond 0.010". I took the girdle off and started over and met success the next time. Could have been this, could have been something else.
Not to hijack the thread but the Tech Sheet also specifies limits on storage temperatures for the product:
"Storage below 8 °C or greater than 28 °C can adversely affect product properties."
Crap, a range of 46 deg F to 82 deg F! Really? I can't imagine that some of this product sees temps well above/below those numbers during shipping or storage in warehouses. Not sure what to do about that?? Only buy it in the spring or fall and store it your wine cellar along with the Lafite Rothschild?
http://www.loctite.sg/sea/content_data/93789_574EN.pdf
"The product is designed for close fitting flanged parts with
gaps up to 0.25 mm."
That works out to 0.010". Take away message is that all the sealing surfaces need to be pretty much spot on. Which brings to mind one engine rebuild where couldn't get a prime and found that the front edge of the girdle was sitting proud of the front edge of the block. The oil pump seats over this interface. The difference in the 2 surfaces was easily felt with my finger and I suspect if was beyond 0.010". I took the girdle off and started over and met success the next time. Could have been this, could have been something else.
Not to hijack the thread but the Tech Sheet also specifies limits on storage temperatures for the product:
"Storage below 8 °C or greater than 28 °C can adversely affect product properties."
Crap, a range of 46 deg F to 82 deg F! Really? I can't imagine that some of this product sees temps well above/below those numbers during shipping or storage in warehouses. Not sure what to do about that?? Only buy it in the spring or fall and store it your wine cellar along with the Lafite Rothschild?
10-31-2013, 02:28 PM
#30
Burning Brakes
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Next question what methods have people used to get the block mating surfaces clean and free of old locktite prior to remounting. I used permatex gasket cleaner on the actual pump and after several applications and very careful passes with a blade the pump is clean but I am afraid of going to town on the block with this stuff since the engine is still in the car and I am thinking the over spray will do damage to other stuff nearby like hoses the water pump nipple etc. I was thinking of masking everything off but I am sure there is a better approach.