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| Oil Pressure Issues https://slantsix.org/forum/viewtopic.php?t=28939 |
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| Author: | polara pat [ Wed May 14, 2008 11:03 am ] |
| Post subject: | Oil Pressure Issues |
My new motor is having issues, which is expected but this is a new one to me. I fired it up this morning to find no oil pressure for over a minute...bad. I fired it again and held some throttle which worked but once pressure started reaching 40# the motor labored and died. I did this two more times with the same results and now I'm here. One thing I did do was tighten the large bolt on the oil pump, the one opposite the sending unit. It had a steady drip. Thanks for any advice, Pat |
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| Author: | polara pat [ Wed May 14, 2008 1:11 pm ] |
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Nothing huh, well I couldn't wait anymore for a response so I attacked with elbows deep. It seems that my park adjustment is a little off so it's partially engaged in "P". I did the same test as above in neutral and it made oil pressure but is running poorly. I'm in the process of rebuilding my BBD so I have a different known good one on. While hot I adjusted the valves, running of course. The engine rocks like crazy and when I put it in gear it dies. |
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| Author: | SlantSixDan [ Wed May 14, 2008 1:13 pm ] |
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This what you're calling a "large bolt" on the oil pump is actually the oil pressure regulator valve access cap. I can't explain your "reaches 40 pounds, labours, and dies" symptom — that's a strange one. But low/no pressure on startup suggests a significant internal oil leak (e.g. a stuck-open oil pressure regulator valve), blockage of the oil pickup screen, and/or an air leak on the intake side of the oil pump (cracked pickup tube, for example). |
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| Author: | polara pat [ Wed May 14, 2008 1:22 pm ] |
| Post subject: | |
Quote: This what you're calling a "large bolt" on the oil pump is actually the oil pressure regulator valve access cap. I can't explain your "reaches 40 pounds, labours, and dies" symptom — that's a strange one. But low/no pressure on startup suggests a significant internal oil leak (e.g. a stuck-open oil pressure regulator valve), blockage of the oil pickup screen, and/or an air leak on the intake side of the oil pump (cracked pickup tube, for example).
Upon further investigation I realized that it was not making pressure in gear. Does that make sense in any way? I don't think it does. Could I have damaged the oil pressure reg valve by over tightening the access cap? or does it even contact the valve? Thanks for helping to chip away at ideas. If all else fails I may have to drop the pan tomorrow. What kind of pressure should I be seeing at idle, in neutral, hot? |
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| Author: | Doc [ Wed May 14, 2008 1:34 pm ] |
| Post subject: | |
Quote: What kind of pressure should I be seeing at idle, in neutral, hot?
45 to 55 psi.I would remove the oil pressure releief valve "cap" (the large bolt you tightened) and pull-out the relief valve & spring for inspection and cleaning. Once the cap is off, you will pull-out the spring and the valve should slide right out. You may need to sand it's OD with some fine sandpaper, clean and reinstall. Reach in with your little finger and slide the valve up & down it's bore, is should move freely. Reinstall the cap, restart and re-check for the correct oil pressure. DD |
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| Author: | SlantSixDan [ Wed May 14, 2008 1:35 pm ] |
| Post subject: | |
Quote: Upon further investigation I realized that it was not making pressure in gear. Does that make sense in any way?
Not per se, no — the engine oil pump has nothing to do with the transmission status. But, when you put the car into gear the engine speed will drop a couple hundred RPM, and if (as sounds to be the case) you have a problem with the engine oiling, the reduced engine speed means slower oil pump speed, which means the problem becomes...a bigger problem.Quote: Could I have damaged the oil pressure reg valve by over tightening the access cap?
No. But it will be worth your while to remove the cap and the spring underneath it, then remove the valve shuttle, inspect it for burrs or dirt, and generally service it as described in these two threads: thread 1, thread 2. Is this a new oil pump? Used? Rebuilt? What's on it for a filter? What's on it for a filter fitting (the threaded central tube the filter screws onto)? Quote: What kind of pressure should I be seeing at idle, in neutral, hot?
At least 10 pounds. What grade oil are you using?
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| Author: | polara pat [ Wed May 14, 2008 1:56 pm ] |
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O.k. I'll service the pump. It is the pump off of my old slant that has maybe 3000km on it, tops. It is the one without the tall stand pipe though. I changed the oil after the cam break-in and I'm running 10w30 with a Wix 51515 filter. |
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| Author: | vynn3 [ Wed May 14, 2008 2:02 pm ] |
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Did you use a brand new oil pump with your rebuild? If so, did you have Doc blueprint it for you? (Sorry, just read your last post.) I had a similar problem with my new engine. Brand new Melling pump, but I didn't know about Doc's rebuild service, so I just packed it with vaseline. Lost pressure after a few hours of use. Turned out to be the pump gear (which is press-fit these days, BTW), which had loosened and was spinning on its shaft. I had to replace the pump, but this time I had a local muffler shop place a few spot-welds on the gear where it meets the shaft. Hope you don't have the same problem. Replacing the pump with the engine in the car was a PAIN. |
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| Author: | Aggressive Ted [ Wed May 14, 2008 2:31 pm ] |
| Post subject: | |
If your worried about drain back with that low stand pipe grab a Wix 1806 next time. It has the tall standpipe built in. I get an instant 50 pounds on start up with 0-30W Mobil 1. Don't use synthetic on break in, just an example of what mine is doing after a 25,000 mile break in with Dino oil. |
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| Author: | LUCKY13 [ Wed May 14, 2008 4:46 pm ] |
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If you dont have a machanical oil pressure gauge hooked up I would do so. The old electric unit could be giving you false readings and on a new engine startup that is something you cant afford to not know the truth about. Oil pressure dropping when you put the trans in gear could just be from the engine running slower as meantioned , or it could be a wiring problem if its a electrical unit, or there could be a pump problem, or a engine problem. A new engine that is cold should have a lot of pressure at idle, even when in gear. ON a cold engine anything less than 30 psi idle would not be good. After it gets hot then things can be different. The funny thing about oil pressure is you dont need any more than is really needed. There are some engines ( other than slants sixs) that will only have as little as 3 or 4 psi at idle, but there are reasons for it being this low. THe bottom line is that idle pressure really doesnt matter much as long as it has some, plus when you give it RPM it climbs to a good amount of PSI. 10 PSI at idle hot would be OK, if when you give it throttle it raises to atleast 40 to 60 psi, depending on what RPM you was going to run the engine at. ON a average though, I am going to say if your showing anything less than 30 at idle there is a good chance you may have a problem. If you had a blue printed pump I would say different than this, but with a store bought pump and a new engine you should have quit a bit of oil pressure at idle. Just wandering, if this is a new engine, what are the oil clearances on the rod and main bearings ? Jess |
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| Author: | SlantSixDan [ Wed May 14, 2008 5:02 pm ] |
| Post subject: | |
I'll also add: The rough running and stalling probably hasn't got much to do with the oil pressure issue. I think you have two separate issues at work here. The rough running could be anything from grossly incorrect ignition timing (don't "knock" this theory; it's really easy to get this wrong and still swear you got it right...even when you've done it a zillion times), or a big vacuum leak...let us hope it's not something like improper cam timing. |
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| Author: | polara pat [ Thu May 15, 2008 10:38 am ] |
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Quote: I'll also add: The rough running and stalling probably hasn't got much to do with the oil pressure issue. I think you have two separate issues at work here. The rough running could be anything from grossly incorrect ignition timing (don't "knock" this theory; it's really easy to get this wrong and still swear you got it right...even when you've done it a zillion times), or a big vacuum leak...let us hope it's not something like improper cam timing.
I am running a mechanical guage and believe what it tells me. I installed the cam straight up and as far as ignition timing I'm looking at 10* initial and I've done nothing to the dist at this point. As far as two problems at once goes, that would really be par for the course these days. I'll figure it all out, I appreciate everyones input, it makes a big difference in diagnosis.
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