36hp rebuild with no oil pressure? Help!

[mark1laura]

First engine rebuild ever. Entirely stock 36hp. Followed the VW Trends article and Bentley manual as close as possible to the letter. Ready to start it for the first time but wanted to make sure I had oil pressure. Removed the oil pressure switch and have cranked it for a total of 2 minutes (10-15 seconds at a time) and there is NO oil coming out where the switch screws in. Pulled the cover back off the oil pump and rechecked clearances but everything seems correct. I have no doubt made a rookie mistake but just can't figure it out. Can't imagine it is the oil pump, as I am getting NO oil to the switch, but my next step is to replace the pump. Any help/ideas would be greatly appreciated. (Yes, it has 2 1/2 qts of oil in it up to the top line on the dipstick).

[vwhelmot]

Oil pick up pipe attached inside the case? Take the sump plate off and have a look and maybe wiggle it to see if its seated properly.
Did you grease the gears a little to help with pick up?
Oil pressure plunger seated correctly?

[KOMBI NIKO]

Take the oil switch out and pump some oil in to the hole then try again, it will take a few cranks.
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[splitjunkie]

Was this a running engine before you rebuilt it?
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Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[Bub]

If your oil pump is spinning then it'll pump oil, that's a guarantee.
Good job being careful, but if you fire it up for 1-2 seconds you'll get pressure.
If you don't get pressure you haven't done any damage in that time, and there's a possibility you got a bad part or a bearing in the wrong place blocking an oil hole.
I personally haven't ever had an oil priming problem, but I've heard about it. Many people grease the oil pump gears and say it helps with priming initially.
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[splitjunkie]

If it is not an engine that was running before the rebuild, it could be several things. Could be a blocked oil passageway in the case, a stuck or missing oil relief valve, or broken spring, a lose or rusted out oil pickup tube.

If it was a running engine, I would check that the oil relief valve got installed right side up and that it moves freely and also that the spring hasn't broken.

Two minute total of turning it over is a lot if it isn't getting any oil pressure so I wouldn't turn it over any further until I found out what the problem is. It's not as bad as running it for two minutes, but it is still long enough to do damage without oil flow.
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Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[mark1laura]

Thx for the responses. It was a running engine when parked but several years ago. Should not be a worry though as when the case was apart it was thoroughly cleaned and all the oil passages blown out to ensure no blockages. Will double check the oil pressure relief, prime, grease and try again. Any moving part was covered with assembly lube so I may try firing it for 1-2 min and see if that does the trick if all else fails. Thx again to all for the help!

[splitjunkie]

Why on God's green earth would you turn it over for 1 to 2 minutes at this point after troubleshooting?

You will have either fixed the problem or you won't. If you don't have oil pressure in 5 to 10 seconds max, something is still wrong and it doesn't matter if you turn it over for half an hour, you are not going to get oil pressure and you will just do further damage. Assembly lube isn't some magic lubricant, it goes away as quickly as any other oil.

I am also not so sure I agree with putting grease in the oil pump. I have never had any problem with a well oiled oil pump getting pressure the first time within that 5 to 10 second window.

Also make sure you are using the super thin gasket between the pump housing and the pump cover. The thicker one is meant to go between the pump and the engine case.
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Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[VW_Jimbo]

[splitjunkie]

[VW_Jimbo]

[mark1laura]

Solved!! First, thanks to everyone who offered advice - much appreciated. In the end it WAS a "rookie" move way back when I was cleaning the case halves. A friend suggested removing all the small plugs in the case at the end of all the oil passages in order to make sure all the passages were clear from start to end. I tapped out each plug hole and replaced the plug with a properly sized screw in plug that could easily be removed in the future if I was to rebuild the engine again. Not paying enough attention I inadvertently screwed in one of the plugs too far blocking the main oil passage from the pump. Once corrected there was oil at the hole for the pressure switch with only a few cranks of the engine and with the pressure switch back in the light was out with 15-20 seconds of cranking. Glad I was cautious! Thanks again to all. Great forum!

[VW_Jimbo]

Awesome! Glad you found the issue. Nice sleuthing!
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!