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So I fabricated a special tool to remove the oil pressure relief plungers, very simple:



Just a section of 1/2 aluminum tubing with one end slightly ovaled so that it's a tight fit into the hollow plunger. The mark shows the normal insertion depth, and the tool can also double as a holder to polish the plunger using a 3M polishing wheel. Which is what I did until the plunger slid in and out easily for all rotational angles.

However, after satisfying myself that the plunger wasn't sticking, on re-start, I'm still seeing over 100 psi, as verified by multiple gauges, both analog as well as digital. I have no oil cooler, and have connected the in and out ports of the oil pump, as suggested in the assembly manual. I'm using a general multi-viscosity oil currently, 10W30 I think it is. The engine has now run for a total of probably 15-20 minutes, and I've seen the oil temp just over 100F. The oil pump was assembled as per the manual, with lithium grease, but I'd think that that would have been distributed/diluted by now. I haven't verified the aft plunger, could it be an issue?

I would start with trying the right oil. They factory recommends 20W50 Valvoline VR-1. If that doesn't solve it I think you are probably looking at an engine teardown as something is most likely blocked.

Keith
#554

Yes, the rear oil pressure relief valve could be sticking too. Also make sure there are no burrs inside the port itself that could be causing the relief plungers to stick. Do not, however randomly try to work the inside of the port because they are precisely machines to regulate the oil pressure. If you do find a burr, take great care in making sure you don't leave any grit in the port.

Like others have said, USE THE CORRECT OIl! You just spent $8,000 to $11,000 on an engine, your life and your passenger's life is going to depend on that engine! Don't think you can save a few pennies using the wrong oil. The lifters and cam on your engine require a high zinc content that regular motor oils no longer have. I have read earlier accounts of people quickly ruining their engines using the wrong oil.

Perhaps you should consider an oil cooler also.

After your engine runs a minute or two what is your oil pressure?

Good luck!

Jake

OK, let me start by saying that OF COURSE I'll be using recommended oil. I really don't think that there is much science behind suggesting that an engine can be ruined in less than an hour of sub-1200 rpm by using Quaker State multi-grade automotive oil. I absolutely get it that a higher zinc content is desirable, but please... an hour of Quaker State is not going to trash my cam and/or lifters, anecdotal accounts aside. But rest assured, the next engine start will be with a sump full of 20W50 Valvoline VR-1.

And yes, I will be installing an oil cooler. Just unnecessary in this cooler Canadian climate right this very minute. But eventually.

I will take a look at the rear relief valve. As for 'something is most likely blocked', it would be enlightening to know where on the oil galley map a blockage might cause excessive pressure at the two places I have monitored: the front galley, and the top oil cooler block-off plate. Hmmm...

Thanks for the input!

Good description and pictures of how the aircooled vw oil system works:

http://www.thesamba.com/vw/forum/viewtopic.php?t=280293

The diagrams are accurate for those using the top mount oil cooler. If you are using the under mount oil cooler just look at the diagrams as if the two sides of the oil cooler in the pictures are capped off and the cooler doesn't exist. I If you haven't already checked it I would take a close look at the rear plunger. The front plunger sets the oil pressure and the rear plunger is a relief valve for if the pressure gets too high.

Keith
#554

Thanks, Keith. Someone else had suggested that the forward valve was the high pressure relief, will definitely verify the rear one. And great schematic, thanks! Good solid data.

If you read the vw forums you have to be careful with Fwd vs Aft. The aerovee is mounted backwards compared to a vw engine installed in a car. In the car the transmission is in front of the motor so they call the forward side of the engine the side with the flywheel. on the sonex the flywheel is on the aft side of the motor pointing towards the firewall opposite a car.

Keith

good point.

And here is a good explanation of both valves:

http://www.vw-resource.com/oiling_system.html

Excellent! Thanks.