1977 Bus - Extreme Oil Pressure & A Big Leak!

Post by **Sluggo** » Mon Nov 02, 2009 9:31 am

Went to start up the '77 for the first time since tear down and it wouldn't start (plenty of cranking). Pulled the wire for the fuel pump and ran it straight to the battery for a second to prime the carbs. Fuel tank started making a bubbling sound as soon as the pump started running. Like someone blowing into a drink with a straw. Checked the pump and the flow is going the correct direction (arrow towards the engine). Thought maybe it was too little gas (doubtful as it already had 1 1/2 gallons). Added 2 more gallons and the same thing happened. Fuel filter was just cleaned. No pressure according to the gauge on my regulator.

Sounds like it is pumping backwards and blowing air into the tank.

Redline Weber (Pierburg) rotary fuel pump.

Anyone have any ideas?

dtrumbo · Post by **dtrumbo** » Mon Nov 02, 2009 11:51 am

Sluggo wrote:Anyone have any ideas?

It's wired backwards? Just a guess and I'm sure you already thought of it, but I'll just throw it out there.

Post by **Sluggo** » Mon Nov 02, 2009 2:26 pm

dtrumbo wrote:
Sluggo wrote:Anyone have any ideas?
It's wired backwards? Just a guess and I'm sure you already thought of it, but I'll just throw it out there.

DING DING DING....We have a winner. I think I need to slow down. I've given myself a deadline because I desperately want to take my vacation and the Bus is a central part of that. I think that the deadline and the ensuing anxiousness/desperation is causing me to miss things. I've made a couple of very stupid, amateur mistakes in the last few weeks.

Got bigger problems now! Engine started up and ran beautifully. But I have a good deal of oil (about 8th of a quart after only a few minutes of running) dripping from the bell housing. I think the gallery plug by the mechanical fuel pump pushrod is leaking. I was messing with it a year ago and the oil seems to be coming from there and also pooling at bottom center. Guess I'll be dropping the engine again.

Post by **Sluggo** » Mon Nov 02, 2009 6:01 pm

I think my Mann filter may have had a bad bypass. Oil pressure over 100PSI. Down to 45 after running for 20 min. Have lost about .25 quarts since discovery. Barely dripping now.

Post by **Sluggo** » Mon Nov 02, 2009 6:42 pm

Just reread Hippie's oil filtration comparison and realized there is no bypass on Mann or Mahle filters. What next?

Post by **Amskeptic** » Tue Nov 03, 2009 8:51 am

Sluggo wrote:Just reread Hippie's oil filtration comparison and realized there is no bypass on Mann or Mahle filters. What next?

The bypass is in the mount:

Please note that the bypass is utilized only to maintain oil supply to the bearings in case of a an extremely neglected filthy filter. Excessive oil pressure is handled by the pressure relief valve and on all engines after 1971, the oil control valve.
Colin

Post by **Sluggo** » Tue Nov 03, 2009 9:18 am

Amskeptic wrote:
Sluggo wrote:Just reread Hippie's oil filtration comparison and realized there is no bypass on Mann or Mahle filters. What next?
The bypass is in the mount:

Please note that the bypass is utilized only to maintain oil supply to the bearings in case of a an extremely neglected filthy filter. Excessive oil pressure is handled by the pressure relief valve and on all engines after 1971, the oil control valve.
Colin

Checked the relief valve and it operates perfectly. Changed out the filter and I still have over 100 PSI (off the scale). Drained the oil and pulled the bypass piston & spring next to the oil filter and it moved smoothly. But it had a small divet dead center of the top.

The only thing I've changed on this engine is the flywheel & pressure plate. everything else is exactly the same and it ran beautifully before. Still does except for the leak and high pressure.

Post by **Sluggo** » Tue Nov 03, 2009 2:47 pm

Amskeptic wrote:Excessive oil pressure is handled by the pressure relief valve and on all engines after 1971, the oil control valve.
Colin

So I gotta pull the oil control valve between the pushrod tubes?! DAMN!!! Can that be done with the engine installed and intact? I've only messed with mine and that was only once during a complete rebuild.

Post by **Sluggo** » Tue Nov 03, 2009 3:10 pm

Just found this thread on TS between Chitwn & Colin. I'll be trying this tonight. I remember having to borrow the socket from a friend so I'll be trying the 3/8" extension idea. And cutting a slot for a wide screwdriver too.

http://www.thesamba.com/vw/forum/viewto ... ol&start=0

chitwnvw · Post by **chitwnvw** » Tue Nov 03, 2009 4:23 pm

Sluggo wrote:Can that be done with the engine installed and intact?

Probably faster to pull the rockers and pull the pushrod tubes, take you like ten minutes tops, than try to monkey around with that stuff blocking your way. My 2 cent.

Post by **Sluggo** » Tue Nov 03, 2009 5:43 pm

chitwnvw wrote:
Sluggo wrote:Can that be done with the engine installed and intact?
Probably faster to pull the rockers and pull the pushrod tubes, take you like ten minutes tops, than try to monkey around with that stuff blocking your way. My 2 cent.

Did it right after I posted this. Very easy without pulling anything except the lower tin (which was already off). Took just a few minutes. I couldn't tell if it was stuck because I couldn't reach the piston. Came right out with a telescoping magnet. Piston was nice & smooth but I did find some Permatex slivers in there. I think some may have smeared on the piston during original install. Maybe one of the flakes got lodged between the piston & bore. Cleaned it out, cleaned the assmbly and put it back in. I'll fill her with oil and start the engine tonight. Hope it worked.

chitwnvw · Post by **chitwnvw** » Tue Nov 03, 2009 5:46 pm

Did you check the spring resistance?

Post by **Sluggo** » Tue Nov 03, 2009 6:14 pm

chitwnvw wrote:Did you check the spring resistance?

Checked it manually (with my fingers). No Micrometer. I couldn't see it changing that much in a few months of not being run.

Post by **Amskeptic** » Tue Nov 03, 2009 8:56 pm

I think your oil pressure gauge is what is wonky.

You said it was over 100#, then dropped to 45# well, that sounds like a gauge that is "sprung" and is actually 60 going down to 10.

The leak is the real deal, and it must be tracked down.
Colin

Post by **Sluggo** » Tue Nov 03, 2009 9:07 pm

Ran the Bus for another 1/2 hour. Took that long for the pressure to go down to 80 (so I thought). Turns out my gauge was lying. Still got the leak but the issue is NOT oil pressure. My VDO Gauge apparently decided to go on the fritz and read much higher than real PSI. After I had shut off the engine I turned on the ignition for a second to see something else and noticed that my gauge went back up to 80PSI but the idiot light was on. That didn't make sense so I hooked up a mechanical gauge and started her up. 11PSI at warm idle. Grabbed a used VDO gauge I had purchased for my now sold 411 and popped it in. 15 PSI at (slightly cooler) warm idle. The engine leaked about 1/4 of a quart during this time. Actually seems to be smoother than before when it was in the '72.

Now for the leak. I'll be dropping the engine on Sunday. I may have set my endplay a little tight. My dial indicator and it's stand kind of suck. I did it several times and set it on the average but it may have been a little tight.

Could tight endplay cause a front main seal leak and a slight grind from the fan at idle (grind goes away with the slightest throttle)?

Itinerant Air-Cooled

Itinerant Air-Cooled

1977 Bus - Extreme Oil Pressure & A Big Leak!

1977 Bus - Extreme Oil Pressure & A Big Leak!

Re: '77 Bus - Fuel Pump Flowing Backwards?

Re: '77 Bus - Fuel Pump Flowing Backwards?