Relief, Oiling system in a type 4 Options

[worn]

If anyone has read my previous threads my two week vacation turned from driving to lying on the creeper under the new engine and transmission. Low oil pressure after warm up. I ordered a new Melling 30 mm pump and we shall see, but at the same time I looked into the pressure relief system - especially where it shunts oil away from the cooler because it is easier to see in the car.

What I found surprised me. First, looking at two different cases (72 1.7 and 76 2.0) I found that the piston seats on a shoulder in the bore that is at most a mm wide, and is not at all uniform in width across the piston face. OK, maybe it isn't supposed to seal.

Second I found that by the time you have opened the valve to shunt past the cooler, you are also dumping into the sump. That is there is a small overlap between the outlet to the oil gallery and the grooves cut in the bore leading to the sump exit.

Finally, the piston is simply loose in the bore. I can understand a fear of seizing, but there is no way that with my system oil isn't streaming into the sump, and it will stream faster as it thins - much faster.

I also spent a long time cruising the Samba - they ought to know whats up. What I found is a recurrent theme of new engines built in a variety of ways making low oil pressure. Many people were happy with what I ended up with - 10 psi at idle. On a new engine.

It is steel against untreated aluminum, so wear would be expected, but mine do not look worn - just poorly made. Maybe they are worn and I cannot tell. I got a face full of oil on one attempt at examination, so I may have missed things.

It seems an ideal situation for machining or sleeving during the rebuild, and I actually found a manufacturer of a sleeving kit with a ball bearing valve.

Thoughts ladies and gentlemen? (IMG:style_emoticons/default/idea.gif)

[eyesright]

worn

I agree with yeahmag. My VDO CHT shows 350F. Len Hoffmann did my heads so I wasn't too worried while I sorted out some other stuff. Then I got an IR thermometer which showed 200-210F inside the tin on #3.

Like 76 says, verify. I'll dump the temp sender in a pot of boiling water when I get a chance. Then I want to try different gas grades. And do the same with the oil temp sender at the next oil change. And double check the IR thermometer too. And after all the stuff I've done behind you I wasn't TOO worried but I have a direct reading pressure gauge that I'll hook up.

If I was serious I'd spend the bucks on aircraft stuff ....good advice. Mine's a driver. The VDO's look good and I just want to calibrate and look for consistancy. But I may put some greeen and red stickers on the gauges. That'll make my aviation buddies smile.