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]

PS Worn, oh yeah, one more thing. When you open the engine lid after a run, does it SMELL and FEEL hot?

I had my cooling flaps hooked up wrong once on a prior car and when I got back from a short break in run I could tell things were not right. This was a stock car with no gauges. It just SEEMED too hot. And I knew I didn't understand the cooling flaps when I put it together so that's the first place I looked into. Figured out the error of my ways and set things right and ran it again. The engine bay was hot but a "normal" hot.

My gauges are/will be good information but my engine runs smooth, starts hot or cold, plugs look good, doesn't ping on regular even when I floor it @2000rpm, and when I open the engine bay after a good run it smells and feels normal. (Hoffmann heads and case decked, Raby 9550 cam kit, 2.0L, FI)

I'll keep looking into the gauge readings, but mine's been on jack stands too long and too often. The next time it takes an indefinite rest on jack stands it will be because of REALLY bad news. I hope I don't have to eat my words here on the forum but so far my engine runs well enough that I think I am enjoying worrying it just enough to keep looking as I DRIVE!!!!

Good luck and keep posting. I'm getting good ideas from you and the rest of the posts.