So we rebuilt the engine and fired it up for 20 mins to break in the cam. During this period we developed a pretty good sized oil leak - about 3/4 quart in that 20 mins. So did some investigating and determined the oil was coming from the top of the oil pump. Turns out PO had decided to pry the case apart right where the oil pump seats and made not only an indent but raised some of the material also. So we thought this was keeping the pump from seating on the case properly. We shaved off the raised part and sealed her back up like this: case-permatex3H-gasket-permatex3H-pump-3H-ORing-3H-Cover

Then we fired her up and fixed the spark timing, synchronized the carbs, and set the idle - checked underneath - no leak. Great (we thought) and we drove it around for 20 minutes and broke in the new piston rings. Got back home and sure enough: the same oil leak!

We think the reason it started to leak while we drove it (as opposed to in the garage) is beacause we revved it higher during piston break-in. We think the problem is the groove left behind from the POs prying. Although we shaved off the stuff that was sticking off the engine there is still a little groove (1.5mm deep, 1.5mm wide) that runs up the seam of the case. We crammed a whole bunch of 3H in there but maybe it didn't work.

The other thing is we tried using a "high flow" oil pump from Engine Builder Supply (ebsracing.com). The flange on the pump is a little thicker than the stock one. It also slips into the case pretty easily - as if the round portion of the oil pump isn't seating or sealing well on whatever is in the case. We've heard that the oil pump is pretty tough to get in and out and we thought maybe it's supposed to seal inside the case; preventing oil from getting to the flange. Is this true?

Anyway, we need to fix this. Any suggestions? We were thinking maybe there is another kind of Permatex that will be harder and more permanent than the 3H?

OK, here's some more info. Our pump came with longer studs, nuts, and a super thin gasket. We used that gasket between the pump and the case. And we found an o-ring in our engine gasket set that seemed to fit in the groove in the pump cover. See, our cover is pretty thick and on the inside surface there is what looks like an o-ring groove. This groove also connects to the main internal body of the pump via a short channel. We think it's a Type1 pump.

Should we just go back to the stock pump? The only reason we changed it was because we thought it would be a good thing to do while we were rebuilding the engine. The rest of the engine is stock. Well, it's a 1.7 with 1.8 pistons and cylinders and a Scat C25 cam (which is pretty mild).

Sucks about the oil leak. I have employed the methodology bestowed upon me by Bob Donalds - aka "Boston Bob" of Boston Engine.. A good friend and I've had a number of motors built by him and they have never leaked a drop.. [end shameless plug]..

Anyhow, after graciously learning from him some techniques of engine building, there are a couple of things that make for a leak-free case. first, is clean clean clean clean clean.. and then clean some more.. And imperfection in the mating services can promote a leak - it sounds like unfortunately, the PO got impatient and pried the case apart without proper tooling.. The second trick that Bob uses every time (for the past 25 years), and which I utilized on my first from-scratch engine build last Spring, is to use Rector Seal #5 "pipe dope"

Check it out: 2.0 Rebuild

I'm not exaggerating when I say my 2.0 hasn't leaked a single drop in 12,000 miles, and I haven't added a drop from burn-off or blow-by. The underside of the engine is dry to the touch after thousands of miles..

Good luck.

-greg-

where do they sell that stuff. Rectorseals website is useless.