Leak down

[SuperRat2110]

Hey guys, finally was able to get a proper leak down test and was awesome to see it go right but I did have some sort of leak coming off the inlet manifold. Must have a some kind of pore leaking through. Anyone else ever have something similar?

[taber hodaka]

How many pounds are you putting to it 3?-------------------Clarence

[SuperRat2110]

The test was done anywhere from 6 to 8 psi. But mostly 6 and then timed. In one minute it only lost about 1/3 psi.

[Bullfrog]

While your test results indicate a "passing" score, it should be pretty easy to seal up the porosity of that reed manifold casting. A thorough cleaning on the inside surface of the manifold throat followed by a thin sealing coat of JB Weld should stop that leak entirely. (If I were doing it, I'd smear on the JB Weld very thinly, then try to wipe all of it off with my finger. In that way, any pores should be filled and there is no excess epoxy left in the throat of the manifold.)

I'm curious about the fine bubbles nearer the bottom left - that appears to me to indicate a larger problem off sealing at the "face" of the manifold. What's up with that? (It doesn't seem to match up with the quite slow leak down rate you measured.)

Ed

[SuperRat2110]

Ed, yeah I didn't even notice those. That is where my homemade gasket was. Now that I think of it I took the photo before I switched my set-up. Prior to that I had it set up differently and was wondering where I was losing air because at that point I was right around a minute pass/fail. I switched my set-up took the rubber out of the equation. That is when I had the passing test but still had leak in the manifold. But good catch, not sure how I didn't see that.

[SuperRat2110]

Thanks for the advice on how to seal that up. I will do that when I get some more time.

[thirdstone]

Just by coincidence I posted a way to fix this on this message board not long ago .
Ed I have tried the JB weld method but found that J B Weld is not air tight to that degree required to hold air tight , you would think that it would. Perhaps with heating it up with a hairdryer will thin it out to really get in the pores , you might have more luck than me Super Rat .
What I found the best for me was painting on fuel tank liner paint. I’ve also thought of using fuel tank expoxy , JB make that as well. I’ve never got to actually trying it, just a thought.

Kev