Finding exhaust leak

[biggjimm]

Hey all

I've got a possible exhaust leak at the rear of the starboard manifold on my 260. It is a 79 & still has the log style an I folds on it & I can't see or get to anything down there without some major disassemble.

Can't really tell if it is an exhaust leak or a lifter that's not pumping up right but now it sounds more like exhaust. If I pour or spray some wd40 or fogging oil or something down the carb will it smoke enough to see it if it is indeed a blown manifold gasket?

Has anyone ever tried this?

These manifolds are a major pain to get to. And I'm planning on putting some center rise manifolds & thru hulls on it over the winter.

Supposed to be going to the lake next weekend so I may just take it easy on the boat & make that my last trip for the season & wait til I tear it down to do the manifolds here I'm a couple months rather than do it twice I guess.

Still curious if you can "smoke out" the leak.

Thanks.
Jim.

 

[QBhoy]

Heard someone say to squirt some transmission oil down the carb and it should smoke like nothing else at the leak. Sounds like a great idea.
Other time honoured techniques would be;
Get a soapy solution in a spray bottle and spray round the joint. Any leaks should show bubbles.

Another would be to get a white sheet of paper and hold a corner round the joints. Watch for it flapping or even any sign of black soot appearing.

 

[Bondo]

Ayuh,.... For an exhaust leak, just run yer hand past the suspected spot,...

If it's leakin', yer hand will tell ya it's extremely HOT in that spot,...

 

[biggjimm]

Bondo, that's the problem, I can't get my hand down there to it.

Be doing good if I can get a piece of paper down there like QBhoy suggested. The soap solution trick sounds interesting. I may try that just for giggles.

Thanks guys. I'll check it out when I get back home.
Jim.

 

[QBhoy]

If the noise is fairly loud...you'd think it might be easy to find. Hopefully it is just the exhaust.

 

[biggjimm]

Well, one of my biggest pet peeves on any motor is an annoying exhaust leak. None of the oil down the carb tricks worked & the soap bubbled everywhere as soon as it hit the hot manifolds. I suspected the leak to be on the bottom side & I can't see a thing under there anyways.

I decided to bite the bullet & pull the manifold beings I had already ordered a pair of the good metal header gaskets & had them laying here & sure enough it was blown. The bottom of #8 was blown & #2 wasn't far behind. I hate those junk paper gaskets.

It's got good ones on it now though. And I don't have to listen to that annoying ticking any more or explain to people why my brand new motor sounds like an old tractor, lol.

Thanks for the input guys. I might just take her to the lake tomorrow & finish my tuning & prop testing.
Jim