Thursday, January 16, 2014

Exhaust manifold

One thing I noticed about the '79 Polaris Cobra is that the front of the engine was really greasy. This extended down into the belly pan. At first I thought the exhaust manifold gaskets were leaking but then I happened to look into the exhaust manifold while holding it up to a light:

See the light peeking through in the middle of the pic? The manifold was made in 2 halves pressed together and tacked. It would appear its separated in the middle. I ground out the joint and welded it back together until I couldn't see light anymore. Then painted with some high temp.

While I had the grinder and the paint out I figured I ought to clean up the exhaust pipe some. Thats when I found:

A line of welds where one had pulled through the metal. Again and easy fix but then I discovered what I think is a cleanout plate on the other side that had been booger welded all around. You can see in the pic above where it looks like the plate as been swaged or tacked to the rest of the pipe. Apparently the other side leaked so somebody ran weld all around it. It looks awful but weld is really hard and after 15 minutes of grinding I'd only cleaned up maybe 1 inch out of 24. I'll work on it again in the spring. In fact I'll probably keep the pipe out of the sled all summer and just nibble away at it.

Anyway I did finish putting the engine together last night, took longer than expected because the fan housing was really dirty both from the leaking exhaust and the leaking crank seal. Then I realized I'd put the motor plate on backwards. That was the last straw and I gave up for the night...

No comments: