E: Engine More Adventures with the Comet

[greg brillus]

Complete new barrel assembly and piston bored to the correct clearance, plus the oil feed drilled bellow the bottom ring groove will fix all that........Bill is correct, sloppy guides wont cause that much oil on the piston and the spark plug. Mucking around with the old barrel assembly will be too much trouble, the new liner will also restore the correct fit up in the head recess to give correct sealing.........If you've gone this far you need to fix it properly or else it will give more trouble sooner than later.

 

[ClassicBiker]

I got the movie working on my lap top and the exhaust valve was flopping about like there wasn't a guide there at all. Very much reminded me of when my exhaust valve guide left via the exhaust pipe without turning in its notice.

 

[Cyborg]

That’s probably why we should spend extra time setting up the timing chest. Keep the background noise down to the point where one can actually hear the death rattles starting to manifest themselves. That way if the guide starts to file a grievance, you have a chance to reach for the decompressor before it buggers off completely.

 

[Alyson]

Once you got inside the engine, check cracked or weak piston rings - obviously - and check for a correct and working engine breather. Could that have slipped from seizure ? So then the timing would be wrong and internal engine pressure would lead to very oily pistons. I´d go for reed type breathers anyway.

Vic

I'm not sure how a piston ring would be checked for weakness ? Checking the ring gap though should be number 1 I would imagine if a ring were cracked, it would be evident at the bore with scoring apart from falling apart when the piston was removed. But yes, do check the rings, and make sure they were installed properly as well i.e. there is an up side to the rings. Hope this helps, Alyson

 

[Martyn Goodwin]

Looked at the video - the exhaust guide is toast and I suspect that the exhaust valve stem will also show extensive wear. At a minimum I would replace ALL valve guides, both valves and their valve springs. You may also need to have new valve seats fitted to the head.

While at it check the forked end of the rocker arms, there should be a 0.5 inch radius on that surface that bears in the valve collar - if it has worn showing flats, then replace with new rocker arms as well.

Reach out to your local VOC section for suggestions on who you get to do the work.