Expensive belt replacement

[Mark Maulden]

I tightened up my alt belt and I always turn the engine over and recheck tension. Turned the key and received a very violent reaction from the engine MD 17C..Smoke,, wisping out of the middle air intake..&$@&!....Pulled the middle valve cover off and unloaded the middle valve train and spun the push rods..Intake was really bent. So now the head comes off and everything "looks" great. Machine shop confirms a stuck intake valve. I guess its good that it happened here and now. Gives me something to do while I recover from some ear surgery.

 

[jssailem]

Thank God, the belt did not split and wack you in the ear....
It is always something. I think that is why they call them boats...

 

[Charles Erwin]

Mark

Did the shop provide an opinion concerning why the valve stem became bent?

Was the stem stuck (valve open) and a piston collision ensued. If so be sure to assess the piston top to rule out secondary piston interference collision damage. Or was it on the rocker side of the stem? If so then consider why and whether the rocker and push rod are damaged. ie bent or twisted or factured.

Charles

ps You probably don't want to be in North BC with a motor issue.

 

[Mark Maulden]

I probably could have been a little clearer. It was the push rod that was bent. The machinist took the valve assembly apart and really had no explanation why. They just cleaned it up and it now works fine on the bench. I'm also going to put the push rod into both tappets and rotate the engine and verify similar movement. Oil came out with both push rods and the rocker assembly also has oil. There are no collision marks on piston or valves. The rocker assembly looks normal.

 

[Mark Maulden]

The tappets move fine. The hardest thing is getting all the gasket material/residue off the surfaces. Every engine I've ever had apart came back from machinist with all parts cleaned up. I'm going to try a remover that spins in a pneumatic motor. This seems to be the what machinists do. I'll have to "haul" air down to the boat...

 

[Terry Cox]

Wow. Sounds like things are coming back together in preparation for your trip north this summer. Good thing it happened here. Nothing to speak of up there.

 

[Mark Maulden]

Not going to do the spinning remover. They are actually RoLoc 3M bristle pads that are
loaded with Al Oxide. And spraying around it gets into oil passages and cooling passages even if orifices are pluggd with towels. Auto forums state to not use these as they can cause dips in the surface while at the same time spray oxide all over the engine into internal parts. Known to trash bearings etc in short time. So i think its just scraper and razor blade and some 220 witha shop vac...

 

[njlarry]

Glad all is now well.
Have you already used gasket remover?
Can a regular automotive machine shop do that kind of work or is a marine machine shop needed to access the specs and parts?

 

[Mark Maulden]

Any machine shop should be able to do it. I used the one that reconditioned the heads several years ago. I have the head and heat exchanger ready for paint. There are some rust areas so while it is off..... Razor blades worked well followed with a little rotary wire brush on my dremel. Tomorrow is at the boat doing exhaust ports of the two remaining heads and the cylinder. Naturally the one I'm working on is the middle one....

 

[Mark Maulden]

Scraper/razor blade/dremel worked well! Its not bright metal but I can't feel anything with a thumbnail scrape. Waiting for gaskets to show up!!

 

[Mark Maulden]

Put things back together today. Pulled the fuel shutoff and cranked. No funny noises. Turned fuel on and turned they key. It was running before I could let go of the key!! Whooaaa, and no bleeding. Laser thermo'd the whole engine so I got the manifold gaskets right. Ha! This engine ran so well, I'm thinking there were some issues for awhile with the push rod. And then, it finally said "enough"...Tomorrow is cleaning up which will probly take just as long....