Continental Flathead 4-cyl / Kohler Generator

richard5933 · July 04, 2019, 12:31:47 PM

Still working trying to rehab an older generator that was pulled out of a bus conversion. Not sure what I'll do with it once it's running. The Kohler parts I set aside since they are the same as what's in our bus. The Continental is just a project left over from winter that I want to get out of the way.

I've separated the Kohler from the Continental, installed a tune-up kit, changed fluids, rebuilt carb and fuel pump, and then put it all together to see if it would run.

The engine was originally started by use of the generator head, but since they are separated at the moment I've been trying to start it with the hand crank. I definitely have spark, and fuel is flowing. Almost got it to fire once, and only once., Just little puff of exhaust.

Then I ran into a problem - the engine started to get stuck when turning it over. It would turn 180 degrees and catch. If I pushed it backwards just a bit I was able to turn it over again. Now it will go 180 degrees and stop dead in its tracks, as if something inside is hitting the block. I can turn it back the other direction 180 degrees, and same thing.

I'm looking for a bit of advice where to start looking for the problem. I've pulled the inspection cover on the valve lifters and see nothing in there out of place. Could it be something on the bottom end? Maybe the crank gear? Broken ring?

I've never really torn into a flathead before, so I didn't want to just randomly start tearing things apart until I had some idea which way to go.

Any suggestions would be welcome.

luvrbus · July 04, 2019, 12:37:53 PM

Remove the spark plugs and see if turns over is a good starting place

richard5933 · July 04, 2019, 12:56:10 PM

I did that when I first got the engine. It did turn over. Then the problem started where it would occasionally 'catch' while turning over. Now it catches every time at 180 degrees. I can go backwards 180 degrees and it catches again. Something is definitely getting hung up inside, but I can't tell from where.

Seems like something came loose inside - maybe a bolt worked loose, maybe a tooth on a gear, who knows?

I was hoping that perhaps there are some common failure points on these old Contentals Y112 engines which would give me a place to start.

chessie4905 · July 04, 2019, 02:22:47 PM

Timing over advanced? Plug wires mixed up?

richard5933 · July 04, 2019, 02:32:10 PM

Quote from: chessie4905 on July 04, 2019, 02:22:47 PM
Timing over advanced? Plug wires mixed up?

It's not firing problem that's I'm talking about. There is something physically catching/hitting inside the engine which only allows it to turn 180 degrees. Once it hits whatever is hitting, I can only turn it back the other way 180 degrees until it hits again.

I've got no idea what happened. The engine hasn't fired up since I've had it, so whatever happened did so while I was cranking it over with the hand crank.

chessie4905 · July 04, 2019, 02:39:17 PM

Well then tear it apart and report back. We'll wait. Start with the head. Should take 5 minutes with an air wrench.

richard5933 · July 04, 2019, 02:50:42 PM

Quote from: chessie4905 on July 04, 2019, 02:39:17 PM
Well then tear it apart and report back. We'll wait. Start with the head. Should take 5 minutes with an air wrench.

Yeah - I could have done that already. Kind of was hoping someone had run into something similar and could at least give me a starting point.

Not much under the head in a flathead engine, so I'm guessing it's not there. Perhaps something in the crank gear came loose or broke, or perhaps something on the bottom end.

Guess it's going to have to come apart...

chessie4905 · July 04, 2019, 03:02:38 PM

First the head. Did you drop something in the plug hole? Then pan and timing cover. Those old head gaskets can be reinstalled and retorqued if they are a metal sandwich design. Like a flat head lawn mower.

Utahclaimjumper · July 04, 2019, 03:36:26 PM

You are probably going to find a nut or bolt laying on one piston,, if you force it you can break the piston.>>>Dan

DoubleEagle · July 04, 2019, 03:42:13 PM

Get or borrow a borescope to look in the spark plug hole.

buswarrior · July 04, 2019, 04:09:46 PM

I'll go one easier...

Spark plugs?

Wrong ones go too deep...

Like luvrbus suggested, remove plugs and see if it turns...

Whatever got touched is first on the list for the cause, nothing more complicated until they get proven...

Common knowledge on these engines will be resting in peace with a lot of the Detroit knowledge...

Happy coaching!
Buswarrior

richard5933 · July 04, 2019, 04:53:50 PM

Plugs were out on the last attempt, so they weren't the problem. I'll start with the scope and then got from there.

chessie4905 · July 04, 2019, 05:30:53 PM

Scope??? Don't waste the time. Take it apart. Probably needs rings and valve job anyway. You can use the experience.

Utahclaimjumper · July 04, 2019, 05:53:45 PM

This reminds me of many moons ago most of us had a threaded "plug" that we would screw into the plug hole until it bottomed against a shoulder.. Then turn the engine by hand until the piston contacted the plug (gently),, make an index mark on the bell housing and a corresponding mark on the flywheel.. Then reverse the turn and rotate until the piston touched the plug again,, make another mark on the flywheel.. Exactly half way between the flywheel marks was the TDC
for that engine, and it could be used to set the valves,, set the timing advance and several other functions..>>>Dan

richard5933 · July 04, 2019, 06:01:44 PM

Quote from: chessie4905 on July 04, 2019, 05:30:53 PM
Scope??? Don't waste the time. Take it apart. Probably needs rings and valve job anyway. You can use the experience.

Yeah, but if there is something lose on top of the pistons it would be an easy solution. I'd love to get the engine to fire and run for a minute so I can evaluate it before tearing things apart.