FH601V has whistling sound

[Hayward51]

I've purchased a Scag Tiger Cub with 1200+ hours with a blown engine. I decided to take on the project of a complete engine rebuild. I cleaned up the block that had 2 broke piston rods and galled crank shaft journal. I took the housing to a local machinist who measured the cylinder diameter and assured me it was within specs for standard piston/rings. He said the crankshaft was toast. He didn't take any crankshaft bearing/bushing measurements in the housing. I ordered rebuild kit with new rods. Bought a used crankshaft on ebay with warranty. I reused ignition coils and valves. After lots of stressful work to get everything back together by the book, I started the engine and was pleased that all seemed fine except it has a whistling/squealing sound coming from the engine. I pulled the muffler, hoping ...then pulled the cover off the flywheel and saw nothing out of sorts. I'm thinking about the crankshaft bearing/bushing that's built into the housing must has been out of spec. ?? Before I tear into the engine again, does anyone have a clue what kind of mess I may find ? The engine seems to run fine otherwise, 100 PSI compression. I've pulled the flywheel looking, pulled the heads off to check gaskets for leak. Is it possible the valves could cause the whistling ? I'm stumped ! I made a video with my phone but don't know how to attach to here.

 

[Hayward51]

Lease use this link for video of engine noise:

 

[Scrubcadet10]

That's a new one for me, The bearings really should have been measured when torn down, since they are non replaceable they can make or break an engine build, granted a good machinist could machine the case and install a bushing, but that may drive the $$$ up..............first i would check to be sure there is proper clearance between the ignition coils and flywheel and that they aren't rubbing, as for the Flywheel side plain bearing, see if you can move the flywheel side to side any.

 

[Hayward51]

That's a new one for me, The bearings really should have been measured when torn down, since they are non replaceable they can make or break an engine build, granted a good machinist could machine the case and install a bushing, but that may drive the $$$ up..............first i would check to be sure there is proper clearance between the ignition coils and flywheel and that they aren't rubbing, as for the Flywheel side plain bearing, see if you can move the flywheel side to side any.

Thanks for your reply, I've checked both coils and flywheel play.

 

[hlw49]

Those old FH engines had a habit of wearing out the top main bearing. Grab the fly wheel and try moving it from side to side to from and to the ign modules. You might move the ign modules away from the fw first since if you set the air gap the fw would pull the magnets to the fw and not move the crank shaft.

 

[sgkent]

use a small hose, stethoscope or long screwdriver to isolate the sound if you can safely. Typical safety measures, no long hair near moving belts etc, no long loose sleeves, no hanging dog tags,chains etc..

 

[Hayward51]

Thanks, I'll try to isolate tomorrow. I don't feel nor see any movement with flywheel.

 

[Hayward51]

I tried the long screwdriver around the engine and could not tell anything.

 

[sgkent]

now use a long piece of fuel hose - long enough to hold one side to your best ear and follow to the whistle. I've used that to find sounds that are not internal to the engine like a vacuum /air / exhaust leak etc.. You did put an air filter back on it?

 

[Hayward51]

I did not put the air filter back on.