FD rod knock

[stanley]

That’s good information.I’ll check that also.

[stanley]

Well,checked again and have same amount of play at any piston position,on both cylinders.As Frank said,”seems to call for further investigation.” I’ll pull the inspection plates and exhaust plate off and look at the ring clearance.

[fleetwin]

Keep in mind that what seems like play in the connecting rod might just be side to side movement on the pistons….Pulling the intake covers might provide a more accurate assessment..

[stanley]

fleetwin wrote:

Keep in mind that what seems like play in the connecting rod might just be side to side movement on the pistons….Pulling the intake covers might provide a more accurate assessment..

That’s a very good point.I’ve cleaned every thing up and am going to see how it does in the barrel.If it shows promise,l’ll follow advice and take off intake and exhaust covers and maybe the head and take a look.

[garry-in-michigan]

Most failures were in the needle bearing wrist pins. Eventually all models 10 horse and higher used the roller bearings used on later model Big Twins.

• This reply was modified 4 years, 7 months ago by garry-in-michigan.

[fleetwin]

Yes, I would attempt to start the engine in a test tank/barrel. An engine with sloppy wrist pins/bushing/bearings will tick at idle…The noise will go away if the throttle is raised a bit…I’m not sure if you engine has plain wrist pin bushings or actual needle bearings. The 10hp engines with plain wrist pin bushings are known for wear issues…Your FD11 has wrist pin needle bearings, I have never heard of any issues with them….
Let us know what you think when you run the engine, I wouldn’t pull the exhaust cover, leave the intake bypass covers in place also…
Have you done a compression test on this engine?
At this point, I am not convinced you have any issues with wrist pin bearings…

[stanley]

Thanks for all the input.I hope to have time to run it in a barrel soon.Compression is 112 psi on both cylinders.

[stanley]

I Finally had time to run it in a barrel.It started and ran fine without any alarming noises.Here is a short video of “knocking” while moving flywheel.It’s most noticeable when both pistons are at 1/2 way in cylinder.

[frankr]

Wow, I just watched the video. That is a lot of slop somewhere. Right now, I’m guessing the wrist pins are beat loose in the pistons. Only a guess, mind you.

[stanley]

When time allows,I’ll tear it down and we’ll have the answer.

[Author]

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