Jump to content

Strange engine noise,help needed


Recommended Posts

Hi guys,engine is a KFM 112M ,hasn't been run for a while,only 300 hours.When turning the motor on the prop there's a clicking noise,somewhat like a impulse connection but more a clicking evenly spaced and not as loud as an impulse.It's there turning it either way,and there for the whole revolution.Evenly spaced,like every 5 degrees.Motor turns smoothly,no grating .It seems to be coming from the front.

 

Any ideas before a complete teardown ?

 

regards

 

colin

 

 

Link to post
Share on other sites

Well i've done some searching and it's possibly a dry Gerator oil pump.Just needs priming possibly.Will have a go at it this morning,fingers crossed

 

 

Link to post
Share on other sites

How long is a WHILE and was it inhibited? You can't just let motors sit and then fire them up and fly years later. You should pressurise the oil system before running and check cylinders with a borescope and check all valve guides, particularly the exhausts for corrosion and sticking. at least, if the storage period is significant. Nev

 

 

Link to post
Share on other sites
How long is a WHILE and was it inhibited? You can't just let motors sit and then fire them up and fly years later. You should pressurise the oil system before running and check cylinders with a borescope and check all valve guides, particularly the exhausts for corrosion and sticking. at least, if the storage period is significant. Nev

Good point Nev,it could have been a number of years, will make a phone call.As to the pressurizing,that's a good idea too,i imagine that will require removing the oil filter and pumping oil through the outlet.Will report back how we go.

 

colin

 

 

Link to post
Share on other sites

You can use the tapping your oil pressure sender goes from. IF the engine is out of the plane you can put say a litre into the case and roll the engine around to distribute it to the pistons and cam lobes/followers, timing gears. Nev

 

 

Link to post
Share on other sites

We've now gone thru and got oil circulating,engine started and runs fine,but low compression on one cylinder,looks like we''l have to do a valve job all round.However the clicking noise is still there,even after the motor was run for 15 minutes.I'm now thinking it may be the magnetized alternator rotor,and clearance in the accessory drive gears moving back and forward.I realize there's basically no parts for these relic's from the past,does anyone know someone with KFM experience?

 

cheers

 

colin

 

 

Link to post
Share on other sites

Check how much the engine is breathing. You may have a ring of rust in some bores and that could do bad things to the piston rings.. End float noises are usually intermittent not regular and are worse when hot. Nev

 

 

Link to post
Share on other sites
Check how much the engine is breathing. You may have a ring of rust in some bores and that could do bad things to the piston rings.. End float noises are usually intermittent not regular and are worse when hot. Nev

thanks Nev,will pull one cylinder today if possible,looks like head and barrel are 1 piece,

cheers

 

colin

 

 

Link to post
Share on other sites

Retension the studs that go through with spacers, before rotating the engine. Protect the cases from damage by the conrod dropping in it. (Just general advice). Nev

 

 

Link to post
Share on other sites
Retension the studs that go through with spacers, before rotating the engine. Protect the cases from damage by the conrod dropping in it. (Just general advice). Nev

No worries Nev,haven't had a chance to get back onto it,and leaving for Wanaka monday so will be away few weeks,but the clicking is definitely not coming from the

cylinders according to the stethoscope,and it's exactly the same hot or cold. colin

 

 

Link to post
Share on other sites
  • 5 weeks later...

The mystery clicking of this type motor has been solved ,Rod from Jabaru says it is the "permanent magnets in the alternator and the gear drive of the

 

alternator"the clicking transfers all the way through to the Prop.If there's no clicking then some thing is wrong.

 

cheers

 

colin

 

 

  • Agree 1
  • Informative 1
Link to post
Share on other sites
The mystery clicking of this type motor has been solved ,Rod from Jabaru says it is the "permanent magnets in the alternator and the gear drive of thealternator"the clicking transfers all the way through to the Prop.If there's no clicking then some thing is wrong.

cheers

 

colin

Good news. What aircraft is the engine in? I'm in Mackay I'll keep a eye for you.

Cheers

 

Mike

 

 

Link to post
Share on other sites
  • 6 years later...

Rod Stiff would certainly be familiar with that engine as the first Jabiru's used it and when it went off the market no suitable engine was available so they built their own design from the ground up. Their first engines (1600 cc) had no replaceable bearings probably for lightness and simplicity.. Plenty of engines do that as an example the little FN 300cc 4 cylinder engines of 1904 of which thousands were made. Nev

Link to post
Share on other sites

You mean this Ind of FN? This one I snapped at our local hardware. The owner has ridden it back to visit the manufacturer in Belgium.

I have the book he wrote about that trip.

Link to post
Share on other sites

@coinz Are you still running the KFM engine ?

 

Cheers,

Skelly.

No ,but someone else is,i found the Pup a little cramped.Sold it with spare motor.They are around,in hangers,sheds.Best thing is advertise under "wanted".

cheers

  • Like 1
Link to post
Share on other sites

I have the book he wrote about that trip.

Sorry about my triple post. I had trouble attaching the picture, then had trouble deleting redundant posts. Yes, same FN.

The bike now has a period wicker sidecar.

Link to post
Share on other sites

Hi guys,engine is a KFM 112M ,hasn't been run for a while,only 300 hours.When turning the motor on the prop there's a clicking noise,somewhat like a impulse connection but more a clicking evenly spaced and not as loud as an impulse.It's there turning it either way,and there for the whole revolution.Evenly spaced,like every 5 degrees.Motor turns smoothly,no grating .It seems to be coming from the front.

 

Any ideas before a complete teardown ?

 

regards

 

colin

 

Have you had somebody else come and have a listen?

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...