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Urgent answer needed prop bolt bushings

Brantel

Brantel

Well Known Member
Need an answer on what to do about my prop bushings sticking too far out past the flywheel.

I am trying to mount my new Hartzell CS on my plane and noticed that the oddball prop bolt bushing is sticking too far past the flywheel and there is no counterbore for it on the prop flange.

What to do?

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Ummm, press that oddball bushing out the back of the crank flange and grind a little bit off of the nose of it on a belt sander? :D

So when you press it back into the flange it'll fit flush.
 
I have a set!!!!

I bought a complete set of the correct prop bushings to mount a hartzell prop, never installed them, replaced the crank, and ultimately bought a brand new engine. Lycoming Service Instruction 1098G covers the required part numbers.

Long story short, I have a complete set of the bushings you need and I don't need them. If you source these from parts suppliers, they are obscenely expensive ($150ish each). I'm literally stuck with these right now (bought em six months ago and can't return them). I'll make you a ridiculously good deal if you want them.

Paul
 
The fishy thing is that one company made the crank, one company made the flywheel, one company made the bushings, one company made the prop and another company inspected, reworked and yellow tagged the crank. Oh and all of this stuff happened with a total span of about 50 years.

The new CS is a R flange prop. The crank is setup as a K flange crank. The Hartzell manual says that a R flange prop can be installed on a K flange crank or a R flange crank. This was never an issue before because the FP spacer has counterbores all the way around it on the back. The new CS prop has one bolt hole that has no counterbore and it must be installed in one of 2 locations on a K flange crank. My bushings just happen to sit a little proud in those to locations. I was super cautious when installing and noticed this. Not sure if someone in a hurry would have even noticed it.

I was looking at the work order from Aircraft Specialties and they did do the oil seal area repair to this crank.

No threads were removed during this grinding operation. Only the area in front of the threads was ground down and re-chamfered..
 
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Brian, Sound's like you have a good understanding of the problem,as long as threads are not involved,your solution is fine. My crank had an "Oil Seal repair" as part of the yellow tag and two bushings were replaced with up to 1/1000"off the rear face I can see how this could happen. Sam at Saber can make these in Stainless steal for a reasonable buck if needed. my 2 cents worth:)
Bob
 
rhill said:
Brian, Sound's like you have a good understanding of the problem,as long as threads are not involved,your solution is fine. My crank had an "Oil Seal repair" as part of the yellow tag and two bushings were replaced with up to 1/1000"off the rear face I can see how this could happen. Sam at Saber can make these in Stainless steal for a reasonable buck if needed. my 2 cents worth:)
Bob
Click to expand...

I was looking at the work order from Aircraft Specialties and they did do the oil seal area repair to this crank.

No threads were removed during this grinding operation. Only the area in front of the threads was ground down and re-chamfered. The part was kept very cool during this operation.
 
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az_gila said:
These important bushings take the load from the crankshaft to the propeller, not the bolts.

Since one is wrong, are you sure the rest are OK for your power level?

A check here with the Lycoming model you want to copy might be worthwhile -

http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1098H.pdf
Click to expand...


Thanks for the link Gil...

I have inspected that document and see that one of two part numbers may be installed in the position F in question and those two part numbers vary in length by 0.006". They are the same otherwise. It is possible I guess that I have the longer of the two.

The other 4 appear to be correct and fit the prop flange nicely. The one in position C opposite F is also the correct diameter but was a little proud as well. This did not matter however because the prop flange is counterbored in position C.

The bottom line is that it looks like everything I have is correct with the exception of the length of the two bushings installed in position C and F. Those were a little proud of the flywheel. The others have positive engagement with the counterbore of the prop flange as specified in the Service Instruction No. 1098H.
 
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As you pointed out these engines have been around. I changed the ring gear support from a small belt drive to a new 149tooth large pulley, I haven't miked
the flange of the ring support but like candy bars and everything else I bet there putting less in the package then they use too. Tolerance creep it's everywhere.
 
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