YS91 question

[buster1]

While inspecting my Tempest last night, I decided to check the 4 bolts which hold the back casing onto the engine.
Question - the engine only has about 10 flights on it and the 4 bolts were slightly loose - I retightened them down - is this common?
Should I locktite these bolts with some kind of high temp. stuff or just regularly check and torque them down.
Thanks,
Jeff

[Bonsai]

Yes you need to use blue locktite on all YS engine bolts... I had a head come loose in flight and the engine had about 2 gallons thru it...I come to find out that it is common.....so now I locktite all the engine bolts..just make sure that you dont over tighten the bolts when you reinstall them...I torque them all to 45 inlbs and I think that is above what they are suppose to be....
Dean :glasses2:

[DavidH]

3mm bolts are suppose to be torqued to 14 inch lbs. I never use loctite on any of the bolts in the engines. I have a torgue wrench and I torgue all the 3mm bolts to 14 inch lbs. I do not torque them fully the first time. I torque them to 5 inch lbs, then 10 inch lbs, then the final time to 14 inch lbs. The several years I have been doing this, I have not had bolts come loose on engines.


David

[Dr.Ben]

Same here. Never loctited an engine bolt and never had one come loose on me. I use a Tork-It wrench in the manner David described. I do know for a fact that Yamada uses MUCH less torque at the factory on the bolts in their engines than OS typically does. Sometimes the bolts in an OS sound like a cap piston firing when they break free.

Ben Minor

[buster1]

well, I took Bonsai's advice and loctited the bolts down - I hope it doesn't cause a problem - seems like it wouldn't.
Thanks,
Jeff

[rcheliflyer]

well, I took Bonsai's advice and loctited the bolts down - I hope it doesn't cause a problem - seems like it wouldn't.
Thanks,
Jeff

I've done it both way's and have had no problems, some say the loctite
is defeated by engine heat, but I still think it helps some.
What I usually do on a new motor is go over all bolts paying particular attention to the head, no loctite.
After running if I can reach the head bolts I'll give them a snug, I have not had any loosen.