Compression check

Service and maintenance tips, questions, and issues.

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seneca2e
Posts: 395
Joined: Mon Feb 11, 2008 10:35 pm

Compression check

Post by seneca2e »

Normal procedure in checking a piston engine is to grasp the prop and bump in back and forth on tdc to obtain the best compression reading you can get. That's a little hard in a Brantly lol. So far I've just resorted to man handling it by grasping the flywheel but of course you pretty much have to have it on tdc and not move it any. Is there a flywheel tool or ?? that you use to be able to easily rock it back and forth around tdc? I'm pretty sure there is but I've just not run across one yet. Come to think of it maybe I should look at the generator nut or fans as a possibility?? What about it? How do YOU do it or HOW have seen it done?
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Ron Spiker
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Re: Compression check

Post by Ron Spiker »

We use a 3' flat steel bar with 2 holes in one end that mate up with the flywheel. The bar goes below the flywheel and put the 2 bolts up through and the nuts on. Nuts don't have to be tightened down. I find it easier to do from the left side of the helicopter, with the bar in about the 10-11 o'clock position (if looking down from above, with 12 o'clock being to the front), or wherever the holes line up, with the other end that you hold heading back towards 7-8 o'clock. Have one person hold the end of the bar tight to keep from spinning. Definitely don't want to be doing that by hand.
seneca2e
Posts: 395
Joined: Mon Feb 11, 2008 10:35 pm

Re: Compression check

Post by seneca2e »

Thanks Ron! That's a simple but effective method-sounds good to me!
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