Compression

by andrew owen in 912 / 914 Technical Questions 6 years ago

Hi all, I have noticed when pulling through the prop to gurgle the engine that the compression on one cylinder is lower (pulls through top ded centre with less resistance) , after the engine has warmed up it’s fine, is this normal ? The engine is a 912ul with 350 hrs on the clock.
Thanks Andy.

Re: Compression

by Roger Lee » 6 years ago

Roger Lee

127 5.21k 4.79k

Normal. If you feel like you want to check it do a differential compression test.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: andrew owen

Report
Re: Compression

by andrew owen » 6 years ago

andrew owen

13 17 3

Thanks Roger, I take it this is done with the engine at running temperature,
Andy

Report
Re: Compression

by Roger Lee » 6 years ago

Roger Lee

127 5.21k 4.79k

I did a research project with a 12 912 engines. I did a compression test cold and hot on each engine. Really no difference. A couple may have had 1 psi difference, but that isn't enough to worry about. This just goes to show the tight tolerances of this engine vs a Continental or Lycoming. I do most of them cold anymore. I use 87 test pressure and usually get 84-86 psi on a cold engine.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Report

You do not have permissions to reply to this topic.

Title	Category	Replies
Compression test	General Tech Discussion	12
compression problems	2 Stroke Technical Questions	1
914 fuel line compression fitting	912 / 914 Technical Questions	1
low compression until starting	912 / 914 Technical Questions	3
Low compression low hours 912uls	912 / 914 Technical Questions	8

Compression

Recent Videos

Safety First!

ROTALK News

Prize Giveaway!

Log In/Out

Login