Oil leak from front cover of the Gipsy Major

Terry Lee · Post by **Terry Lee** » Sun Feb 13, 2011 1:23 pm

I note that DH support ran an article in one of their news letters on this subject suggesting there's easy cure. has anyone read this article? and if so could they pass on the information.

My engine is the 10-1-1, the leak isn't bad but I find that flying for more than half an hour results in enough oil escape to find its way down the rear of the prop and then onto the windscreen in small droplets.

I would be keen to hear from anyone who's had similar problems especially if you've found a cure.

Thank you

Dave Reid · Post by **Dave Reid** » Thu Feb 17, 2011 9:08 pm

I haven't seen the DHSL article and I personally, I can't believe there's an easy cure for any engine problem!
I have had the same problem with my engine, albeit a Gipsy Major 1H. Oil on the windscreen would indicate it coming from a pressurised crankcase and finding its way out through the prop shaft.
I tried changing the front thrust cover (same setup on a 10 series?), but that wasn't the cure. The proper fix for mine was a rehone of the bores, some new pistons, rings etc - of course, we did more, as the engine was in bits. It wasn't a cheap fix, but it was a good fix, and I've flown some 150 hours (18 months later), with no problem.
If it's a Permit aircraft, you might be able to do a fix with a proper oil seal on the front, rather than the labyrinth-type seal on mine (not permit, sadly). It looks like that could be an easy fix... Maybe that's what the article was about?
Good luck...
Dave

ROB THOMASSON · Post by **ROB THOMASSON** » Wed Feb 23, 2011 7:10 am

Before you go spending lots of money it might be worth checking the oil breather system out. There's a large oil catcher on the right hand side. If this blocks the crank will pressurise and blow oil past the end of the crank.
I've not had this on the Gipsy but other engines of the same vintage have this problem.

Terry Lee · Post by **Terry Lee** » Wed Feb 23, 2011 8:28 pm

Guy's, thank you for your input, thought I'd just update. we'd checked compressions anyway and they were all good. ''Rob what do you mean'' 'large oil catcher on the right side' ?

My breather exits the crankcase at the rear, and is piped to the atmosphere at the bottom rear of the cowl I've checked that it is clear!
Anyway, I spoke to Deltair today as I had found a Mod, 1840, which replaces the front cover with one that has a weston type oil seal incorperated but alas it is for Gipsies with the SBAC splined crankshaft. But they do a replacement front cover with the front opening machined to the smallest size possible, so I think my best option will be to try that.