914 oil leaks from tappet covers

by Richard A Herber in General Tech Discussion 13 years ago

Engine 914 UL 300 hours
Impossible to stop minute oill leakage from the tappet covers.
To date three technical rotax repairman have failed to repair this problem!
New o rings from rotax were used each time without a good result.
Would appreciate some help.
Regards
Richard herber

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Re: 914 oil leaks from tappet covers

by Brian Mackie » 13 years ago

Brian Mackie

0 2 0

I have a similar problem with a 912ULS with 400 hours. The leak is from the right rear cover. We swapped the right front with the right rear cover, to no effect, so it can't be a distorted cover. Tried a gasket sealant. Still no cure. Have been recommended to use Loctite Superflex no 59675, which is on order. We later spotted that the 912 maintenance manual mentions a requirement for a min. 2mm gap between the rocker covers, presumably to avoid distortion and leakage if the two covers expand and contact each other. We'll be checking that, too. Keep in touch! :unsure:

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Re: 914 oil leaks from tappet covers

by Richard A Herber » 13 years ago

Richard A Herber

2 6 0

Hi Brian

I have noted there is indeed no gap at all between the tappet covers on both sides of the engine.
i have leaks on all 4 tappet covers.
Having looked at a brand new 914 UL engine this morning -it is clearly noted that Rotax have ground away a small portion on each tappet cover where they meet, to allow extra clearance.
i will be doing the same in the hope that this will solve the problem finally.
thanks
Richard

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Re: 914 oil leaks from tappet covers

by Brian Mackie » 13 years ago

Brian Mackie

0 2 0

Hi Richard. If that works, please let us know. We'll report back on the sealant, too, in due course.

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Re: 914 oil leaks from tappet covers

by Ted Norris » 13 years ago

Ted Norris

22 47 0

If you don't succeed in stopping the oil leaks there's a way to do it, with the cover off cut plastic film, like Saran Wrap, spray it with Pam or just put oil on the surface that the RTV will mate to and apply it to the mating surface on the engine, put a 3/32 line of Hi Temp RTV on the cover, it's hard to do this but don't worry about it, read on, install the cover finger tight but snug and let it cure over night, do not cover the RTV, it has to be exposed to cure, after it's cured pull the cover and with a new razor trim the excess off, the plastic will peel right off, you can now tighten the cover down and have a perfect seal that has formed to any irregularities that may exists and wont leak, been doing this on motorcycles and noisy car/truck windows for years and it works.

It's a good idea to mark each head with the cylinder number to keep them mating to the cylinder they were mated to.

For those of you that don't know RTV= Room Temp Vulcanizing

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Re: 914 oil leaks from tappet covers

by Richard A Herber » 13 years ago

Richard A Herber

2 6 0

Hi Ted

Many thanks for your reply with regard to the RTV gasket method.
I am not entirely clear on your proceedure.
To clarify, as I understood your mail - PLEASE CORRECT ME where I am wrong so I can proceed.

1)Cover the engine side of the tappet cover with a plastic cling wrap or film.
2)Apply a releasing agent such as oil to the film on the side facing the tappet cover (outwards).
3)apply a bead of RTV silicone liquid gasket to the tappet cover.
4)lightly secure the tappet cover to the engine allowing the bead of RTV to make contact with the plastic film- then leave overnight.
5) Peel off the film the next day and secure the tappet cover in place.

Let me know if I am corrent - and correct me as soon as you can

Kind regards
Richard

Thank you said by: Dennis King

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914 oil leaks from tappet covers

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