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Leaking cylinder head valve cover

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JonathanMilbank

Joined: 14 Apr 2012
Posts: 390
Location: Aberdeen area

Posted: Mon Jun 05, 2023 3:08 pm Post subject: Leaking cylinder head valve cover

I'm given to understand by someone who has a very slightly leaking valve cover that he's tried after-market O-rings, which didn't seem to make much improvement. He even tried Hylomar Blue around the outside edge of the O-ring, before replacing and tightening the cover, to avoid Hylomar getting into the oil system. However the leak soon reappeared.



My suggestion was to buy a piece of slightly thicker O-ring material, cut it to the required length, glue the ends together, fit this new O-ring into the groove with the join at the top, then see whether that stops the oil leak.



Has anyone already done this and exactly what thickness and type of make-your-own O-ring was obtained and from where?

Matt Dovey

Joined: 13 May 2017
Posts: 48
Location: st albans, england

Posted: Tue Jun 06, 2023 10:35 am Post subject: Re: Leaking cylinder head valve cover

If its a Rotax, why not buy a rocker cover O ring from Rotax!! It will take the guess work out of it.

trevord

Joined: 10 Jul 2018
Posts: 36
Location: Auckland

Posted: Tue Jun 06, 2023 10:46 am Post subject: Leaking cylinder head valve cover

If you do the valve collet upgrade, the kit includes new rocker cover o-ring seals ..

Regards Trevor

Sent from my Galaxy



-------- Original message --------

From: Matt Dovey <mattdovey(at)hotmail.co.uk> 

Date: 7/06/23  6:39 am  (GMT+12:00) 

To: europa-list(at)matronics.com 

Subject: Europa-List: Re: Leaking cylinder head valve cover 



--> Europa-List message posted by: "Matt Dovey" <mattdovey(at)hotmail.co.uk>



If its a Rotax, why not buy a rocker cover O ring from Rotax!! It will take the guess work out of it.





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http://forums.matronics.com/viewtopic.php?p=510920#510920

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JonathanMilbank

Joined: 14 Apr 2012
Posts: 390
Location: Aberdeen area

Posted: Tue Jun 06, 2023 11:47 pm Post subject: Re: Leaking cylinder head valve cover

Neither the Rotax factory supplied O-rings (via a UK agent) nor the after market items which are supposedly slightly thicker have stopped the very slight leak.

Matt Dovey

Joined: 13 May 2017
Posts: 48
Location: st albans, england

Posted: Sat Jun 10, 2023 1:47 am Post subject: Re: Leaking cylinder head valve cover

It would seem that the O ring is not the problem. Must be damage to the head or rocker cover

JonathanMilbank

Joined: 14 Apr 2012
Posts: 390
Location: Aberdeen area

Posted: Sat Jun 10, 2023 8:15 am Post subject: Re: Leaking cylinder head valve cover

Cover checked in an engineering workshop and found to be flat i.e. not distorted. Head contact surface for O-ring not scratched or cracked. It would be difficult to distort the head, I think, without losing compression. Thanks for the suggestion.

Rick Moss

Joined: 21 Sep 2014
Posts: 96

Posted: Mon Jun 12, 2023 1:19 am Post subject: Re: Leaking cylinder head valve cover

If you swap 2 rocker covers around, does the leak move with it or stay on the same cylinder?

JonathanMilbank

Joined: 14 Apr 2012
Posts: 390
Location: Aberdeen area

Posted: Mon Jun 12, 2023 8:07 am Post subject: Re: Leaking cylinder head valve cover

Difficult to say! Having used "sticky stuff" carefully applied outside of the O-ring of another cover to avoid contaminating the oil and not remembering which cover it was, we're reluctant to open another can of worms. We'll just experiment with different sealants (Hylomar Blue didn't work) until we find something which does the trick. The leak is miniscule anyway.

Area-51

Joined: 03 May 2021
Posts: 395

Posted: Tue Jun 13, 2023 10:49 pm Post subject: Re: Leaking cylinder head valve cover

181's 80hp had weeping forward covers upon purchase... both covers were removed and o'rings inspected for condition and seating height; all were sufficient... both covers were assessed for warping with none identified... both head surfaces were inspected for burring, scratches and other damage; none identified... both covers and o'rings reinstalled with a smear of OEM factory assembly grey engine sealant and left to cure.... just pulled the cowls after 50hrs for service; both front covers weeping as before... pulled the worst one for another inspection, refit and reseal... will check situation again after next 5hrs...



Possible causes... High crankcase pressures and component warping at temperature; possible but unlikely... Component Porosity; possible; replace faulty component and monitor for further 5hrs operational time... Heat expansion of the retaining bolt; possible; remove all covers, remachine o'ring channel for thicker o'ring, ensure 0.040" o'ring height above cover face, refit retaining bolt with Loctite, ensure 0.020" expansion gap between cover and head, inspect retaining bolt tension and visual for leaks after first operational hour.

peterz(at)zutrasoft.com
Guest

Posted: Wed Jun 14, 2023 1:57 am Post subject: Leaking cylinder head valve cover

Try some hylomar blue.  Great stuff.



Cheers,

PeteZ



 	  Quote: 	
		   On Jun 14, 2023, at 2:55 AM, Area-51 <goldsteinindustrial(at)gmail.com> wrote:

 

 ï»¿

 

 181's 80hp had weeping forward covers upon purchase... both covers were removed and o'rings inspected for condition and seating height; all were sufficient... both covers were assessed for warping with none identified... both head surfaces were inspected for burring, scratches and other damage; none identified... both covers and o'rings reinstalled with a smear of OEM factory assembly grey engine sealant and left to cure.... just pulled the cowls after 50hrs for service; both front covers weeping as before... pulled the worst one for another inspection, refit and reseal... will check situation again after next 5hrs...

 

 Possible causes... High crankcase pressures and component warping at temperature; possible but unlikely... Component Porosity; possible; replace faulty component and monitor for further 5hrs operational time... Heat expansion of the retaining bolt; possible; remove all covers, remachine o'ring channel for thicker o'ring, ensure 0.040" o'ring height above cover face, refit retaining bolt with Loctite, ensure 0.020" expansion gap between cover and head, inspect retaining bolt tension and visual for leaks after first operational hour.

 

 

 

 

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SPURPURA

Joined: 04 Apr 2015
Posts: 68
Location: KAPV

Posted: Wed Jun 14, 2023 4:43 am Post subject: Re: Leaking cylinder head valve cover

Iâ€™ve had that problem before. I installed the o ring as usual then clean off the oil from the face and valve cover. Apply the same sealant used for the gearbox onto the cover and o ring and let cure for an hour before installing. Worked for me.

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timothyferriss

Joined: 20 Jun 2023
Posts: 8
Location: USA

Posted: Tue Feb 06, 2024 7:18 pm Post subject: Re: Leaking cylinder head valve cover

Forums or online communities dedicated to DIY automotive repairs may have members who have experience slice master with similar issues and can provide specific recommendations based on their experiments

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