The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: cosmikdebriis on 13.03. 2012 12:27

Title: Anybody tried fitting stem seals?
Post by: cosmikdebriis on 13.03. 2012 12:27
Leading on from the thread about oil leaks...

I just wondered if anybody had tried fitting stem seals to the valve guides?

I would have thought that before fitting new guides it would be fairly easy to turn the outer on a lathe to accept stem seals from a car?

If anyone has done it I'd like to know what seals he/she used?
Title: Re: Anybody tried fitting stem seals?
Post by: chaterlea25 on 14.03. 2012 20:33
Hi Cosmic,
Yup  *smile*
The guides can be machined to take Triumph T140 seals
My Super Rocket has this mod, and has been great for 10 years
HTH
John O R
Title: Re: Anybody tried fitting stem seals?
Post by: t20racerman on 14.03. 2012 21:32
Mine has them on the inlet valves only. My head was gas flowed and new seats fitted, and the company that did it - wimbledon cylinder head services - recommended seals only on the inlets. You have to open the slide up a bit with a file though as otherwise at tick over, the engine sucks through too much fuel which washes down the bores causing wear. The head company were really insistent that this was done - as the seals stop air from coming down the sides of the valves when the throttle is shut.
Title: Re: Anybody tried fitting stem seals?
Post by: Tumbleweed on 19.04. 2012 15:31
hi chaterlea25 . where can i get t140 valve stem seals tms arent listing any ? cheers tw
Title: Re: Anybody tried fitting stem seals?
Post by: sprint on 21.04. 2012 20:33
hi chaterlea25 . where can i get t140 valve stem seals tms arent listing any ? cheers tw

Try Wilemans or LP Williams
Title: Re: Anybody tried fitting stem seals?
Post by: chaterlea25 on 21.04. 2012 21:15
Hi Tw
PM replied to

Regards
John O R
Title: Re: Anybody tried fitting stem seals?
Post by: duTch on 22.04. 2012 14:23
If it's any help, I jammed on mine some that I think come from a Gemini,(maybe Oz equivalent of a Vauxhall Vivas' little sibling/cuz -'70-80's), just about a 2mm or so square section 'O' ring and as I think someone said a while back that they maybe don't do much, except stop any excess running down, as they sit at the top of stem/end of down travel, but I can't see it doing any harm??
         Put 'em on a long time ago but as the maggie shat itself soon after, I'm still getting it back up'n running so can let you know later. cheers ,duTch
Title: Re: Anybody tried fitting stem seals?
Post by: muskrat on 13.01. 2019 18:46
G'day fellas.
Next time I do the guides I'll try these.
https://tinyurl.com/y97o7d5x
Cheers
Title: Re: Anybody tried fitting stem seals?
Post by: JulianS on 13.01. 2019 22:43
My A10 alloy head has used Norton seals on the inlets for many years. Very happy with them.  I do remove the garter spring before fitting the valves.
Title: Re: Anybody tried fitting stem seals?
Post by: mikeb on 14.01. 2019 03:18
would you bother to fit them to exhaust guides Musky?
Title: Re: Anybody tried fitting stem seals?
Post by: Klaus on 14.01. 2019 06:43
No seals on the exhaust guids, they are not nescessary. Exhausts blow, so no oil will sucked up. If oil appers in exhaust the pistonrings and or the guides are badly worn.

cheers Klaus
Title: Re: Anybody tried fitting stem seals?
Post by: muskrat on 14.01. 2019 11:58
I agree with Klaus, inlet only.
I had a hard time finding an "air leak" in a mates A7 until I ran it without the tappet covers and sprayed WD at the valves.
Why do you remove the spring Julian?
I just wonder if there's enough clearance between the top of the seal and the bottom of the collar at full lift, especially with a 357 cam.
Cheers
Title: Re: Anybody tried fitting stem seals?
Post by: JulianS on 14.01. 2019 12:17
Spring removed to avoid any chance of it coming off, getting chewed up and causing damage in the engine.
Title: Re: Anybody tried fitting stem seals?
Post by: muskrat on 14.01. 2019 12:46
Fair call. The Kibblewhite ones (link in previous post) don't have a spring and are viton.
Cheers
Title: Re: Anybody tried fitting stem seals?
Post by: JulianS on 14.01. 2019 13:45
There was enough clearance for the 357, thats what was fitted in the bike, the guide is shortened when machined for the seal.