Sealing Wyvern valve guides

[Andrew EvansParticipant @andrewevans67134]

[Andrew EvansParticipant @andrewevans67134]

Hi All

I am half way through building the Wyvern IC engine with castings from Hemmingways Kits and am currently making the bronze valve guides. These are bolted onto the cylinder head. I made the first one slightly loose in the head in error – about 0.002" too small. Can anyone advise if I can use something like Hylomar blue to seal the guide in the head or should I remake the valve guide? I believe Hylomar has a max temp of 250C will the head get that hot do you think?

thanks in advance. Andy

[alan-lloydParticipant @alan-lloyd]

Andrew, scrap it, re make the valve guide, I'm not familier with the design, but if it comes loose it could wreak your engine, Regards Alan

[JasonBModerator @jasonb]

Rod should be along later, He has just finished a Wyvern and did mention what he used to seal the valve guides the other day when discussing Jo's Centaur which is very similar. Should not need to scrap them and one of the liquid gaskets should do the job.

[Roderick JenkinsParticipant @roderickjenkins93242]

Here I am

I used this . Even if it degrades with temperature I think it will still provide a seal. Mines been OK so far, the compression has improved with use. Sealing the valve guides (or guides if you've modified it like most of us have to cope with the ally cylinder head) is tricky so a bit of goo helps. Alan's caution is sound but in this design the piston doesn't go anywhere near the valves so I have no fear that a loose valve guide could cause havoc.

Cheers,

Rod

[Andrew EvansParticipant @andrewevans67134]

Thanks All.

Rod, like you, I modified the exhaust guide so it is similar to the inlet guide. It's quite awkward to get a tight fit, the head itself seems a bit flimsy to achieve a press fit and there isn't much spare metal there.

I don't think the guide will come loose as it is bolted on it is more for gas sealing. I will try the silicone. There is also a lip at the bottom of the guide which ETW recommends can be ground in. I will try doing that with fine valve grinding paste.

cheers Andy

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