Valve guide help/advice please.

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David Tew
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Valve guide help/advice please.

Post by David Tew » Fri Nov 08, 2019 2:39 pm

I experienced a bit of a calamity this morning and would appreciate any advice or guidance.

Earlier this week I started the engine for the first time in about 24-months. It started easy enough but ran a little roughly, "putt-putting" as if the valve clearances needed adjusting. No problem, I thought. This morning I removed the rocker covers and noticed that some of the valves had huge gaps and it was clear these valves hadn't fully closed. Initially I thought the exhaust valve lead-free inserts had dropped but no, the valves concerned were the inlet valves.
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I've just removed one head and all three inlet valves were jammed partially open. On stripping the head further it became apparent that the K-line inserts had dropped and jammed the valves. :shock: I had to drive the valve out of the head. I have no idea how this has happened as the engine has only run for a few hours since I had the heads rebuilt by Vulcan a few years ago (it has been a long rebuild!). Could be varnish from the fuel, perhaps? I have read that unleaded heads need extra valve-guide clearance so perhaps this wasn't properly done in the first place.
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I managed to remove the inserts and drive them (with a very soft drift!) back into the head after liberally coating them with Loctitie 603 and they seemed a very tight fit. I coated the valve stems in moly grease and they now run very smoothly in the guides. However, I'm very unsure about leaving them like this. I do have some spare original heads but the heads fitted are unleaded and gas-flowed with screw-in rocker studs and don't really want to lose all that.
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Does anyone have any thoughts on whether the re-inserted guides will remain in place or should I look to get the heads reamed for larger guides, if you can get them? Any advice on the best place to get head-work done? I don't think I'll go back to Vulcan.

Luckily the pistons are unmarked as that would have really ruined my day.

Many thanks for any support. I'm going to close the garage door for the rest of the day! :hand:


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Valve guide help/advice please.

Post by scimjim » Fri Nov 08, 2019 4:33 pm

Bugger! Is the other side the same?

603 is good stuff but 638 would have been better.

If it was mine I’d run it (knowing you have backups if necessary).


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Valve guide help/advice please.

Post by David Tew » Fri Nov 08, 2019 5:25 pm

Thanks Jim. I was so disillusioned when I saw the LHS head that I haven't checked the other yet but I suspect it'll be the same. A job for the weekend.
I used 603 as I couldn't guarantee the surfaces were completely clean. I think the inserts are a designed to be a press-fit so anything is better than nothing.

I think you're right, I'll put it back together and see what happens. I have emailed Vulcan so I'l be interested to hear what they say.


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Valve guide help/advice please.

Post by gtcse8 » Fri Nov 08, 2019 7:59 pm

K Liners are SH*TE, I personally would not touch them, they are an interference fit in a reamed hole and because they are a split type, rather than a solid tube, they can slip out, as you have found.

IF your going to spend money on re furbishing valve guides it`s easier/cheaper (in most cases) safer, to just bore out the worn hole and press higher grade Iron sleeves into place.
You can then also use newer better oil seals.
The later heads used really good oil seals on ALL valves rather than the "Umbrella" type only fitted on half of the valves.

Done 50 or 60 heads over the years ( but could NEVER drum up enough business from Scim owners to keep my business alive ) and the best route is to fit AE branded guide sleeves.
They will UP grade early OVAL port heads to the newer type oil seals IF you have spent serious money on gas flowing.

Last month I did a set of heads that had exactly the same problem and had also dropped something into the engine that has buggered up the pistons on only one side??? :?:
They were Mr Wade`s gas flowed OVAL port heads and were an expensive job when Richard had them done.
Last edited by gtcse8 on Sat Nov 09, 2019 11:50 am, edited 2 times in total.


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Valve guide help/advice please.

Post by David Tew » Fri Nov 08, 2019 8:34 pm

Thanks Mark. I didn't know Vulcan had used the damned things until now.
The heads do have the later valve seals on all valves so I appear to have a b****ard mix (which is exactly what I called the heads earlier today!).

In your expert opinion do I now take a chance and leave the heads as they are or do I get them bored out for proper guides? If the latter, any recommendations on who could do the work? I don't mind paying again for a proper job and I suppose this would be my preference for future peace of mind ...... but don't tell the wife!

Cheers. :)


- My wife says I don't listen to her ...... or something like that! -
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Valve guide help/advice please.

Post by gtcse8 » Fri Nov 08, 2019 8:44 pm

David we have overlapped messages tonight. lol


Mark Wilson. See the Beast on youtube under" RELIANT SCIMITAR CONVERSION LOL.,Se5,Se5a, Se6a, Two Se6b`s,1 & 1/2 GTC`s, SST 1800Ti & not a lot of sense

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Valve guide help/advice please.

Post by David Tew » Fri Nov 08, 2019 8:53 pm

Thanks Mark, I'll PM you. :wink:


- My wife says I don't listen to her ...... or something like that! -
SE4B Coupe - rebuilt on brand-new chassis.
Bought in 1978 and an RSSOC member since. 😲

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