MK1 Valve guide seals

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camstevens
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MK1 Valve guide seals

Postby camstevens » Thu Aug 27, 2020 5:33 pm

Hi All
I have my MK1 engine apart again to sort out some problems (was a heart-wrenching thing to have to do, but need to look forward positively as I've found the root causes). Whilst to the engine is apart, I'm considering having guide seals fitted and wondering what the general consensus was on this as to whether it was rather unnecessary (t**d polishing?) or if it really does make a positive difference. One positive of not fitting them is not having to risk damaging the head.

Cam

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simon.holyfield
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Re: MK1 Valve guide seals

Postby simon.holyfield » Thu Aug 27, 2020 6:16 pm

I don't have them; mine doesn't smoke.
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Re: MK1 Valve guide seals

Postby JohnnyBeckett » Thu Aug 27, 2020 6:55 pm

HI I would not use guide seals, you need to get a bit of oil down the guides to stop them wearing and nipping up wen they get hot :!:

camstevens
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Re: MK1 Valve guide seals

Postby camstevens » Thu Aug 27, 2020 7:03 pm

That sounds sensible, and as per Simon's response I'm pretty certain my oil problems were not coming from above.

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simon.holyfield
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Re: MK1 Valve guide seals

Postby simon.holyfield » Thu Aug 27, 2020 7:06 pm

I should add that mine has a Morgo fitted and runs at 50-75 psi. I have the small pipe to the rockers.
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Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
http://ariel-square-four.blogspot.com

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paul.jameson
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Re: MK1 Valve guide seals

Postby paul.jameson » Thu Aug 27, 2020 7:37 pm

I once fitted them to my first 4G. They didn't do much good and within 1000 miles or so they had gone hard, fractured and were lying in the rocker box. They might work in a water cooled car but not in a Square Four.
Paul Jameson
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Re: MK1 Valve guide seals

Postby paul_turner » Thu Aug 27, 2020 8:15 pm

Were the ones you fitted like the old BMC ones Paul ? a bit like a plastic umbrella ? I had heard they had a tendency to go hard with the heat. I had a discussion with Cynric Richardson about this as he fitted modern seals over the top of the guide to his 4g's with great success . It looked really tight amongst the double valve springs but they were in there. I take Jonny Beckets point on board but when you look at the seals they have what I would describe as rifled flutes on the inside to allow some oil down the guide but not too much. I'm going to give them a try on the next mk2 so will report back but dont hold your breath it a good way down the line !

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Re: MK1 Valve guide seals

Postby john.whiting » Fri Aug 28, 2020 12:16 am

Been mentioned many times here before ......valve stem seals have a very short life in a S 4 due to the heat being much in excess of what the rubber can take..........putting seals in my 4G was a waste of time,and I dont think a Mk1 runs much cooler in the head.....I suggest putting seals on the intakes only ,due to cooler running.You may also get scoring on the exhaust stems with seals ......IMHO ,the exhaust has some backpressure which tends to stop oil running down in operation..

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Re: MK1 Valve guide seals

Postby paul.jameson » Fri Aug 28, 2020 9:15 pm

My oil seals were BMC type, like a small thick O ring, if memory serves correctly. My 1948 4G was usually fitted with a sidecar, often containing a young lad called Rob, and was used for some long journeys, so possibly worked rather harder and got warmer than Cynric's solo bikes.
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Re: MK1 Valve guide seals

Postby nevhunter » Sat Aug 29, 2020 12:57 am

I think that would work fine. If i recall correctly a thin formed stepped washer went on first on top of the springs then the "O" ring dropped in and the colletts and normal retainer went above it. Nev


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