1961 Matchless G3 head change.

[Ianwilko13]

Hi all, my 1961 Matchless G3 came fitted with the wrong head (an earlier type with the longer pushrod tubes) I now have the correct head for the year, I think that the valves and associated parts will switch on to my correct type head, I don't expect to gain anything as my present head works well, please feel free to correct any of my assumptions, kind regards, Ian.

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[Ianwilko13]

Too late to turn back now, very pleased to discover plenty of oil around the piston skirt and everything below it having just completed a 25 mile run, the bore is at 70mm with no apparent wear, no need to remove the piston just remove the carbon, paint the barrel and fit a new base gasket, please let me know if I'm doing anything wrong, best regards, Ian.

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[clive]

All looks good to me. The valves etc should be compatible and transfer over ok.

[Ianwilko13]

Thanks for the reply Clive, it was running well before, but I acquired the correct head and wanted it right, also wanted to look inside as I don't like surprises, I have purchased the shorter pushrod tubes and various seals/washers and have my valve grinding stick at the ready, thanks again for the information, Ian.

[dave16mct]

Use O rings on the pushrod tube tops. The club sell Viton O ring sets for this. The sleeves in the gasket sets always leak.
Dave

[Ianwilko13]

Hi Dave have brought the bevelled washers plain washers and also the rubber sleeves and stainless pushrod tubes from the club spares scheme, the sleeves are very tight in the head will this be o.k.??? base gasket was a mile out

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Ian.

[dave16mct]

The sleeves are OK if you don't mind oil leaks. That gasket doesn't look right at all.
Dave

[Ianwilko13]

Hi Dave, the base gasket holes next to the pushrods were too close together?? have had to slot them to fit and have used "Threebond" as a sealant, I'm sure that it will seal, the head that I removed didn't leak from the pushrod tubes, even though it only had the rubber sleeves with a single bevelled washer at the top?? it's still not too late to purchase the "viton" O rings, I just need a bit more convincing, best regards, Ian.

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[dave16mct]

The sleeves are OK for a while until they harden then they leak. I've used neoprene O rings but the Viton ones are better. They will stand higher heat. Do a search, see what others have used.
Dave

[Ianwilko13]

Thanks Dave, will check previous posts, best regards, Ian.