G80CS Pushrod Tube Sealing

[Iron Head]

This follows on from my earlier post about lapping-in versus a head gasket on a ‘54 G80CS. I'm completely confused about what seals, washers whatever should be fitted on my pushrod tubes. In the light of my ‘48 G80 tubes ‘rising' and leaking due to seals not compressing properly I'm keen to find a proper fix.

Currently since someone did a head job likely in the 60's I simply have nice chamfered bottom seals and a decent length rubber tube seal in the head and all was totally oil right. I now have the top tube seals that come with the gasket sets from AMC Classic Spares and the heavy ‘O' rings to fit the bottom of the tubes. I'm going to fit a Cu head gasket so will have a bit more overall length to take up.

What is the definitive sealing system that clamps up, seals and stops the ruddy pushrod tubes rising. Seems to me that all that is required is top rubber sleeves about twice as long (as my old ones are) than you get in the sets?!

Any guidance much appreciated.

Iron Head

[SPRIDDLER]

I've always used BS210 Nitrile 'O' rings at the top in place of the rubber 'tube' section, keeping the dished and flat washers and using the standard thick 'O' ring at the base of the p'rod. Never had any trace of a leak.

100_1420 (640x480).jpg

BS210 Nitrile.JPG

[Plugsnpoints]

I've always used BS210 Nitrile 'O' rings at the top in place of the rubber 'tube' section, keeping the dished and flat washers and using the standard thick 'O' ring at the base of the p'rod. Never had any trace of a leak.

100_1420 (640x480).jpg

BS210 Nitrile.JPG

These are exactly what I have used on my M16 recently Neville. Not even a hint of a weep so far. The original tubing type supplied in the gasket set wasn't good at all.

Andy

[Iron Head]

Thanks guys these ‘O' rings look like the answer. I have no plain or dished washers fitted at all can I do without ‘em if I use a stack of the ‘O' rings? If not and I need washers and ‘O' rings I have seen 19mm x 25mm copper washers on line which look like they might do the job.

Iron Head

[SPRIDDLER]

Unless I've completely the wrong end of the stick you should have an arrangement like this, but using 'O' rings instead of the top sleeve.
Aren't the correct washers available from usual AMC parts suppliers?
The missing washers are part of your leaking issue. Without the dished washer the bottom of the rubber sleeve will gradually creep down the top of the p'rod.
Over time the 'standard' rubber sleeve heat and age hardens until it resembles Bakelite.

Pushrod tube washers and seals.JPG

Grease the 'O' rings and fit as many as will leave about a 1mm gap at the bottom of the tube when the head is tightened down. I can't remember how many I used but I think it was 5. If the bottom of the p'rod tube is hard against the c/case the p'rod bottom flange will split.

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Pushrod tube should move a tad (640x480).jpg

[g80csp11]

Nev, just to be clear the steel washer at the bottom is only fitted when a compression plate is fitted

[SPRIDDLER]

Nev, just to be clear the steel washer at the bottom is only fitted when a compression plate is fitted

Indeed. Same with the 'extra' washer 'A' at the top, depending upon year, as written on the illustration. Always assuming that the correct length p'rods are fitted.

[clive]

Just a note, the bottom flange can split if using new pattern pushrod tubes. The original ones were rolled over very slightly at the top to ensure they settled inside the top washer as the head is tightened down. Some early pattern ones had too much rolled over and wore the pushrods. Later ones have little or no roll over. They can be used provided they are well fitted in the head before bolting down ensuring they fit centrally in the top washer. If thy bind the bottom flange will split as you tighten it down. Yes been there....

[Iron Head]

Have ordered my missing concave and plain washers for my model and year from AMC Classic and have ordered Spriddlers recommended size O rings but have gone for Viton. Should be good for around 300 degrees C service?! Got 50 for £20.00 delivered so if anyone needs any let me know. Thanks for everyone's help.

Iron Head

[arty]

Been following this thread as my 55 G3LCS has the same problem even after fitting new rubber seals and steel washers, would be interested in how many O rings it takes to seal and if its successful.
Cheers Arty