im rebuilding t140 head pre 79, im considering fitting steam seals, i read somwhere triumph fitted 'o' rings in 80,81,? instead of the 1979 seals. if this is correct can i fit these to early valves, is it worth it, did they work. or should i not bother. any opinions thanks
Your T140 guide can easily be modified to accept the Norton valve guide seal.
I have heard he "O" ring trick, but never seen it in a Triumph from the factory. The "o" ring finds its way under the valve collar and deflects the oil from running down the valve stem.
In comparison to other motors, the area around the guide is subjected to very little oil. If one was to modify the oil feed to the rockers, as discussed on other threads, it might make sense. In my experience it snuggles right in there with the Boyer - points; AMAL - Mikuni; etc discussion.
If this group is as predictable as I believe, what will follow is 60-40 split, with 40 for the oil seal and 60 against.
Now I would spend my time and effort buying REAL valves and REAL valve guides: Nitrided valves and guides made from real valve guide material, not free machining brass...
Btour, I'll not answer for John, but might try to repeat what I remember when asking the same type question when I saw 2 umbrella type seals in my gasket set when rebuilding my son's '66 TR6. More oil feed to the rocker shafts usually means running a pressurized feed from the oil pressure switch output up to the rockers. It was done by some guys who raced, but I don't know if it is a reasonable mod for any bike. The problem created is that the volume of oil goes up, and it has to drain through the same holes in the guideblocks, thus the oil can theoretically back up in the pushrod tubes and fill the rocker cavity. Then you need to enlarge the drain back holes, by how much? Who knows? The factory rocker feed seems adequate for street use and most if not all racing applications.
I mentioned the umbrella seal for your problem to band aid a possible sloppy valve guide. Chamfering would tend to make the oil slide off the outside rather than going down inside the guide, and maybe avoid fouling the plug. Either would help a guide that is marginal.
Bottom line for me, I didn't use the valve seals.
'Never argue with an idiot, they'll bring you down to their level, and beat you with experience'
I would go with John Healy on this one. The Meriden factory never fitted the O ring but Harris did to his Bonnies along with cast iron guides on some of his bikes,untill the UK dealers moane about them and went back to the normal bronze type material.
Bert: That seems like a simple question and there is a simple answer: emissions. But I get the feeling that you know this and want my opinion on using valve guide seals on Triumphs.
As far as emissions is concerned it is a problem in some states in the US. Thus in these localities I would certainly do what I had to do to get my bike to pass the emission tests. Fitting valve guide seals is certainly one of them.
If I was doing a customer's "E" bike, again I would install the seals. It seems to be custom in this industry to blame the previous mechanic for all sorts of unrelated problems... That **** healy didn't fit the valve guide seals, that is why I have to charge you $3,000 to replace the main bearings. The last mechanic never seems to have done anything right in this business!!!
If it was for my personal bike here in Massachusetts, where we do not have emission testing for motorcycles, I would do what I have been doing for years... not fit them.