Hardened valve caps

Hello John thanks for that. i will leave them on the 19s valves that will be fine. i was just concerned if my es2 will run ok without them as i haven't run it as yet. i have just had the head done so i wanted to get it right. i cant see any listed in the manuals i have. so i think its a case of just run it as is. Baz

Previously andy_marks wrote:

Hi Barry

I've never seen any mention of hardened valve caps for the ES2 in any of the manuals or the parts book. I don't have them fitted in my '51 ES2, it's done about 1800 miles since rebuild and is now in bits again (unrelated problem), there appears to be no real wear to any of the valve gear so it will all go back as is.

Regards

Andy

Hello Andy, thanks for that. cant find anything about them myself. so i think its a case of build it up and just run it. Baz

Previously ian_cordes wrote:

I don't suppose a compression plate is fitted under the barrel? The lash caps would then restore normal valve clearances.

Hello Ian . i cant see any compression plate under the barrel. i cant understand why they are fitted unless someone in the past has added them for some reason. like you say for a compression plate which they may have discarded but they still left the the caps fitted . Baz

Previously ian_cordes wrote:

Hi Barry.They could have been added for a number of reasons. I don't know about the singles, but different valve lengths were used in the twins at different times, and these caps add about .040" to the valve stem length, which may compensate for something which was done in the past. A previous owner may simply have fitted them in order to prevent wear on the end of the valve stem, assuming there was sufficient leeway in the valve clearance adjustment to accommodate them. I would be inclined to visually check the angle of the rocker to the valve as each one opens, as increasing the valve length will alter the angle, for better or worse. If the angle is wrong, it could increase valve guide/stem wear, as well as altering the valve opening a little. If all seems ok, I would be inclined to leave them in.

Hi Ian, yes i think i will leave them in. there must be a reason for them being there. Baz

Previously tony_harris wrote:

In the latest RH Mike P has an artical about ths and he shows a picture and gives the amount the valve should be from the casting (48mm if I remember). Check this out with and without your valve cap. Make sure the end of the valve is hard to as this might be why the cap has been fitted.

Hi Tony, thanks for that. i will check the valves. i will have a look at the RH that will help me to have a better understanding as to why they would have been fitted. Baz

Previously dave_graham1 wrote:

My Manx has valve caps for the reason that there are no tappets to adjust and so you skim the cap to get the correct valve clearance.

There isn't this problem with the Model 19's as there are tappets to adjust. As valve seats wear and are regrounds, the valve stem would protrude more, not less. A cap on the valve would make the angle of the rocker worse. As already mentioned, the latest Roadholder states a max distance of 50mm before Mike Pemberton would change the valve seats to get the distance to 48-49mm. The only reason I can think of to fit caps would be if someone has ground the top of the valve stem to get the valve stem to head distance correct instead of fitting new valve seats in the head. A cheap and easy fix. If the seats were worn the head would be down on compression but probably wouldn't make that much difference on an old thumper used on the road.

Hi Dave thanks for that. like you say its an old thumper unlike your Manx a lot more refined setup. when i get to strip the engine down completely it will become clear why the caps were fitted . Baz

Previously jonathan_newton wrote:

May i suggest that it was just athingthat wasdonebackwhen owners "tinkered", Its acommon tweak especially on Triumph Twins (Anything to control thatclatter...). Ithink you will find its a mod discussedin PI's "Tuning for speed", givinglargercontactarea, allows fixing of the adjustment (used asashim) thusenableremoval of these partsfor weightcontrol. As long as you take care of the angles why not...

Hi Jonathan thanks for that. it gives me a better understanding as to why they were fitted. Baz