valve spring insulating washers

rebuilding my RH 10 head... there was only insulating washers under the exhaust springs only... I'm replacing the springs with kimblewhite stock 850 springs, just devived today....( the springs removed are 3 piece 2 springs & dampener...alot heavier duty ) It would make since to me to have insulating washers under all 4 springs... we ride alot in the hot Florida summers & taking this all into consideration with oil cooler & exhaust wrapping .... The manuals I have just shows them under the exhaust ..... I'm thinking this would be preventive maintenance for premature valve spring heat fatigue/ failure..... Probably no clear answer just owners preference..... I would get me a parts manual if the was not such a bastard project going vertical with 73 cases , G15 750 crank, 850 top with which Jim Comstock balanced, in a matchless frame... Good Grief.... Although I'm just about at the finish line...
I will here this beast come to life soon

The meaning of life, is to live it
Tripower

I've only seen the insulating washers under the exhaust springs.

Be sure and check the installed spring height.

Also check how installing the insulator may affect the way the bottom spring seating collar will sit on value stem as will as possible coil binding issues.

I have just fitted R&D springs with titanium collars to my Hemmings big valve head it has bronze guides which are of a different style for inlet than exhaust. So insulator fits happily on exhaust but on inlet it fouls on the shoulder that bottom spring collar fits against.

The PO fitted 4 isolation washers when head was stock but i have higher lift PW3 cam so am just fitting 2 under exhaust. Here in England water proofing electrics is far more of an issue than heat build up :lol:

Check the valve spring installed height and install insulating washers if there is room. There probably will be. Jim

When I fitted KW valves and springs there was not enough room to fit the insulating washers as the springs would have gone coil bound at full lift.
I run it without the washers on the advice of various people including the knowledgable folk here.

Just off the top of my thoughts...The exhaust springs need insulators because exhaust ports have super hot gasses flowing. Intake spring maybe don't because intake ports have a cool mix running through. Sounds good to me.

comnoz said:

Check the valve spring installed height and install insulating washers if there is room. There probably will be. Jim

Click to expand...

Gidday All.
For years my poor ol thing ran in Western Queensland. Mt Isa, Clermont, Emerald. summer ambient temperature average. 35 centigrade. did not do much harm, but gee it ran a bit hot sometimes

Mostly had no problems but once on a hard run between Mt Isa and Townsville I burned an exhaust valve. I never found the cause. replaced the valve and all was good for years again. it could have been the heat

So they can run OK in high heat.

But, Jim is absolutly correct. If they can be fitted to inlet they should . if there is no room perhaps Jim would tell us how to make the room please.
any thing that increases the likely hood of better reliability sounds good to me.
Best wishes Aussie bradley

I would agree, intakes can get along without them but if there is room I would use them.

The exhaust valve spring definitely lasts longer with a insulating washer under it.

I make room for washers by machining the collet groove higher on the valve. That is usually needed with KW performance spring kits but their stock replacement kit usually gives enough room with no mods. Jim

That's good info..... I just found a cd for a 850 part list publication, that also includes 750 models from 212278... I should have purchased it a long time ago... Good reference's, with good break down on all components of the commando... it does show the break down of the head with washers under all springs... other good to know information is that the valve guides on the 850 takes circle clips on the valve guides..... I was about to throw the head in the oven & put the new bronze guides in with out them... after a closer inspection I noticed the groove under the flange I don't know if it would have mattered, but glad I caught

You live by the judgmental calls you make.....Tripower

tripower said:

That's good info..... I just found a cd for a 850 part list publication, that also includes 750 models from 212278... I should have purchased it a long time ago... Good reference's, with good break down on all components of the commando... it does show the break down of the head with washers under all springs... other good to know information is that the valve guides on the 850 takes circle clips on the valve guides..... I was about to throw the head in the oven & put the new bronze guides in with out them... after a closer inspection I noticed the groove under the flange I don't know if it would have mattered, but glad I caught

You live by the judgmental calls you make.....Tripower

Click to expand...

Bronze 850 guides with a flange do not use circlips. Only the flangeless guides need a circlip. Jim

That good information coming from you Jim... I will make a note..... that's what I thought also being a flanged guide... it is interesting that there is a groove under the flange to receive a circle clip ... Thanks Your knowledge is well taken... Tripower

tripower said:

That good information coming from you Jim... I will make a note..... that's what I thought also being a flanged guide... it is interesting that there is a groove under the flange to receive a circle clip ... Thanks Your knowledge is well taken... Tripower

Click to expand...

The groove is just a way of eliminating a stress riser. It is not meant to hold a circlip. Jim