Shim replacement...before and after a "valve job"

Ok so since my head is coming off to do the head gasket I was pondering:

I've checked the tolerances already and am replacing/swapping around 7 of the 8 valves. If I decided to replace the valve stem seals/have a valvejob done at a shop do you think it would greatly effect the shim clearances? As it is with the new shims they will all be on the loose side of spec.

Finally, how much would a shop charge for this kind of head work?

 

If part of the valve job includes lapping/grinding the valve seats and/or re-facing the valves....which it should include......then yes, that will change the clearances.

Prices will vary by locality and competency of the shop, but figure about 3 yards and you're in the ballpark......

 

Yep, a "valve job" will completely level the playing field, shim-wise; you'll be pretty much starting over. Remember shims come in .05mm increments, that's HALF a TENTH of a MILLIMETER. Doesn't take too much "lapping" to change things that much...

 

3 Yards?? hmm sounds excessive. Maybe just replace the seals myself and lap the valves....

 

by yards you mean hundred? never heard that one before...

so, theoretically, a valve job could get previously tight clearances within spec?
i'd still bolt the cams back on and set the timing and check them, but it'd be nice not to shell out more $$ for shims.

how long does a valve job take? it's $76/hr at the shop by me, so 4 hours?

 

A valve job or lapping will make tight clearances even tighter (since the valve will seat into the head further)

Pretty much guaranteed that you'll be changing all the shims.

At least there are only 8 instead of 20 on the X

 

Amen to that...

 

I get $25 a yard, so 3 yards is $75 !!

 

A good head machinist will cut your valve seats and grind the valves and flip the valves over in the valve grinder and top off the valve stems. He can also measure "Installed valve height" The machinist can take a measurement before he takes the valves out and cut everything and then top off the valve stems so your shims will be close. If you have the shop set up your cams and valves on the bench that would be the best because they can dial your clearances in better then you can swapping shims. Once they do that you just pop your cams out and install the head and install the cams as per the manual. You need to do this right or you will bend your valves. So pay attention to the set up in the book. Once you get it back togeather all you need to do is double check the clearences and away you go. A fresh valve job makes a good seal and you have a new running bike. Check everything again after a few hundred miles and your good to go till the next scheduled maintenance. Just make sure the shop can do the work and don't be shocked when they tell you the price. Its alot of work to make these right and just takes time.

 

Depending on how thorough (see MN's subsequent post on 'topping" the stems) it could make them tighter. If you do a simple clean and lap yourself with new seals they will be tighter.

That's probably about right. Last time I had new guides done on the Nort and new valves professionally installed, it was 3 Hrs., and that's a twin.

 

It's only money And ANY competent shop will set valve clearances as a part of the head job. Would be a pretty shitty shop that did not.

 

so to have the shop set the clearances what would i have to bring in? the cams? the sprockets? chain guide? if he finds the guide clearances to be out of spec, can he fabricate new guides or should i order them from chacal? what about oil seals?
sorry so many q's, i understand this is a time consuming and expensive process and i want to make sure EVERYTHING gets done RIGHT the 1st time.