ckpitt55

iTrader: (4)

In the process of shimming my rocker arms for proper wipe pattern - I need somewhere north of .140" but have been unable to find any shims of that thickness with a reasonable tolerance attached to it.

Mcmaster has .125"s but at that thickness the tolerance is +/- 0.013" ... pretty unacceptable when you're trying to be consistent arm to arm. I could sit there and juggle shims or sand them until I get uniform thickness between rocker pairs, but really have no desire to do so if I can order them in a usable form. Tolerances on thinner shims are much better, but I don't like the idea of stacking oodles of shim to get the thickness I need.

Really just looking to make life easier for myself here - rocker arm shim affects push rod length, which has tolerances of their own attached. The better I can manage the tolerances of the parts I actually have control over, the easier it will be to consistently hit 0.025" - 0.030" lifter preload (I only have a 0.005" window to work with).

Any ideas?

vettenuts

iTrader: (4)

I bought them from McMaster (0.125", part #3088A820) and checked them when the arrived. McMaster advertised the thickness as +/- 0.003" so not sure why your are finding such a large tolerance. I picked the sixteen closest in thickness, but in all honesty they were pretty consistent. If you stacked mine with a 0.015", you would get your 0.140" thick with a tolerance of +/-0.004".

Have you tried the wipe with 1/8" so that a single shim will work?

Also, I had to really clear out the inside of the valve covers, including the baffles and the coil mounting hole bosses, because of these thick shims and needed longer bolts that wouldn't penetrate into the intake port.

ckpitt55

iTrader: (4)

just the man i hoped would weigh in..

probably because i was looking at stainless steel....the tolerances on the regular steel are +/-0.003" as you said. i don't know why I was under the impression you went with stainless.....so maybe I'll try those.

when checking the wipe though, I was just stacking the washers provided with the arms because I didn't have anything else on hand. since I can only increment in 0.04x" or so at the moment, it doesnt allow me much finesse on creeping up on the optimum height. the best wipe I was able to get was using 3 of the provided washers under the pedestal, totaling 0.140". It looks to me like the pattern could creep a little more towards the middle of the valve....what do you think? (side towards the bottom is the intake side of the head). I may order a variety of checker shims that I can stack up in a more precise combination to really try and zero this thing in. right now it feels like trying to adjust a fine watch with a sledgehammer



also as far as valve cover clearancing....are you running the thicker yella terra valve cover gaskets or stock ones?

vettenuts

iTrader: (4)

I am running stock gaskets. From the photo, the pattern is very narrow but looks to be a tad towards the intake side. You may end up with a very narrow pattern in the end.

What I did to get the thickness was use some regular washers I had laying around to play with the thickness. Once I was happy with the result, I measured the total stack height. You may be able to go to a hardware store and pick up some washers. Fender washers are typically thinner but you need to drill out the center and clean up the hole if you go that route.

RonSSNova

iTrader: (3)

What you have shown is sweet. Why would you want to change that?

What rockers etc?

Ron

ckpitt55

iTrader: (4)

I don't necessarily want to change it, just want to be able to confirm that that's the best I can do.

Yella terra 6645 rev 3's on milled afr 215 heads, johnson short travel lifters

RonSSNova

iTrader: (3)

You bought paper machet YT's?
Sorry, couldn't resist.

I have milled 205's, and the shims provided worked fine. You and Bob seem to need thicker shims. I just find that interesting.

I ended up with 7.450" PR's and got a nice narrow pattern nearly centered. Of course with the short travel lifters you need to nail it pretty close.

When I put the new rockers on this weekend, I think I'll rig up a dial indicator and do a direct measurement of the actual pre-load I ended up with.

Ron

vettenuts

iTrader: (4)

One other question, are the AFR springs on there? You may be compressing the lifter when you turn it over and skewing the pattern if it does. Careful of that.

RonSSNova

iTrader: (3)

Good point Bob.

I would also think that the adj pushrod wouldn't enjoy the spring pressure either.

dirtbag

iTrader: (2)

If you are dead set on using a single shim, you could always buy http://www.mcmaster.com/#3088a88/=np5o5i this shim and mill them down to your desired thickness. Stainless probably isn't necessary since the chance of non-coated steel rusting in that oily of an environment is nill to none. Or just do what was mentioned above and stack shims to get your desired thickness.

edit: a quick google search and I found this company. http://www.phoenixspecialty.com/products/shims/ give them a call maybe they could help you out.

ckpitt55

iTrader: (4)

No - I'm checking wipe just as you did....heads sitting on 2x4s on the bench with checker springs, rockers snugged down on the pedestals. No pushrod/cam/lifter involvement in this.

Yeah that's probably what I'm going to end up doing once I determined the final size I need. I've got a bunch of shim of various thicknesses on the way that will allow me to make more precise adjustments...will probably do just what you said and mill the .188"s to thickness once I'm ready.

And yeah I came across phoenix, not sure what a quote would be for something like this but it'd be cheaper and faster to make them myself I'd imagine.

RonSSNova

iTrader: (3)

You could actually make one shim per pair with 2 holes ground flat to your desired height.

That would be cool.

I just replaced my rockers last night, so I got to see the pattern on all the valves. Looks just like yours. Although, you can tell the valves spin from time to time.

Ron

dirtbag

iTrader: (2)

This. Half as many mill setups, and a much higher probability you will end up even across the board for each rocker pair. Let us know how it turns out.

ckpitt55

iTrader: (4)

I see what you guys are saying, perhaps I'll try that. Should be getting the "measurement shims" on Monday so I'll at least be able to determine heights - will post an update then.

Ron, what size shim (if any) did you need to use on your setup?

RonSSNova

iTrader: (3)

I used the shims supplied with the YT rockers. Heads are AFR 205.
I set them up on the bench just like you did.
My cam is an EPS custom, LS7 lifters and the pushrods ended up at 7.450 (off the shelf Trick Flow) to get approx .050" preload.

I should mention that my heads were used, and the valve stem tips were a little rough so my machinest did a cleanup cut on them. Not sure how much. Prev owner ran high lift and stock rockers it appeared.

Ron

ckpitt55

iTrader: (4)

I checked one head last night, they all seemed to like .130" shim. 0.125" was passable but the extra .005" seemed to center the wipe up a bit better. going to check the other head tonight probably but I'm not expecting much to be different. probably just going to end up stacking a .005" on top of the .125" shim and calling it a day - I'm going to measure each shim height and ensure that they're close but I don't think there's much to be gained from machining the finished shims from scratch.