enginjoe

iTrader: (11)

Ok. So I'm trying to finally assemble this motor and I was checking to see what my pushrod length should be and what the heck? It looked like my rocker was touching the retainer. I took out my smallest feeler gauge .0025 and tried to stick it in there and no dice. It is touching. Here is a pic. This is a set of ARE heads with bigger valves, comp duals I bought off here a while back. Is there a way to make this work?



Any help would be great thanks.

parks450

iTrader: (17)

you would have to clearance the rockers where they are touching the retainers. Which in turn would weaken them alot in that spot. Not a good idea in my opinion. Really the only realistic thing you should do is buy new aftermarket ones and be done with it.

Nmbr1GMfan

iTrader: (1)

Whats the spring install height?

enginjoe

iTrader: (11)

Clearancing is definitely not the thing to do in my opinion. Could I raise the rocker pedestal a tiny amount without screwing anything up?

enginjoe

iTrader: (11)

How would I get that?

SweetS10V8

iTrader: (4)

You would have to measure it.

What springs are those???

enginjoe

iTrader: (11)

They are comp duals according to the guy I bought the heads from. They only sell one kind that I could see from their website. Looks like these - 26921.

How do I measure installed height. What am I measuring, the base of spring to part that touches retainer?

enginjoe

iTrader: (11)

I measured bottom of spring to top with calipers it was 1.817"

trans_am7935

iTrader: (15)

even if you were to get the rockers to work, look at the geometry of them. the rocker looks like it is trying to hard to stay on there and it is not on the center of the valve.

enginjoe

iTrader: (11)

Well, they are stock rockers with a trunion upgrade. I measured from the bottom of the washer under the spring to the top of the valve the best I could and it was 2.013". I had to eye ball it because you can't get the caliper on the tip and at the bottom at the same time. It looks like to me that the valve is sitting just a bit too high. Could the valve seat have been ground too much?

trans_am7935

iTrader: (15)

i was also thinking the same thing. the normal install height on these motors ins around 1.800 or so. if you wanted, you could get you a bunch of 0.100 washers (typical size) and throw then under the shaft mount, see if you can get the geometry right on the rockers, this is the same concept that Yella Terra uses as they provide "shims" (washers) for placing under their pedestals to shim for correct valvetrain setup.

vettenuts

iTrader: (4)

First, you need a valve spring micrometer to properly measure. You can't do it the way you are doing it and your measurements are incorrect.

Second, have you checked the wipe which must be done prior to measuring for pushrods. If not, check wipe and find out if the rocker geometry is even correct. From the looks of it, they are sitting too far back and the rockers may need to be raised.

Third, do not grind the rockers. Doing so will weaken them in the location that carries high tensile loads which is a recipe for disaster.

You need to get a couple of tools and sort things out prior to making any decisions.

Do the heads have new valves or was valve work done? If yes, then the valve stem height may have been increased which would necessitate moving the rockers as well.

99Bluz28

iTrader: (35)

It looks like the valve spring seats needed to be machined down a bit, then you could use some VS retainers that allow the valve tip to actually sit higher than the retainers.

hiltsy855

iTrader: (35)

You could also shim the rockers up and use lash caps.

Paul Bell

iTrader: (9)

vettenuts is, well, nuts on with what he said.

I'll add that installed spring height is determined by the valve stem length to the spring pocket/washer. It's measured with this tool (note the absence of a spring):

Paul Bell

iTrader: (9)

I would also add that you might be able to have the rocker arm pivot support shimmed up but everything needs to be very carefully measured. You'll certainly need longer push rods to get the wipe centered on the valve. This is all stuff an experienced performance machine shop should be able to do with ease.

enginjoe

iTrader: (11)

I've been out looking for a micrometer that will fit my retainers. None really say, or will they all fit.

One question. Do you take the little spring seat washer out to do the measurement or no? I'm leaning towards no as we are measuring the spring.

Now, if I find out that the spring is higher than 1.8 like it is supposed to be, should the rockers be shimmed up by that amount? Let's say it's 1.85 spring height, so I shim the rockers by .05? I don't have pushrods yet, because I need to measure...that's what I was doing when I found this problem.

RonSSNova

iTrader: (3)

First.
The installed height simply sets the seat pressure of the spring. It does not move the position of the retainer.
If it too large, you shim below the seat cup. If it's too small, you use a thinner seat cup.
Find out the spec required for the springs you have.

Second, because your rocker is hitting the retainer, you need to shim the stand to get clearance. I would shoot for .025". It's safe. And not all of the retainers will be at the same height, especially if the seats have been ground.

Third. Pushrod length won't change the wipe on the valve stem. In a non adjustable system like this, they only change the preload on the lifter.

Fourth. Once you get the retainer clearance set up, you need either a solid lifter or a light weight spring to check the wipe pattern. Set the pushrod length to 0 lash, rotoate the engine and see what the scrub looks like. You may have to change the rocker stand shim thickness to get it right. Obvioulsy, you can't shim them down much. (I don't know if you can get the correct solid lifter, so a light weight spring is probably the best option. With those springs in there, and a hyd lifter, the lifter will collapse during the measurement and mess up the results)

Once you are happy, add the lifter preload amount to the pushrod length and you are done.

Now, if you can't get the pattern correct, you might have to use springs with a smaller OD on the retainer and no shims. The retainers on my AFR heads are 1.23" OD. I haven't set mine up yet, so I may have the same issue.

A last fix would be to switch to roller rockers. They more than likely have more clearance available. (I have .640" lift, so I plan to run rollers anyway)

Let us know if this all makes sense.

vettenuts

iTrader: (4)

Fitting the retainer shouldn't be an issue with the duals, with beehives the retainer fitment can be an issue as it falls within the upper cup of the micrometer. When you measure, leave the seat in place.

If the measured height is greater than 1.800, then the valve stem lengths are longer than stock or if the valves are stock they have been ground and set deeper. Shimming the spring won't change the retainer position, it will only change the seat force of the spring. If the retainer is too high relative to the rocker due to a change in the valve stem height, then you likely need to raise the rockers to correct the geometry (wipe pattern). Once geometry is correct, re-check the clearance.

You may want to consider the LPE or other rocker stand, which is steel vice aluminum, if you need to shim more height into the rockers.


The pushrod measurement is the last measurement you will make and only after the other geometry issues are resolved.

enginjoe

iTrader: (11)

Ok. It has SBC dual springs (they are 1.43 OD instead of 1.3). The rocker looks too far back because it is resting on the retainer.