freshspecbluegt

I'm thinking about this the right way right? Had three angle valve job done, now the number 1 and number 3 clearances are too tight. This is because valves are now sitting further into the seat correct?

It originally struck me odd that the clearance would be too tight BTW cam run out is nil and stock buckets and shims all went back in the way they came out.

so thinner shims on those two and I'm good to go right?

iamsuperbleeder

the rocker clearances? I'm confused...


22r?

freshspecbluegt

sorry should have been clear its a 3.0 sohc

xxxtreme22r

by the look of his other posts its a 3.0

iamsuperbleeder

ooooh, well the clears things up, lol

yeah that would explain the clearance thing becoming an issue, cause on a 22r you'd just adjust the rockers

I understand how the valve train works on the 3.0, but I have no knowledge about them, lol. Sorry

xxxtreme22r

if they are shimmed like a post 2001 hyundai 2.0 motor is which it looks like it is, I would tell the machine shop that did the angle job that it's off and fix it and not with shims. You shouldn't have to compensate with different sized shims in 1 or 2 of the valves.

check this out, about half way down the page, mentions their specs on valve shim issues.

http://www.enginebuildermag.com/Arti...sohc_head.aspx

freshspecbluegt

Sorry my question wasn't very clear. let me try again.

The #1 and #3 exhaust valve clearance (between the bucket and cam lobe, measured according to the FSM) are at .006" which is .003" too tight. The cam is true and all the buckets and shims were kept in order.

In general would a valve job on an SOHC head cause the valve clearance (again between the bucket and cam lobe) to get tighter?



XXXtreme in regards to your response, if we are on the same page here:

What could be off? The machine shop did not set the clearances for me, I am doing it myself. I provided the head without the cams and buckets, they just did the valve job and returned the head to me. Shims are used to set the clearance on the 3.0 so what would they do to fix a .003" difference without using the shims short of the grinding the valve stem?

If I am thinking about this correctly as long as the keepers and everything are seated correctly, and they are, any change in the clearance would be due to the work done to the valve causing it to sit "deeper" in the seat, resulting in the stem sitting higher and thus decreasing the clearance between the cam lobe and the bucket.

Sorry for any confusion, first full engine rebuild that I have undertaken and I am trying to 1) make sure I do a good job and 2) learn more. This forum has been a great resource during my rebuild.

xxxtreme22r

my guess is they took off too much on those valves/seats and were not cut even across the board. If they did not come out like that then they shouldn't be going back in with a few off like that. There is no reason why 2 and not all are off. Unless someone else can confirm there is no harm in using different shim sizes between valves, what I would do is tell the machine shop to fix their inconsistent work on the other valves and then reshim all using the same size.

abecedarian

If you had a valve job done, you may have to adjust the valves. 0.003" is not all that much and can easily be burned up cutting a 3 angle job, assuming that's what was done, and not simply just lapping the valves.
Chances are that the other valves were on the 'loose' end of tolerances and those two were on the 'tight' end, but still within tolerance, and the work simply caused them to go out of tolerance.

freshspecbluegt

3 angle job was done. So my thinking wasn't out of line then. I'll get the thinner shims and move forward. Thanks

XXXtreme:
The FSM doesn't say anything about not using different shim sizes, there are a ton of shims available so I would imagine that mixing shim sizes wouldn't be a problem, what i would think is more important is that the clearances are all within spec.

abecedarian

Your thinking is perfectly well in line. Grind material off of something, other things move accordingly.

As for the shims- yes, there is a plethora of shims available and they are all for the explicit purpose of adjusting the valves in to spec. You determine your clearance, mic the shim you have (because it may be worn from contact with the cam), then calculate which thickness shim you need to bring the clearance within spec.

Unlike intake valves which can be run tight since they're cooled by the air and fuel being drawn into the engine, tight exhaust valves are more prone to burning and warping, so keep that in mind. I mean, overall, for best performance you should have things as tight as possible yet within tolerance. However, exhaust valves run hot, by their nature- burned / burning gasses passing over them, and have a greater tendancy to pull the seat into the head if they are run too close to the tight end of the tolerance, which in turn makes the valve clearance even tighter, compounding the problem.

xxxtreme22r

If I am thinking right, by using different shim sizes and not correcting the original problem wont that in a sense affect each valves lift amount making them uneven in those two that are off?

abecedarian

There is one shim per valve and each shim's purpose is to adjust the clearance on the valve it sits on top of.
Changing one valve's shim will not affect the other valves.
Think of the shim as doing the same thing the rocker arm adjuster screw on the 4 cylinder engines- it takes up the clearance between the cam and the valve.