Valve stem height past the retainer?

Topic: Valve stem height past the retainer? (Read 1134 times) previous topic - next topic

Valve stem height past the retainer?

August 15, 2008, 12:47:27 AM

I talked to the machine shop who worked on the heads but want to get your guys' opinions. I have some heads that have valve stems that randomly stick up higher or lower than others around the heads, same valuve type (intake/exhaust), or not. The culprit seems to be some having keepers that are flush with the retainers while others are sunken in further. There is no order to this madness so it isn't a front to back or intake to exhaust difference.

What are your guys' thoughts on this? There is probably 1/8" or a little more of extra valve stem last the retainer on the worst than on the least. The valve stems themselves are all as long as one another, it is just the keepers and retainers that are in different positions. Is there any issue with a setup like this when using hydraulic lifters?

Valve stem height past the retainer?

Reply #1 – August 15, 2008, 09:29:22 AM

are you sure you're not looking at a few lash caps?

Valve stem height past the retainer?

Reply #2 – August 15, 2008, 08:43:11 PM

They're bare valve stem and is isn't just two lengths past the retainer - half the valves fit into this +1/8" range. I'll try to remember to get pictures this weekend.

Valve stem height past the retainer?

Reply #3 – August 18, 2008, 09:38:08 PM

Here is an example of what I'm talking about. Look at #1 and #3.

Valve stem height past the retainer?

Reply #4 – August 18, 2008, 09:42:44 PM

Looks like those valves have 2 lock grooves and some are set in the second groove that or the retainers or locks are differant then the others If a machine shop done the work I would take them back and look into another shop..In a pedestal rocker arm system all the valve heights need to be the same use a straight edge to check the stem heights

Valve stem height past the retainer?

Reply #5 – August 18, 2008, 10:43:40 PM

The valves themselves are straight, ignore the lens distortion of the camera. Its that large difference in visible valve stem that has me worried. That shop is telling me that it doesn't matter with hydraulic lifters but even with the lifters, their tension, and preload amounts, I'd still like to see even spring force among things like this to keep revs smooth. I don't need any cylinders doing more than others.

I didn't notice this until I was down torquing the heads nice and good. We have the tools to pull these things while the heads are still on the motor so if need be, it can be done fairly quickly. You can see some keepers sitting lower than others in the below pictures.

Valve stem height past the retainer?

Reply #6 – August 18, 2008, 10:58:46 PM

Mandatory engine progress picture below. Still have to get a new balancer and remaining transmission components. The engine wasn't supposed to look so boring but we had powder coating problems - the major one being the candy and chromes not working out too well. The base coats apparently were never fully curing and causing them to come through when they shouldn't. The timing cover worked well as you can barely see but the intakes didn't do well after the black base coat began to come through on the clear coat bake. The valve covers are black with multiple candy red coats so in the right light, they have a red hue. Iron parts are all just paint.

I'll have to make up for the stock, but glossy, look elsewhere in the engine bay. At least it'll be easy to clean and keep shining with the Caswell powders.

Valve stem height past the retainer?

Reply #7 – August 19, 2008, 12:02:22 PM

They should all be the same height, like this.

Valve stem height past the retainer?

Reply #8 – August 19, 2008, 09:32:23 PM

In that second picture, it appears that, from left to right, #2 and #8 have different heights past the retainer.

Valve stem height past the retainer?

Reply #9 – August 20, 2008, 09:59:53 AM

Quote from: Seek;232758

In that second picture, it appears that, from left to right, #2 and #8 have different heights past the retainer.

Nope that's just a light reflection. The are all the same height. I'd pull off a valve cover to show you but that's a lot of work for a picture :hick:

Valve stem height past the retainer?

Reply #10 – August 20, 2008, 08:45:28 PM

i posted that pic on another board, and a machinist said someone used different year valves on a few of those. basically, you need to take those back, and have them redone with the proper year valve.

Valve stem height past the retainer?

Reply #11 – August 21, 2008, 04:06:42 PM

Since the problem ones do appear to be intake only, after looking at the heads again this weekend, does anyone see a problem with replacing all the intake valves with the ones on my gt40 heads? Same intake valve size and I believe the seats are but from the factory the same.I have E6's, E7's, Cobra GT40's, and GT40P's all sitting around so there's plenty to mix and match as long as the valves themselves are good.

Valve stem height past the retainer?

Reply #12 – August 21, 2008, 09:49:59 PM

replacing the valves is a call you can make by installing an alternate valve then turn the head on its side with the exhaust port pointing up. Add water / paint thinner to the exhaust port until it fills.

look for seepage out around the seat. this does not tell you anything other than your valve seat is good enough to seal,, says nothing about the grind on the valve matching the head. I dont know if they did all three angle grinds or just one or two but thats stuff you need to know.

On to the valves stem issue and my thoughts.

Measure from the head up to the top of each valve spring cap and do all 8 of each head using something that would work as a depth guagesuch as the pointy end of your dial caliper.

write all that down
I am all the curious about how they match up.

My thoughts for why a valve stem would purtrude so wild like yours are isolated to the keepers or the replacement valve. If the seats were cut too deep, the springs would have a different height but usually very very minor. The keepers should be locking in at the same location on the valve no matter what. Soooooo ,, it appears either the valves have been replaced with like type and they thought you would be ok with it, or ,, they reused some of the old keepers and thats just the way they turned out. either way is hosed. Your putting odd presures on your lifter springs IMHO and they should be nearly even or alike.
A seat cut too deep wil make the spring taller but the nipple of the stem pertrusion will maintain the same height.

I can find it in my heart to agree with your shop that the lifters do absorbe differences like that to a degree but it still does not make it right.

My biggest issue with all of this is the lack of uniformity. Uniformity at 5500 rpm means the difference between floating a valve or throwing a push rod or not.

If all of your springs measure the same hieght, then the valves are just too long but the lifters "could" take up the difference.
This means the distance from the valve seat up to the upper most edge of each keeper are equal,, and you do have uniformity from that perspective meaing equal tension on each spring.

if they measure different, then your valves are machined in such a way that the keepers are located at different spots or the machine shop got carried about on the seat grinds. It also tells you that there are different tensions on the springs which will add more to the lack of uniformity at higher rpms.
Hell, while your at it, find out what the stock "installed" spring height is compared to your highest one that exceeds limits. This will be the floating valve you "would have been" chasing.

This IMHO,, qualifies as a reject.

DId you do your own leak test on each valve? with thinner or water ect? if not, your screwing yourself.