Hey Cylinder heads guys- advice needed

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SSG_Karg

SSG_Karg

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I’m putting together the W2s for my stroker build and came across a little hiccup. I installed the valves and springs and noticed the installed height varies from intake to exhaust. Approximately.050” difference. Exhaust side is higher. I figure this is due to the 2.08” intake valve being installed and the 1.60 exhaust valve being sunk a hair.
My first question is, should I worry about the .050” differences or not?
Also, looking at the valve tip to rocker contact makes me nervous. The intake rockers look pretty good but the exhaust are definitely side loading the valve.
Second question is, do I need to address the valve to rocker contact issue and if so how?
Cam is Howards SR .600/.600 245/[email protected]
Springs are Comp 938 180#/468# installed @ 1.94”
What are your thoughts?

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On second thoughts I don’t think a lash cap will help that. Are those rockers the same ratio.
 
That's a significant difference and should have been handled from the perspective of the valve job. I too would have to ask how the machinist let that go. "I guess" you could remove all the valves and cut the stems all the same....but that's not the correct way. Or, you COULD sink the intake valves to match. I cringed when I typed that. lol The most correct way at this point is to replace the exhaust seats. Contact Mike at B3 and see what he recommends. He might have some better ideas. At least about the geometry for sure. I don't see any other way to get the stem heights right......you could cut them like I said, but that's just "not right", IMO.
 
That needs to go back to the machine shop and figure out why the stem heights are wrong.

And you need to raise the rockers. Your geometry is not good.
 
pittsburghracer said:
On second thoughts I don’t think a lash cap will help that. Are those rockers the same ratio.
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I’m quite certain that all the rockers are 1.5. The intakes are two different brands left and right. The exhaust are factory 273.
 
Those exhaust rockers are 273 rockers, you might look for the correct ones
 
Do you have any pics of the valves installed prior to mounting the heads on the engine ? If the valves were the same leangth that means you intakes are sitting way up high on the seat or your exhausts are sunk way down .

Were these used heads ? Is it possible the intakes had been cut for 2.055 or 2.08 vales previously ?
 
OH GOOD ! your heads are not installed . Whew! That makes things easier .
 
A little background on these heads....
I bought many years ago at separate times on eBay each separately. One was a long valve econo and the other a standard length valve econo. I had the pedestals milled off according to Shady Dell’s advice and now use offset stands and offset shafts from FABO member Rocket.
So these are definitely a grab bag of mixed and matched parts that I’m trying to get to work.
I suppose I could raise the rockers with shims under the stands but the difference in rocker tip to valve tip will still be there.
 
I think the majority of the problem lies in the exhaust seat. I had to shim all the springs on the exhaust valves to get the installed height correct. Every one of them took a .045-.060” shim.
 
The problem there is you will have incorrect geometry on either the intake or exhaust . If you had T&Ds it would be an issue... but with shafts I can't see how to vary them and still have propper geometry .
Call Mike @ B3 on Tuesday . He helped me with both my 5.9 and my 408 W2 motor. He can advise you .
 
SSG_Karg said:
I think the majority of the problem lies in the exhaust seat. I had to shim all the springs on the exhaust valves to get the installed height correct. Every one of them took a .045-.060” shim.
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The shims wont effect your installed heights but they will give you different spring rates ( or should I say pressures)
 
I would start with shimming the stands a 1/8" and see what happens, it will fix the exhaust rockers from hitting the edge of the valve.
 
mbaird said:
The shims wont effect your installed heights but they will give you different spring rates ( or should I say pressures)
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Are you sure about that? Adding shims under the spring to get the spring height correct should have no effect on spring rate. I understand that it doesn’t affect valve height but it won’t change the spring rate. Adding the shims is no different than having the valve seat higher, or “shallower” if you will.
 
It’s pretty obvious that the exhaust valve is sunk compared to the intake. Can new seats be put into these heads? And what should I expect to pay for that job?

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SSG_Karg said:
It’s pretty obvious that the exhaust valve is sunk compared to the intake. Can new seats be put into these heads? And what should I expect to pay for that job?

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I can’t see a top cut on either valve, but for sure the intake valve is too high. You need a top cut about as wide as you can get.

That’s not sinking a valve, that’s doing a correct valve job.
 
The way that exhaust valve looks if it was on a flowbench you probably wouldn’t see any flow till .150-.200. Man it’s shrouded.
 
You are correct .. installed height doesnt effect spring rate but does effect pressure .
Find a good local shop to install seats and valve job. Ask them to look over the whole head .
Way better to find this now then after its in the car.
 
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