2G Cylinder head: confirming final measurements

[JoshGSX95]

Hey guys! So I’m getting ready to do a final assembly on my cylinder head. After taking all my measurements, with the most optimized combinations, I end up with 2 valves that fall under spec. It turns out that 4/8 valves are relying on 2 of the valve positions in order to be in spec.

Head specs
7 bolt head
3 angle valve job
Stock valves
Stock guides
Kiggly beehive springs & retainers
Stock keepers
Stock valve seats
Top line 3g lifters
Billet gsc s2

So my question is, what are my options? Am I going to have to get the valve seats cut? Send it? If you would like to check my work here is a Google sheet link. I’ve included a table of the final measurements as well.

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[motomattx]

They sell valve spring shims to get the taller springs to the same height as the lower ones, but its not exactly that simple, you need to make sure that your not going to get spring bind by over shimming the springs, you need to check your maximum lift on your particular cam to see what the set height should be as in the range of measurements and you can shim accordingly.

Unless your talking about valve installed height, maybe thats what your question is about? if thats the case then you can have the tip of the valves ground to shorten them, and or have the seats cut which I don't recommend unless its totally necessary, better to cut the valve face if need be.

 

[JoshGSX95]

Unless your talking about valve installed height, maybe thats what your question is about? if thats the case then you can have the tip of the valves ground to shorten them, and or have the seats cut which I don't recommend unless its totally necessary, better to cut the valve face if need be.

So the chart I showed above is the tip heights. The 2 valves in question are in positions 3 & 6. They’re both under the minimum spec of 1.9055, one being 1.901 and the other being 1.9025, So grinding the tips is not an option, as they are already way too short. which ends up making the installed heights way under what they need be at. The installed height is 1.475, every single valve is under it anywhere from 1.4582-1.4701.

So ultimately my question was is cutting the valve seat what needs to be done?

 

[bastarddsm]

have the valves and seats been cut? have the valves been tipped? Are the guides good?

 

[JoshGSX95]

have the valves and seats been cut? have the valves been tipped? Are the guides good?

Hey @bastarddsm Thank you for taking the time . I had a 3 angle valve job done and they also did the valves to, Is back cut the right term? I can’t measure the ID of the guides but doing a wiggle with a valve theyre tight. And for the tips as far as I can tell I don’t think they’ve ever been ground.

 

[bastarddsm]

Measure the overall length of the valves, compare to value in service manual. You can buy a cheap set of split ball gauges and then measure them with a micrometer.

If they have not been tipped there is almost no way possible for the tip height to actually be that low.

 

[motomattx]

I suppose that you could cut the valve face more, but that takes away some margin each time its done, cutting the valves is cheaper and less risky than cutting the seats at this point if the seats are otherwise fine and have been cut already.

 

[JoshGSX95]

Measure the overall length of the valves, compare to value in service manual. You can buy a cheap set of split ball gauges and then measure them with a micrometer.

If they have not been tipped there is almost no way possible for the tip height to actually be that low.

got a set of split ball gauges in

			109.7-109.2	Valve stem to guide inches		0.05-0.09	.15 limit
valve 6 (guide 4)		valve height	109.68mm	Stem .2573
			4.3181in	guide .260		(.0027)in clearance
			109.7-109.2	Valve stem to guide inches		0.05-0.09	.15 limit
valve 2 (guide 6)		valve height	109.63mm	Stem .2574
			4.3161in	guide .2594		(.002)in clearance

 

[JoshGSX95]

I suppose that you could cut the valve face more, but that takes away some margin each time its done, cutting the valves is cheaper and less risky than cutting the seats at this point if the seats are otherwise fine and have been cut already.

So if i understand this correctly if I reduce the size of the actual valve itself by cutting the tip, it's going to further reduce the valve stem projection ( seat to tip) height, putting them further out of spec. I need more height. Removing material from the spring seat will increase that distance.

 

[motomattx]

Removing material from the spring seat will change seat pressure, to increase tip height you need different length valves or cutting the valve face/seat.

 

[JoshGSX95]

I think I see where my disconnect was, regardless of removing material under the spring, the actual height of the tip is still the same