Shorter valve length?

[sexyL]

I'm building a 219 head that was incomplete when I got it years ago and I'm having issues setting the rocker arm heights. In order to get the correct valve lash I am needing to set the rocker pivot height ridiculously tall. I've put in thicker lash pads (.265 at the thickest) which didn't fully correct the problem. I pulled the valves to measure and compare to ones in an A87 I had and these are nearly .1" shorter in OAL. I also noticed there is a number etched on the top of stems. With these valves I also was getting spring bind on two of the valves.

These are the measurements:
____219____A87_
I: 114.27---116.3
E: 115.24---117.32

Edit: valve diameters are 1.73 and 1.38 so these are definitely L28 valves.
The etchings say FAS3229 for exhaust and V3238X for intake. Would these valves be the culprit to my valve lash issues? The cam is a Schneider 284-94F which has just as much material on the base of the lobe as a stock cam. Any other thoughts?

Picture shows the valves from the 219 on the left and the A87 on the right.

[datzenmike]

Seems obvious that a shorter stem length is the cause.


1/ I know you shouldn't, but how about re-grinding the seats and sinking the valves slightly? A mm or two is well within reason. Would remove the binding problem also.

2/ What about removing the cam towers and have the base milled down to lower the cam position?

[sexyL]

Seems obvious that a shorter stem length is the cause.


1/ I know you shouldn't, but how about re-grinding the seats and sinking the valves slightly? A mm or two is well within reason. Would remove the binding problem also.

2/ What about removing the cam towers and have the base milled down to lower the cam position?

The valve seat had me questioning the work of the valve job and with some swapping of valves from the A87 I noticed those valves sit more flush with the head than the 280z valves. I am now wondering if the larger 1.73" (44mm) valves are just the wrong size for this valve seat? Measuring the valve seat OD from the A87 and the 219 they both come out to around 1.8". When I stick my 1.65" (42mm) valves in the 219 head they sit flush with the head, and the 1.73" protrude out a bit. Should this be considered normal? Are these 1.73" valves too big for this valve seat which is causing them to sit lower in the chamber?

Pic shows the 219 head with 1.65" intake on the left and the 1.73" on the right.

[abisel]

When I rebuilt my U67 head because one of the brass seats fell out, I had the machine shop replace all the seats with steel and at the same time, machine the pockets to accept the larger 280Z 44mm intake valve seats. All resulting in the correct protrusion of the valve stem once all was ground and lapped. So, if you want to go with the larger intake valves, maybe consider replacing the valve seat and/or grinding the valve seat deeper. But what about the brass valve seats? How are they? If the head does have brass seats, you should consider replacing those with steel. Not much fun when a seat falls out.

And what about the valve guides? Are they the original steel or did you replace them with bronze?

The machine shop that did all the work recommended SI Valves for the parts. So far, with another 5000 miles on the clock, all is well with the rebuilt head. http://sivalves.com/pdfs/2016-SI-Catalog.pdf

[sexyL]

When I rebuilt my U67 head because one of the brass seats fell out, I had the machine shop replace all the seats with steel and at the same time, machine the pockets to accept the larger 280Z 44mm intake valve seats. All resulting in the correct protrusion of the valve stem once all was ground and lapped. So, if you want to go with the larger intake valves, maybe consider replacing the valve seat and/or grinding the valve seat deeper. But what about the brass valve seats? How are they? If the head does have brass seats, you should consider replacing those with steel. Not much fun when a seat falls out.

And what about the valve guides? Are they the original steel or did you replace them with bronze?

The machine shop that did all the work recommended SI Valves for the parts. So far, with another 5000 miles on the clock, all is well with the rebuilt head. http://sivalves.com/pdfs/2016-SI-Catalog.pdf

A previous owner already had a valve job done where the seats were replaced with steel and these larger valves were put in place. It looks like the shop who cut the seats did a poor job on some of them leaving a little burr on the edges, which makes me believe they weren't cut deep enough either. I'm looking at SI's 8102E and 8001SG and will go with that, then see how lucky I get with the seats currently in there. Might get them recut if I can.

[abisel]

When I had the machine shop do the repair on the U67 head, I had them replace all the seats to match up with those of the 280z valves. It has been over a year ago and I think I had them install the 8000SG (46mm intake) and 8002SG (38mm exhaust) valves. I need to double check that however. The shop also machined the head to get rid of any warp. That meant I needed to get shims for the cam tower to regain the factory dimensions. https://zcardepot.com/products/cylinder ... gI7WvD_BwE#

The shop installed Ferrea competition valves. https://www.ferrea.com/
They replaced the steel valve guides with manganese bronze.
They set up the correct valve stem protrusion and installed stock 280ZX valve springs/seats/and seals.
They ported the head intake and exhaust runners to match up with the intake/exhaust manifold gasket.

So, if anyone wants a good machine shop to do the job. Steigemeier can do it for ya. They are in the St. Louis area. http://stiegemeier.com/