92 GSR-4

iTrader: (18)

Long story short I picked up an VIII with motor issues and am currently going through the cylinder head.

The head itself has some professional port work done to it and has SS valves. It also had HKS 272 cams in it (AM003 + AM004).

I need some help identifying the valvetrain and the head itself:

Starting with the head, I think it's a Jackson Auto Machine head, though not sure. It was built with SS Valves, 34mm Intake (STD) and 31.5mm Exhaust (+1mm) valves. One thing I noticed when taking it apart is the professional port work. Having been in DSMs for about 11 years, this is a professional job - not a DIY'er. So I am very interested in using this cyl head with some Kiggly and GSC hardware.

Another thing I noticed was the valve guides seem to have some sort of a "sleeve" or "Bushing" in them. The guides appear to be a stock steel-type guide and not a bronze valve guide.

And yet another anomaly from what I have ever seen in DSM/Evo stuff...the intake valves had SHIMS under the valve spring seats! .030". Anyone have insight as to why they would throw shims under the intake valves only? What kind of factors would influence the decision to shim the valve springs in the first place?



Last, the JAM stamp at the bottom of the cyl head. Anyone got one like it?

Here's the cylinder head stamp:



Next up are the valves. They are SS valves, no black nitride that I can tell, though I have yet to clean up the exhaust valves. They appear to be swirl-cut / back cut valves. I think they might be Ferrea, but they have no markings whatsoever...so I can't tell. Again, there are no markings on the face of the valve or anywhere else on it. They simply appear to be a SS valve...





Last, here's the valve springs. They appear to have titanium retainers. Again, no markings. Ferrea?








Any help with the parts ID would be great! Thanks!

BogusSVO

iTrader: (1)

Supertech is the only brand I know of that does not mark there parts, Crower, BC, manley ect all stamp there name on the retainer.

The shims under the valve spring is good, that points that the builder measured spring installed height and set the spring pressures up.

Now the the part numbers on the valves would be just under the lock groove.

With the JAM stamp on it, I would look for a stamped number on the head too, I would call JAM and ask.

The bronze bushing you refer to is a "K-Liner" it is just what you said, a bushing, the guide ID will be reamed over sized then the liner is installed, then burnished to the finished size.

Personally I do not like them, I do not use them, But I will go on a rant about them another time.

stunt2

iTrader: (8)

when running high boost, the intake valves struggle to close when boost pressure is pushing them from the other side. hence the shinms and more spring pressure

TonyJAM

Some of the info doesn't add up.

We stamp our heads with "JAM" but not in that spot.
We don't use heat tabs.
We did use single springs and shim the intake side.
They look like our retainers.
We do NOT use guide liners on performance cylinder heads.
The valves could be ours. Back then we weren't using coated valves. However, the 45* seat angle on the valve doesn't look quite right. Neither do the other angles.
We rarely used +1mm exhaust and std intake valves.

It looks like it could be one of our heads but someone has been in there since and changed a few things.

BogusSVO

iTrader: (1)

Tony.. Glad you chimed in on this.

Also glad you do not use the guide liners.

OP maybe a few more pics of the head would help, the gasket surface and such.

Most shops can tell if it was there machine that milled the head due to surface finish.

92 GSR-4

iTrader: (18)

Tony spent a long time with me on the phone so I decided to send the head to him and let him check it out. I'll report back here when he gets it. I also included one of the valve springs for him to identify it if it's his.