964, 92... Cyl head received after machining, need to know if timing change & gasket

[Rahul]

Hi guys, I had send my cylinder head assembly to a reputed machine shop, i had to send them to machine shop as I ordered new 6 mahle piston cylinder assembly, which were not sitting perfectly with old head.
I took rough measurement of ( cylinder head top face + cylinder base) length , it was around 119 mm, which is same as with the machined assembly as well...
My question is
1. I can do timing for 964 very well, but now I am not confident if I have to take some more things into account , please advice ..
2. The new cylinders have a wide groove where should I get a gasket, can someone send me how the gasket should be.....


[img]http://forums.pelicanparts.com/uploads26/IMG_20210401_1407051617302453.jpg
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Thanks guys

[yelcab1]

The old cylinders have groove at the bottom where it fits against the case. A green viton gasket goes in there. What you are showing is your new cylinders also have a groove machined at the top of the cylinders where they meet up with the heads. If so, the metal rings you hold in your hand go into those grooves.

The ruler in your picture is really not precision enough for engine work. Get something else.

[Rahul]

Originally Posted by yelcab1

The old cylinders have groove at the bottom where it fits against the case. A green viton gasket goes in there. What you are showing is your new cylinders also have a groove machined at the top of the cylinders where they meet up with the heads. If so, the metal rings you hold in your hand go into those grooves.

The ruler in your picture is really not precision enough for engine work. Get something else.

Thankyou for the reply sir
1. , I have o-rings for bottom of the cylinder, it is the top gasket I am concerned about, as the groove on the top is wider than the aluminium ring (1st picture), if I put that metal ring there I think it will not cover properly, so I am thinking of installing a wide copper gasket there, but in parts catalogue there is no such part...
2. I do have varnier & other tools as well, just don't know the procedure to confirm the clearance so that my valve does not hit cylinders, my plan is to install 1 cylinder head assembly on each bank & than rotate the assembly .....
Thanks

[fred cook]

Originally Posted by Rahul

Thankyou for the reply sir
1. , I have o-rings for bottom of the cylinder, it is the top gasket I am concerned about, as the groove on the top is wider than the aluminium ring (1st picture), if I put that metal ring there I think it will not cover properly, so I am thinking of installing a wide copper gasket there, but in parts catalogue there is no such part...
2. I do have varnier & other tools as well, just don't know the procedure to confirm the clearance so that my valve does not hit cylinders, my plan is to install 1 cylinder head assembly on each bank & than rotate the assembly .....
Thanks

Put a piece of clay on top of the pistons and you will be able to see just how much clearance your setup will have. Or, you can bring the piston up to TDC with the intake valve open and by tightening the adjuster (count the turns) until the valve touches the piston you can calculate the clearance.Good luck!

[john walker's workshop]

That cylinder was designed for a 4mm graphite sealing ring. Probably hard to find these days. Must have been old stock. It's a fluid barrier, not really a head gasket. The thinner seal does do the job.

[john walker's workshop]

Check out TSB 9404.

[Rahul]

Thankyou for the tsb. I did find it online, I will check everything as per the document tomorrow.. I don't think I need to check piston to valve clearance if machine shop has done their job perfectly ( at least this is what I think of), there is great deal of knowledge in TSB, it states to install a steel ring in groove but does not says if timing/ clearances ( valve to piston )for proper engine timing to be checked...

[john walker's workshop]

Wouldn't worry about it with stock cams. The machine work should only take off a couple of thousandths, just enough to clean.

[Rahul]

Originally Posted by john walker's workshop

Wouldn't worry about it with stock cams. The machine work should only take off a couple of thousandths, just enough to clean.

Thankyou for your reply, I feel a lot confidence now for the build, I know how to do timing, but was afraid if valve will touch the piston I will loose my new parts.