C1J build.

[Red October]

Hi guys.

Ive had the head back completed and it the dogs. One worry I have is that the stem on the metro turbo valves I used for larger exhaust valves are slightly shorter than the oe ones.

As you look down the top of the head keeping your eyes in line with the valve caps (tops) the new caps sit about 6-8mm lower than the inlet caps (tops). Now I know adjusting the pins on the rocker will get my optimum clearance but what are the chances of the springs binding? Aka valve bounce.

Did the others whove attempted this selected valves with a stem slightly less than oe and co.e across this problem too? Cheers in advance.

[Nottswoody]

I'd say talk to no1 hi5 Glenn and scoff see what they say

[Woznaldo]

Hi guys.

Ive had the head back completed and it the dogs. One worry I have is that the stem on the metro turbo valves I used for larger exhaust valves are slightly shorter than the oe ones.

As you look down the top of the head keeping your eyes in line with the valve caps (tops) the new caps sit about 6-8mm lower than the inlet caps (tops). Now I know adjusting the pins on the rocker will get my optimum clearance but what are the chances of the springs binding? Aka valve bounce.

Did the others whove attempted this selected valves with a stem slightly less than oe and co.e across this problem too? Cheers in advance.

Sounds good. Get some pics up so we can check out the handy work.

[Markey Mark (BD)]

The head I had on my engine in the blue car had the valve springs seats machined down alittle to avoid valve spring binding

[Red October]

The head I had on my engine in the blue car had the valve springs seats machined down alittle to avoid valve spring binding

Off the top of your head can you remember how much meat you chopped out mark?

[Markey Mark (BD)]

Off the top of your head can you remember how much meat you chopped out mark?

Honestly can't remember mate, was about 7yrs ago now

[Scoff]

I'd say talk to no1 hi5 Glenn and scoff see what they say

We didn't use metro valves sorry, so I don't know the answer to this one.

[Scoff]

Off the top of your head can you remember how much meat you chopped out mark?

Surely you want to remove however much the difference is between the new stems and original.

[Red October]

Surely you want to remove however much the difference is between the new stems and original.

Took out 3mm on the bases and a little off the top if anyones interested! Springs coil levels are all the same now.

[gttjames]

want pictures

[Woznaldo]

Anymore updates with this build?

[Red October]

Anymore updates with this build?

Hi woz thanks for bringing the sunshine over from prison island

https://www.rtoc.org/boards/showthread.php?t=32799

Some pictures in there somewhere, the head has now got honda civic goodies a full update soon mate.

[Woznaldo]

Looks like this thread has well and truly faded away.

I've got a Stage 4 GT Tuning Head that's currently off the car. I'll take a few pictures for reference. I'm not saying this is how things should be done, but there are a lot of simple mods that will work on any head.

[Markey Mark (BD)]

Think so mate
Can't believe how many years ago I started it

[Fordy]

Port head
Chamfer the squish areas to reduce likely hood of detonation,
Correct head thickness for compression ratio,
Single groove Metro turbo race valves, 35.6mm inlet and 31mm exhaust with matching titanium retainers
Machine Spring seats to ensure no valve Spring binding

That's a good cylinder for most on here without efi.

Cylinder head water flow mods seem to be just opening up the water ports

[Woznaldo]

I know CTM did a race head, but it was around 800 quid, so a bit rich for anyone other than a racer looking for that extra bit from the same level of boost. Still, it would be nice to see one theirs in the flesh.

[Markey Mark (BD)]

I know CTM did a race head, but it was around 800 quid, so a bit rich for anyone other than a racer looking for that extra bit from the same level of boost. Still, it would be nice to see one theirs in the flesh.

I had one of those heads on my old C1J with the VNT

[Woznaldo]

So, my Stage 4 GT Tuning head hasn't had a great deal done to, but what has been done, can be replicated by the average DIYer. The Inlet ports have been opened up to the gasket max size and the Inlet Manifold matched to the head. The Valve Guides have been cut back so they don't protrude into the inlet tract. The exhaust ports have been cleaned up a bit too.

Here's a couple of pictures. The quality isn't as good as I would have liked, but they illustrate the above.

Inlet port.






Exhaust port. You can see that the gasket and Exhaust Manifold are bigger than the port. This helps to prevent reverse flow.




I've got another head that I might have a play around with over the next year, just to see what works and what doesn't.