We normally use mineral oil to do the CC'ing of chambers. Sometimes the valves don't seal properly then the water can drain past them, where the oil will not. Also on the pistons the mineral oil works better since it won't drain past the rings so fast.

Plus oil doesn't cause rust...

It is beneficial to know if the valve-to-seat is not sealing. You want to know if water leaks past this, because it tells you it needs to be fixed. A good head will hold water in the combustion chamber overnight with no leakage.

For the piston CC, I think I will use light oil.

kero, is the go.

Yes it's definitely beneficial to know if the vales aren't sealing properly, but not while you are CC'ing chambers or ports for that matter. Found that we normally do CC'ing before and while we do flowing in the ports and chambers, but before we do the seats.

This is because you sometimes just nick the seat when busy with the porting and flowing, which will cause enough water to drain to make the measurements inaccurate. Also on old heads that you want to take preliminary measurements on, the seats could be pitted and not sealing properly. At this point it doesn't matter if the valves don't seal 100% yet, because they are still to be cut. So it's useful to use a thicker type fluid that doesn't drain away very quickly through the smallest of hole/s.

Once that kind of work is complete, you do the seats then we normally use paraffin(kerosene for US) or diesel as a final measurement. It's thin enough to show any leaks the vacuum test might not have picked up, but it won't cause your pristine seats and valves to get rusted.

Ah that sounds good. Thanks.

Sounds like the h92 has the h95 C.Chambers but with unshroudded inlet ports unlike the h95? if so then this is a very good head for economy and can be opened up more for performance. Shorter valves help with weight and Combustion chamber is superior design as fuel is directed in the centre of cylinders and not on its walls like other heads.

Thanks. I meant H95, the shrouded-port head (edited the earlier posts to correct). There are other A-series swirl port designs (for superior mixture burning), but the H95 one uses a the shroud design and medium oval ports for decent airflow.

H92 is the EFI head. I wish i had one!

Good stuff all of this.

I am playing around with a 1400 head off a B310 Sunny about 1981 model fitted originally with an automatic transmission. This is presently fitted to an A12 block.

I am looking at getting a new cam for this motor and the cam grinder wants as much info re the motor as possible.
At the moment I am not ready to pull the head off.

What was the combustion chamber size typically used on these heads here in Australia?

H89 head is typical, and it is 29cc typically. Works best 3500-6000 RPM. Shift often and keep it revved up.

ddgonzal,

Thanks for your prompt reply.