Lister 6/1 CS cylinder head

Would anyone happen to know if a Lister CS 6/1 will run ok with a 3/1 cylinder head  
The reason I ask is because I have a 6/1 with really badly recessed valve seats and I have 3/1 head with really good valves and seats.
I appreciate that the 3/1 valves are much smaller diameter than the 6/1 and this would greatly sap the power output but is there any reason the 3/1 cant be used? the stud pattern and water ways all look the same, not sure about the volume of the indirect injection chamber in the head though although the volume would be easy enough to check.
I wont be putting the engine to work so the power output doesn't really matter.
Thanks.

If as you say, the stud pattern and water ways align that's a good start.

It seems that the 3/1 has a swept volume of a 1.0 litre and the 6/1 is 1.435 litre; this from
Stationary Engine Spares web site, an increase of almost 50%.

So yes, maybe you should check that the compression ratio is similar. Remember that the clearance volume will be:- the volume in the cylinder head + any volume in the cylinder at TDC including the dish in the piston, and the space in the head gasket.

If you can find what the compression ratio of the engine should be; you could measure up the clearance volumes and see how much higher it is with the 3/1 head.
If too high you could possibly lower it using a thicker head gasket, or shims under the cylinder.

I've just found some information on C.R.s of these engines which may be of interest to you.

For 5/1 6/1 10/2 and 12/2 engines with start valve :-
the compression ratios are - 19:1 for starting and 15:1 for running.

Later engines without the start valve are :- 17.5:1

For 3/1 and 3.5/1 engines :-
the compression ratios are - 22:1 for starting and 18:1 for running.

I hope this is of some use to you.

Many thanks for the information.
Thats a big difference in the swept volume. Hmmmmmm   Also a big difference in the compression ratios. 15:1 and 18:1 running.
Both the 3/1 and 6/1 cylinder heads are completely flat so I guess that alone won't effect the compression ratio the only thing I'll will need to check is the volumes of the indirect combustion chambers in the heads.
My heads all have the starter valves.
I was kinda hoping someone before me would tried the 3/1 head on a 6/1.  

Yes, the 3/1 would need a high compression ratio to give reliable ignition, but working cylinder pressure would need to be limited to keep bearing loads within bounds.
The 5/1 and 6/1 would have to have the cylinder pressures limited, for the same reason,
I presume that they used the same sized crank bearings; but with a larger diameter piston. the bearing loads would be greater hence the lower compression ratio.

If you wanted to use the 3/1 head assuming it would physically fit; you would need to measure all volumes.
As well as the combustion chamber volume, you would need to measure :- the volume of the valve recesses in the piston, and the bowl in the piston (if there is one), and the volume between the piston at tdc and the head face with gasket fitted and head torqued down. If the valves are recessed they will increase the volume; if they protrude below the head face they will decrease the volume.
All these added together will give you the clearance volume, that is, the 1 part of the compression ratio.

So whatever compression ratio you are aiming for; you need to take 1 from the big number and divide the swept volume by the result,
example: for 17.5:1 17.5-1= 16.5
swept vol. 1435cc divided by 16.5 = 87cc clearance volume.
so in this example; to achieve c.r. of 17.5:1 you would need to adjust the clearance vol. to 87cc. Most likely by shims between the cylinder and crankcase. You would need to do the calculations to check that the required shims were not excessive.

Or you could possibly get new valve seats fitted to the 6/1 head.

Sorry if I'm trying to teach my granny to suck eggs; but I never knew my grannies.

If my either of my grannies knew all that stuff, I'd be most impressed!
Sadly I never knew any of my grandparents.

I've no doubt someone out there will have all the answers but finding him/her or them is a different challenge.

o.k. your 6/1 with the 3/1 head would give a c.r. of 25.54:1, lets say 24:1 to allow for the greater volume below the head face.
To reduce the c.r. to 17.5:1 you would need to increase the clearance volume to 88cc; that would be an increase of 29.5cc which would require a 2.9mm shim to be added between the cylinder and crankcase.
To reduce the c.r. to 15:1 which is the original c.r. for your 6/1 you would need to increase the clearance volume to 104cc ; an increase of 45.52cc, that would require 4.4mm of shims to be added.
If this were done, I think it would have a very bad effect on combustion. Also probably be impossible to set the valve clearances.

I would be surprised to find that some one had actually done it.

Good luck.

Wow! I'm very impressed, you have certainly went into the science of it. Looks like I'll stick with a 6/1 head then . Luckily I do know of one that's supposedly has good un-recessed valves. Many thanks for your troubles. I'll keep you posted on hoe it goes.

Good! I'm glad you that you have the option of a 6/1 head.

I think the 3/1 head would, on consideration, have presented so many problems.

Apart from the physical problems of shimming and having enough adjustment on the valve mechanism and the piston operating in a different different part of the cylinder; it would have very poor ignition and oil dilution with unburnt fuel, and maybe, carbon packing behind the rings.

It looks like you've got plenty of engines there to keep you going.
Good luck.

A friend has a supposedly good 6/1 head for me so I guess I'll leave it until I can go and collect the 6/1 head.  
I'm never stuck for a project. There is a few more engines to come out of the woodwork yet.
I have a JP1 and another 6/1 in a engine house which is an annex of my workshop but I'm going to have a right struggle someday when I eventually try and get them out.
At to that three classic cars two tractors and two motor bikes. Not enough hours in a day