15 replies to this topic

[kit352]

So the urge to get upgrade the head on my little 998 is becoming too much to ignore and with christmas coming its the perfect excuse to spend some money.

My 998 is a stock a+ with just a stage 1 kit on it and the normal cam4810 head. I may add a mild cam in later but for now i am keeping the original one.

So with rising prices of heads now i only have a few options really. A 295 is near impossible to find in good shape and at a reasonable price so i am leaving that out.

Option 1- buy a calver ported head. This is a ported cam4810 in exchange for mine. This is the most costly option but maybe the best? Im not sure how this head compares to others in its ported state.

Option 2- get a 202. These seem to be the new budget friendly and widely available heads now. I can get one fairly cheap but of course it needs a fair amount of machining to make decent compression on my little motor. Most likely it will need leaded guides put in then a valve job etc. I think the price will end up being close to the calver head in the end but of course it wont be ported. That can be done later i guess. I dont know how a ported 202 would match up against a calver ported 4810 though. It sounds like a 202 gets pretty weak once skimmed to get the compression up which troubles me.

Option 3- a 940 head. Either sinking the valves or pocketing the block would make it work for sure. Research says if i get the small valve variant it will be better for my little motor and i may get away with just bolting it straight on with a stock cam and rocker set up, maybe put a thicker headgasket on if needed. The water pump pulley needs to be the smaller one and i may need file the water pump a bit but no big deal. This head should never need to be ported for a 998 as its quite big anyway. Again, no idea how it stacks up compared to the other two if they have been worked over.
These heads would be by far the cheapest i think if i can find a small valve one in good shape.

[paul50]

I have a 202 that calver st. Done for me. 20hp gain.

[dangparker]

I'd say give Calver a call or email.  I've just bought a head, cam and rockers from him and his advice was invaluable.  I'm located over in California, so corespondace was via email.  He's a wealth of knowledge and willing to share

 

Cheers and good luck!

[kit352]

Was that on a 998 and was that in addition to a stock 202 or was that a total gain

[Maccmike8]

I have a 202 that calver st. Done for me. 20hp gain.

[Algordo1100]

I fitted a 940 to a 998 years ago. I did not pocket the block as it didn't need it.

That thing flew. In many ways my favorite mini motor I've owned due to its willingness to rev. I wish i hadn't sold it.

The car was still on the road up to last year according to the DVLA. I saw it changed hands a couple of times and was advertised as a standard car. Someone will have got a suprise with that.

[Bobbins]

Will a pre A+ 12G202 head fit straight onto an A+ 998? (obviously rebuild and possible skim aside).

I need to get our 998 A+ converted for unleaded and it could be wiser to invest in a 12G202 instead.

[kit352]

The chamber size is really big on a 202 so it will need to skimmed a lot if you have flat top pistons.

[Turbo Phil]

The chamber size on the 202 is only 26.1cc, so would only need around 0.020” skimming off to make it comparable to a 4810. That’s nothing to worry about at all.

Phil.

[Bobbins]

Thanks guys. So with regard to A vs A+ differences there's nothing to be concerned about? 20 thou skim easy enough when the inserts are fitted.

[paul50]

Mine had 38hp to start with. Calver head. Free flow manifold and twin hs2 came out with 62hp got k&n filters and ac Dodd dizzy as well . All done on rollin road at regency autos in Cambridge set up by Peter Baldwin

[toppers3933]

I have a Cooper conversion head which I might be selling. It’s based on a12G202 and was the head supplied with the Cooper kits along with twin carbs etc. Goes well on my engine but I’m changing the engine so this may well be for sale.

[kit352]

I may be interested if your selling it. Ive had to put the head swap on hold as my brand new paint job has started failing after 2 months and its kind of put me off of the car at the moment but for the right price i might grab it.

[rock1day]

I have a Cooper conversion head which I might be selling. It’s based on a12G202 and was the head supplied with the Cooper kits along with twin carbs etc. Goes well on my engine but I’m changing the engine so this may well be for sale.

What size intake valves are fitted 1.1or 1.2 inch?  

[gazza82]

So with regard to A vs A+ differences there's nothing to be concerned about?

A vs A+ was all about the block and not really the heads. Later A+ probably gained underleaded inserts on some heads.