4 replies to this topic

[IronmanG]

I'm on the look out for a " stage 3 " cylinder head for my 1310. If anyone has anything they want to sell please message me

[Lucas1988]

I'd be a bit more specific in terms of the spec you want so people can tell you what they have, I've got a few heads but its a bit of a mixed bag in terms of inlet/exhaust valve sizes so knowing what you are actually wanting. Knowing what your expecting helps quite a bit.

[Cooperman]

'Stage 3' really doesn't mean anything.

People who modify heads by gas-flowing them will also fit bigger inlet and, maybe, bigger exhaust valves. The amount of metal removed from the combustion chambers will vary and you need to specify the chamber volumes you want in order to achieve your desired compression ratio.

Do you want unleaded valve seats, as this will determine how large the exhaust valves are, assuming you go for the 35.6 mm inlet valves which are fitted to most modified heads?

You may be best finding a standard unmodified 12G940 head casting and modifying (or having it modified) to suit your required use of the car.

For example, you could pay a lot of money for a fully flowed race or rally prepared head, but you can moderately modify a head yourself with a bit of guidance from Mr. Vizard's excellent book and get excellent results for a small outlay.

[mccarefree]

Hello.

 

Cooperman is correct, 'Stage 3' is meaningless - many people have different definitions of Stage1, 2, 3 etc. I have modified several heads myself - one for my 1275 Tahiti which, with a Maniflow inlet/HIF44, Maniflow LCB and system, 1,5:1 rockers and standard cam, produced 84bhp after being dialled in by AC Dodd, and a second one for my son's 998 based on a 12G295 head that produced 68bhp likewise. I've also done two for 'paying customers'.

 

To do it properly means fully understanding what is needed and what is in place, particularly regarding compression ratio and to do it well involves a lot of work/time and new components (valves/guides/springs) in addition to machining costs. It's perhaps a bit more of a Pandora's Box than one might imagine....

 

Kind regards,

 

Martin

[Ethel]

All true, but I think Ironman's choice will be what's on offer more than what he wants. It might be more use to a potential seller to know the basics of the engine it'd be going on (cam, piston dish...) as, presumably, they'll have run it on an engine of similar, or different, specs to have an idea if it'll be of interest.