Lotus Elan and Lotus Elan Plus 2 Forums

I just came across this http://www.davidgathercole.co.uk/

I have no association with this company.

Looks like a good reproduction of the early heads. Be interesting if the FIA forces their use versus later heads or the new high hp, big inlet reproductions that all the racers are now using... in their supposed original replicas and supposed original cars!!!

cheers
Rohan

I have one of these early heads - LP1916
Is there any difference in terms of compression figures etc to later heads?

Almost all original heads will probably have been shaved by now so compression will depend on the state of the individual head. The Mk1 heads had the same thickness originally as the Mk2 heads up until the introduction of the sprint engines in 1970 which had the head machined to be thinner with higher compression when new.

The most significant difference with the Mk1 heads were the smaller diameter inlet tracts which restricts their breathing and porting possibility in a high hp engine which is why racers dont use them

cheers
Rohan

Thanks Rohan,
I ask because I have a Super SE block 'H' prefix and wondered how this head would differ interms of set up with the old head which is fitted with standard 'un-grooved' cams. It seems to run okay (apart from way overfueling which I have to look at next) but wonder what else I might have to do regarding having an old head on a Super SE block.
Kev.

My understanding was that the super S/E engines were basically a sprint specification engine without the larger valves. The bottom end did not change just the cams and compression ratio when new. Sprint specification setting for carbs and timing would be a good starting point for setting up a super SE head on an engine.

cheers
Rohan

QED have been selling 'new' heads for a few years now here in the uk.

http://qedmotorsport.co.uk/qed-shop/lotus-twin-cam/cylinder-head-components/cylinder-head-small/large-bore

Tony Thompson told me the early heads we more rigid and better cast that the later heads, He also said the produced about 3 more HP when they had the same spec.
James

pereirac wrote:QED have been selling 'new' heads for a few years now here in the uk.

http://qedmotorsport.co.uk/qed-shop/lotus-twin-cam/cylinder-head-components/cylinder-head-small/large-bore

But they are the later type, they look odd on earlier engines/cars and visa versa early heads are wrong on late cars.

You have that lovely yellow Sprint don't you? You may not have noticed the difference.

holywood3645 wrote:Tony Thompson told me the early heads we more rigid and better cast that the later heads, He also said the produced about 3 more HP when they had the same spec.
James

mmmm ...what heads ? what spec ?

What ultimately limits HP is elan heads is the intake tract . The early Mk1 heads had smaller tracts and cant be ported to the same extent as the later Mk2 head. The new SAS and QED and DaveBean heads all have bigger inlet tracts again to maximise HP. They did this by copying the work done by John McCoy at Omnitec with the inlets he developed for their Stromberg to Weber conversions. Johns inlets closely follow the Hart inlet shape but are better flowing due to more freedom with the replacement casting and ability to go closer to the original inlet valve spring pocket base as this does not need to be deeper with modern springs

The porosity in the die cast early heads I have seen is certainly less than many of the later heads. I have not seen an early die cast head sectioned to be able to say if its more rigid than the later sand cast heads

cheers
Rohan

I just hate it when people promoting their latest whizz bang product neglect to mention the most important thing, the price.....