Esprit Models
Esprit History
For Sale
Other Stuff
Buying & Running
Parts & Specialists
Other Esprit Stuff

Gas flowed and ported Esprit head
by Vulcan Engineering

The Job is to extract as much extra flow out of the sports 300 cylinder head as possible.

The basic Idea is that if you can get the head to flow more air you will get more Air & fuel in to the cylinder & in turn get a bigger bang & then more power.


This job is best left to the professionals in our opinion.


You will need the following parts:

Vulcan Engineering
The name in performance Engines & cylinder heads
185 uxbridge road
W7 3TH

Tel: 020-8579-3202 or 020-8579-2988
Fax 020-8579-7390

web: www.vulcanengines.com
email: sales@vulcanengines.com


The first job is to make a jig to fit the cylinder head on to the flow rig so that we can do a flow test. We then flow test the Cylinder head in its STD form so that we know how good or how bad the std head is and then make a flow chart so that we have a comparison when we have finished.


The next thing to do is to work out a port size that will work well with the STD valves sizes.
The next thing is to make a mandrel so that we can grind out to ports to the Same size ,we use old valves because it has a head that we can grind to the desired size & shape that we want.


Once we have done all this we then heat the cylinder head up & nock back the valve guides so that they are not protruding in to the ports & then its in to the grinding booth for some serious grinding of the ports & throats.


Once we have a pair of ports roughly ground out its back on to the flow rig to see how much better it is.


When we have got the ports as good as they can get we then polish up the ports, we polish the Inlet ports with 60 grit paper to give a slightly rough finish so the it will help to create turbulence in the ports to help the fuel & air to mix before it enters the cylinder to give a better burn & we polish the Exhaust ports on 150 grit so that we get a very fine finish in the ports to get the burnt gases out as quick as possible.


Once all this is done we then nock the valve guide back to its original position & then ream the guides to make them true again.
Then we cut a finish valve seat and then we polish the combustion chambers.

One more flow test to get the final figures & all that’s left to do is to wash & assemble the cylinder head,
Once the cylinder head is completed we go off to the computer and enter the final flow figures so that we can see how good the newly ported cylinder head is.

The final flow test showed a increase of 12.6% increase on the Inlets & 11.2% increase on the exhaust.

LEW's Verdict

Gas flowing a head is very good for performance when you are running a normal aspirated engine,(no turbo) but with turbo charged engines, the turbo forces the air down the ports into the engine so a larger turbo is more significant for power gain.

This rebuild was performed by Vulcan Engineering on LEW's 1992 SE

If you have any comments, feel free to e-mail me with at admin@lotusespritworld.com

return to top
home email news esprit models road tests buying an esprit running an esprit esprit owners maintenance pictures for sale history Lotus models links