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engine modification and unleaded fuel.


jms700

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hello, not sure weather my engine has been converted in my mark iv spitfire and was also looking at possible engine upgrades.

iv seen a bit about stage 1, 2 , and 3 head upgrades and was wondering if any one knew more about them.

i dotn want a racing car and would liek to keap fuel economy buut was wondering if any of these would replace my valve seats and give me a performance boost.

thanks

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Stage 1 / 2 / 3 etc doesn't really mean anything. Generally stage 1 is considered to be air filter and exhaust manifold, stage 2 adds bigger inlet valves and a port / polish job to the cylinder head and stage 3 adds bigger exhaust valves and more cylinder head work. It varies so much between suppliers that you really should find out exactly what they're doing or supplying for the money. If you go for an upgraded head you may also need things to go with it. A fully worked head really needs webers, camshaft and other mods to work.

If you want to run on unleaded you can just do it. Most times it will work anyway without valve seat recession. If you really want to be sure you can have hardened inserts fitted to the exhaust valve seats - no other work required.

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Hi, im about to have my head upgraded next month and here's the website.

http://www.peter-burgess.com/index.html

This site was recommended to me and the price for the work is very good. As for fuel economy i want to keep this too as its my only car and is used every day to commute. Its pretty much standard to convert to unleaded valves now so this will be done when the heads reconditioned. It all comes down to What cam you use and how you drive. You can get the big valve fast road head (like myself) and still get good mpg. You just need to keep your foot light. If you use the new power that will be on tap after the upgrade then obviously you'll use more fuel. Also make sure your carbs are setup properly and in good fettle. Then there is the cam. Canley do the Spitfire mk3 cam for your engine this will give you improved power and torque with out killing mpg. I personally am going one step further with the TR5 profile cam. This gives more power but moves it up the rev range. However i have a revy 4-1 exhaust manifold which moves the power higher anyway. If you have a 4-2-1 then this gives more torque low down, on the other hand you might still have a standard exhaust manifold in which case you need to spend money here first or the head wont be able to breathe. As for carbs you don't need Webber's unless you want over 110bhp. Which to be fair you will need a race cam etc anyway to make the power.

Hope this helps. Chris.

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