Spitfire Advice on Spitfire engine

[billspit]

I just spent this weekend pulling and tearing down the 1500 engine from the free Spitfire I got from Paul Slice. As usual, the engine is worse than I had hoped. Its stuck and the exhaust manifol is cracked. I plan on doing some upgrades and want some input from you guys. I am not interested in building a racing engine.

I'm not too sure what intake I'm going to use, but it will likely be twin SUs or a single SU on an enlargened intake. I'm interseted in the new single barrel weber too, but haven't checked into that much.

What is a good cam to go with for a street engine? I'm guessing the 1500 had a pretty bad cam profile (smog), while the MK III had a pretty good one. Any suggestions on grind and supplier?

The big issue is about pistons. The easiest way to go is to go with 9:1 standard type pistons. But I've read that it is best to cut the block and remove the grooves around the cylinders (on the 1500 engine only). If I do this, do I have to cut the pistons down too? Secondly, some folks use TR6 pistons. Do these have to be cut down too? IIRC, the standard TR6 piston is the same as a .040 overbore Spitty. Any suggestions on brand and supplier?

 

[cjm]

https://www.totallytriumph.net/spitfire/engine_building.shtml

this link is a great source of info. best of luck with your project.

 

[70herald]

Keep it simple. TR6 pistons require major reworking of the block since their wrist pin is at a different height. - machining and probably making the thread holes (for the head studs deeper. There is also no benefit to machining off the grooves around the cylinder. The only reason you would do that is if there was damage to the top of the block. Then you could remove the grove and substitute a 1300 style gasket. As long as there is no damage to the top surface of the block, use whatever 1500 type pistons you want and the correct 1500 gasket.

 

[CinneaghTR]

Why don't you look at the Triumph Factory Competition Manual for the Spitfire and see what it suggests? Kas Kastner's three memoirs have a lot of great info, too.

 

[foxtrapper]

The link given by CJM is very good. Read it, several times.
As a supplier of modified parts, I'd suggest Ted Schumacher at https://www.tsimportedautomotive.com/ He's very down to earth and will talk with you quite a bit about what you want the car to do before trying to sell you camshaft X and such.

An early camshaft runs in bearings, which fit into the 1500 block just fine. This is a good thing as bearings can be easily replaced. The early camshafts had an excellent profile.

Flat top pistons raise compression and that helps performance. No modifications need to be made to the block for their installation as long as you use the right ones. Using TR6 pistons to achieve the same thing costs a lot more money and takes a lot more work.

Generic headwork, consisting of really nothing more than a multi-angle valve job does good things. There is some unshrouding that can be done in the valve pockets pretty easily. But beware of letting billy-bob go at a set of heads with a hand grinder. Usually the results are disapointing.

Dual SU's work very well and is well supported.

A decent header compliments the above, and helps finish the good breathing.

Do this all and you'll roughly double the power of the stock US 1500 engine.