You are here:

Triumph Repair/cylinder block


i have a spitfire with a recessed cylinder head. between cylinders 1 & 2,3& 4 there is a small gap allowing the compression to go from one cylinder to the other. will a gasket seal this off or is this a ruined block.

Hi Dwight,

You first need to clear something up for me. What do you mean a "recessed cylinder head" ? Do you mean that there is a recess in the head at two points? (1 to 2 and 2 to 3)?

Next question, is there a recess all around the block at the top? Is this burned recess in the top of the block or the head or both?

Next question, how deep is this recess? (aprox.)

Some Spitfires had a recess all around the top of the block called "flycut" This required a special head gasket with a thick ring around the top of each cylinder that fit down into the flycut in the block.

Often when a mechanic would put on a new head gasket he would get the wrong gasket as they both looked alike. Often aftermarket suppliers would get them wrong and sell a flat gasket in place of the thick ring gasket and vice versa. It was common then for the head gasket to burn through and the easiest place for that to happen is between two cylinders because they are close.

Most burned blocks and burned heads can be machined flat again but care must be taken to ID which block you have, the fly cut one or the flat one. If you are not sure what I mean take a close picture of the top of the block (not the head) and send it to me.

An auto machine shop can look at it (block or head) and usually tell you if machining will clear it up. (in absolutely NO way should you try to seal it up with just a new gasket)

Keep in mind that after machining, the engine will have a higher compression ratio. Meaning it must use high octane gasoline and probably needs to have the ignition timing set to match the engine not the book specs. If you don't have anyone that knows how to do that let me know when you get to that point and I will go through the procedure for you.

This is very important because the higher compression ratio will increase horse power and even mileage but it also puts the engine closer to the detonation point. (called "pinging") which will destroy the engine.

Let me know.


Triumph Repair

All Answers

Answers by Expert:

Ask Experts


Howard M. Fitzcharles III


Triumph TR-4 up & Spitfire, and Engine theory


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

Associate member SAE EAA member

Import Car magazine

ASE Master Auto with L-1 certification up to 2000

©2017 All rights reserved.