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Triumph Repair/78 spitfire


Hi Howard, first i checked dry compression in 1234 have 135 in every hole. Car does start sometimes but is miss firing . cant get it to idle. sprayed starting fluid still wont fire. have check gaped points. new wires spark plugs cap rotor. 6v brand new coil. then it sometimes starts. took out plugs all sooted up. the distributor is of a mg 73 with the cap with a arch cut out for coil- wire. checked carb diaphragm for splits check metering needle says 45L. is this dist ok to use...maybe get electronic module...carb??

Danial, you need to check your compression gauge on another engine or test with another compression gauge because it is not normal for all cylinders to test the same.

Also You need to check the distributor as the 73 MG is an Austin engine and the Triumphs are Standard brand engines and the distributors are not interchangeable.

If you have a 6v coil you must have a ballast resistor attached to it because if you have a distributor (Probably an earlier Spitfire)with contact points you can't use a 6v coil without a ballast resistor.

You will have to explain what you mean about "the cap with a arch cut out for coil- wire." ????

Any time the plugs are sooted up (if you mean a flat black powder) that is excess fuel so either the carb is flooding, or set too rich or the choke is on.

Also any time you spray starting fluid into the intake when trying to start an engine and it don't fire, it means you have lost ignition for some reason.

It sounds to me that you need to start from scratch and check your compression gauge first or get another one to try.

If the compression tests ok then you can proceed to ignition but only after you confirm the compression because it is not normal to have all cylinders exactly the same.

Then remove all the plugs and clean them or replace them and connect them to the plug wires and lay the plugs on a metal part of the engine and spin the engine over with the starter and watch the plugs. They must spark with a thick spark (as thick as a pencil lead) and the color must be blue. (not in bright sun light) If the spark is thin like a hair and colored yellow or orange it is a weak spark and probably will not spark at all under compression.

Then if you have that you must set the ignition timing to specs. Then confirm the firing order of the four plugs. (1342)

Only then can you look at fuel. The first thing to do is ID what kind of choke it has. (coolant temp operated choke) Then lift the piston to see that you feel hydraulic resistance then you lift it and then drop it and confirm that it hits the bottom. Check for fuel in the float chamber vent hose that runs over to the charcoal canister. There must not be any signs of fuel in that hose.

Let me know,


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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

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