TR4/4A spark plugs

[les m]

Hi from New South Wales Australia just got fully rebuilt engine in my 65 TR4A running took it for a run about 40 miles and checked the plugs when home and plugs 1 and 4 are normal but 2 and 3 are clean no carbon on them at all. i am thinking maybe a tune problem. maybe running too rich. does anyone have any ideas please. never seen this before on any car. thanks

 

[Hamish Racing]

Unusual as these are not paired for intake thus unlikely to be fuel mixture related.
Check the spark on all plugs as a first step.

 

[poolboy]

As well as checking that you have the spark plug wires in the distributor cap in the counterclockwise firing order

 

[sp53]

Getting 40 miles is a good thing because you have it running. I would get some new plugs and see how they look after 40 miles. I find carboning up is a challenge on these motors. What brand plugs did you use? I find the Bosh plugs to work well.

 

[les m]

Hi yep all new plugs actually i put 2 new sets of plugs in in case a couple were no good. i put new electronic dizzy in. i will replace the plugs leads next as they seem to be the only thing left to try. using NGK plugs. she runs ok but when i slow down to stop and then take off it sometimes backfires. Thanks for all your help let you know how i go.

 

[bobhustead]

You might want to go to Champion plugs. While I don't understand the why, I have an outboard that specifies NGK and when I put the corresponding Champion plugs in it they don't last 2 hours. There are obviously some manufacturing differences.
Bob

 

[mezy]

If you have two cylinders putting unburned fuel into the exhaust system this will cause the backfire.
Had an Austin A60 van years ago, you could turn off the ignition going down hill while still in gear and pump the gas peddle a few times, and then turn the ignition back on, then BOOOOOOOM.
pumping the peddle too much was not recomended, its amazing how the silencer would dissasemble itself.

 

[KVH]

Are you blowing any black puffs of exhaust when you shift at higher rpms? I was never able to tell until I asked someone to watch. Because your cylinder issues are not paired to the carbs, I agree it's likely not fuel. But is there any operational issue?

 

[poolboy]

As well as checking that you have the spark plug wires in the distributor cap in the counterclockwise firing order

Done this ?

 

[les m]

Yep am waiting for a new set of plug leads to arrive. See how it goes then. Just had the generator light come on so have to fix that as well. No other problems with the engine. I will get someone to watch the exhaust to see if puffs of smoke or not. Thanks everyone for your help.