TR2/3/3A TR-3B Spark Plug Wire Question

[Vaark01]

Hi,

I just bought a set of Cobalt spark plug wires for my TR-3B. I also had to buy a plug-in distributor cap (MOSS part #163-815) to replace my stock side entry cap.

The problem I have is trying to figure out where to plug in the spark plug wires on the new plug-in cap.

Can someone send me a sketch or picture to help me?

I also bought new plugs from MOSS (Champion Copper Plus). My service manual says to gap the plugs at .032" Is that correct?

Thanks.

Paul

 

[Mickey Richaud]

Hey, Paul -

Plug gap should be .025", unless you're running electronic ignition. And the firing order is 1-3-4-2. How that translates to your cap depends on where the rotor's pointing for the #1 cylinder.

Here's a great little handbook that covers all the basics:

Manual

 

[TR3driver]

Normally, the HT terminal nearest the #1 plug will be #1. But you might check your old wires & cap to see if they were installed that way, since it is possible that someone has installed the distributor drive gear wrong and moved the plug wires to compensate.

Then the firing order moves counter-clockwise around the cap, ending with #2 usually nearest the #2 plug.

I run .025" even with electronic ignition. Opening the gap made no measurable difference in how the engine ran or how much fuel it burned; and puts extra strain on the rotor (a common failure point).

 

[Geo Hahn]

...My service manual says to gap the plugs at .032" Is that correct?

Your confusion may be if your manual (like mine) only shows the specs for [TR2,3,3A = .032] and [TR4, 4A = .025] with no mention of the TR3B which would generally be regarded as a TR4 engine.

FWIW - I run a wider gap (and a sport coil) with no problems though, OTOH, can't really claim improved performance either.

 

[PatGalvin]

Hi Mickey

What's the recommended plug gap with Pertronix ignition? Randall, the reminder regarding the counter clockwise rotation of the dizzy for firing order was helpful. Was a rookie mistake on my part.

Thanks much

Pat

 

[TexasKnucklehead]

To make matters more confusing, be aware that at least 2 types of "side exiting" caps are available. If you compare the two, the orientation of the wires are moved/rotated by 1. The cap has small grooves cut in the bottom, so it will only fit onto the distributor one way. When I change a cap, I first position the rotor such that it is pointing at the #1 cylinder wire. Then I use an ohm meter to make sure the contact on the under side of the cap is connected to the place I will install the #1 wire. Then its a simple matter of firing order.
The plug-in caps are more obvious.

 

[Geo Hahn]

The plug-in caps are more obvious...

...because they're designed with MG owners in mind?

 

[trrdster2000]

Now Geo, you are letting the full moon show your bias.

Wayne

 

[sp53]

Nothing there Mickey

 

[Geo Hahn]

Nothing there Mickey

Try this:

Practical Hints for the Maintenance of the Triumph TR3

I'm embarrassed that I failed to mention it -- I reference it so often that I have 2 copies so one can reside in the cubby box full time.