MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Spark Plug Connectors

I've noticed something disconcerting today. I was troubleshooting a an intermittently rough idle, and when I placed a screwdriver against the block next to each spark plug, I noted an arcing from the front of the connector to the screwdriver. Upon pulling the connectors, i noted that the metal portion of the connector that grips the plug head was even with the front of the plastic connector. On my old Champion connectors, the metal portion is well recessed. These are Moss original replacement connectors, and I was wondering if this is correct, and why the metal grips are not recessed to avoid arcing.

Think I've narrowed the idle/starting issue to a possibly stuck Gross Jet, but we'll see.
L Karpman

No one have a comment?
L Karpman

Ignition is one of the systems where the high-quality parts are most important, and some reproductions are sometimes below the required level, as probably in your case. Faults in the parts are not always visible.

I love the fancy period-looking wires and connectors, and carry some of them in my cars, but in case of having to sort out some engine firing problem, I revert first to modern parts, and then I start checking.

Jesus
J Benajes

The improper use of screwdrivers is the #1 cause of arcing.

Put the screwdriver down. If you don't see arcing at night, don't sweat it because it isn't happening during the day either. Your system will work just fine without any insulators on the caps.

One of my A's:

.....

MAndrus

Agree with above. No way the spark will jump that far without help. Don't grab with hand either- trust me on that! George
George Butz

I have seen some early cars where there was NO covering over the ends of the spark plug wires. There was a bare connector pushed onto the plug.
They ran just fine.

Jim B.
JA Benjamin

Perhaps I am misreading your post..if so, my apologies. I agree with the above comments regarding if it isn't broke don't fix it...but if you are not happy with the boot location....Are the outside boots molded to the wire insulation? If not, just slide the boot further down the wire. Regards, Tom
tm peterson

Tom:

Sorry for the lousy pic. The connector on the left is the Moss repro. The metal portion that connects to the plug tip is even with, or for that matter, extends beyond the plastic boot leaving it slightly exposed. The connector on the right is a Champion connector, and the metal that connects to the plug tip is "recessed" well below the boot. It seems obvious to me the Moss repro can arc, and the Champion will not. That said, if it can only arc to a screwdriver placed next to it, but not elsewhere during normal running, I won't worry about it. Thanks for all the input guys. Note: The screw on the side of the moss repro is a replacement screw, not the one that came with it that was lost at some point. It's a spare anyway.

L Karpman

I just installed those same Moss supplied connectors on my ignition wires and found that there is another problem with those copper inserts. The issue is that the copper "tulip" like copper connector that pushes over the spark plug end is a simple press fit over the internal brass portion off the connector that the center wires of the HT lead are screwed too. After you push the connector over the end of the plug then go to remove the connector the copper "tulip" piece separates from the brass inside and stays on the top of the plug. I had to dismantle all 4 of the connectors and then silver solder the copper to the brass. Silver solder as it's stronger.
Best regards
Rod
Rodney G Murray

Well here is a case where Moss duplicated an original that should have been put in the dust bin.

Those tulip connectors were original and they were fraught with the problems you describe. I have at least two of them on my car (originals).

BTW none of them arc. They are just loose but the connection is adequate.
Christopher Couper

Larry, thank you for the pic. Regards, Tom
tm peterson

Non insulated HT terminals are fine until moisture is present. Retaining authenticity is a compromise to reliability, rubber moulded caps are the solution. Ask a Mini Minor owner what happens on a wet day if you dont fit a rubber boot over your coil connections.
G Evans

I had the same issue with the original tulip plug caps coming apart so I fitted the long black NGK plug caps with "NGK" facing down so you can't see it. I know they are not original but they are a lovely fit.

Regards
Declan
D Burns

D Burns:

Do you know if they will fit 8mm bumble bee wire? If so, which model NKG cap are you using?
L Karpman

L. Karpman,
NGK Model SBO5E
http://www.ebay.co.uk/itm/1x-NGK-Resistor-Spark-Plug-Cap-SB05E-black-8374-/320892055087?hash=item4ab6a82e2f

I don't know about the bumble bee wire. I just screwed them into the existing HT leads and it only takes a few minutes.

Regards
Declan
D Burns

Moss Europe actually recommends them so they should fit your bumble bee leads.
http://www.moss-europe.co.uk/bumble-bee-competition-ignition-lead.html

Regards
Declan
D Burns

Thanks Declan. While searching I've come across the following for these caps:

"are for motorcycle, marine, snowmobile and small engine applications only."

That said, they obviously work on the MGTD. Any downsides?
L Karpman

Larry, why do you want to use suppressor caps with a standard ignition? Bud
Bud Krueger

Bud, I don't. I just want a cap that has better insulation than the Moss repro caps or the originals. No big priority, just something that came to my attention.
L Karpman

This thread was discussed between 12/09/2015 and 16/09/2015

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now