4 replies to this topic

[Keith Grendahl]

I don't know much about this 1275 motor. The car was stored in a barn since 1984 and the owner that built it isn't available to tell me anything about it.

It has Champion C59YC spark plugs. "Projected nose racing gap plugs initiate the flame front closer to the center of the combustion chamber by projecting the firing tip an additional 0.60-inch. You must make sure you have sufficient clearance to valves and piston to use these plugs. Initiating the flame kernel closer to the center of the combustion chamber has an effect similar to advancing the timing, thus it allows you to reduce the timing and receive better throttle response. Projected tip also contacts more of the incoming air/fuel mixture which aids in plug cooling at higher RPM. Constructed with a nickel shell for faster heat dissipation and copper core or double copper (when noted) for further heat"

I am not going to race this Mini. Is it okay to continue to run these plugs or should I replace them?

What I know:

1275 "H" engine from an Austin or Allegro
Dizzy is non-vacuum 23D4 from a Cooper S
Twin HS2's with "M" needles
Cylinder Head is the smog head used on Austin America, AH Sprite, or MG Midget.

Don't know if any machining has been done to the heads or cylinders. Really nothing at all about the internals.

The electrics were a mess so I installed a new loom from Autosparks, new Pertronix coil and ignitor. Starts much better but won't run without the choke pulled, even after sufficient warm-up.

I will be tuning the carbs once my stub stacks and filters arrive. It only has ram horns now. I assume the carbs are set lean since the choke must be out to run. It definitely runs rich now, black sooty plugs and tailpipe. I don't think there are any vacuum leaks. I had previously removed the intake manifold and carbs to give them a good cleaning. New gaskets installed on everything.

Any help is appreciated.

[Mal_whitby]

I don't know much about this 1275 motor. The car was stored in a barn since 1984 and the owner that built it isn't available to tell me anything about it.

It has Champion C59YC spark plugs. "Projected nose racing gap plugs initiate the flame front closer to the center of the combustion chamber by projecting the firing tip an additional 0.60-inch. You must make sure you have sufficient clearance to valves and piston to use these plugs. Initiating the flame kernel closer to the center of the combustion chamber has an effect similar to advancing the timing, thus it allows you to reduce the timing and receive better throttle response. Projected tip also contacts more of the incoming air/fuel mixture which aids in plug cooling at higher RPM. Constructed with a nickel shell for faster heat dissipation and copper core or double copper (when noted) for further heat"

I am not going to race this Mini. Is it okay to continue to run these plugs or should I replace them?

What I know:

1275 "H" engine from an Austin or Allegro
Dizzy is non-vacuum 23D4 from a Cooper S
Twin HS2's with "M" needles
Cylinder Head is the smog head used on Austin America, AH Sprite, or MG Midget.

Don't know if any machining has been done to the heads or cylinders. Really nothing at all about the internals.

The electrics were a mess so I installed a new loom from Autosparks, new Pertronix coil and ignitor. Starts much better but won't run without the choke pulled, even after sufficient warm-up.

I will be tuning the carbs once my stub stacks and filters arrive. It only has ram horns now. I assume the carbs are set lean since the choke must be out to run. It definitely runs rich now, black sooty plugs and tailpipe. I don't think there are any vacuum leaks. I had previously removed the intake manifold and carbs to give them a good cleaning. New gaskets installed on everything.

Any help is appreciated.

If you don't know much about the internals of the engine, then I'd be tempted to use NGK BP6ES plugs as a starting point, which are plugs for standard engines. These plugs are fine for mildly tuned engines of any size, some of the rallycross engines have them with no problems too.

Some people don't like NGK plugs and say that Champions are much better, which is fine, personally I've not had problems with NGKs but I did once with Champions, others say the opposite. But either way, standard plugs are a good starting point and see how they run. A rolling road session will tell you a lot about the state of the engine, and the man running the road should be able to advise if standard plugs are suitable once he's finished the session.

[JakeJakeJake]

Sorry for the vague answer but "race" spark plug run either hotter or colder than standard (can't remember which), basically they are more prone to sooting up, which isn't a problem in race engines as they spend most of there life flat out, in a normal car they will soot up on idle and low revs (traffic) and cause poor running, got for a set of BPR6ES or BPR6S.

[liirge]

they run colder to cater for a higher compression ratio.

[twrminisport]

NGK plugs are the best. Iridium really. But at the end of the day its a spark plug. If it runs and the plug comes out biscuit coloured its all good.
McVities digestive colour - Perfect
White - Engines too lean
Black - Engines too rich
Higher the number the colder it is.
This is why race engines use lower plugs because they run hotter and stop soot bulding up when running rich in the mid range.

Edited by twrminisport, 14 March 2011 - 03:15 PM.