engine running weird on my BN6

[bighealeysource]

Hey all,
Before I get in and muck things up, my freshly rebuilt
engine was running very smoothly on my 59 BN6 as I have
been in the completion process on the restoration. Could
not drive it but would start it up occasionally to make
sure everything stayed ready to go. Then for some
unexplained reason, it is now running a little rough,
can feel it almost back firing from the exhaust pipe -not a
loud noise but a distinctive pop or pressure release through
the pipe. Will warm up and run smoother but I have no
idea what has happened. Frustrating as it was running
smooth and now some gremlin has moved in. I do have a
couple of plug wires that I found some nicks in the insulation
around the core but that has apparently been there. Going
to change out to new comp/bumble bee wires but any thoughts
I where I should start looking ? Like I said, sure don't
want to mess it up worse.
Thanks,
Mike

 

[GregW]

Frustrating as it was running
smooth and now some gremlin has moved in.

Maybe a gremlin really moved in. After you ran the engine in cold weather, a mouse might have gotten in the tailpipe for warmth.

 

[bighealeysource]

Hey Greg,
wish it were that easy but if there's one in it now must be one tough
mouse as I let it run about 15 minutes the other day. This is the same
Healey with the unusual way the plug wires are in sequence which I have
not dealt with yet. As I mentioned was running great and now it's not.
I will see if anyone has an idea that might help but do plan to re time
and get everything in the right sequence but would like to get it back to
how it was first if possible.
Thanks,
Mike

 

[Randy Forbes]

How long since it was rebuilt? Could be possible that the rubber diaphragms on the carbs are dried/drying up and messing with the fuel mixture.

Pops like you describe usually speak of lean burn conditions.

Might as well see what the plugs look like, though they won't tell much of a story, never having been under load. They may still lead to a problem though, if the front three (3) look significantly different than the rear three (3).

 

[Johnny]

Mike, what do you mean "This is the same
Healey with the unusual way the plug wires are in sequence"? I thought there was only the correct way for the wires. Could you or someone else relocated a wire? Also, check the rotor maybe you got a bad one. Also check the fuel for dirt etc.

 

[GregW]

This is the same Healey with the unusual way the plug wires are in sequence which I have
not dealt with yet.

Hi Mike,
Well if that's the case, flipped sparkplug wires might be firing on the exhaust stroke causing the backfire. When you get the bumblebees, double check the rotor position for power stroke TDC on #1. Then wire the cap as per that photo and let us know if that solved the problem. Good luck!

 

[bighealeysource]

Hey y'all,
Thanks for all the feedback and advice. I posted an earlier thread
where I mentioned that this BN6's plug wire set up with the dizzy
did not follow what is correct. It had been running good but now have
the missing as described in this thread. Greg sent me a link with
the correct way everything should be connected so will get it to TDC
and install the new plug wires due in from AH Spares. Whole thing
has just been puzzling since it had been running good even with
things done wrong. But, it's a Healey so it's just trying to drive
me crazy. I'll let everyone know how it turns out when I put everything
back together correctly.
Thanks,
Mike