Up-date on engine running rough on my BN6

[bighealeysource]

Update on engine running rough on my BN6

Hey,
Well, got the timing light out and with the timing mark and
pointer perfectly aligned and running pretty smooth, the rotor
is pointing to # 6, not # 1. A buddy of mine that was helping
with the timing and whole problem of running rough thought
maybe the guy that rebuilt this engine looked at the BMC
manual and based on one of the diagrams, thought # 1 was
at the rear of the engine, not the front. Basically set up
180 degrees off. He is concerned that if we try to get it
in the right order, we could mess everything up due to the
way the timing chain was probably installed with the 180
off firing order. It is also popping through the rear carb
, not a backfire through the exhaust pipe, but you can actually
see air, fuel mixture, ??, popping through the air cleaner.
It actually runs smooth as choked when started, idling at
2000 rpm, but if you blip the throttle, then you get the
popping noise, air, whatever. I did replace the plug wires with the bumble bee comp wires so those are brand new. I am not an engine guy so any HELP is really appreciated.
Thanks,
Mike

 

[GregW]

Re: Update on engine running rough on my BN6

Hi Mike,

Hey,
Well, got the timing light out and with the timing mark and
pointer perfectly aligned and running pretty smooth, the rotor
is pointing to # 6, not # 1.

How much advance are you running?

A buddy of mine that was helping
with the timing and whole problem of running rough thought
maybe the guy that rebuilt this engine looked at the BMC
manual and based on one of the diagrams, thought # 1 was
at the rear of the engine, not the front. Basically set up
180 degrees off. He is concerned that if we try to get it
in the right order, we could mess everything up due to the
way the timing chain was probably installed with the 180
off firing order.

I suppose anything is possible and I understand your lack of confidence in the engine builder. However the manual is pretty specific on how to install the timing chain with the cam and crank, so I think it is a pretty good chance that was done correctly (I know, never assume :laugh: ) If the distributor is 180° off, but the rotor cap is wired to compensate (but still in the correct firing sequence) it should work fine.

It is also popping through the rear carb
, not a backfire through the exhaust pipe, but you can actually
see air, fuel mixture, ??, popping through the air cleaner.
It actually runs smooth as choked when started, idling at
2000 rpm, but if you blip the throttle, then you get the
popping noise, air, whatever.

That sounds like your still running lean. Didn't you have a problem with the carb piston sticking? Was that resolved?

I'm having a problem remembering what's been done. It would help me (and possibly others) to keep ongoing issues in the same thread to see the progress and zero in on the trouble spot.