Amazon: Cam Gear Nut loose and Gear Moves

[tdz840]

Are you running points or electronic ignition? What setting at idle, perhaps something conservative at this stage?
Sounds to me from the little information given it’s a combination of cold start and perhaps advanced ignition.
If you have set to a conservative number (say 8Deg BTDC) look to set your carbs for idle next.
Are you running twin SUs and all the basic initial settings have been checked including syncing carbs, centralising needles, pairing dash pots, springs and damper oil. Are your ign cable good, damp can affect them and often exacerbated at low idle. If it’s dark in the garage you may be able to see arching if not. Check the primary and secondary resistance of the coil and check with specs
I’m sure I’ve missed something but all appears well and a symptom of first start, basic settings and the need for a tune up on a warm engine
Good luck
Russ

[gothamus]

It's a former B20e - fi removed and twin SU-HS6 in place. 123Ignition
She was tuned and running fine before- except the sound that started this. Adjusted carb jets for winter, gave filters a good cleaning.
Tuned to specs in manual for '74 - B20e- that's about .40-.45 instead of .50-.55 (exact not in front of me, but it's .10 less from B20b).

I had my nightly 4am wake up to lie in bed pondering. A thought sprang- what if there is something wrong with the pulley fitment? Slightly crooked for some reason. If one was not flat and parallel with others, maybe, it might result in a wobbling engine? Worth a check, no pain in it.

Checking distributor positioning and valve lashing and on from there. It may be distributor position is slightly off. Twice yesterday I started and it backfired once, which never happens. Perhaps she needs to run and get warm too.

[arcturus]

Check the center contact inside the dizy cap hasn't broken . I have had two break giving similar results. rough running.

[gothamus]

It’s all good. Did a general tune up. Oil needing topping up. Slight adjustment to valves 1,2,3 and 5 matched them exactly to the rest. Small amount of oil to dash pot and increase idle 100 rpm. Maybe I was being skittish. That’s better than the opposite. Too many experiences where I went a step backward than forward!

Much better feeling. And quiet and steady sound. Thanks again!

[Derek UK]

If your engine is full B20E spec but with carbs it will have a D cam and 10.5:1 compression. Both D and K a bit lumpy at tick over but F.I does help with that. B20F with K cam went down to 8.7:1 and that is better with lower octane gas. The B20E really needs the best Premium you can find in NY. If the local gas gets winter additives that can lower the octane too. E gas best avoided if you can.

[gothamus]

I always put in BP Premium (that’s what they call the most expensive, right). No loyalty to BP. They are all over my area and the rest are independent with no benefits like no ethanol or what-not.

What you say resonates. I’ve still had some performance inconsistencies. Not what started this post. Today I went ahead and removed my SUs to give a cleaning and inspection. There was enough trash in the bowls that one of them could have been clogging. I’ll be pulling my fuel filters. With 2 filters and a 5 year old tank I wasn’t expecting what I found. This might explain some performance inconsistencies I have been tracing down.

Thanks All!