Bon Ami Success Rate

[YukonJack]

Just curious how many have tried the Bon Ami down the carb move. How many have been successful and if anyone had a problem afterwards. Thinking about trying it but I'm a little hesitant. I'm getting smoke from my tailpipe on accel and it seems to come and go.

[Niel Hoback]

I am a crazy that tried Bon-ami. It smoked horribly while I did it and for a few miles after. My problem is really not the rings, but the valve seals, I think. It smokes wordt on decel.

Today, after maybe 100 miles, the smoking is nnot noticable and may be less than it was before I tried Bon-ami.

It does not appear to have done any damage, and may have helped.

There is a slight problem when you are standing there pouring Bon-ami down your carb, but its all psychological.

[Suddensix]

I am a crazy that tried Bon-ami. It smoked horribly while I did it and for a few miles after. My problem is really not the rings, but the valve seals, I think. It smokes wordt on decel.

Today, after maybe 100 miles, the smoking is nnot noticable and may be less than it was before I tried Bon-ami.

It does not appear to have done any damage, and may have helped.

There is a slight problem when you are standing there pouring Bon-ami down your carb, but its all psychological.

Hey Niel, what valve seals?

[FMSPEED49]

Mine at almost 750 miles and purring away, all good, no bad.

[Niel Hoback]

I don't know if there are valve stem seals, not being an OHV engine. I do know that oil is getting burned on deceleration. It is hard for me to believe that oil could get up to the valve guide area, but somehow oil is getting into the combustion chamber. If there are no seals, and I would not be surprised to learn there aren't, then the guides are pretty worn, which would also not surprise me.

On the whole, I do believe that oil consumption is less now than it was before the Bon-ami incident, since I am sure that the rings are in no better shape than the valve guides and/or seals.

[RHDSP15C]

This whole problem is caused by cylinder glazing. In the days I owned an airplane engine shop one of the worst nightmares we had was that after overhaul the owner would baby the engine and end up with glazed bores.

The best cure was to was to run the engine at maximum manifold pressure

(max throttle) at load to increase the cylinder pressures. This in turn increases

the ring pressure against the cylinder walls and allows the ring to seat.

The Bon Ami treatment is doing more or less the same thing by abrasion but you are not getting a free lunch. It can be argued that the abrasive only gets to the top end of the engine but piston lands and valve guides are going some of the effects.