All Small Six Which cylinder head?

[Otto]

but if it were me, I'd advance the timing by loosening the distributor hold down and gently tapping the distributor with the 1/2" open end wrench to move the vacuum can 1/4" in the advance direction. Lock down and try it. Keep doing this till pinging is heard, then go back 1/4" and you then know timing is perfect for those highway conditions.

I can certainly try this the next time I take it for a spin. It's easier to reach the distributor bolt from under the van than from the engine box, so I'll try to make a wrench.

When driving the van, I'm only applying light throttle right in the meat of the torque curve- It scoots along very well. If it wasn't burning more gas than a Buick station wagon towing a boat, I'd think it was running perfectly!

 

[Otto]

Fabricated a phenolic spacer and installed it on the engine under the carb. The aluminum adapter runs very cool when the engine is running, but when you shut it off it transmits a lot of heat up to the carb. Plus, the heat inside the small engine box is considerable. During an initial start up, the spacer seems to be blocking heat after turning off the engine- the aluminum is hot, but the spacer is not. A test drive will be the true test.

 

[Otto]

A test drive this evening was disappointing; I bumped up the timing like Frank described- advancing a bit at a time and listening for pinging. I tried this a few times and the doghouse’s Lizardskin thermal and sound application must work well because I couldn’t really hear the engine ping. With it being right next to me between the seats you would think it would be more noticeable.

I still didn’t see any more vacuum than the 10” Hg the gauge shows at any time during the drive except coasting. After I got home, I attached the timing light and measured 55* total mechanical advance as my last adjustment where before it was at 35*. All that timing was accomplished before 2000 rpm. Baffling.

After shutting the engine off at the end of the test drive, the aluminum adapter got very hot but the phenolic spacer and carb base was not. I’m calling that a win, so something went right.

 

[awasson]

My 200, with the weber 38/38, header and clay smith camshaft didn't so much ping on hard acceleration but there was a point somewhere around 2000 RPM if I had my throttle partially open and it had a little load when I could hear the ping if I was driving somewhere the sound could bounce like driving beside a tall road divider median with my windows down. I backed mine off a little at a time over a few sessions and now I think it's as good as it's going to get.

Initially, I was running mine with about 22° initial + 10° vacuum advance + 14° mechanical. After some tweaking occasionally during the first 1000 miles, I brought down the initial and am probably now closer to 15° initial. I will have to put my light on it and confirm that. Mine is all in sometime before 3000 RPM.

 

[Frank]

A test drive this evening was disappointing; I bumped up the timing like Frank described- advancing a bit at a time and listening for pinging. I tried this a few times and the doghouse’s Lizardskin thermal and sound application must work well because I couldn’t really hear the engine ping. With it being right next to me between the seats you would think it would be more noticeable.

I still didn’t see any more vacuum than the 10” Hg the gauge shows at any time during the drive except coasting. After I got home, I attached the timing light and measured 55* total mechanical advance as my last adjustment where before it was at 35*. All that timing was accomplished before 2000 rpm. Baffling.

After shutting the engine off at the end of the test drive, the aluminum adapter got very hot but the phenolic spacer and carb base was not. I’m calling that a win, so something went right.

Thanks for the update! Since you saw no power or vacuum improvement, put the timing back to 35* if you haven't already. Thanks for doing the test. It didn't pay off in your case, but now you know.

 

[Otto]

Thanks for the update! Since you saw no power or vacuum improvement, put the timing back to 35* if you haven't already. Thanks for doing the test. It didn't pay off in your case, but now you know.

10-4

 

[Otto]

My 200, with the weber 38/38, header and clay smith camshaft didn't so much ping on hard acceleration but there was a point somewhere around 2000 RPM if I had my throttle partially open and it had a little load when I could hear the ping if I was driving somewhere the sound could bounce like driving beside a tall road divider median with my windows down. I backed mine off a little at a time over a few sessions and now I think it's as good as it's going to get.

Initially, I was running mine with about 22° initial + 10° vacuum advance + 14° mechanical. After some tweaking occasionally during the first 1000 miles, I brought down the initial and am probably now closer to 15° initial. I will have to put my light on it and confirm that. Mine is all in sometime before 3000 RPM.

Thanks for your response, I did have a similar experience with hearing what I thought was some light detonation up a slight grade on light throttle with the AFR meter reading high 14, low 15s but it was very inconsistent. I'll set the timing back tonight and I have another experiment to try- I'll work on that.

 

[awasson]

@Otto, I put the light on mine this evening to see where my timing was. I have the original line on my damper and then added 2 more lines 14 degrees apart so I can see up to 42 degrees of timing. I put a white, yellow and amber line on each one so I could see them and quickly calculate my timing.

As I mentioned, I’ve been finessing the timing, idle speed and idle mix for the past 2000 miles and for the last couple of months I’ve been playing by ear and smell. It is no longer overly rich. It’s still a bit rich because it’s got a carb and not catalytic converter but it’s not horrifically bad. The timing I’ve been doing by ear and smoothness and it’s about as good as it’s ever been.

I put the light on and to my immense surprise, it’s at 12 degrees initial. Timing is all in around 2,200-2,500 RPM or so. It runs as best as it ever has. I’m running Chevron 94 with zero ethanol.