"Since I went back and adjusted the slop out of the timing advance lever, I'd guestimate that it is engaging in the 1000 - 1500 RPM range now"

Cheaper, did you just loosen the torx (might be an Allen) screw and slip the advance and take the slop out that way?


Anyone know when the advance is to start kicking in? The way it sounds at the very least the cold advance should add 1* at cold idle – any thoughts?<O

Thanks in advance, 93

 

Quote:
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"Since I went back and adjusted the slop out of the timing advance lever, I'd guestimate that it is engaging in the 1000 - 1500 RPM range now"

Cheaper, did you just loosen the torx (might be an Allen) screw and slip the advance and take the slop out that way?
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Ya know, that is what I originally planned. Got to looking at it and saw right away that it was epoxied to the shaft AND the allen screw head was full of epoxy too. At that point I pretty well figured that it might be kinda' critical for it to stay in the EXACT place that the factory put it.

As I was looking it over and working the throttle, I noticed that the lever was kind of sloppy between the two tabs on the side of the pump - the ones that the fulcrum shaft for the lever goes through. I also noticed that when the ramp on the cam contacted the roller on the lever the lever would first shift forward until it came into contact with the front tab before it started to actually ride up the ramp and advance the timing.

So, I dug up a small 1/8" ID washer that was about 1/32" thick out of one of my nuts, bolts, and screws bins. I then removed the circlip from the front of the lever fulcrum shaft and slid the shaft back until it cleared the front tab. After slipping the washer between the lever and the tab (to fill the gap and keep the lever shifted to the rear), I slid the shaft through the washer and the front tab. Reinstalled the circlip and VIOLA', no more forward/backward slop in the lever.

Now when the ramp on the cam contacts the roller it starts riding up the ramp and moving the lever to advance the timing immediately. The difference is that before the throttle had to be rotated until it was almost halfway open before the lever would start to move. Now the lever starts moving before the throttle is even a quarter of the way open. Big improvement.


Quote:
<TABLE cellSpacing=0 cellPadding=4 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by 93_E_350
Anyone know when the advance is to start kicking in? The way it sounds at the very least the cold advance should add 1* at cold idle – any thoughts?<O

Thanks in advance, 93
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Dunno' exactly, but when Spectramac was adjusting my timing he commented on how far the throttle had to open before the lever started to move. He said it should start moving just right after the first few degrees of throttle shaft rotation. That's what got me to looking at it to see what was wrong and if there was anything I could do about it. I guess finding such a simple solution was pretty much just dumb luck on my part from that point..... </FONT></FONT></FONT></FONT>

 

OOPS! - Double Post. Sorry....

 

Don't confuse cold start advance with the advance lever and piston on the side of the pump.

 

Nope I'm not. Did I say something to indicate that I was confusing the two, or maybe something that might confuse others? If so then my bad. Or was that comment not directed at me?

As I understand it, the cold start is electrical solenoid operated and internal to the pump. It advances the timing for easier starting and better running when the engine is cold and predetonation is less of an issue.

The timing advance lever is mechanical and external to the pump - it advances the timing as the throttle opens to make it run better at higher RPMs. Very much like a vacuum advance or centrifugal advance mechanism on gassers.

 

Spectramac,


Can you explain how the advance mechanism works, both cold and warm – does it kick in right a way or at a specific rpm?

Thanks, 93

 

The cold start advance is electric, run by a temp switch in front of the right side head. It's on under 110 degrees.

The regular advance is called the advance piston. It sticks out the bottom side of the pump and is controlled by a cam on the throttle and a rocker lever on the driver side of the pump. The two pieces are aluminum and tend to wear out giving you a lazy advance curve.

 

Spectramac / CheaperJeep

Did you guys check the scribe marks on the IP before moving? if so how far would you say you moved it? I've got mine about 1* ATDC using the lumonsity probe, i moved the IP about 3/16 i was thinking that i may need to go more?

93

 

We probably moved mine close to a quarter of an inch. The pump scribe line was almost 1/16" to the DS of the one on the housing when we started, and it was over 1/8" to the PS of the one on the housing when we were done.

Supposedly .015" is about one degree IIRC. So 1/32" would be ~2 degrees. Since we moved mine around 10 degrees we had to have moved it more than 5/32"

 

Thanks Cheaper, good info!


I moved IP timing to about 2* BTDC @ 2000 using the luminosity style meter. Was noisy all the time and lost a lot of power, moved it to 2* ATDC @ 2000 and it seems to run pretty good.


93