auxillary pulley timing

[grantgsr]

I'm still tinkering with the timing on my 71. After I changed the timing belt it has a very significant miss especially on acceleration. I thought I might be a tooth off on the timing belt so I adjusted that and it still does the same thing. I'm going to look at a couple of other issues with plugs, etc., but in the meantime, I'm trying to think what I could have screwed up on the timing belt install. I'm pretty certain I had the cam timing marks at the right alignment while the crank was turned to TDC. My main question here is about the auxillary shaft. All the instructions say to set the timing mark on that pulley to "about" 34 degrees. Someone else said about 1-2 o'clock. How do you set this to the right mark? How do you measure it? More importantly for my purposes, what does that auxillary shaft do? If it is not located at exactly 34 degrees, what does it do to the overall timing or performance? I'm trying to figure out what part of the system is causing my misfiring and I don't know if that auxillary timing pulley could be the culprit. Someone please explain. Thanks

[rlux4]

The auxillary shaft has a lobe on it, originally to operate a mechanical fuel pump. If the lobe is not in the correct position, worst case, 180 deg. out, the lobe will hit a nut on the #1 connecting rod.This is why it isn't as exact as the cam timing, it just has to be lobe down when the piston is in the down position.
Ron

[So Cal Mark]

point the dot on the aux cam pulley towards the pivot bolt on the tensioner. On your 71 the aux shaft also drives the dizzy, and on all of the TC engines it drives the oil pump as well as the mechanical fuel pump as Ron stated.
When you say you adjusted the cam timing, was it off initially, or is it off now? Usually a misfire on acceleration is ignition related

[grantgsr]

Thanks for the replies. It helps having some assurances. Mark, the car was misfiring bad on acceleration and slightly missing at idle (although it would start easily) after I first changed the timing belt. I thought I was one tooth off on one of the cam pulleys, so I got the crank to TDC and checked the marks. The exhaust cam pulley looked maybe a tooth off, so I slid off the belt and adjusted and put it back on. After getting everything hooked back up, I started it again, and it did the same thing. I changed the plugs when I first changed the timing belt, so I wondered if that had anything to do with it. The gap on the plugs I installed was greater than the range indicated in the manuals and on the engine bay, so I've got some more and I gapped them to the correct space and I'll try to install those tonight. Would that account for the very bad miss on acceleration? At this point, I've also installed new wires, but I haven't touched the distributor at any time since I bought it a month ago. It was running OK before the timing belt change -- a slight miss on idle but nothing like I have now on acceleration. It's possible I could still be a tooth off, I'll check it all again. It seems like I read something where there is something else to adjust if your cam timing marks cannot be made to line up 100% exactly on the dots with the belt on. Does anyone recall what that is and how its done? My next area to check is probably going to be the fuel system, but I just don't think that's it. Any ideas? If I don't clear this up soon, I'm going to videotape it running and put a link to the video so one of you guys can hear it and see if that helps diagnose the problem(s). Thanks.

Grant

[So Cal Mark]

since you changed plug wires, did you double check the firing order? I'd check cam timing by turning the engine by hand rather than starting it. If the plug gap is too wide, your coil may not have enough output to fire them. With the engine idling, remove the wires from the dist cap one at a time and see which cyl doesn't make any difference