Vacuum and timing Question Again

[72-LT1]

Hey guys, I was just reading the vacuum questions here. I posted a question on the other site on this subject and still do not think it has sunk in.

My carb still has the vacuum hose running from a T at the front of the carb through the chock and down to the TCS and then to the dist.

If I want to eliminate the TCS can I just come right off that T and go to the Dist?

This whole question came up for me as I was adjusting the points and the timing, i'm only getting around 36deg total initial and mech adv because I can't test or run it while getting the vacuum advance kicked in.

After I gaped the points the car sure seemed to run better and the stumble seems to be gone. When I checked the gap there did not seem to be any or very small like .003 but the car was running pretty good it just had a stumble from a stop. Will these cars seem to run and idle OK with the gap being off?

Thanks

 

[RodsnRides]

Hello 72LT1 and welcome!

My first suggestion is to lose the TCS. The "tee" probably feeds the carbon canister,too. I would just run a direct vacuum feed to the distributor. Plug the rest, other than the 3/8" tank feed to the carbon canister.

Didn't catch your location and altitude but suggest base timing at 10-12 degrees BTDC.

While I run points in several cars, I like the Pertonix electronic conversion-although I have had one failure. Some don't like it. Suggest having the ability to switch-doesn't take up much space. I like the consistency of electronic ignition and reduced maintenance.

I hope this is helpful for you.

Rick

 

[72-LT1]

I had a picture up for the last post, but the T comes right off the front of the Carb (holley 4150) past the chock, which it T's off too and then down to the TSC, and then the other plug on the TCS goes to Dist.

If I can't go off of the T where should I go from?

I think I'll stick with the points, but I was just wondering about how a car would act with the point gap being way off. My timing is good now, until I get the vacuum sorted out for the total timing, and my points are correct now, and I think the stumble from a start is gone. I am kind of hoping it had something to do with the points gap, but you never know I might go for a cruise tonight and the stumble might be back.

I still need to get the carb rebuilt, but I have not done anything under the hood since I got the car in Nov. I spent the whole winter replacing everything from the doors back.

Thanks again

 

[magoo]

The stumble probably went away because when you opened the point gap, you advanced the timing. It is best to adjust points with a dwell meter to 28 to 32 degrees and then adjust timing. I assume the vac to the choke is to a pull off diaphragm, just take the vac line from there direct to the vac advance. There are many good threads here at CAC about total advance, but 10 to 12 at idle with vac off and plugged is a good start. My 62 likes 16 deg. initial. Depending on your compression ratio maybe you can move up a bit more too as long as you get no ping.
Just my $.02, hope it helps.

Mike

 

[72-LT1]

Thanks Mike,
I think I am about 10deg right now (bad memory), with a total of 36 coming in somewhere around 2800RPM. I couldn't tell exactly because my wife would not come out and sit in the car. This was all after I set the points.

I don't have a dwell meter but the gauage always worked in the past when I worked at a service station in CA.

So when I rerun the Vacuum line from the T I will be able to see the total timing, it dosen't really matter right now if I unplug the vacuum advance because it gets no vacuum from the TCS.

Thanks for the reply though, I will rerought the vacuum, check the timing again and it should be good. I think after rerouting the vacuum, with it plugged in I should be around total of 50deg, if vacuum is 14 or so.

 

[RodsnRides]

Here's something to remember "big gap = small dwell" The larger the gap, the lower the dwell. I set mine at 28-29 degrees. As the points wear (gap gets smaller) the dwell will increase. Setting the points at 28 degrees dwell will allow you to stay "in tune" longer. Also, every degree of dwell = 1 degree of timing. For example, if you are set at 30 degrees dwell, 10 degrees BTDC timing, and adjust to 28 degrees dwell, your timing will advance 2 degrees to 12 degrees BTDC.

Another point to remember is for every 1000' of altitude, you can advance timing 1-2 degrees. Here in Denver, I'm running about 15 degrees BTDC in a couple of cars.

I think you want to stay around 36-40 degrees total advance at about 2800 RPM. I could be off on this last, but I think I'm close. Good luck.

Rick

 

[72-LT1]

I think you are right for initial and mechanical advance, but don't you want somewhere around 50deg total once the vacuum advance kicks in, ~10+36+14?

I guess my car was running around 50 before then, because the gap in the points was pretty small to none before I adjusted it. Now after adjusting the points the timming is where it should be. I probably should have checked the timing before gaping the points.

The points, cap and rotor were all changed in Nov before I picked up the car, so I am not sure why they were off, I drove the car 500 miles home after I picked it up and it ran fine.

 

[RodsnRides]

Make sure your distributor cam has lubricant. I also put a liitle dab on the points arm where the rubbing block is to make them stay in tune longer.

Always adjust points first, then timing, then the carb, in that order. I'm not positive on 50 degrees total. I'll have to get back to you on that one. I'm thinking 36-40. John Z?

Rick

 

[magoo]

Thats right, 36 degrees initial and mechanical and total of 50 to 52 maybe a degree or 2 more. Also you want vac advance at idle to aid cooling so the line you're using for vac advance should be fine. I think John Z. has posted on all these things if you want to try a search under total advance or something similar. My .02

Thanks

Mike

 

[72-LT1]

Thanks Mike, is that the reason for the TCS, no vacuum at idle, runs hotter and reduces emisions?

Hey Rick, How do you lube the dist cam and what kind of lube do you use on the rubbing block and the cam?

 

[RodsnRides]

You normally get a little red capsule of lubricant with a fresh set of points. NAPA should have "distributor cam lubricant", or, your local Harley dealer will have lubricant used for flyweights on older Harleys-that works, too.

While your in there, take off the rotor and clean and lube your mechanical advance. I also use the same Harley lube to lube the pins the weights ride in, as well as the little round "dot" the weights rotate across.

For the points, take a little dab and put it on the rubbing block, keeping in mind distributor roatation, so that a little dab of lube stays on the rubbing block as opposed to getting rubbed away immediately. Finish with a little dab around the cam itself at the location of the points rubbing block-you'll see the wear marks.

"A little dab will do ya"-don't get too liberal or you'll have the grease on the points.

Also, highly recommend you get a dwell meter and set them points at 28-29 degrees. Much more accurate than a feeler gauge.

Rick