VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1929 6 Cylinder Factory Timing/ Tune-Up Specs

Was doing some research and was wondering what the Factory Setting for Timing are for my First Generation 1929 194CI 6-Cylinder.

I have an Old Document Titled "Specifications International Jan. 1, 1929" and it list the following:
...Spark Control Type: Semi-Automatic
...Firing Order: 1-5-3-6-2-4
...Timing, Spark Advanced: 12 Degree BTDC
...Distributer Interrupter Point Opening: .030

Then on Another Paper titled: "Standard Auto-Electrician's Manual" dated 1929:
...Spark Plug - Gap: .025
...Firing Order: 1-5-3-6-2-4
...Breaker-Contact Separation: .018 - .022

I know the recommended VCCA Settings are:
...Spark Plug - Gap: .040
...Firing Order: 1-5-3-6-2-4
...Breaker-Contact Separation: .018
...Timing, Spark Advanced: 18 Degree BTDC

I would like to know what everyone's View is on the Chevrolet Factory Settings for:
...Spark Plug - Gap: _____
...Breaker-Contact Separation: ___
...Timing, Spark Advanced: __ Degree BTDC

trying to get back to my 1929, want to set it up to Factory specs get it right, then venture over to the VCCA Specs.

Also read in a Post about going to .045 gap on the plugs, and may run smoother/ happier ?? Any thoughts on that or test, trials ??

I am currently using AC Delco C86 plugs, but also understand a modern day substitute would be the C87 Plugs which are readily available, would the C87 follow the same guidelines as the C86 ??

I use the recommended VCCA settings (0.40 / 0.018 / 18 BTDC) with C87 plugs. When I first obtained the car ('30 Coupe) back in 2005, I tuned it to the factory settings and it ran ok, but not great. Then I found this site, and tried the new settings. It made a NOTICEABLE improvement.

Happy Motoring,

Dan

We have had numerous discussions in the past on many of the questions that you have asked above. You might want to do a search on Chevy Chatter for all of the information that is related to the spark plug gap, timing and etc. This has been a good discussion that has been going on for years.

Also, check out http://1931chevrolet.com for more information on timing and spark plug gap.

Yeppp
done that, and that as well . . .

Always do my homework before posting and asking a question. My question was mainly in regards to the conflicting info that I have found and have on hand about the Factory Settings.

would have to say most of the searches returned results about the VCCA recommended settings, 1931 is bookmarked as a favorite, and assuming since it was referenced that the 1931 shares the info from the 1931 as per tuning.

Hello BearsFan315,
My Chevrolet Repair Manual, effective on and after March 1st, 1931, copyright 1931 by Chevrolet Motor Co., Division of General Motors Corp. Detroit, MICH. First Edition, Reprinted 1976, lists:
Spark Plug Gap- .024
Breaker Point Gap Setting- .018
Spark Advanced Timing Mark Setting- 12 Degrees BTDC
So goes the Factory Settings for 1931 194 Cu. In. 6 Cyl (Stock)
Are these numbers different from 1929 194 Cu. In. 6 Cyl (Stock)?

The numbers are the same from 1929 thru 1932, however with the modern gas and the higher octane, the gap of .040" on the AC C-86 and the AC-87 plugs is recommended along with the timing of 18 degrees. With these modern settings the vehicle will run a lot better and have way more power than with the original factory settings.

BearsFan315: If you have read all of the information and have done your homework then you are ready to go.

I assume that goes for a 30 as well

1929 thru 1932.

I went out and began to do a complete Tune-Up on my 1929, getting it ready for it's Maiden Voyage, or so I hope !! has not been out on it's own power since the rebuild began !! Hoping to Tune it in the Sweet Spot.

I put in new plugs (AC Delco C87 gapped @ .040"), New Coil, and my New Wires from Bob @ Marx Parts LLC. Points Gap is set @ .018" as well.

Got it running and then went to the timing set up. I set it to 18Degrees but it seems to run rough/ missing. Put my hand by exhaust to feel the flow coming out, and it would have a skip in the flow, to me this is engine missing ?? in stead of a steady flow at idle ?? I backed the timing down some so the engine would smooth out and settle down. Checked Timing and it was at about 12 Degrees.

I know the recommended settings per above post, but know some people have had to tinker with these to get the just right and the car to run in the Sweet Spot.

I would like to know am I doing something wrong ??

Where Should I start in getting the Tune-Up RIGHT and the car RUNNING in the sweet spot ??

Should I increase Spark gap then tinker with timing ??
Should I decrease Spark gap then tinker with timing ??

Looks like NO ONE messes with the Points Gap, it stays at .018"

When in the sweet spot, I assume that it should idle smoothly, no missing, sputtering, etc... and also when you press the accelerator it should rev up and not sputter, stutter, or hesitate ??

Thanks for the Advice & Tips . . . Really can NOT wait to do my First Test Drive. but want to make sure everything is RIGHT before taking it out.

Did you lube the cam that the points ride on? If not the gap will soon get less as the rubbing block wears dOwn? EspeciallY true for todays poor quality parts. I always begin with around .022' TO ALLOW FOR WEAR.
Also as the gap changes so does the timing.

I did double check my point gap last night, was still .o18" will go back and check that tonight to be sure/ safe.

Just as an FYI, my 32 runs really well with all the specs mentioned but my timing is set at 16 degrees as it seems to run better at 16 than at 18; cranks over real well and starts very quickly. I also do not use ethanol fuel and we drive our 32 a ton at 40 miles and hour on the way to cruise -ins and car shows. Around town in 80-90 plus temps in the summer here in Clemson and it runs pretty cool. We have to watch out for the students and the way they drive!!!!! I have to stay after the point adjustment a bit though and I just adjusted the valves for the second time since January.

Mac

Well double checked my points, they were still sitting at .018"

Did some tinkering with the point gap, plug gap, and timing.

I can tell you that trying to run with points at .022" did not seem to make the car happy with any of the settings. also I put all the settings to factory and would not idle smoothly no matter what . . . also if I wanted to rev it up had to do so VERY slowly if not it would sputter cough and shut off.

I think it was happiest when Points @ .018", Spark plug gap @ .040", timing was about 12 Deg.

I was wondering if maybe the flywheel was off, installed off. but if I remember it can only go on ONE way, due to a pin that keeps it all aligned for timing marks.

Guess the ultimate goal is to get it to idle & run smoothly as well as accelerate with out hesitation. and call it a day, what ever the numbers may be.

Will do some more tinkering when I get time.

Check for a vacuum leak and bad spark plug wires.

Hmmm... Vacuum Leak

What is the best method of doing so ?? no Smoke machine here

Also does the same with the old wires or the NEW Wires.

got it set up as so:
...Point Gap/ Breaker-Contact Separation: .018"
...Spark Plug - Gap: .040" AC Delco C87
...Timing, Spark Advanced: 18 Degree BTDC

Car fires right up and idles semi smooth.

Now to check for Vacuum Leaks
...To check for vacuum leaks I used a trick an old mechanic told me about. Used a can of Carb Cleaner with the Straw Attached to control the direction of burst. Used small short bursts and sprayed it around intake gasket at each point. if engine picks up or changes it tune then there is a leak. well on the intake gasket nothing happened, I went back over all the areas, top and bottom a second time to make sure, nothing. I was happy because there was no detectable leak, but disappointed as to not KNOWING what else to do.

Next step I decided to check the carb connection. and WHAMMM as soon as I sprayed it around the Carb -to- Manifold connection the engine settled down and changed tune. a few seconds later it was back to its semi smooth idle. so gave it another burst of cleaner and changed it's tune.

From this I will now be changing out the carb gasket. From my understanding and research it should just be the gasket and NO Gasket Sealer of any type.

So basically loosen the two nuts holding it on, drop it down, clean the two surfaces, insert NEW gasket and bolt it back up. Should I tighten them SNUG or any Torque Specs on these ??

Anything else I should tend to while I am in here ??

Tighten the carburetor flange nuts until they are tight so that you won't have a vacuum leak.

should I just tighten the Flange Nuts up and see if that works or should I replace the gasket just to be safe ?? I do have a few sheets of gasket material here to make a new one.

Tighten the nuts first to see if that works. If not, then replace the gasket with the correct flange gasket.

Great will try that out tonight if I get time, if not I have a new Flange Gasket from The Filling Station As Well !!

Ok Tightened up the Nuts, and fired it up...
seemed to be ok, but once it warmend up I did a burst test and same issue. so if It cools down tonight I will change out the gasket & check the surfaces. If not will try again tomorrow !!

Also when I have it in the idle, it will cough if I step on the gas quickly. however if I rev up slowly it will do just fine and sing all day. could this be attributed to the leaky gasket or something else to look at ??

Sounds like the accelerator pump is not functioning properly.

I do remember JY Dog talking about how to check the Acc Pump, so I will have to do a check when I replace the gasket.

Question is IF it is NOT working properly, does the Carb need a Complete rebuild or ??

To check the accelerator pump, while depressing the throttle arm look inside of the air horn of the carburetor and see if the pump jet, which is located on the left rear inside of the air horn, is squirting gas. If it is not squirting gas your acclerator pump is not working. (Check your parts book and your repair manual regarding the accelerator pump).

Replace the accelerator pump plunger leather first and see what happens. If that doesn't cure the problem, and if you think the problem is in the carburetor, then a complete rebuild is probably in order.

Remember.....no matter what you are working on....do the minor stuff first and if the problem is still not corrected then do the major stuff next.

Thanks JY Dog, will tinker with that when I get a chance.

Did a compression check as well to be on the safe side.

I am getting approx. 75 PSI on all 6 cylinders !! so that makes me feel a little better.