The Stovebolt Site Forums The Shop Area Engine Shop 216 timing issues....

Im having a timing issue that is getting the best of me lately, that probably has an easy solution that I am missing.

Its a 216, 12 volt, Pertronics electronic ignition, rebuilt Rochester carb. Has fuel and spark. Valve lash is set cold @ Intake .010 & Exhuast .018. No play in disty body, and octane selector set at 0. Plugs gapped to .38, if I remember corrrectly. Vacuum advanced blocked off.

I have removed disty several times, found TDC (tried the ball and triangle), restabbed disty and run #1 wire from where the rotor is pointing. Tried several different rotor locations by turning oil rod w. screwdriver.

I can get her to fire off, be it very roughly, but by advancing the timing by way of turning disty ccw, she'll run better and smoother. But with a timing light its at 14-15 degrees advanced and runs rough when giving it throttle.

Shutdown and wont restart at this timing and have to retard timing back down to restart?

I have even attempted to rotating all my wire ccw by one. And same results.

What am I missing?

Oh and she also did the same when she had points still.

Has the truck ever ran good since you have had it? Have you checked the compression? Have you checked the voltage to the + side of the coil?

Have you tried to adjust timing with a vacuum gauge attached the intake manifold vacuum-wiper port? Set timing to maximum vacuum at idle. That gets you close enough to run smoothly.

First, set timing mark for #1 cylinder at compression/firing stroke (at that mark, the distributor rotor should point to the #1 spark plug wire). Wires in clockwise order should be 1 5 3 6 2 4.

Yes, I forgotten to add that I am using a vacuum guage. I can obtain 19-20 inches of vacuum once advanced 15 degrees, according to timing light on the ball.

But it won't restart at that position. And firing order is confirmed.

The truck ran a better when I first got her, but was over carb'd. Compression test was done, cylinders 1 &2 were a tad low at 95. The rest of cylinders were 115-120. I know not idea numbers, but should run.

Should I be checking the voltage at coil when running?

15 degrees of advance at idle is WAY too much. if it won't run properly at 5-8 degrees of initial advance you've got other problems. What is the total advance at 2,000 RPM with and without the vacuum line connected? It should be around 30 degrees without vacuum, and close to 40 at light-throttle cruise speed with the vacuum advance connected. It sounds like your centrifugal advance is not functioning and you're having to compensate by using too much initial advance.
Jerry

Is it still blocked off?

I haven't checked total advanced timing yet. Can't get her to run that well yet, with vac advanced disconnected and connected. I have tried both ways.

If my centrifugal advanced wasn't working properly, then it should've been good when disconnected then, right?

The distributor housing is moving when rev'd, when vac. advanced is hooked up.

Would valve settings cause this, there is no obviously bent push rods or valves.

If the distributor was 'a tooth off' wouldn't rearranging the wires or by turning disty correct this?

Is there any way to determine when the Pertronix system throws spark to #1 cylinder, like how you can with the points? when turning the engine over by hand.

It won't run 2,000-2500 RPM, even for a minute or so? You've got a lot more problems than spark advance, it seems! What's the timing and lift of the cam, checked with a degree wheel and a dial indicator? Your initial post mentioned being "over carbureted". What kind of fuel system are you running?
Jerry

I'll have a chance to mess with it more this weekend, and I'll check timing at 2k rpm, or try to. Got me curious on this too.

Cam is stock, wasn't a rebuild. She has some miles on her.

I say she was over carb'd before, because she had a carter w-1 from a 235. And all the spare carb's I got with the truck were all for 235's. I got a 216 rochester rebuilt to eliminate that problem now.

New gas has been runned, and thru the stock pump/filter assembly to a new filter before the carb. Carb is giving a nice steady, solid stream of fuel.
Also checked for any vac. leaks, none.

Would the need to advance it so much to achieve highest vac. reading and smoothest idle, be indictive of valve lash adjustment?

I want to let her idle for 30-40 minutes to get warm/hot, then do a valve adjustment once again.

Thanks for the ideas/suggestions folks, been beating my head against the wall on this one.

One quick check of the centrifugal advance is to grab the distributor rotor and try to turn it clockwise. It should move freely, and return to its original position from spring pressure, without any hesitation or stickiness. The weights and springs are located under the breaker plate and they're prone to get rusty or sticky. Out of sight, out of mind- - - -until a problem develops! Since the vacuum advance moves the whole distributor housing, it's easy to see if it's working. Centrifugal, not so much!
Jerry

Distributor does return, but could probably be smoother. I did not know that the springs/weights were under that plate. I will remove and throughly clean that part out this weekend.

I was able to spend a few hours on this again this weekend. Pulled distributor, throughly cleaned thru out, and reinstalled. same results, no start.

With ignition on, truck not running, I have 6-7 volts at positive side of coil. I also tried running 12 volt straight from battery to the igniter. same results, no start.

I retard the timing to get it started then advanced for smooth/higher idle.

I did eventually find that choking it 10-15% made it run alot better. Does this point to a 'lean' condition? I richen up the carbs air/fuel mixture with no change.

I did check timing when it was running, with vac advacned hooked up and was running 25.5 degrees of timing at idle. what amount should i roughly be at at idle?

She was running real good at idle and reving it, but once shutdown would not restart at all. I was done for the day after that.

Following day, went out and she started right up no problems, but rev'd rough.


I am now thinking that the issues may be tied to the carb as well, it has been rebuilt, just not dialed in correctly yet.

Who rebuilt the carb? Symptoms sound like carb issue. You did the right thing to save the carb for last in your diagnostic plan. Seems like too many folks jump on the carb before everything else when diagnosing problems. The other components are easier to diagnose and are more likely to be the problem than the carb in most cases.
Carl

To summarize:
It did the same with points/condenser.
It did the same w/a W1 Carter and also w/a rebuilt Rcchester B.
You need to retard timing to start then advance to run smoothly.
It will not restart w/the timing advanced.

You are now indicating it runs better w/partial choke.
That is generally an indicator of the engine running lean and other than correcting the fuel/air volume via the adjust screw, you have a vacuum leak.....
How did you test for a vacuum leak?
I've used carb cleaner w/very good results but if/when I need to troubleshoot a vacuum leak again I'm going to try my handheld propane torch to see if it can detect easier/faster. If not carb cleaner.

If you can't locate a vacuum leak you might want to pull the intake manifold, check/clean and ensure the mateing surfaces are smooth, check all sides for cracks and put all new gaskets on it.

Set the timimg w/the BB on the pointer idling at 450-500 rpm.
I wouldn't worry w/setting via vacuum at this point. I would recommend road testing to test these settings and slightly retard via the octane adjust if it pings under load and/or advancing via the octane adjust if it hesitates badly after it's warmed up. Then try the warm restart.

My 49 w/a 216 and Rochester B starts very easily cold (w/choke) and 9 times out of 10 restarts just as easily with out choke when warm. It doesn't ping under load and pulls hills impressively for it's rated HP. All w/the timing set w/the BB on pointer at 450-500 rpm.

Good luck
Dave

UPDATE: Got her running smooth as butter.

Thanks for the help along the way.

I decided to remove the electronic ignition and reinstall a 12 volt coil and points. Upon doing this swap, I noticed that I had reversed polarity on the coil. New coil with the negative side to the distributor, and she runs good.

'49 3600