Distributor timing/advance help

[bosephus 10]

I've got a 69 mach1 with 351,4v,auto. New plugs,wires,cap,pertronix trigger. Timing says 6 btdc at idle,8 @2000 rpm and 10 @3000 rpm. This is with vacuum advance disconnected and plugged. Are these figures where it needs to be at? Vacuum advance adds around 16 degrees to the above figures (@ 2 and 3000 rpm). Any advice is appreciated, thanks

[Rsmach1 71]

You should definitely have more mechanical advance then what you do. I would probably pull the distributor (although it can be done in car) and check the advance to see if everything moves freely (weights and breaker plate). By 2000rpm you should have roughly between 19.5 and 24.5° (mechanical only), according to the original Ford manual.

 

Edit; your vacuum advance is in spec, manual calls for 11-16° MAX.

[Rsmach1 71]

One more thought, it's possible at some point someone put hvy advance springs in, or limited the mechanical advance to keep it from pinging (detonation).

 

Edit; Is this a "stock" 351w 4v?

[jholmes217 65]

6 degrees is what Ford called for when these cars were new and the gasoline had a higher octane.  6 degrees probably won't work.  Try setting the static times like this.  

 

Pull #1 spark plug, then bump the starter until you feel a puff or air come out of the spark plug hole. Then using a wrench on the crank bolt, continue to turn the crank until the pointer is pointing at the 10 degree BTDC mark on your balancer. Now make a mark on your distributor body where the #1 plug wire is on the distributor cap. Now pull the cap back off. Then pull up your distributor and then drop it back down until the rotor points to the #1 plug wire location where you made the mark on the body. Put the cap back on. Now hook up a timing light and turn the key on, but don't crank. Now, slowly turn the distributor back and forth with the timing light pointed at the timing marks and pointer. When the timing light flashes, stop right there and tighten down the distributor. Now try to start it.  If it starts, try to set the timing to 14 degrees at 1000 rpm.  Please post your results so we know if it started.  We can then go from there.

[bosephus 10]

One more thought, it's possible at some point someone put hvy advance springs in, or limited the mechanical advance to keep it from pinging (detonation).

 

Edit; Is this a "stock" 351w 4v?

[bosephus 10]

This car is surprisingly correct,to the point where I don't want to get too crazy with the mods. Car starts and idles well but lacked any "punch". I believe it needs a carb rebuild as well but just wanted to sort the timing first. Looks like I'll be pulling the distributor. It will be another couple days before I can get back on it but will post up results /questions then,

[Rsmach1 71]

If it starts, try to set the timing to 14 degrees at 1000 rpm.

IMHO 14° initial for a "stock" 69 351w is asking for trouble.

[jholmes217 65]

IMHO 14° initial for a "stock" 69 351w is asking for trouble.

He says he is running a Petronix unit in it, so it should like more timing.  I would still start at 10 degrees and slowly advance it.  If it starts to ping, then back it off a degree or 2.  Best way to find what it likes is to get it running, then take it for a test drive.  Afterwards, bump the timing up a degree or two, and take for another test drive.  Also keep in mind that as you advance or retard the timing, you may need to adjust your carb.  Speaking of carbs, have the idle mixture screws been adjusted to provide highest idle and/or vacuum?  If it were my car, find what timing the car likes 1st, then adjust your carb idle speed and mixture screws.

 

Every car, even stock, will behave a little different.  The more aftermarket stuff is added, the more it may change.  My last 302 I built with 351W iron heads that were ported and polished liked 16 degrees of timing with a Accel electronic distributor.  My 428 with a Mallory seems to like 15 degrees.

[barnett468 418]

SETTING TIMING CURVE

 

16 degrees is way too much from the vacuum can once your timing curve is set to its optimum level.

 

Throw the stock specs in the trash can.

Before you start driving it normally, I would set the timing curve so it is optimum for your particular setup . Below is just one way to do that . In general, the goal is to run as much timing as possible without it pinging under heavy load.

The more timing you have, the more vacuum it will have until the timing reaches its optimum level.

The more vacuum it has, the smother it will idle and the more you can close the butterflies.

If the butterflies are too far open, you will be into the transition circuit of the carb which can cause idle problems . One of the indicators that the butterflies are too far open at idle is when the carb has vacuum at the ported vacuum port.

1. Disconnect and plug the vacuum hoses to the dist if you have any and leave them plugged permanently or until further notice.

2. Reduce idle as much as possible then start your timing at 8 degrees BTDC.

3. With the engine warm and idling, advance the timing 4 degrees . Listen for a slight but noticeable increase in rpm and irregular/rough running.

4. If the rpm increases and it still runs smoothly, reset the idle speed then increase the timing 2 more degrees and check for the same things.

5. Retard timing back to 8 degrees btdc.

6. Reset the idle speed.

7. Increase the rpm to around 2000 then advance the timing 4 degrees . Listen for an increase in rpm and irregular/rough running.

8. If the rpm increases and it still runs smoothly, reset the engine speed to 2000 rpm then increase the timing 2 more degrees and check for the same things.

POST RESULTS


TEST DRIVING

After setting the timing curve you can do the following test to see if you have too much advance.

Get the engine up to operating temp.

Drive at around 20 mph in second gear for a few seconds then floor the gas pedal as fast as you can until you reach around 30 mph and listen for even the faintest pinging sound coming from the engine . If it pings, you have too much timing for the octane gas you are using . You can either reduce the timing some or use a higher octane . The highest timing level you can run without it pinging and/or running erratic will SAFELY provide the most power.

It may ping in hot weather even if it does not in cold weather . If you find this to be the case, the easiest thing to do is reduce the timing until it stops or try higher octane gas . If it still pings with the highest octane gas, you can reduce the timing then.
 

[bosephus 10]

SETTING TIMING CURVE

 

16 degrees is way too much from the vacuum can once your timing curve is set to its optimum level.

 

Throw the stock specs in the trash can.

 

Before you start driving it normally, I would set the timing curve so it is optimum for your particular setup . Below is just one way to do that . In general, the goal is to run as much timing as possible without it pinging under heavy load.

 

The more timing you have, the more vacuum it will have until the timing reaches its optimum level.

 

The more vacuum it has, the smother it will idle and the more you can close the butterflies.

 

If the butterflies are too far open, you will be into the transition circuit of the carb which can cause idle problems . One of the indicators that the butterflies are too far open at idle is when the carb has vacuum at the ported vacuum port.

 

1. Disconnect and plug the vacuum hoses to the dist if you have any and leave them plugged permanently or until further notice.

 

2. Reduce idle as much as possible then start your timing at 8 degrees BTDC.

 

3. With the engine warm and idling, advance the timing 4 degrees . Listen for a slight but noticeable increase in rpm and irregular/rough running.

 

4. If the rpm increases and it still runs smoothly, reset the idle speed then increase the timing 2 more degrees and check for the same things.

 

5. Retard timing back to 8 degrees btdc.

 

6. Reset the idle speed.

 

7. Increase the rpm to around 2000 then advance the timing 4 degrees . Listen for an increase in rpm and irregular/rough running.

 

8. If the rpm increases and it still runs smoothly, reset the engine speed to 2000 rpm then increase the timing 2 more degrees and check for the same things.

 

POST RESULTS

 

 

TEST DRIVING

 

After setting the timing curve you can do the following test to see if you have too much advance.

 

Get the engine up to operating temp.

 

Drive at around 20 mph in second gear for a few seconds then floor the gas pedal as fast as you can until you reach around 30 mph and listen for even the faintest pinging sound coming from the engine . If it pings, you have too much timing for the octane gas you are using . You can either reduce the timing some or use a higher octane . The highest timing level you can run without it pinging and/or running erratic will SAFELY provide the most power.

 

It may ping in hot weather even if it does not in cold weather . If you find this to be the case, the easiest thing to do is reduce the timing until it stops or try higher octane gas . If it still pings with the highest octane gas, you can reduce the timing then.

 

Thank you for the advice, I can't get to the car till Thursday but will try this and post back results. I didn't think it was getting enough mechanical advance so I definitely need to investigate. To clarify, engine is bone stock as far as I know (had the car a year)and runs and drives fairly well with the incorrect timing and aging carb. I know carb needs rebuilt because when given full throttle the back butterflies move very little (if any at all) and I don't see.any fuel coming out of the "squirters". This is a holley 4160. I've always been told to get the timing first then worry about fuel but I could be wrong. Anyway, thanks for the help and I'll be getting back with you guys on Thursday

[barnett468 418]

your squirter is not working because the check ball in the accelerator pump or under the nozzles is gummed up . easy fix . remove carb to fix it . if it has been sitting long, it likely needs an accelerator pump and 6.5 power valve also.

 

if it sat for years and the gas is coming out yellow, boil the tank out or replace it before you run it or it could damage your engine.

[Rsmach1 71]

6 degrees is what Ford called for when these cars were new and the gasoline had a higher octane. 6 degrees probably won't work. Try setting the static times like this.

 

Your statement is backwards, the better the fuel, the more timing you can run. Although I do agree you can run more than spec initial, on a stock 351w, 14° is pushing it.

 

I agree 10° would be a good starting point.

[Rsmach1 71]

He says he is running a Petronix unit in it, so it should like more timing.

Trigger type has ZERO EFFECT on how much timing an engine will tolerate or need.

[Rsmach1 71]

Did nobody read the OP's original post???

 

With only 4° mechanical advance @ 3000rpm even if he sets his initial at 14° he'll only have 18°total at 3k, it should be all in by then at roughly 34°.

 

So before we try and set up timing, why don't we figure out why his centrifugal is not working properly.

[Rsmach1 71]

Edit from my original post.

 

Mechanical advance @ 2000rpm should be 19 1/2 to 24 1/2°.

[1969_Mach1 333]

Did nobody read the OP's original post???

 

With only 4° mechanical advance @ 3000rpm even if he sets his initial at 14° he'll only have 18°total at 3k, it should be all in by then at roughly 34°.

 

So before we try and set up timing, why don't we figure out why his centrifugal is not working properly.

I agree.  Before timing curves start getting tweaked, I think its time to pull the distributor, take it apart and thoroughly clean it.  I haven't tinkered with original distributor in a long time.  In high school I disassembled, cleaned and checked timing curves using a distributor machine on several mid-late 1960's Ford distributors and a couple of early 1970's Mopar distributors.  Plus checking advance curves on running engines over the years.  I have never seen only 4 degrees of mechanical advance on a stock distributor.  If it were mine, I would pull the distributor, disassemble and clean it before going any further.  Don't be surprised if after it's cleaned, you find the shaft bushing is worn out.  I use to buy bushings at my local NAPA store.  I don't know where they are available now.

 

FYI, an older worn stock Ford distributor on a distributor machine quickly and easily reveals a weakness.  As they age and normal wear occurs, the dwell decreases as the vacuum advance moves the breaker plate to advance the timing.  Eventually, the wear is to the point the engine will misfire when the vacuum advance increases the timing due to diminished coil saturation causing weak ignition.  I haven't seen that issue on a stock Mopar or GM distributor.

 

Yeah, if the car has been sitting a long time, a carb rebuild should be done as well.    

[Rsmach1 71]

+1 with 1969_Mach1, depending on how many miles are on the distributor and it's overall shape, it might best to rebuild/replace it.

[bosephus 10]

Thank you all for the advice. Due to the lackluster performance and the tendency for the car to slightly surge at cruise speeds is the reason for all the new ignition parts and the inspiration for me to put a timing light on it.When I bought the car a year ago I believe it wasn't a regular driver. The first time I filled the tank over 1/2 it leaked all over the garage floor (the day I had to leave for a two week work hitch). Tank has been replaced and all the minor things I thought could be causing the issues have been replaced (wires,plugs,cap,rotor,pertronix trigger,checked for fuel filter in tank and carb inlet). I will pull distributor on Thursday and get back with you guys with the results. Thanks for your interest and help!

[barnett468 418]

Thank you all for the advice. Due to the lackluster performance and the tendency for the car to slightly surge at cruise speeds is the reason for all the new ignition parts and the inspiration for me to put a timing light on it.

 

 

ummm...surging at cruise is most likely jetting not timing.

.

[bosephus 10]

Well,I took the distributor apart and cleaned it all up since it was pretty gummed up looking. It didn't change anything. I did notice it had 1 light spring and 1 HEAVY spring. I guess I either need to recurve with new springs or send the distributor off to be rebuilt/recurved.I've heard Glaser nolan for the rebuild but am open to suggestions. I have no idea about getting the springs,guess I'll call summit. Does anyone know the approximate "all in" mechanical advance spec? Thanks,Bo

[Mach1 Driver 560]

I think this article would help you:

www.fordmuscle.com/archives/2000/03/timing/

[1969_Mach1 333]

The distributor must be than it was before.  I'd rebuild the carb before sending the distributor anywhere to be rebuilt.  During the rebuild go to Holley's website and in their tech section they have a document with the specs for all of their carbs.  Look up your list number and during the rebuild make certain the jetting, power valve, accel pump nozzle, etc. are correct for that carb. Also, since you cleaned the dist just make certain the vacuum advance is also in good working order.  If it's the original distributor, it shouldn't need to be recurved.

 

FYI:  Might not be related to your issue, but that looks like a Holley list 1850, 600 CFM carb.  That is not one of Holley's better carbs.  Don't know why.  Maybe because they are so universal.  I have yet to see one work very well on anything.  They usually cause lazy, sluggish, engine performance.

[barnett468 418]

 Does anyone know the approximate "all in" mechanical advance spec? Thanks,Bo

 

Too many variables for there to be just one but around 34 at 3000 rpm is usually safe and reasonable unless you have high compression and/or fast burn heads.

[bosephus 10]

A little update... I put a rebuild kit in the carburetor(holley 4160) and recurved.I've the distributor with new springs. The carb was HORRIBLE,I am amazed it was running as well as it did. As for the distributor, I bought an msd kit that had several springs included. I ended up using two midrange "blue" springs in my application. Car runs good and I didn't hear any pinging so I guess everything is ok.Thanks for the advice, Bo

[KipDurran 18]

I had a Pertronix stock look distributor in my car that I bought new from Summit. This is on a new 347 stroker. When I brought it to the dyno it ran 227 HP at the wheels but the guys told me that there was something not right with the distributor. At one point they had it to 47 degrees total timing(no pinging) but there was always a popping or motorboating sound occasionally.

 

I got a new MSD dist and box for it. No other changes were made. When I took it back, first dyno pull was 247 HP.  20 HP from just a distributor change.

 

I have read many people here and there complaining of the quality of the Pertonix product. I have had a poor customer support experience with them on a different product.

 

I wonder if the change to the MSD made the difference in your case?