Technical Timing and carb adustments 49 8BA

Now that the Model A is rolling under it's own power, I'm trying to dial the engine (49 8BA) in. And could use some guidance.

It has the Speedway dual carb kit with their carbs on it.

I'm currently using a points distributor and 12V generator It came with an HEI, but the manufacturer said to not use it without an alternator.

First - timing: I started with the timing set so the marks align, which, from what I read here is 2deg BTDC. I have a digital timing light, but hadn't used it before. I tried adjusting it using the light, but it didn't seem to change readings. So... I could use some guidance on how to adjust the initial timing without any degree reference. Perhaps the distance between the marks at different degrees. Or better instructions on using the light (Actron CP7529).

Also, timing advance - the timing doesn't change with RPM. The distributor appears to need a vacuum connection for advancing. The Speedway carbs don't have any vacuum ports on them (that I've found). The only vacuum port I've found is on the manifold at the back. I've read that won't work for timing, but could be wrong. Where can I hook up the vacuum, or ??

Carbs - Currently using an electric pump with a pressure regulator set to 2lb. The car is running pretty rich, soot gets on the plugs pretty quickly. I hope it's the idle mixture. I haven't adjusted that yet, and have ordered a vacuum gauge to do that. Where else should I look to get it running leaner or firing hotter? Open the plug gap some?

Other suggestions welcome.

 

First of all, we need the make of "points distributor". Stock 8BA? Mallory? MSD? Somethin' else?

It makes a big difference.

 

2nd with multi carbs get a Uni Syn its imperative!!! Also with the 97s yyou won't have any vac advance port for the stock dist, ifn a points dist with mech advance it should advance start out your idle with all idle jets out 1 1/2 turns then turn each one in until she starts running rough and back out 1/2 turn and you are set this is after setting the carbs with the uni syn to be in sync. If you know someone with a lathe get an ol chevy dual point Mallory and turn it down to fit the flathead and adjust total advance to 22 degrees......

 

Well, so much for the systemic approach......

 

It's stock 8BA distributor

 

Also -
Last night I recalled something.

To get the car running, I adjusted the points until I saw a spark and left it.

So... brain fart; It'll probably help to actually set the gap (or dwell, if I can find the meter).

Thanks for the info so far.

 

Ford Load A Matic? Hope not. They don't have mechanical advances and you don't have vacuum for an advance so that is no bueno.
Stromberg makes a E Fire distributor that I hear good things about. No boxes, neg ground and 12v.

 

Basically, you have a combination that cannot be made to work together. The stock 8BA distributor uses a proprietary Ford advance system called "Load-A-Matic". The distributor itself has no provision for any kind of mechanical advance, meaning it is a vacuum-only system. Ford engineers devised a way to use a combination of venturi and ported vacuum to make these distributors work. Unfortunately, these distributors require a carburetor with internal passages customized to supply this specialized vacuum signal. Certain Holley 2 barrel and 4 barrel carbs are made this way, but not many. Stromberg 97's don't have if from the factory, while the Speedway carbs certainly don't. With this combination, you will have no advance at all.

It has long been known than a change in carburetion on an 8BA requires a corresponding change in ignition. The usual distributors used were mechanical advance only Mallory dual-point setups, which have been replaced lately by SBC distributors, modified to fit into an 8BA. Both kinds have their total advance setup to around 22 degrees, which fits a flatheads needs best. Bottom line is that you will need to change distributors if you want to run that carburetor setup. I am personally in favor of using and old Mallory dual point "flattop" distributor, mainly because they look "right". If in decent shape, they run fine and produce adequate spark for the application. Your other practical alternative is an SBC modified to fit your engine. Not only has the unit have to be modified to physically fit, but the advance curve has to be modified to run properly. (SBC distributors usually run a total advance of around 36 degrees, which is too much for a flathead.)

Once you get the proper distributor installed, you will still should tailor the advance curve to fit your engine (which is where the "Advance" timing light comes in useful). After this is set right, you get to attempt to get the dual carbs running properly, which is where @roseville carl and the Uni-syn come into play. But that all comes after you have compatible and properly functioning ignition and carburetion systems in place.

I just saw @Bandit Billy's response and remember you mentioning an HEI distributor. I would advise against any of that (at least initially) and would check "The Ford Barn" for recent threads about the "Perils of E-Fires".

 

And to be clear, I have never tried the E-Fire so proceed with due caution as with all things and advise, I just know it to be a simple plug-n-play unit that doesn't require timing or ignition boxes that clutter up an engine bay and look a bit funky in an old car. I personally run an MSD on my flathead and it has been foolproof for years and many thousands of miles. I run them on 4 of my cars right now so you might say I'm a believer (sounds like a Monkey's song).

 

Do they even make an 8BA version of the e-Fire?

 

Yep. Proud of it too. But I can say it looks cool.

 

Though I don't have dual carburetors, I am using the stock load o matic distributor with the vacuum disconnected and the advanced mechanism wired, so it does not move. I have my timing set at 20° and it starts and runs awesome. Stock 6 volt starter with a 12 V system. Just something to think about before you shell out a million bucks for a distributor.

 

Billy, your idea of "looks cool" and mine diverged a while ago.

 

All I can say to this is that Henry Ford, cheap bastard though he was said to be, decided to spend the money to put a spark advance lever on a Model "A".

 

And I’m totally good with that.

 

This is going off-topic into personal taste and preferences; let's see if we can get back to the original subject. The O/P should take awhile and decide what he is trying to accomplish. Maybe I'm assuming too much to think that anyone who spends the time and money to build a H.A.M.B. worthy hot rod would want it to perform at it's best, but I don't think so. With all due respect to @wheeltramp brian, I had a magneto with a locked advance on my dirt mod for a while, and it's definitely not something I would want on a street driven car. A distributor with a tunable mechanical advance is a must in my book. What kind is purely up to the O/P's individual tastes, but I put my suggestions forth because they have been proven over the years and hey, this is the H.A,M.B. Get a decent distributor installed, and then go after the carburetion. Some people have had good luck setting up the Speedway packages, but a lot haven't. Suffice it to say that for the initial run in and tuning of an engine. I personally try to eliminate as many variables as possible, among these being the vagaries of inconsistent aftermarket products.

 

Very true, aftermarket parts look very inviting but compared to OEM engineered parts the cost behind the engineering of aftermarket parts is prolly 10% of OEM.

 

My goal at this point is to get it running well enough to drive around while I continue to finalize it. And learn about the flathead. Those updates will include adding an alternator and the hei distributor that came with it.

Thanks for the info so far.

One of the local club members that runs flatheads stopped by this morning to help.

We reviewed the basics and double checked the basic mechanicals - Compression 120 all the way around. Then we checked the plugs - all were gapped to .020. Set them to .035, runs MUCH cleaner and smoother. The rig he drove over has the Speedway carb set up and re runs his vacuum off the manifold port, works quite well. I'll get some fittings for the vacuum and give it a try.

 

Sounds like you're making positive progress. What kind of HEI distributor are you planning on using? A converted GM unit?

 

The immediately prior owner bought a TSP JM7740 HEI for it. It comes with mechanical advance; he set it up for vacuum. I hope to set it back to purely mechanical, but may need to obtain bushings and springs. https://topstreetperformance.com/pr...ck?_pos=9&_sid=ba99e6f09&_ss=r&_fid=36e00d9a5

Per TSP, it won't work well with a generator, so will need to wait until I buy one, which is pretty close to the top of the shopping list.

The plan is to get the car usable with the components that it came with. THEN start modifying the engine (more).

 

I guess I did gap the distributor first thing - it's at .018. Now to find the dwell meter - 2000 miles, new garage and 3 1/2 years since I packed it...

 

Now 'back' to the timing...

How do I read how much timing it has?

The only timing marks I see are the pointer and the 'button', which, if I saw here right is 2 deg BTDC when they align.

How do I know how much total advance I have without other timing marks? When I get a SBC, the first thing I do is add a timing tape to the pulley. Is there something available like that for the flathead?

 

I marked mine myself as there were none. Using a plastic zip tie about 12-14" long, remove the number one plug, insert the zip tie wire nut down in the hole, hand crank it till the piston traps the nut against the head and make a mark on the pulley under the pointer with a sharpie. Now turn the crank by hand the opposite direction until it stops again, make another mark. The center of those two marks is TDC. Mark the pulley and wipe the off the other two marks with solvent. Now, with the zip tie still in the hole, hand crank it watching the zip tie until it bottoms out. At the zip ties lowest point is 180 degrees out, make a mark. Remove the pully carefully so as not to disturb the marks you just made.

Halfway between that last mark and TDC is 90, then 45 halfway, then 22.5, so on and so forth. I have mine scaled from 45 to TDC and 22 the other direction. After making sharpie marks, I filed the marks in the pully and did a paint fill in red for TDC and white on the others to make them easy to read under a timing light.

It seems like a lot of work but it's only once and then you are done with a nice easy to read, custom, timing marked pully on your flathead. There are likely better methods that some expert will mention so you will have plenty of options to choose from. This is just how I did mine.

 

First off, a little basic information on engine timing is probably in order here. There are two ways to advance the ignition timing in these engines : mechanical and vacuum. The Ford Load-A-Matic is the only system that works by vacuum only. As mentioned before, it uses a combination of venturi and ported vacuum provided by a special carburetor, and is usually not suited for use in modified engines. Other systems are mechanical only (centrifugal) and vacuum over mechanical. Mechanical advance works by weights inside the distributor reacting to centrifugal force causing the engine to have more advance as it's speed increases. Adding vacuum to this system causes the distributor to advance even more at periods of high vacuum. This can happen during cruise or idle when the additional advance is beneficial for fuel economy. The advance provided by the vacuum cannister is unrelated to engine speed.

It sounds like the previous owner may have fooled with the distributor, trying to remove the mechanical advance. This would be a fool's errand, as the mechanical component of the advance is what causes the distributor to respond to changes in speed. If this is the case, the mechanical component must be restored before this distributor will be any more usable than the stock unit. (My personal experience with flatheads is that mechanical advance only is sufficient for general use, the vacuum component mainly yielding better fuel economy. However, unless the distributor has all of it's functions installed and working, don't expect to much in the way of support from the manufacturer.) On paper, this distributor looks good, coming with both mechanical and vacuum advance, and extra springs and bushings to tune the advance curve. They have been around for a while, but I would be afraid that they are just more imported crap. I think your money would be better spent on a converted SBC distributor from Charlie Schwendler rather than on an alternator, which are quite expensive if they're any good.

I have purchased "sets" of timing strips for Summit. They are an assortment of self-adhesive timing strips in different lengths. As I remember, there was not one that exactly matched a flathead. I believe there was one for a 7" pulley and a flathead front pulley is 7 1/8". I would just use the 7" strip and "fudge" a degree or two. I usually mark the front pulley at 22 1/2° (total advance) and just "wing it" from there. If you are so inclined, preparing your pulley like @Bandit Billy describes is an excellent idea.

When it comes to using an advance timing light to check total timing, etc., I am sure that there are many good tutorials on the internet that would be very helpful. There are videos on YouTube that go through the whole process in detail. I suggest that you check the website of your light's supplier, or the web in general.

 

Thanks - I'll have to see what's involved with pulling the pulley.

 

Thanks for the info on the strips and the pulley size, That may be the ticket for now. Or use some math to determine diameter and degrees/inch, then mark from there.

At this stage, I'm just trying to get it running decently with the components I have. I may have attained that. Next stage is building a new firewall for the engine intrusion and getting the body back on. That way I can drive it more than around the block and tweak/modify from there.

 

They have went up in last few years by
$40-50,

my F -H's liked around
12-16 deg BTDC

Autozone on shelf & others

 

OK, an update.

The pulley size info was VERY helpful. With that and some basic math, I figured out that it's about 0.06"/degree - 0.6 for 10 deg and 1.2 for 20deg.

All of which told me I was using the the advance timing light properly, just not enough. I adjusted the light setting by 20 deg while looking at the timing marks and saw the difference. With that I'm able to read and adjust timing to my preference. It's currently at 20 deg Btdc with no vacuum. I'll take it out for some low speed tests (no body yet) and see how it behaves.

Your guidance helped me learn a lot more on how this all works. Which is a big part of the reason I build hot rods - to learn new things.

It looks like an alternator is next so I can install the HEI unit (once it's set back to mechanical advance).

Thanks everyone.

 

If want to have a great running car dump the duals and go back to stock. Make sure it’s all in spec.

You’ll have a car that runs a drives better in all conditions than most of these poorly set up “hot rods”.

People will spend $$$$$$$ for bling with no care for actual performance.

Choose one side of the road or the other.

 

It sounds like you're close. Most folks like a total advance of 22° to 25° at 2300 to 2500 rpm. You're a tad short on that, but the car should run fine with it. As long as you can get it started, you should be good for now. You will find that when driving a car on a regular basis, a working advance system will make life more pleasant.

I am concerned with one thing. It sounds like you will be trying to switch to an imported electronic aftermarket distributor of dubious reputation that someone already has been monkeying with. I don't think I have to tell you where to looks first if the switchover doesn't go smoothly.