Distributors

[eeh1]

hallo.
what is a good Distributor for a 1950 8ba engine.with vaccum or not vaccum.

[corvette8n]

If it's a stock setup and your looking to tool around town, the and original vacuum setup is fine, if your running multiple carbs, and a performance cam your looking at a mechanical advanced distributor.

[eeh1]

The 8 ba engine is original and he have the original intake manifold with one holley 94 carburator.the Distributor is a mallory with no vacuum port.

[BUBBAS IGNITION]

Originally Posted by eeh1

The 8 ba engine is original and he have the original intake manifold with one holley 94 carburator.the Distributor is a mallory with no vacuum port.

Then you need nothing. Drive it ........

[eeh1]

ok so i do that.
i read in Posts that the original marker is 2 degrees befor on the crankshaft pulley.
is that correct or is it at 0tdc.

[19Fordy]

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It's correct.

[eeh1]

ok this means the marker on the pulley is 2 degrees befor.


and what is please the best idle by rpm


i mean 600 or700 rpm by ....degrees.

[Phil Gillespie]

Originally Posted by eeh1

ok this means the marker on the pulley is 2 degrees befor.


and what is please the best idle by rpm


i mean 600 or700 rpm by ....degrees.

Yes for 8ba the dimple is at 2 degrees btdc.
See Van Pelt site he has all the information for these engines. His list shows 450 to 500. I like around 550 to 600 rpm for idle.
Recommend this site.
Phil NZ

[eeh1]

also is it ok when i have 2 degrees btdc by 600 rpm for idle?

[JSeery]

It depends on the advance curve, at 600 rpm it may be starting to advance. A question Bubba may be able to answer.

[Gene1949]

IF you intend on driving it much LOSE the Mallory. A non vacuum advance dissy is a "race only" item.

[eeh1]

ok and which distributor should I take then?

[Gene1949]

Bubba makes a real good Chev that fits your 8ba. I built one 25 years ago because I put a 56 Buick 4bbl on my 49.. A Chrysler pickup coil/reluctor, a GM HEI brain and a late model E-coil and you are good to go for about 25 years. Never have to worry about spark plugs fouling etc.
IF you have the stock carb and are a purist the old Load0matic works pretty well if properly serviced.

Not a big fan of "all in one" distributors but MSD has a pretty stock looking unit. Not too sure about the reliability of the electronics.
Many of the members here sort of back themselves in a corner by using proprietary electronics (Pertronix or a clone) or mix and match "old school" ignition.
I wanna be able to go to NAPA and fix my outfit off the shelf.

[Gene1949]

6 volt ignitions are inherently high maintenance items but that was all we had back in the day. There was also a gas station and backroom mechanic on every other street corner.
Today look at the many threads/problems here on this board. Failure prone (outsourced) ballast resisters and coils and secondary market electronics manufacturers trying to create electronic ignitions for owners of 6 volt cars. Starting issues, reliability, drivability issues, it's all here.
When the point setting gap/dwell changes so does your timing. Flattys are very timing sensitive relating to overheating during the summer.
6 volt ignitions are very hard on components, even the original "good stuff". Due to the high amperage loads to create a spark.

[tubman]

Originally Posted by Gene1949

IF you intend on driving it much LOSE the Mallory. A non vacuum advance dissy is a "race only" item.

I will have to disagree with this. I have a mechanical advance only Mallory on the '51 Merc engine in my '51 Ford club coupe. It starts on the first touch of the key and runs excellently. As a matter of fact, I replaced a vacuum advance converted SBC unit with it when I couldn't get the car to run right with that distributor. I am completely satisfied with the way the car performs with the Mallory and would not consider changing it. Last summer, I made a 280 mile round trip, mainly on the interstate, averaging 70 mph and 19 mpg. This in a car with 3.55 rear end gears and no overdrive.

Also, as I reported in my reply to "adileo" about condensers, After an initial tune up in 1987, this same car performed flawlessly for 30 years and over 20,000 miles until I upgraded the engine in 2017. This was with a completely stock 6 volt system. Just make sure the system is in good shape and quality components are used. A lot of the time, components on cars as old as these are just plain worn out, which can lead to lots of problems (think worn distributor bushings).

[JSeery]

I have run full mechanical on a lot of vehicles, daily drivers. There is a fuel economy advantage with the vacuum, but not that much in my experience. I tend to like the mechinical only. Had a 73 Country Squire with a 400 automatic that I towed a large boat with, it loved the Mallory mechanical distributer!

[rotorwrench]

The vacuum spark control is more of an advantage if the country has a lot of hills or mountains. It needs the retard under load for that. Any car can benefit some with automatic spark control. It helps keep the coolant temps down as well when under load. Centrifugal advance will work OK if there is no other easy method for getting both centrifugal and vacuum controls. Chevy distributors can be set up utilizing the adjustable vacuum can but it takes some trial and error or someone with a distributor machine and experience to dial them in on the bench.

Aircraft engines just have the magnetos set for full advance then use a retarded spark starting aid on one or both mags to get them to start without blowing the starter up. They run well but they aren't know for fuel mileage either.

[Ggmac]

I also have a Mallory mechanical only advance distributor on a stock 8ba , it runs great . Simple to set and forget . Drive and enjoy .

[tubman]

I thought I'd bring this back up because I just got done going through setting up the Mallory dual point in my car after changing points. First of all, the instruction sheet that came with the distributor said that total dwell should be between 31 and 35 degrees which can be obtained by setting the point gaps to .022". I did this, and the engine did not run as well as it did before. Over the next couple of days, I pulled the distributor and reset the points several times to try to get it right. As an aside, the points were extremely difficult to adjust, mainly because the distributor and points set (genuine Mallory, BTW) lack the slots that you insert a screwdriver in to precisely move the points. I could not get it to run right, so I finally broke down and bought an old "Accurate" brand dwell/tach meter off eBay. When it showed up, I put it on the distributor, and lo and behold, the dwell was sitting at a paltry 22 degrees. Obviously, something was wrong. To make a long story short, I changed point gaps a couple of more times, finally setting them at .018", which resulted in a dwell reading of 33 degrees. The car now runs better than it ever did. In the final analysis, setting the points on one of these is a tedious, difficult job, but if you get it right, the results are worth it. Given the variance between the point gap given in the instructions and what actually produced the proper dwell, I would say that a dwell meter is essential to get the points set right.

As someone mentioned above, the vacuum advance starts to come in at idle speed (600 RPM in my case) making the factory timing marks questionable. I finished this procedure by setting the timing using a vacuum gauge. Once it's running, advance the ignition until the vacuum gauge reads the highest, and the retard it just a little, until the vacuum reading starts to drop. That should get you to a reasonable initial advance. I use this technique to set the initial advance on all modified engines I have, because changing cams, compression, and other factors alters the proper settings from factory specs. Once you have the initial advance set properly, you should check for total advance, which may involve making some internal changes to the distributor if it is not correct. However, that's a subject for another day. Some late Mallory distributors come with an advance curve that can be adjusted using a plastic "key" that you insert in the breaker plate to limit the advance. If this is not set right, the distributor may have a total advance built in of 36 degrees, instead of the 22-24 degrees that works best with a flathead. When I dug out the instructions for my distributor, I found the sheet that describes how to use this "key" if anyone needs it.

[51504bat]

Originally Posted by Gene1949

IF you intend on driving it much LOSE the Mallory. A non vacuum advance dissy is a "race only" item.

Consider me as another who disagrees with this. I've been running a Bubba Chevy mechanical advance distributor on my single carb 8ba with EAB heads and a stock Merc cam for several years now with absolutely no issues whatsoever. Starts as soon as I hit the key and gets driven almost daily.

[Gene1949]

Come on guys
The auto manufacturers were wrong for 40 years? It's a fact of life a leaner mixture [cruise] requires more advance to fire properly.

[tubman]

I think you are comparing apples to oranges. The last flathead was produced (in the U.S. at least) 56 years ago, so you are correct instating that the manufactures haven't been wrong for 40 years. Things change with the times. A typical flathead wants 22 to 24 degrees of total advance, while the typical OHV engine needs around 36 degrees. This makes a flathead less sensitive to changes in timing. Sure, you might get slightly better gas mileage with a vacuum advance (which can be very tricky to set up), but your statement "lose the Mallory" simply is not good advice.

[Ol' Ron]

The problen here is, Progress. Todat we have means to teat the engines thru the engine management systems on new cars. This type of system when applied to the flathead, would accomplish the same think.
Richard Kunc back a few tears ago ran a series of test on a built flathead (276.l-100) and many carbs a d ignition systems . THis was done with a (Road rig), this recorded all the engine functions. Load, rpm,vacuum, and AF.On tape. for review . With this information adjustments could be made to improve the performance and econmy of a flathead.
Now ALL that information was posted on the barn, and mostly ignores bu most of the Know it Alls. Today we still have the doubters.
Most spend a great deal of money building these engines. Yet very little thought is given to tuning.
Fortunately I had a chance to drive the car, and was very impressed with it's performance.

[tubman]

What Ron is saying is very true. That's why I spent the better part of 3 days to determine that the point gap settings specified by Mallory were incorrect (at least for the distributor in my car). Had I just gone ahead and run with the gap set at the "official" .022", I too, would be advising folks to "lose the Mallory".

[Gene1949]

agreed Tubman
(22-24 degrees) at wide open throttle AND 1900-2200 rpms seems to be optimum.
BUT most of us never run those motors at wide open throttle AND tootle around town at 1200-1500 rpm or run down the road @ 70 mph (2600 rpms) and part throttle.

Don't know about setting the Mallory @ 22 thou. Maybe the OP was trying to set single points like that when any point distributor/coil needs" 32-34 degrees dwell. Setting single points that wide does all kinds of negative things as far as timing and spark quality especially running 6 volts.

I use feeler gauges for other things instead of setting points. Most point sets even back in the "good old days" needed to have the contact arm "tweaked" to optimize the contacts when beginning the dwell cycle.

[tubman]

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Agreed. One of the reasons I replaced the points in my Mallory was because one set was so severely mis-aligned that I could not bend them enough to get them even close. Had I not purchased that dwell/tach meter, I'd still probably be chasing my tail setting the point gap with a feeler gauge.

[Ol' Ron]

The only reason I wouldn't run aan old Mallory distributor is: It's old tech, designed back in the 50's when the industry didn't have the knowledge we have today. One reason why Richard's "Road rig" was so important. Now tuning a "STREET" engine, is abit different than a performance engine. Timing and carbonation have to work together. Just like today's engine management systems. After many carbs and ignition curves we found that the following system worked best on his engine. Now this is a "street driver. "

Mechanical advance 16* all in by 2000

Vacuum adv 8*

initial 2/4 not important now.


The only carb that worked well with this system was the Edelbrock 500 cfm. Others were tried but their tuning was more difficult. Jet changes in the Holley 390 and the 4GC were time consuming, However with a little effort could probably work just as well. I wanted to use dual to tipple carb intakes, but Richard thought that their only advantage was aesthetics. Actually we never considered them.
With an AF meter, he began the tuning process. It was during this process he realized he didn't have all the information he needed to make a "Logical" change. And thus the invention of the "Road Rig" He set up a 50 mile route that was 60% street and 30% hiway. Over a few months of trial and erroe . he established the following results.

20* at WOT

28* at cruise

This gave excellent acceleration and no detonation, with 91 Oct fuel and 20/22 MPG. I wouldn't get as good a mileage, because I was in the throttle most of the time
Thes numbers might nor suit rou engine but they are close and a good place to start. Changing rods in the carba\s mia a 5 min job.


Richard sold the car, baught a Camaro, and went back to Han radio

[Gene1949]

Tankx Ron. Your numbers are pretty much where I'm at. Great setup for a driver with my 4GC. I'm still using the GM HEI brain and a newer "E"- coil. I did set the vacc can down to 13" though. I know you recommended 15". Opened the plug gap to .045. The drivability around town is amazing (Butt gauges/seat of the pants.).

[tubman]

Originally Posted by Ol' Ron

The only reason I wouldn't run aan old Mallory distributor is: It's old tech, designed back in the 50's when the industry didn't have the knowledge we have today. One reason why Richard's "Road rig" was so important. Now tuning a "STREET" engine, is abit different than a performance engine. Timing and carbonation have to work together. Just like today's engine management systems. After many carbs and ignition curves we found that the following system worked best on his engine. Now this is a "street driver. "

Mechanical advance 16* all in by 2000

Vacuum adv 8*

initial 2/4 not important now.


The only carb that worked well with this system was the Edelbrock 500 cfm. Others were tried but their tuning was more difficult. Jet changes in the Holley 390 and the 4GC were time consuming, However with a little effort could probably work just as well. I wanted to use dual to tipple carb intakes, but Richard thought that their only advantage was aesthetics. Actually we never considered them.
With an AF meter, he began the tuning process. It was during this process he realized he didn't have all the information he needed to make a "Logical" change. And thus the invention of the "Road Rig" He set up a 50 mile route that was 60% street and 30% hiway. Over a few months of trial and erroe . he established the following results.

20* at WOT

28* at cruise

This gave excellent acceleration and no detonation, with 91 Oct fuel and 20/22 MPG. I wouldn't get as good a mileage, because I was in the throttle most of the time
Thes numbers might nor suit rou engine but they are close and a good place to start. Changing rods in the carba\s mia a 5 min job.


Richard sold the car, baught a Camaro, and went back to Han radio

Sounds like a real enthusiast. I'm not sure that this is someone we should try to emulate; sorry Ron.

[40 Deluxe]

Originally Posted by tubman

Sounds like a real enthusiast. I'm not sure that this is someone we should try to emulate; sorry Ron.

C'mon, tubman! Sounds like Richard did a thorough job of testing and documenting, and was successful! What's not to emulate? Seems he saw a challenge, conquered it, and went on to new endeavors. Lots of people are like that.

[tubman]

I wasn't there, don't know what really happened, but I am very satisfied with what I have accomplished. I'm still at it; driving my car every day. I'm justifiably suspicious of secondhand accounts of anything. Where is it documented? I haven't seen anything but hearsay.

[40 Deluxe]

Originally Posted by tubman

I wasn't there, don't know what really happened, but I am very satisfied with what I have accomplished. I'm still at it; driving my car every day. I'm justifiably suspicious of secondhand accounts of anything. Where is it documented? I haven't seen anything but hearsay.

There were pictures of the car on here, and Ol' Ron drove it, as I recall. seems there were a lot of posts about it.

[tubman]

I'm interested in what's happening now, what's working and what's not. I spent the better part of three days discovering that Mallory produced some documentation that may not be correct. Please try to understand what this thread is really about; some guy wants to know if a Mallory distributor is a good fit for his car. I have contemporary real world experience that has direct bearing on the O/P's original question. What someone said someone else did umpteen years ago is not really very useful.

[Ol' Ron]

I worked with Richard for several years, He had built several aircraft. A KR-1 that looked just like Spitfire with a VW engine. He wanted me to build an engine for him. However the shipping cost prevented him from sending it to me. Told him to find a machineshop that could do the work and i would help him assemble. Over the next several months he got it running and driving. He put a 94 carb on an adapter he mad for the 4bl intake. We sent many emails and phone calls, I hooked him up with JWL for the crank asy and Cam Techniques for the cam. I told him not to bother with the ports and valves, just a good valve job would do. I sent him a converted SBC distributor and he was off and running. Unfortunately the fuel mileage wasn't very good, so he took it on himself to find out why. The first thing he discarded was my distributor, reason no Vacuum advance, and the quest for better mileage was on. Sure I was Pi**ed, This no nothing tossed my dist. Fortunately I swallow my pride and went to work for him, and the rest is history. Sorry Tubman, I respect your knowledge here on the barn, but you might give him alittle slack.

[tubman]

Bottom line? My advice to the O/P still stands. A Mallory dual point without vacuum advance is a good choice for a flathead ignition system. How did this morph into a quest for gas mileage?

[Ol' Ron]

I won't disagree with that, however, It is limited to a performance application, Although it may run well on the street, it prevents the engine from operating correctly under varring load conditions found in a street application.

[Ol' Ron]

over 1200 people read this post, and no more comments. It's how we learn. Conversation is the best tool in the tool box.