Hey all, I've been doing quit a lot of reading about 8BA distributors, how they work, upgrades, etc, and trying to figure out what I've got in my engine. I understand the theory behind the mechanical advance, and vacuum advance, I've read about the issue with points and why folks will convert to the electronic ignition. Here's a shot of mine. There clearly isn't a vacuum can on the side, so there is no vacuum advance. It has the Pertronix electric ignition upgrade. I see the springs for the mechanical advance, but shouldn't there be weights to activate it? Is this a stock dist with the Pertronix ignition upgrade? Is it worth replacing it with the vacuum advance? My mileage sucks right now, so what I've read, it seems like it would be. Can the vacuum advance be added to this or is that a whole new unit? Currently running this on 276 8BA, dual 97's, Clay Smith 3/4 cam Thanks in advance!
That sure looks like a stock 8BA distributor to me. If it has no vacuum can, there is no advance at all. How does your engine run?
Engine seems to run fine. Have a couple hundred miles on it around town so far. It's a gas hog though and the plugs are sooty black. I'm new to flatheads so it's tough to have anything to compare it to. If there's no advance on it at all, what are the springs for?
What do you consider good mileage? Flatheads normally run between 10-15 mpg. Throw that petronix away and install the original points. If you read everything about 8ba advance you should know that the original distributor needs Venturi vacuum from the Venturi port of a Holley 94 carburetor. Did you check these things??? Another thing. Check your vacuum diaphragm under the distributor points plate. Does it advance with Venturi vacuum?? https://www.jalopyjournal.com/forum/threads/holley-94-101.186744/ Great article on 94’s. https://www.carburetor-parts.com/assets/manuals/holley-94-2100-2110.pdf
The springs work in conjunction with the (venturi) advance can that seems to be missing. As I said earlier, that looks like a stock distributor with the advance can removed. I might be wrong, because I mainly use Mallory distributors and I haven't worked on a stock one for years. If I'm wrong, someone will be along to correct me. I think you need a new distributor. Either a converted SBC unit or an old Mallory. I think MSD still makes a flathead distributor to be used with one of their boxes, but they are expensive. The dual 97's rule out a stock distributor as they are totally incompatible. Your best bet would be to contact "Charlie ny" on "The Ford Barn" and see when he is doing a batch of flathead distributor conversions. If you do an SBC distributor, you will have a distributor with both vacuum and centrifugal advance, which enhances both performance and fuel economy. Old Mallory's in good shape are also quite expensive. I have had Charlie convert an SBC Mallory for use in a flathead, as I like the "old-timey" look of a flattop Mallory (and the SBC units are usually a lot cheaper than the flathead units). It seems that someone thought that a Pertronix conversion would solve all of the distributor problems. It will do nothing in regards to ignition advance. It is just an alternative way (and, in my opinion, not a very good one) to send a pulse of electricity to the primary windings on the coil. They wouldn't be the first to think that.
Those two holes.... That's where the advance can goes. It's Missing! This means you have no advance...at all. Sure it will rev but it'll run hot and be dog. It could also foul the plugs. What carburetor are you running. If you are running the Ford/Holley 94/8BA you need to get the advance can and parts and hook it all back up. The 94 and LOM distributor were "Matched Pairs". LOM means Loadomatic. With a Loadomatic distributor advance was accomplished by ported vacuum from the back of the 94 Carburetor. The was No mechanical advance with the LOM system. It was vacuum only. Petronix is a questionable upgrade and folks either love them or hate them. They do nothing, absolutely nothing for the advance. Untitled by Travis Brown, on Flickr It's a poor photo but this is what a Flatop Mallory looks like. This particular model had mechanical advance the vacuum brake but apparently the vacuum brake has been removed or disabled. OK dual 97s.....I see that now. You need another distributor either a old flattop Mallory or a Chevy conversion.
Thanks guys. I'm definitely fouling the plugs with a lot of soot, but it runs pretty cool, 180-190 all the time.
Petejoe has been successful using Dual Carburetors with the stock LOM distributer. To successfully do this you have to run two Ford 94s, not Stromberg 97s. The Stromberg has no vacuum port. Stromberg did make a replacement for the 94 that was LOM compatible but that was 70 years ago. Again with the 97s, you'll have to get a compatible distributer. It's best to use a vintage Chevy (properly curved) or a old flattop Mallory. The new Chinese Mallorys are not the same quality as the old. The Big Chinese HEI distributers look ridiculous on a flathead. They look like a five gallon bucket with wires coming out the top, that and they are blue or red....It just don't look right and again, the quality.
Hey, thanks for posting about your plugs. That's good follow up and good information. A lot of times people will post questions and not provide any additional info or ever post if the issue was solved. This is a big issue with 8BAs. I dare say, 8 out of 10 guys ignore the LOM advance issue. I see it on many pages and forums where multiple carburetors or 4bbls are used and nothing is done about the LOM issue. A dual set up is expensive. A dual set with real 97s is really expensive. That's a 1000 bucks in carburetors alone. Do not forget about the distributer. Really a good mechanical advance distributer should be the first up grade.
As others have pointed out you need the correct carb to correctly signal the advance diaphragm which is definitely MIA on your distributor. The 94 has a port that produces a vacuum signal as air passes through the carb venturi, the vacuum advance canister never sees any manifold vacuum, it is all from the venturi and it continually adjusts the ignition advance depending on airflow. Sounds great on paper but honestly it does not work as great in real life as a more conventional distributor with mechanical advance and vacuum advance with a manifold vacuum source.
I can't let this go unanswered. A properly functioning "Load-a-Matic" is a great setup when paired with the proper matching carburetor. It's only when people start changing carburetors do things start to fall apart. Properly matching components is important.
I am going to say my 3.5 cents worth on some Dist. they run a Cintrifical advance when the RPM's go up so does the Advance go as far as the Spark Plugs go the Carb is not adjusted right I just had to put my 3.5 cents Just my 3.5 cents Live Learn & Die a Fool
As others have said, the LOM won't work with the dual 97s. I run a MSD ready to run electronic distributer with dual 97s. It has adjustable mechanical advance and works great.
Thanks guys. So other than a vintage Chevy (I'vve reached out to CharlieNY from fordbard about these), and a vintage Mallory, are there any other options? Is it possible to convert what I have into what I need?
thanks for posting this thread, - I am another that needs this information. I also have an 8ba, no ‘can’, - Holley 1&1/16” carb, - vacuum blocked, and it runs really good, except slight hesitation under load, - runs cool, even with no fan - yes that is correct- but I do intend to rectify it all soon.
Without weights on the advance, it’s just springs holding it in place, right? The plate can’t move to actuate the advance. I’m in for a 1/2 penny
Not for the Ford 49-56 V8 and 49-1970s Little 6 Cylinder (including the 240) distributors. The Loadomatic distributor operated on a metered vacuum signal alone. There are no advance weights in a LOM distributor, just the plate and springs, that's it. It had to have the vacuum can to pull the advance plate. Without the correct vacuum signal, it will not work. For a stock engine with a single carburetor it worked really well. It never was a performance ignition. Petejoe and others have had some luck splitting the vacuum lines between 2 94s and working on the springs that's on the advance plate. This was suggested in the Hop Up section of " Fix Your Ford" 1957....This makes the LOM distributor functional for a mild street hop up. This will not work with 97s. Manifold vacuum will not work. Another option is using the Mercury intake with the larger 4 bolt Holley. Still, another option is using a Holley teapot or early Carter carburetor that's compatible with the LOM distributor.
I will expand on the previous post and add that if you go with the Mercury 4 bolt manifold, a small base Rochester 2G is a much better, easier to find, and cheaper carb to use. A small base 2G will bolt directly to the Mercury manifold but it has larger throttle bores. It is quite easy to bore the Mercury manifold out to match the 2G; I have done it many times. There are a lot of variations of the Mercury manifolds and Rochester carbs, but workable combinations are not that hard to come up with. If anyone has any specific questions, feel free to start a "conversation".
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