i have 1950 flathead with stock dist with an ignitor instead of points can i use manifold vackum to the advance the 97s have no va*** ports
Not succesfully. The distributor does 3 different things : It has a mechanism to make the spark (points or pertroniccs module), distributing that spark to the various spark plugs, and (tries to) set the optimal timing for that spark for different engine states (RPM, load, etc.). You are only changing how the spark is produced. Unless you make other modifications to the distributor, you are stuck with the Loadamatic advance scheme, which needs the special vacuum signal provided by the proper 94 carb. Since modifying the stock distributor is impractical (no centri***ual advance), an aftermarket distributor is required.
Tubman is right. You need a dizzy with mechanical advance. Contact Bubbas Ignition, 1-888-809-3835. Or go to his web page. He can answer any questions you have or supply you with what you need.
side_valve, Will that work properly? That vacuum source is in the carb base, while the 94's have it higher up in the carb body itself. Then there is the old argument about whether multiple carbs change the amount of vacuum available for any engine state, and therefore something has to be changed to make up for it. (I have never been involved with dual 94 carbs and a loadamatic distributor, bur do know that there was a lot of back-and-forth about it on the flathead techno-site.)
Here's some tech info on that from Clive at Stromberg: Developed in-house here at Stromberg Carburetor, the new vac-port equipped 97s provide vacuum through a small br*** fitting located just behind the kicker linkage on the same side of the carburetor base (throttle body) as the typical small-block Chevy distributor vacuum canister. The fitting can be replaced with a small set screw (supplied) if engine needs change. Like our cable choke and ‘push-throttle’ options, the new vacuum port makes it easier to use 97s in so many applications. To test the effects on our 350ci Chevy dyno motor, we disconnected the vacuum and locked the throttle at 1800rpm. Once reconnected, the vacuum-induced additional timing raised rpm to 2000 and increased torque by 4 ft-lb – all without adding more gas, of course. The exhaust sound changed considerably, too, so it obviously appreciated the extra timing. Tech note: Unlike manifold vacuum, ‘ported vacuum’ is taken from just above the throttle plate to provide additional, vacuum-activated timing advance only at light load/part throttle conditions and not at idle or full throttle. Claimed benefits of vacuum advance include improved fuel economy and throttle response. Most aftermarket vacuum advance distributors are designed to work with ported vacuum, though the technical specification should always be checked. And of course, multiple 97 applications need only one vac-port equipped carburetor. The new Genuine Stromberg 97 with vacuum port and the new vac port-equipped 97 base are available through the worldwide Stromberg dealer network. Further details, including pricing, and help with installation is available from us here at Stromberg by email or via the Stromberg Tech Center at www.stromberg-97.com. http://www.stromberg-bulletin.com/stromberg-97-with-ported-vacuum/
The description above is accurate for ported vacuum. But the Ford Loadamatic dist. was calibrated to a sort of venturi vacuum with a port in the lower side of the venturi where it picked up sort of combo vacuum, measuring the vacuum created by the venturi itslf as the air flowed past the restriction created by the venturi and flowed into the area above the throttle plates, as I've always understood it. I came of age to drive when flatheads were still sold in new cars and never saw anybody get a '49 or later to run worth a **** with multiple carbs unless they changed to another, mechanical advance distributor. Mallory was the most common replacement.
Thank you d o m; venturi vacuum was what I was thinking of, but couldn't come up with the proper name. side_valve : has anyone actually tried one of these 97's with a Loadamatic to see if they actually work or not?
I am thinking that the H.A.M.B. needs a sticky about Load-0-Matic distributors and their use with anything other than the carburetor that they were designed to work with. I spent the better part of the summer of 1965 trying every conceivable contrivance to make one perform with two 94's after my Dad said it wouldn't. He was correct, as usual. I tried to split he signals between two carbs, isolate it off of one carb, blend manifold vacuum and venturi vacuum........ I am sure that some folks a lot smarter than myself have tried also. I have never heard of anyone being successful in this endeavor. The only recourse is to replace the distributor with one that has centrifugal advance, Mallory (have the advance curve checked), MSD, or have GMCbubba on here make you one from a Chevy core. He does lots of them and most folks seem to rave about the increased performance. Seems like two or three times a month this question is asked.
Any '49-'56 Ford shop manual will detail the operation of the V8 loadomatic distributor, and the very low vacuum signal they require, around 6" Hg max. (Ford used the loadomatic on 6s for many more years) I know first hand that two 94s can be run with a loadomatic on a stock flathead, as I did for several years on my '51 sedan. In spite of what some magazine articles and experts stated, I measured no loss of manifold, or advance vacuum level from one 94. (Splitting the distributor signal from both 94s does absolutely nothing except add unnecessary plumbing) The result was a good running engine, with a normal working advance diaphragm, same mileage with better performance. I made sure the advance diaphragm was in good working order and that the points were set to 27 degrees dwell, then followed the advice from 286 Merc on one of the Ford forums by making sure (1) the carbs were matching and built the same, (2) each carb was run on the stock intake to verify operation and vacuum levels, and (3) the carbs were carefully synchronized with straight linkage. Racing or high performance, no. Good running engine for normal driving, yes, and no worse than with one 94. I did switch to a Chevy point conversion a few years ago because a built flathead with 97s is in the future, and the mechanical advance is a noticeable performance improvement, although mileage has remained about the same.
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