|
|
kelroy
|
-- 03-30-2011 @ 11:22 AM
|
| |
I could use some help setting the 3 - strombergs on my 53, any tuning tips would be appreciated. What about the progressive linkage, is there a best measurement?
|
|
|
supereal
|
-- 03-30-2011 @ 12:53 PM
|
| |
Setting up a triple carb intake on an 8BA engine is a tough job. The distributor must have vacuum from a port in the carb, which the 97 doesn't have. The old engines used vacuum only to retard the mechanical advance, which the later engines don't have. To operate properly, the 239 cu in V8 needs about 300 cubic feet of air per minute. Too much intake capacity will seriously reduce manifold vacuum. Too little will starve fuel. To be able to have an acceptable idle, yet plenty of capacity at high revs, a four barrel carb is a better choice. The best way to set multiple carbs is with a vacuum gauge. Unless you are racing, a multicarb intake is usually more trouble than it is worth just for the "look".
|
|
|
37RAGTOPMAN
|
-- 03-30-2011 @ 2:37 PM
|
| |
What was done to the engine ?
has original distributer ?
this forum will need more information.
hope we can help 37RAGTOPMAN
|
|
|
kelroy
|
-- 03-30-2011 @ 2:38 PM
|
| |
Super,
Yeah I assumed a 4 barrel would make more sense, but I have the manifold and carb's, and I hate to sink much more into this pit! My vacuum line runs directly from the manifold to the ditributor and I've tried getting it to idle using just the middle carb. Should the vacuum gage reading be similiar to a single carb? Oh, it does look good!
|
|
|
kelroy
|
-- 03-30-2011 @ 2:44 PM
|
| |
Ragtop,
It has a Merc crank, bored to make 272 ci. Heads are Edelbrock 8:1, intake is Edelbrock, MSD distributor, carbs 3 - 97's.
|
|
|
37RAGTOPMAN
|
-- 03-30-2011 @ 2:52 PM
|
| |
If you back off the throttle plates screws on the 1 and 3 carb,ALSO disconnect the linkage, make sure the plates are closed, now you should be able to make it idle,with center carb, depending in what condition the engine is in,compression ,timing etc,
I thought the 1 and 3 carbs should come in at about half throttle off the center carb,and all 3 should be open at full throttle.
years ago a friend on mine had a 50 with twin carbs, and the only way we could get it to have pickup was to put a weaker spring on the vacuumn advance.
hope this helps, have fun,,,37 RAGTOPMAN
|
|
|
Stroker
|
-- 03-30-2011 @ 2:55 PM
|
| |
Your biggest headache will be the distributor. The stock Ford/Merc. side mount distributor cannot be used with anything except a stock 49-53 carb with a venturi vacuum source port. Manifold vacuum won't do it.
The reason is that the distributor has no mechanical advance system, but rather uses the vacuum can to time the spark based on the velocity of air in the carb venturi. About the only way to put either multiple carbs or a 4 bbl carb on these engines is to go to an aftermarket distributor such as the venerable Mallory (still available) which have a mechanical advance system or switch everything back to the 48 and earlier system with the front mount distributor.
Attached is some excellent advice from the Late Barney Navarro that was written when your car was new.
|
|
|
kelroy
|
-- 03-31-2011 @ 6:03 AM
|
| |
Stroker,
Great article! It is now all beginning to make sense! My car came with an MSD distributor built to advance via either mech. or vacuum, (the one not used is to be blocked off) I've got to get into it, I suspect it was just dropped in as it came in the box; and the vacuum line hooked to the manifold.
I appreciate everyones help, maybe I'm on the right track!
|
|
|
supereal
|
-- 03-31-2011 @ 10:34 AM
|
| |
IO think Dan (Stroker) covered it all. The problem with all carbureted engines is producing a smooth transition from idle to the best part of the power band. The factors in performance involve compression, spark advance, and mechanical efficiency. At the point the torque and brake horsepower curves cross is the "sweet spot" of performance. For the Ford flathead, it is about 2,200 RPM at full throttle. Thus the intake capacity has to be tailored to that scenario for best overall operation. Multiple carbs were mostly used for either circle or drag racing, where low speed was not important. For street, they do look good, of course. I'm not familiar with all the MSD ignitions, but I assume they did, or should have, provided the info you need regarding advance curves. My charts show that advance of about 12 degrees at 2000 RPM is required, rising from the standard 3-4 degrees at an idle of 500. With unaltered 97 carbs, progressive linkage is probably the only way to achieve a decent idle. You didn't mention the cam, so I assume it is stock.
|
|
|
JM
|
-- 03-31-2011 @ 12:14 PM
|
| |
You might want to contact Uncle Max or Charlie, NY over on the Ford Barn Forum. They are both excellent at setting up multi carbs on Flathead's. I constantly confer with Uncle Max on how to build and set up 97's. He is also a great source for 97 parts, rebuilt 97's or the new 97's from England.
JM
|
|
|
kelroy
|
-- 04-01-2011 @ 10:25 AM
|
| |
Thanks again Guys, You know when I was a teenager I never needed advice, now it seems I can't take a single step without advice or directions!
Supereal,
Sorry I didn't mention the cam, it's an Isky 400 junior. Coincidently, I was just trying to determine the best advance curve. This distributor has 4 advance Stop positions, 18, 21, 25, and 28, what do you guys think?
|
|
|
supereal
|
-- 04-01-2011 @ 12:51 PM
|
| |
The advance curve info should be furnished with the cam. I can't find that cam in my references, but if you don't have the numbers, I'm sure they can furnish it. As mentioned earlier, the stock advance at 2200 RPM is about 12 degress. Obviously the Isky cam will be considerably different.
|
|
|
ford38v8
|
-- 04-01-2011 @ 3:20 PM
|
| |
Kelroy, when you were a Teen, you wouldn't take advice. Now that you are old and wise, you've found that as advice is cheap & free, anyone not taking all he can get at those bargain prices is usually a wet-behind-the-ears teenager.
Alan
|
|
|
Stroker
|
-- 04-01-2011 @ 3:45 PM
|
| |
Kelroy:
Generally speaking, with a cam such as the Isky 400 Jr which carries about 258 degrees
duration, you can bump the timing up a little earlier in the curve, relative to a stock 8BA cam as at low rpms, your effective (actual, not calculated) compression will be less due to the increased overlap, (the 400 uses the same Lobe Separation Angle as the stock cam) hence the tenancy for low rpm "pinging" under load will be decreased. The 400 Jr. "comes-on" at a fairly high rpm, so don't expect a lot of low end torque. You have a very nice combination, with the 3-97's, displacement, cam combination etc. Problem will be that it works best in a very light vehicle. This will not be a motor you'd want to use for towing, but I'm sure that besides looking good it will sound righteous 
|
|
|
kelroy
|
-- 04-11-2011 @ 7:29 AM
|
| |
Stroker you're right it does sound great! But I haven't got it exactly right yet - the MSD dist. comes with several available advance curves, I've resigned myself to trying each, hoping to hit the right combo. But that's OK, tinkering is part of the fun!
|
|