Tuning a 46 flathead

Not sure Im posting this in the right section, but hoping some of you guys can give me some advice on how to tune these carbs I have. I picked up a 46 flathead, partially ***embled on a project that was abandoned. Came with a set of Edmunds heads, Edmunds duel intake, new Mallory distributor, and two ford 94s. About 70% of the motor was ***embled when I got it so I don’t know what’s inside, cam, crank, pistons, that kind of stuff. If I was a betting man, I’d say its all stock in there. Did a complete rebuild on the two 94s that came with everything, wired it up and bam, fired up maybe on third try. Worked on trying to tune the carbs forever but just couldn’t get it to lean out or get a quicker throttle response. I always have to feather the gas a bit. So I finally did some research and changed out the jets to 46s for both carbs, had 53s in it I think. It helped but not much. Next I put a progressive linkage on it so the back carb would open later. Helped, but still needed more. So changed to a hotter spark plug NGK B4L. That seemed to help the most. But still running rich. I have tried adjusting the gas and airflow screws seven ways to Sunday, with just no luck. With a fuel pressure regulator I have it set to about 5-5.5. I think, forgot to look at it before I ripped the carbs off last night. Also wanted to add, the carbs are both 94s but they are different. Not sure that makes a difference. All the inners looked the same. I’m guessing I have too much carb for this motor. Was hoping someone here could give me a little more insight as to what I need to do, or what I’m doing wrong. I added a few pics, thought I may be easier to see what it is I’m working with. Thanks for any help, Ricky

 

Just a quick note...fuel pressure is too high, I believe, for the 94's. Drop it to about 2 1/2 to 3#'s and see what happens. Just thinkin'.....

 

5 -5.5 of fuel pressure way too much It should be around 3. Also check your power valves. The go bad when an engine back fires and will cause you to run rich. I have two 94s on my car with out progressive linkage and it works fine. Do a search on Holly 94s you will get lots of good advice.

Rich

PS you need to do your intro post. That should be your first post before asking for help.

 

Will do, thanks for the advice.

 

Yes too high on the fuel pressure.

 

What power valves are you running? They will make a big difference. I have the same intake I wouldn't use the progressive linkage on a dual carb setup.

If you do a search I covered a lot of my tuning on here or feel free to PM me...

 

On the front carb I have to be what appears to be a 8.5 and the back one pluged. talk with charlie price over at vintage speed a while back when i was rebuilding these and thats what he said to run. along with that progressive linkage. I will look up some of your old posts. thanks.

 

I tried a 6.5 power valve in my front carb with the rear blocked. It ran better than with two 6.5. But it ran even better with the carbs sync'ed and a 4.5 in each.

 

Here you go, in order of which I tried stuff:

http://www.jalopyjournal.com/forum/showthread.php?t=46534

http://www.jalopyjournal.com/forum/showthread.php?t=51935

http://www.jalopyjournal.com/forum/showthread.php?t=57836

I also run 170* stats now, shoulda done that a long time ago.

 

I run my flatty with 2 94's and had the same problem. I was running a mallory dual point set up and it just didnt have enough spark. I changed to a msd electronic setup and that motor runs great. I run my fuel pressure at about 2.5. I dont run progressive linkage either.Aftre running that high of pressure i would double check all my float levels and internals. good luck

 

Okay, no laughing, but if I dont ask I wont know. hahaha. When I got this motor it had this bolt in here. I know its not right. So what should be there, and what exactly does it do. Im thinking it is a timing advance thing. Its run like this for two years now though. ???

 

Yes, you should have a vacuum line going into your intake manifold from there. If you look at my profile pics you can just see a small 3/16 steel line going from there, along the bottom of the intake, and into a port below the rear carb.

 

Just noticed, with your distributor I don't think you have a vacuum brake setup anymore like the stock setup used. You can probably put a nicer plug in it and call it done.

 

Perfect, Thanks! For sure a plug then.

 

I don't think it'l ever work right without the vacuum brake operating as this adjustment controls the advance and retarding of the ignition. See the attached link for better info.

Jim

http://www.vanpeltsales.com/FH_web/flathead_engines_distr-timing.htm

 

Check his picks, he has a mallory type aftermarket distributor, note the lack of vacuum brake ***embly. A vacuum line won't be doing him any good without that

 

I just looked through my books, I replaced the front power valve with a 4.5 and plugged the rear and it ran better, but eventually I took the plug out of the rear and put another 4.5 power valve in there also and it ran better yet. My jets were too lean at #46, #48 seems perfect in mine. Definatly set it up with two idle speed screws and use them to sync the carbs. I thought I could get away with one but I had lots of odd idle problems.

 

Hey nick, Thanks for all the good info, gonna order those rebuilds in th AM and try the 4.5 with the 48s. for some strange reason I feel like I tried that before. Well maybe not with the 48s. Wish I would have thought to keep track of all the different things I've tried to get those carbs to run right. Smart!! You can bet I'll start this go round with em. haha. One other quick question, after I rebuild them, how far do I back out the gas and airflow screws if they were turned all the way in. Is it 1.5 turns, 1.25? I forgot and cant find all the print outs I had on them. I'll let you know how it turns out. funny... after rereading your previous posts I would swear we were talking about the same motor!! thanks again.

 

I know it is not old school but how about welding in a bung and a wideband just til it is perfect? No more guessing and it teaches a lot about what really happens to mixture at different temps, load, etc.
http://www.innovatemotorsports.com/products/db.php

 

Your right, may not be old school, but you know if they had that kind of technology back in the early days, they would have been using it. def worth giving it a try. Thanks for the lead.

 

I'd start with 1 1/4 turns out and go from there.

 

I think I started at 1.5 but 1.25 is probably ok. I honestly can't remember where I found the sweet spot on mine.

 

start at 1 1/2 turn out, then in until it starts to run rough and back off 1/2 turn that's it. But you need to sync the carbs or it will never run right.....