When I dis***embled my 94, I didn't pay attention to the throttle plates. They were dirty, rusty, and gummed and appeared to be flat. Now, however, after cleaning and media blasting, I see that one edge has a built in taper on it. I ***ume this edge goes next to the holes in the throttle bores, but my question is...does the beveled edge go up or down? One way would appear to put the holes "above" the plate and the other, perhaps below. My gut feel says the bevel should go up...but I need to know for sure. Thanks!
I think they are beveled on both edges so bevels align with walls all around...will check and bring in a throttle body to describe. I always scribe a mark on carb parts that are possible to reverse or whatever... When re***embling install the plates slightly loose with a light grip by the screws. Hold the thing up to light and poke, jiggle, and swear at the plates until you get them centered and fitted to be light tight when held up to bright light, then tighten while firmly holding them shut. Stake with screw supported well, something like a bolt in a vise to give a staking surface while you whack the things. Bringing in a sample throttle tomorrow... Will send you Ford how everything works and overhaul info.
I am sorry Bruce, I did not make myself clear. The bevel I am talking about is on the flat surface, not around the edges. I did a lot of looking on Ebay, at carbs and parts for sale and believe that the beveled side goes down, and in the direction of the idle/intermediate port openings in the bore.
OK...hacked my way through a jungle of Strombergs and looked at a couple of 59's and 92's. This gets easy here! I realized they all have two sort of dents in each throttle blade, probably to hold the blades from falling through on the ***embly line between dropping them into the slots in shaft and getting them centered and screwed tight. Said dents in the finished carbs are in the forward half of the blade with their convex bulge pointing down. As I said, when I take a carb apart I generally scratch forward or up directions and L or R on anything I can even imagine screwing up. The Ford overhaul directions i sent you strongly imply some sort of selective fit on 94 plates, so I make sure they go back to their homes. On shafts, I give them a serious shakedown when I find them and generally avoid any that I consider too loose...proper drilling out and bushing really requires serious machinery I don't have, and fatter shafts are not a great idea.
Thanks for your effort/contribution to the cause Bruce, I am now intrigued by your parting comment of fatter shafts are not a great idea. I just finished putting in an oversized shaft (.005) and I guess one could theorize that I have now reduced the airflow into the engine by some miniscule amount. Given that this is a stock flathead in a pickup truck, I can't imagine ever noticing it, from a performance standpoint. While I do have the machinery necessary to rebush the throttle body and use a standard shaft, the choice seems to be equivalent to one of taking the elevator....or taking the stairs, with regard to difficulty, so I took the elevator.
Slab it! After fitting the thing and being sure it moves easily you grind the shaft flat (flats parallel to throttle plates) in the area exposed to air, with a bulge left to accommodate each screw. Super trick truck! I read a very thorough airflow ****ysis of a Q jet (which went from 750 CFM to about a thousand without enlarging venturis) by flow genius Dave Vizard. I had always ***umed that the venturis set the absolute limit on carb flow, and this blew that right away. The biggest single boost was slabbing the shafts! After that it was all detail improvements at casting lines and such, followed by another great leap forward replacing the primary ****erflys with larger ones. The idea here is simple win-win: Go to bigger venturi area and you lose low speed performance, improve flow other ways without increasing V area and you can take advantage of greater flow and still have proper fuel feed at all speeds. Here, it is pretty generally acknowledged that even slightly tired stock flatheads respond to dual carbs. So get all the flow you can out of your single!
Makes sense, at wide open throttle, those shaft areas parallel to the throttle plates are the ones that are restricting the air flow. Skimming a little off the top and bottom should, at least, restore airflow normal flow thru the carb. Thanks for the tip!
When slabbing throttle shafts: Pay attention to the shaft material (steel or br***) and any linkage that may be attached to the end of the shaft opposite the throttle hook-up. You do NOT want the weakened shaft bending For absolute race applications, one can eliminate the "bump" for the throttle screws, and pop rivet the plates in place. One other thing about CFM (and I have not read the above referenced source): some less than scrupulous individuals/companies get a major increase in airflow by: (1) changing from a "wet" to a "dry" rating (2) changing the rating vacuum - http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm And Bruce, the venturii do set the absolute maximum CFM, but production carburetors do not take advantage of this maximum, as per your comments. Jon.
You guys know anyone that has these already rebuilt? I suppose I could send mine in. Looking for a quick replacement. Sent from my iPhone using The H.A.M.B. mobile app
Vintage Speed sells rebuilt 94s with, or without your core. However, I know nothing about them from a customer satisfaction standpoint. ****'s Hotrod Place also rebuilds 94s, but I think he uses YOUR core so you'd have to send it to him. I've dealt with him before, relative to parts and he seems like a nice guy.
Check with CharlieNY over on the Ford Barn. He did the 94 on my 8ba from my core but he may have some available without having to send him your carb. FWIW his turn around time was pretty quick and excellent work IMO
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