Early Ford V-8 Club Forum

EFV-8 Club Forum / General Ford Discussion / 59 A Hot Rod Engine - fuel air issue

Reply to Discussion | New Discussion << previous || next >>

Posted By Discussion Topic: 59 A Hot Rod Engine - fuel air issue -- page: 1 2 3     DEUCEMAN 04-05-2010 @ 7:48 AM reply profile send p.m. Member Posts: 17 Joined: Jan 2010 I have the following engine in my "real" '32 roadster. It's a 1948 59A engine that has the following done to it by the best engine shop around. Bored to 3 5/16" stroked to 4 1/8", Rods 21A, Ported, intake and exhaust, Baffled exhaust, relieved 1/8" Intake valves 1.60 Chevy at 30D, Exhaust 1.50 Ford at 45D, Isky valve springs, Johnson lifters, ford valve guides, Weber F5 S cam, duration: intake.265D,exhaust.260D, Lift: intake .340D exhaust.342D. Offenhauser heads, 8.50 CR. Mallory duel point 13D initial timing 24D at 2500 rpm. 3 Stromberg 97's on a Offenhauser intake. Here's my problem; whenever I run any aircleaners, and I've tried 5 different styles, the engine starves for air and runs awful. As soon as I remove the air cleaners it runs strong. So now I run "scoops" with screens and it runs fine. I want to run a set of Edmunds or Stelling Hellings, but every time I try the engine looses power above 2500 RPM, take the air cleaners off and it pulls hard to 4500. Any ideas or suggestions. Thanks you.... supereal 04-05-2010 @ 8:45 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 With 3 97's and a cam with a lot of overlap, it is likely that the intake manifold vacuum is too low to pull sufficient fuel thru the triple carbs. Put a vacuum gauge on it to see if you have something above 15" hg. You are apparently at the edge without the air cleaners, but fall below when they are in place. We built an engine similar to yours last year, and we installed a mechanical secondary 4 barrel carb so the engine would have a reasonable idle, and plenty of headroom for high rpms. The owner is very happy with the results. carcrazy 04-05-2010 @ 3:08 PM reply profile send p.m. Senior Posts: 1676 Joined: Oct 2009 Super, What kind and size of 4 barrel carburetor did you use? Did you use a spacer under the carb? What 4 barrel setup would work best on an otherwise stock 59A engine with headers? Any advice would be welcomed. Thank you. ford38v8 04-05-2010 @ 8:18 PM reply profile send p.m. Senior Posts: 2769 Joined: Oct 2009 Super, your explanation sounds great, but I'm confused. He should have higher vacuum with the air cleaners in place, and that's just when he starves. Is it because the air cleaners cut back on the available venturi air? Dueceman, Your engine having a lumpy cam and strong valve springs is exactly the type of engine that really does need the extra zinc that was recently taken out of engine oil. I hope you've got that issue covered. P.S. - I'll bet your problem would be solved if you replace your 97's with 81's. Alan 37RAGTOPMAN 04-06-2010 @ 6:08 AM reply profile send p.m. Senior Posts: 1965 Joined: Oct 2009 HI DEAUCEMAN you might try rejeting the carbs or check the size of them in all three carbs, FLATHEAD JACK would be a good source of info,and a set of correct jets,has many sizes to chose from you can tell him what you did and he can suggest what you need to repair, also make sure the throttle plates on the outside carbs are closed completely at idle ? and just for ho's ho's CHECK the timing advance with and with out the aircleaners see if there is any big difference, maybe with the aircleaners it does not advance fully? it seems to me that it runs too rich with aircleaners is that correct. you might have to decrease the size main jets,on outside carbs, at idle the outside carbs should be not working,with throttle plates FULLY Closed till you open the throttle , they should kick in, sounds to me that you should consider playing and fine tuning with the jets, HEY ,,I am just throwing this out there trying to help, hope this helps 37RAGTOPMAN Stroker 04-06-2010 @ 6:41 AM reply profile send p.m. Senior Posts: 1460 Joined: Oct 2009 There is one reliable method to dial in the jetting, and that is to do a proper plug reading. Find a safe, open "un-patrolled" stretch of pavement, and run the car wide open for about a mile. Without backing off the throttle, cut the ignition and push in the clutch simultaneously. Once stopped, pull all the plugs and observe their color. If you don't like driving that fast, you can do the same thing on a chassis dyno, and get an honest rear-wheel horsepower reading while you are at it. Without "quantifying" the lean/rich condition, it's pretty hard to do optimal jetting. You have built essentially a "track motor" which is probably going to be happiest when running wide-open. I have never liked the little dress-up "bonnet-style" air cleaners, as they have no plenum area to accommodate fuel stand-off conditions, and very little filter media area. You might have to plumb-in some big-ugly K&N's to get the required space above the carb, and sufficient media area. DEUCEMAN 04-06-2010 @ 8:09 AM reply profile send p.m. Member Posts: 17 Joined: Jan 2010 Thank everyone who replied, you guys are great. I'm gona try running on thr center carb , just as a test the linkage is adjustible. The timing is right on, the engine runs cool, rarely above 180. I suspect the carbs, I'll check with Flathead Jack, he's helped before, a great guy. I use "Brad Penn Green" 20w/50 oil and add GM EOS as well, that should help with the zink issue, any other suggestions on the zink topic? I run a fake stock fuel pump and a hidden electric pump, I reduce the pressure to 2 lbs because of the 97's tend to leak when the pressure exceedes 2-3 lbs eventhough they were rebuilt by a read Stromberg pro, perhaps I should bump up the pressure and see if that helps? I'm pulling almost 13" of vaccuum, using a tap and gage at the intake manafold. The idel is steady at 750 rpm although lumpy. The compression is 150-160 at each cylinder and the engine has only 1800 miles. The spark is strong and the plugs are new gapped at .32 and the engine does not appear to be running to rich. Any further suggestions appreciated....Thank You. supereal 04-06-2010 @ 10:57 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 It has been a while, so I will look up the carb and manifold we used. With any carb, particularly multiples, sizing the air flow, measured in cubic feet per second, is imperative to maintain adequate velocity thru the venturi(s). Use this formula: Multiply the displacement, in cubic inches, by the maximum rpm limit of your engine, then divide by 3,456 to represent volumetric efficiency. The result is the cfm the engine requires at maximum rpm. Then, choose a carb, or carbs, with the cfm rating closest to that result. There has been a prevailing theory the the more, or bigger, carbs would increase power and enhance performance. It just isn't so in the "real world". When an air cleaner restricts air flow, volumetric flow is altered. Stroker 04-06-2010 @ 3:20 PM reply profile send p.m. Senior Posts: 1460 Joined: Oct 2009 Deuceman: DEUCEMAN 04-07-2010 @ 6:29 AM reply profile send p.m. Member Posts: 17 Joined: Jan 2010 37 Ragtopman, I think you may heve nailed it, running too rich with air cleaners in place. The carbs were rebuilt by a "Stromberg expert" and I gave him the engine specs,cam intake etc, Perhaps he used too large jets. It's got to be a marginal problem as I've used several different air cleaners, some I thought offered very little air restriction but the only thing that works is either no air cleaners or scoops with screen mesh only. The difference is tremendous, it just dies above 2500 rpm with and pulls hard to 4500 without. I don't quite understand how very little filtration could cause such a large differance. Could fuel pressure be an issue? I have a stock fuel pump on the oil filler tube at the ens of the intake which has no guts and a electric 7 lb fuel pump hidden all with 3/8" SS fuel lines. I have a Purolater fuel pressure reducer set a 2 lbs as that's what the Stromberg guy told me to do to prevent leaks, could 2 lbs be too low given the size of the engine, 284 CI, the cam, the porting, the releaving and the headers, the large valves and all the rest? Again any help would be great as I hate to go off in too many directions at once.

<< previous || next >>

PAGE: 1 2 3

NOTE: YOU MUST BE A REGISTERED USER AND BE LOGGED IN TO POST (and reply to) messages in this forum. If you are a first time user, please click the CREATE A NEW ACCOUNT in the masthead above to register and Log In. After that, all you do is LOG IN to enjoy using this site.

DISCLAIMER: The V-8 Club does no independent testing of any of the opinions, thoughts or suggestions presented in the website on the Forum, in the Tech Tips section, or any section. A reader should consider the website to be a forum wherein differing solutions to a particular set of circumstances may be discussed. Ultimately, the selection of an item for an individual's vehicle must be based upon the independent study of the vehicle owner in consultation with people in the hobby and restoration experts.

EFV-8 Club Forum Home | Back to Home Page | Contact the Webmaster

Copyright © 2009 - EFV-8.org
Powered by < CF FORUM > v.2.1