| DEUCEMAN | -- 04-05-2010 @ 7:48 AM |
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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....
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| supereal | -- 04-05-2010 @ 8:45 AM |
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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.
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| carcrazy | -- 04-05-2010 @ 3:08 PM |
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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.
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| ford38v8 | -- 04-05-2010 @ 8:18 PM |
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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
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| 37RAGTOPMAN | -- 04-06-2010 @ 6:08 AM |
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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
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| Stroker | -- 04-06-2010 @ 6:41 AM |
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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.
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| DEUCEMAN | -- 04-06-2010 @ 8:09 AM |
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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.
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| supereal | -- 04-06-2010 @ 10:57 AM |
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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.
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| Stroker | -- 04-06-2010 @ 3:20 PM |
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Deuceman:
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| DEUCEMAN | -- 04-07-2010 @ 6:29 AM |
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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.
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| 37RAGTOPMAN | -- 04-07-2010 @ 6:59 AM |
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hi I would try raising the fuel pressure to 4 lbs and run the fuel line around the dummy fuel pump and see what happens, you are feeding 3 carbs and need volume of fuel, and do not need any restrictions, what size line coming from the fuel tank, are you using the stock 1/4 inch line ? you also may have a exhaust problem, you need some back pressure for the whole thing to come into play, are you running mufflers.? I assume you are using DUAL Headers PIPES, I had a VW BUG with extractor exhaust on it and rebuilt the carb, and it had a bad flat spot in it, and the only way to get to run right was to install the stock exhaust system back on. I was working in a VW dealer and could not rejet the carb,to a larger jet, was restricted to do so, I doubt this is your problem, I have duals on my 37 with 1 baffle in the mufflers and single carb and it runs perfect, hot rodding is harder then you think it it is, you will get it right, just keep plugging away at it, hope this helps, 37RAGTOPMAN LETS HEAR HOW YOU MADE OUT,!!!!!!!!!!
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| RandyP | -- 04-07-2010 @ 7:22 PM |
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Baxter Ford told me that you have to run K & N air filter elements on the big cube motors, they are much less restrictive than regular paper elements.
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| 37RAGTOPMAN | -- 04-08-2010 @ 12:42 PM |
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hi DEUCEMAN I gave this some thought, and am diving in, you have reached maxium cubic inches, I think at high engine speeds with normal air cleaners does not let enough air into the engine,and restricts the air flow, causing it to act like or sort of a choking action,and runs rich and make the engine bog down, you said with air cleaners removed runs good, like the Randy before me said, you will probably need to run with K and N,AIR FILTERS or similar air filters,it would worth a try, CAN YOU POST A PICTURES of your 32 ? would be nice to see it, right guys,,,,,,,,,,, There is Nothing FINER then a DRESSED UP FLATHEAD FORD V8 hope this helps 37RAGTOPMAN This message was edited by 37RAGTOPMAN on 4-8-10 @ 12:57 PM
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| supereal | -- 04-08-2010 @ 1:07 PM |
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I still haven't had time to look up the carb and manifold, but will do so ASAP. We have always used progressive linkage on multiple two barrel carbs to prevent too much intake all at once. I've attached a pic of the hot rod engine we built with the 4 barrel that works so well.
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| supereal | -- 04-08-2010 @ 1:10 PM |
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Here is another view.
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| supereal | -- 04-11-2010 @ 10:59 AM |
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Sorry to be late with this info. The manifold shown is a vintage Edmunds piece. The carb is a 300cfm Holley with a mechanical secondary. You will note that the engine has the later "posthole" distributor, so vacuum for the advance is drawn from the carb. To fit the 4 bbl carb to the old manifold, we had to make an adapter. Flathead 4 bbl manifolds are available from a number of sources that will not require an adapter. The venturis in the 300 cfm carb are very small, allowing good low end performance. When at speed, the secondaries open when there is adequate manifold vacuum to to prevent swamping and loss of power as the carb capacity increases.
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| DEUCEMAN | -- 04-16-2010 @ 4:53 PM |
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SORRY NOT TO GET BACK TO YOU GUYS SOONER, BEEN TRAVELING ON BUSINESS. LAST NIGHT I GOT BACK INTO MY GARAGE, CHANGED THE OIL AND FILTER, SOME OTHER SPRING MAINTENCE. I WOULD POST A PICTURE OF MY HIBOY AND ENGINE, IF I KNEW HOW? MY SON HAS A DIGITAL CAMERA, HOW DO YOU DO IT. I INCREASED MY FUEL PRESSURE TO 3 LBS, UP FROM 2, NOW I HAVE TO FIND OUT WHAT THE CARB REBUILDER USED FOR JETS. TIMING IS SPOT ON AND IT DOES NOT APPEAR TO BE RUNNING RICH. NO VACUUM ADVANCE, ONLY MECHINICAL. THIS ENGINE RUNS STRONG, PULLS LIKE A SMALL BLOCK, EXCEPT WHEN THE AIR CLEANERS ARE ON..SPARK PLUGS READ OK, COMPRESSION VERY GOOD.I HATE TO REMOVE THE CARBS AND SEND THEM BACK TO THE REBUILDER ONLY TO HEAR THEIR FINE.. I INTEND TO GO THROUGH EVERYTHING AGAIN TOMORROW. BY TH WAY DOES ANYONE KNOW WHAT IS THE BEST TRANS LUBE TO USE? I'M RUNNING A '39 BOX WITH LINCOLN 25 TOOTH GEARS, ALL SUPER INSIDE. SOME SAY SYNTHETIC, SOME SAY NO, THE OLD SYNC RINGS DON'T WORK WELL WITH THIN SYNLUBE AND THE TRANS WILL JUMP OUT OF GEAR AS WELL USING SYNLUBE. CURRENTLY I'M USING THE FORD 600 WT LUBE THAT HAS BEEN AROUND FOR EVER, BUT IF SYNLUBE IS BETTER, MAYBE. I'M USING THE 600 WT FORD LUBE IN THE REAR AS WELL, A 39 BANJO WITH 4:11 GEARS, AGAIN EVERYTHING IS NEW INSIDE OF THE REAR..
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| 39 Ken | -- 04-17-2010 @ 5:24 AM |
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I think RandyP nailed part if not all of your problem. The air cleaners of today are manufactured "Off shore" and are too restrictive. As mentioned, K&N filters are the way to go. Also, you shouldn't be using 600 weight oil for anything except to re-coat your asphalt driveway. Drain it and replace with a 140 weight, GL-4 gear oil. It is heavy enough to not leak much(all Fords leak some) and is the proper lubricant for your trans and differential. This is a normal weight for warm weather driving. Use 90 wt if you're driving in cold weather. I use Sta-Lube 140, GL-4 that is available thru NAPA. Just my opinion. Ken
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| supereal | -- 04-17-2010 @ 7:57 AM |
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If your transmission tends to jump out of gear, usually second, almost always it is due to a bad bearing, either at the end of the case or inside the cluster. Occasionally we find that the tranmission input shaft is a bit off center due to a mismatch between the engine and transmission. Also, be sure that the forks and detents are in good condition, and the linkage is properly adjusted. The type of oil doesn't affect staying in gear.
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| 37RAGTOPMAN | -- 04-17-2010 @ 8:55 AM |
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DEUCEMAN on the pictures you have to download to you computer on a photo program this should have come with the camera, [ you can either use a USB port with a cable and if you computer has a media card port you can use that also,] it will ask you were do you want to store them, you have to put them in a folder, PUT a name on folder it were you can find later on, on uploading to this web site, it says browse, you pick the photo out of you folder you gave a name to and will up load and post the pictures for you, once you do it, it will get real easy, hope this helps,37RAGTOPMAN , TIP use the E-MAIL MODE on the camera,when taking the picture,.it might be not as good, but will upload easier, later on you can try more pixles for a better picture, but e-mail is pretty good,
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| supereal | -- 04-17-2010 @ 3:27 PM |
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Most digital cameras produce a huge sized photo, too large a file for most sharing. If you have a "photoshop" program, such as Adobe, reduce the size to less than a full ordinary page (8X10) and use the "export file format" to transfer them to JPEG compressed format, and store as a file. If you want to attach the photo to the Forum, click on "browse", select the file, and just click on "open". It is simple, and can be done with photos, scans, etc.
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