I got all the cooling issues under control on the wing/belly tank car. The engine is what I think is a stock V-8 60 with a Meyers dual intake with two Stromberg 81's. The engine starts up and idle just fine.it revs up ok in neutral and sounds good. This thing is very lightweight,about 1100 pounds. So today I rode it on the road,yeah no plates, lights and open exhaust. To put it mildly,runs like shit other than wide open throttle or real slow. The engine surges and misfires at part throttle, certainly seems too lean. The accelerator pumps push a nice stream of fuel,the main jets are maybe a bit small #39. But before I mess with the carbs again...a few questions....I'm thinking two 81's is way too much carb for a stock V8 60 and it'll never run properly at part throttle. Probably a very poor vacuum signal . Any opinions ???
stock jets for the 81 is .035 main and 71 power valve. 2 carbs is not too many, i run 3 on my 208 cubic inch model b engine, and it runs great
I have no idea.I build this car for my race bike rider on his dime. The engine was in a static non running display. I've messed around with Holley and Carter carburetors ........Anyway, I suppose blocking off one carb is easy to do. as a test.
If you block off one and it runs good, maybe try blocking off the other and see if it still runs good. Maybe one has a problem.
I ran it on the front carb only...much better. Then ran on on the rear carb only,the same ,much better. Hook up both carbs and the engine stutters and bogs when try to accelerate. I raised the float level slightly and that made a small improvement. The jets are 35's....Ran a .037 drill through the jets, very slight improvement....But overall goes lean until the power valve comes on with both carbs hooked up.... I have to say two 81's on this engine is too much...
I`m running 2 81`s on mine and it`ll smoke the tires. If you`re running a stock distributor, you may not have enough spark. I`m running an electronic Mallory distributor.
I did a homemade coil version on the stock distributor. I figure it has enough spark because it pulls ok at wide open throttle when the RPM get up. And it will spin the rear tire... This is not a high bucks project and engine is likely a bit tired so maybe all the variables are just lined up wrong....It's not a race car ,just a hillbilly toy for occasional back roads use.
Two 81's should not be too much for a stock V8-60 if they are jetted right, and you have enough fire from the ignition. If the carb jetting checks out somewhere close to stock, and both accelerator pumps are working, you probably have an ignition problem.
I run two 81's on my banger engines with no problems. Hard to believe they would be too much for a v8-60. There's obviously a jetting,power valve, or maybe a weak spark issue going on.
Yeah,something is lacking that's for sure. But it runs good at full throttle ,must be a race engine Surprising how nice it runs on one carb considering the the fuel/air distribution must be shitty with the carb on the end of the intake. .....The engine compression is even on all cylinders but only about 85 PSI...Once warmed up it does make some blue smoke when reved up, and some blowby....Oil pressure is 15 at idle and 35 PSI at higher speeds. The cylinder sealing is poor and likely that causing problems with additional carburetion.. The non traditional The Honda Civic 14 x 16 aluminum radiator with a junkyard Jeep Cherokee electric cooling fan maintains 160 degree temperature at all times according to the two temp gauges. The cooling system is two into one on the outlet and inlets for the engine.And the stock water pumps have to move the water three feet from the rear mounted radiator...And the pumps don't leak... The owner is out of money , it's been a bare bones project all the way ,hillbilly engineering using hand held tools.A lot of shit in a very narrow chassis to fit the F86 wing tank. It goes down the road straight ,steering brakes and gear shift work as they should.
"The owner is out of money" Never good. I used to tell my customers of this type, "no tickey, no laundry" don
The owner is my race bike rider and friend..... I've built a few old Chevy trucks but never a car like vehicle completely from scratch with no plans...He gave a bike worth about three grand for my labor and he paid for the parts. I gotta say driving this thing down the road at 50 MPH sitting on wood slats tie wired to the frame and the open exhaust barking made me smile...
I assume you did syncro the carbs and are not running any kinda filter in the frog mouths Also maybe your fuel tank should be re evaluated put a pump on it not just gravity feed, might be starving under load
Yes,an attempt was made to balance the carbs....While the fuel delivery is caveman,the engine runs ok at full throttle and idle.The poor running is from about 1000-3000 rpm at part throttle. The spark plugs show a rich condition with the very tip of both electrodes clean...There's no backfiring or popping out the exhaust or carbs.The problem appears to be worse once the engine is full warmed up. Perhaps the carbs go into a super rich condition at part throttle...But running only one carb either front or rear and it's fine... I'm not saying the ignition is perfect but pull off a plug wire while the engine is running and slowly back it off the plug terminal and it throws a snappy blue spark for a good 3/8 inch before that cylinder misfired. there's no money money for $400 ignitions or local wizards to solve the problem...I just have to keep at it.. Shit, I can build the fastest stock frame 650 Triumph bike in the USA, I should be able to fix this flathead V8
Are you running progressive or direct linkage? If it runs good on one carb, maybe progressive linkage will help. Don't bring in the second carb until you are way into the throttle.
Both carbs open together. I thought about progressive linkage but with each carb sitting on the end of the intake the fuel fuel/air distribution would suck. I didn't get out on the road with one carb yet.but a test ride on my long dirt driveway says it runs better.
I am not familiar with 81s but I am very familiar with running dual carbs. If the carbs have Accel pumps it could be a simple as they are too much so any time you move the throttle they squirt and the V60 doesn't need that much. Just for trial I would try disabling one accel pum and seeing of it made a difference. If it was positive then rework the carbs (both) to reduce pump to about 1/2 output which would be the equivalent of the output of one carb. Might be a total waste of time but it is what I would try. Full throttle is good (no pump squirting there) idle is good(no pumps squirting there) ( Your Amals don't ever squirt on your bike.) Anyway something to try that costs zip and may offer a cure. And if it doesn't work you are just out a few minutes work. don
Jets are likely not even relevant at this stage of tune...at low speeds, your engine is running mostly on idle and off idle ports. I would start with cleaning the whole idle circuit from idle jets though base passages very thoroughly. Then double check fuel level. I would guess that your little engine is not running entirely on mains until fairly high in its curve, maybe close to 2,000 even. It has to be moving a fair amount of air to get venturis involved.
hey bruce, I was thinking something very similar... maybe pulling on the mains earlier when he switches to a single carb?? his pilot jets could be pretty well plugged up as not many people do the work to pull them when they clean the carb....
I've had the carbs apart a few times. I made sure the idle port and transfer port hole is clear. Made sure the main body passages are clear,pulled the emulsion tubes and checked them. Used carb spray to observe flow and blew it out with compressed air. I checked for warped mounting surfaces. these carbs were clean inside, and the gaskets look like new. The floats were set wet as described in manuals. The accelerator pumps shoot a good stream of gas. #71 power valves The engine starts instantly and idles ok. with both carbs hooked up.If you rev it up in neutral it stumbles a bit then revs up.With one carb you snap the throttle wide open and the engine responds cleanly. With two carbs it runs like shit on the road, hesitates,stumbles, misfires just like an engine looking for fuel.....Go wide open and it runs a bit better. once the rpm comes up...The temporary fuel system is a gravity feed you see in the photos. There's no smoke or smell to indicate an over rich fuel mixture. It'll sit there and run at idle or a fast idle real nice for as long as you like. Engine temperature is 160-170 with a gauge to each head. But...It has the stock exhaust manifolds but no exhaust system....I have run many other engines before dumping right out of the manifolds and it didn't affect the running..... If I had a a stock intake it would be swapped out right now and be done with it I have another thread on the distributor .....
Sounds like you know your way around a carburetor. I would do a quick test of extremes as a sorting tool: 1. Runnitup through problem zone with accel pump links removed. 2. Run it repeatedly through trouble zone while pulling chokes more and more...rig up a wire or something, I'm guessing the thing wasn't built with snow time in mind! 3. Leave carbs alone, advance timing by 2 gradations on the side scale, see if low speed advance is inadequate to deal with things. This stuff should make something much better or much worse... I think I have a modified 60 single around here somewhere, but that's a chicken way out...
You have probably identified the issue when you said that you have 85psi compression and the engine runs worse when it warms up. 2X81s is something that a healthy V8-60 can handle just fine, but you should have at the very least an even 100psi. I changed that twice from 115 to 110 to 100, that is truly a minimum. With blue smoke as another indicator, you need to check the bores and at least put some new rings in there. Or, alternately, if you did already (I don't remember, getting old), run the engine for several hours at low rpm to seat them. With decent compression and white spark a 60 will run well with 2X81s. Greg in Jax
With two carbs it runs like shit on the road, hesitates,stumbles, misfires just like an engine looking for fuel..... can you hook up a fuel pump up to her she might be starving under load
This engine was half ass rebuilt by someone else.It has good oil pressure but not the best cylinder bores. I did a compression check on a warm engine earlier but not since running it down the road. I'll check it again..Considering the guy who I built the car for is low on money ,a single carb set up might be best option... It does run better at once the RPM get up.... There's a slight delay due to my stupidity....I took off the distributor to inspect it closely and next thing I know it's laying on the floor with a cracked mounting ear.....a replacement distributor housing is on the way.
I had the same issue on my 283. Idle was good, full throttle was great, in between sucked bad. My fenton 3x2 hated straight linkage, especially with idle circuits running in all three carbs. Blocked the idle circuits in end carbs and went to progressive linkage and it made a world of difference.
The distributor is back in...It starts right up,idles ok but still runs shitty with two carbs hooked up. Still runs much better on one carb,front or rear. Looking down the carb throat while the engine is running at a steady 2000 rpm it sure looks like too much fuel coming out from the venturi cluster. The plugs are sooty black....I checked the wet float level and lowered it a bit,still the same. fuel PSI isn't an issue with the temporary gravity system. While the engine is running at 2000 rpm,pinch shut the vacuum spark retard line causes a drop in RPM.So it works ok. With the engine fully warmed I checked the compression, throttle open, all plugs out and the engine spins fast with the 6 volt starter on 12 volts. Compression is between 80-90 PSI on the fourth pump on all cylinders. With the engine running shorting one plug wire at a time doesn't give the RPM drop you might expect. There's too many border line issues going on at the same time here....The owner is sorta out of money...I told him the best bet is to find a stock intake so the engine will be at least useable for a toy because it does start, idle and run ok with one carb.... Including what he paid for the engine,two axles , F-86 wing tank and all the parts new and used, he's got nearly 8 grand into this car including my 2500 bucks for labor. It goes down the road quite nicely but at best it's just a play toy. These kinda projects you need to build yourself or the cost is totally fucking ridiculous for what you get.
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