Holley 470TA Tuning

Got my misfire straightened out:
http://www.earlycj5.com/forums/showthread.php?t=45662

Now I'm driving the Jeep and seem to be running out of gas under load in the 1500-2500 RPM range. Acts like vacuum leak, but all new gaskets, everything torqued down and/or plugged. I seem to have a lean condition. Where is the first place I should look? Wikipedia showing Lawrence, KS is 840ft above sea level. First time I've ever worked on a TA. Here's the instruction manual:
http://www.holley.com/data/Products/Technical/199R10268-4.pdf


Update - Standing there with the timing light in one hand and throttle in the other; is it possible this carb is giving me too much vac advance? I thought the advance would be based on the motor, not the carb. It is definitely putting out a ton of advance. How would I adjust this?

 

This is a 470 on a 225? Unlikely that it's too lean - pretty big carb for a 225. The factory settings from Holley usually get you in the ballpark very reliably. This is a new Holley, yes? If anything, you might have too much fuel for the engine.

As I understand it, the TA is a 4150 with bowl vent and float damping add-ons. If it's like a 4150, you need to adjust the main jets, float level, power valve, pump shot and idle mixture ... that's about it. There are instructions for "sizing" your power valve on the Holley site. Too much pump shot will make a blast of black smoke or a stumble, but not lean at constant speed. Main jets are probably too large considering the plug pictures you posted earlier.

 

Forget my previous comments in this message - you probably have low vacuum, not high, due to the large area of the venturies. Maybe that means that your power valve is not opening at mid throttle. Do you have a vacuum gauge?

Others who have used this carb could comment - who is our CO member with the red flattie in his sig? Warlock?

 

You should check the advance with the vacuum line disconnected, at idle. Normally you would connect the vacuum advance line to ported vacuum, from the base of the carburetor. If the idle is set right, this should be zero vacuum at idle.

 

Yup. That's what I got.

I think you're right, Tim. I drove it in to work today and got to open it up a little on the big road. At least I tried. V6 might as well be trying to drink from a fire hose. At one point I think my eyes started burning. Ah, well. Time to learn how to set jets.

Warloch, you around anywhere?

 

Turns out that part of the problem - by no means all of the problem - was that I had a, ahem, "case of really bad gas." (alright, go ahead with the jokes) All kidding aside, even though I drained the tank out best I could, there were still some remnants of 7 month old gas in there that was mixed with only about a gallon of fresh stuff. I ran the tank out on the way home from work today and switched over to the rear, which is all pretty much fresh. Immediately I noticed a difference. Hmmm... So I pulled into the station and put a couple gallons of fresh stuff in the other tank, which was now bone dry. Fired it up and it is at least driveable, especially at lower RPM. I'm still getting a lot of popping and sputtering at high RPM, especially during acceleration under load, but I think for the trails tomorrow it should be okay in low range. Definitely need to jet down.

 

Finding more little things. Last fall when I took the motor apart, I was getting quite a bit of smoke out of the pass side exhaust. Oil would shoot out on start up. Hypothesized that it was bad valve seals. When I started the motor for the first time this spring, no smoke out of the exhaust, everything seemed fine. Well, then the plugs fouled. Then I started noticing smoke out of the valve cover breathers. Ran it by the machine shop that's done a bit of work for me and the guy immediately starts saying blow-by. WTF? All six rings go bad just from sitting over the winter?!?! So I start retracing my steps. Cut to the chase, I pull out the leftover parts from my Melling oil pump rebuild kit and realize I put in the wrong spring - 70lb unit installed. So, put in the 40lb spring, and noticed a slight improvement, especially at idle. Still sputtering and popping, but I'm pretty sure it's because all six plugs are already fouled again judging by the amount of smoke coming out of the breather. Anyone experience this before?

 

so your saying your new set of plugs have fouled.

two years ago i put a holley 390 on and last year put a 470 on.

i found there was some vary noticeable differences between the two. first the 390 was easier to tune and second the large difference was in low end torque where the 390 made much more. on the opposite side the engine would gain rpm more rapidly with 470.

now for tuning. i would start with a 52 jet in the primary, put the accelerator pump cam in the number two position. drive it at a steady 40 to 50 mph for about 15 minutes and check the plugs.

if your fouling plugs at idle jets will not make any difference as you must re work the ideal circuit. first i would close the secondary butterflies, then drill a one sixteen hole in each of the primary buttery flies. then use some 14 gauge wire strains and put then in the ideal circuit holes in the metering plate. this will reduce the amount of fuel flowing in the carb at ideal.

there is alot of info on the web about tuning the holley carb. do a search and drink a few beers while reading much to be learned....... good luck

 

What's your elevation? I'm at 840ft, but I've seen the barometer read as high as 2000 due to the humidity and air density of the weather coming out of Colorado.

I stopped by the speed shop today and got a set of 53, 54, and 56 jets (57 stock). That's all I had to choose from. I'm thinking 53 in the primary and leave 57 in the secondary.

Is there a good write-up somewhere to swap these jets, or can you walk me through it? I was really hoping Warloch was going to save my butt right about now.

 

Man, that couldn't have been easier. I love this Holley carb! I think I was sweating over nothing. Took me about 10 or 15 min to do both sides.

I went with 53 primary, 54 secondary on account of that's all I had available right now. What a HUGE difference. I'm definitely getting there. Wmunny, I think you may be right on the money with that 52 jet. Will have to see after the holidays. Still have a little bit of popping, but I've gained so much in throttle response.

 

first off. are you sure your carb came with 57 and 57 jets. holley has used about three different combination that know of. my spec sheet that came with the carb listed the jets as 54 and 61. when i pull the carb down it had 54's and 57's and a .031 squirter.

pretty sure that a 53 will still be a little large. i would also change the squirter to a 27 and put a black spring in the secondary diaphragm.

it's also very important that the float levels are correct. if your running rich lower then a little sometimes it will help.

to change the primary jets; disconnect fuel line, remove lower right fuel bowel bolt and have small cup to catch the fuel from the bowel, remove the three other bowel bolts. bowel will pull off now, the fuel tube to the secondary will either come off with bowel or remain in the secondary bowel, when you reassemble put some vaseline on the rubber gaskets. now that the bowel is off the jets are right in front screwed into the metering block just unscrew and put the new jets in. clear as mud

i'm at 100 to 500 feet elev.


here's a link with some helpful hints and advise http://www.bob2000.com/carb.htm

 

see you post while i was typing.

the 54's are to small for the secondary as there is no power valve in the secondary stay with the 57 or a 59 to 60 should be about right and use the black spring. good luck

one more quick thing. if your a little rich for the next few days add two or three degrees of timing this will help compensate for extra fuel

 

Mine definitely had 57/57. I didn't check the squirter as that part wasn't even available to me at this time, but stock is supposedly 25, not sure if that's a Holley part number, or .025.

I've got decent low RPM and decent WOT now, but the 1500 to 2500 range still seems rich with a lot of popping on decel.

 

225 V6, 252H cam, Offenhauser 360, Holley 470TA, stock ignition.

Still playing with Jets. I went as lean as 50 primary 52 secondary. Primary was lean at that point, but not too bad. Secondary was fuel chopping really bad under load. Right now I'm sitting at 51 primary, 54 secondary. I think the primary is really close; I'm probably splitting hairs, but I might try 52 again just for comparison purposes. I think I definitely need to go up 1 jet size on the secondary to 55. It's great under 45mph, but I feel like I'm starting to run out of gas on the big road around 70. I definitely don't want to run it lean at high RPM for long highway cruises. So, this would put me at a 4 jet size difference between the primary and secondary.

Out of curiosity, what is the difference between jet sizes that some of you other TA owners have installed in your carb? Interested mainly in 225 owners. TIA.

 

Absolutely 100% positive. A couple weeks ago I was out visiting Sparky and started having some carb malfunctions. Basically, I had idle and WOT, but nothing in between. I could sit at a stop light, but when I took off it would start to stall, put my foot to the floor and it would go like a raped ape.

Pulled over on the side of the road and found this in my primary bowl:


Jets were so clogged that there was NO fuel passing through the primaries. Float was encased in gunk.

During tuning, I can decrease the secondary jets and get a noticeable fuel chop at mid to high RPM under load. Go the opposite direction and I can get the motor to bog down at mid to high RPM under load.

I'm definitely using secondaries. I was planning on swapping out the secondary jets later tonight. I will see if I can stand over the carb and watch it. With no load, not sure what it will do, though.