Last Saturday, my son was out of town, so I took both the '57 and the Camaro out to the track for a "Club Clash" event. They have two classes with the break at 14.00 sec, so I've been running the '57 in the faster class and he's been running in the slower. This time, I drove the Camaro.

1st TT, no problems, good reaction time, good 60', good ET. 2nd TT the car pushed through the beams when I stalled up the converter, so that was a no-run. I checked the rear shoe adjustment and came up with a sure-lock way of staging before the 3rd TT. I was messing with the head of the guy that lined up with me for the 3rd run, so my RT wasn't that great but the run otherwise was okay.

1st round of elimination, I was lined up with a 90's Bonneville that dialed 16.57. I dialed a safe ET, and we both staged. When both staged lights were on, I stalled up the converter but the starter didn't hit the button right away - like 5 seconds after we'd both staged, so about 8 seconds between stalling up and getting the green. When I hit it, it just bogged dead, then roared away. Result was a messed-up RT, messed-up 60', messed up ET, and a loss to a .110 RT and 16.577 in the other lane.

I was so disgusted I've started watching 6210 Holleys on eBay. My son told me that night that i did it to him once this season as well. I think what is happening is on long stalls like that, the choke pull-off is unloading and allowing the AV to flop open when you nail it (had the same issue on the '57 several years ago when I ran an Edelbrock q-jet w/o the choke pull-off hooked up - except it did it all the time and not just when stalled for a long time), instead of opening gently and coming on smoothly.

If somebody doesn't stop me, I'm going to convert this thing over to a double pumper so I don't have to worry about this anymore. I'll just have to get a non-CC distributor (have one in the garage attic, but it needs help) and lock-up system for the TCC.

 

honestly, why not? they are simpler and easier to get power out of...sorry, i'm not stopping you from anything...i'd like to see you go to a holley, lol!

 

I went from a 750 vacuum Holley to the 650 DP I have on it now, BEST money I EVER spent on that motor, made all the difference. Granted when I street drive it the carb loads up a bit on long lights, but nothing reving it up can't fix.

I say double pumper it, but don't get the same size as the vacuum sec. you have, start smaller and jet the snot out of it.

 

Well, the current carb is not VS, it CC q-jet. The CC q-jet is ~795 CFM, the 6210 is 650 CFM, so that would qualify as "smaller".

And, the 6210 is not the "standard" Holley DP, it's a spreadbore. I would go that way so that I can retain the dual snorkel air cleaner since the dual snorkel air cleaner won't clear the standard Holley fuel bowls, and also because this is still my daily driver and I'd like to retain whatever fuel economy advantages that I can.

 

gotcha, but now won't you end up with codes because it won't have all the feedback from the CC carb??

 

On the up-side, you'd get to curve the distributor however you wanted. You already acknowledged the down-sides. I have no doubt you can get a TCC lockup to work easily.

Without reinventing the wheel, what level of idle vacuum is it holding? Are you using plain AVs or slotted ones?

Just thinking out loud, and I realize that you probably have the carb dialed fairly well, but a few options come to mind for the Q-Jet:

• There are different choke pull-offs. However, after that much time almost any of them will start to back off.
• Another, less desireable option would be to snug the AV spring a bit, but once those are set right, no one likes to start playing again. You'll want that opening once the revs start climbing.
• You could go to a secondary rod with a smaller major diameter so that initial fuel is richer to help compensate.
• Similarly, a taller hanger would get the rods rich sooner, but the taper is going to be critical at low AV opening.

A double-pumper would be the only way to go, since any vacuum secondary will have that tendency.

On a side note, just how much experimentation do you want to do?

 

If you really want to keep your EST, TCC and everything else from your ECM, you could try this:

http://www.becontrols.com/tech/tpsretro.htm

 

i daily drive my double pumper carbed motor and i don't have problems with it loading up at a stop light...

 

Plain AV's. Not even sure what slotted look like. I could go with a lower letter hanger, probably wouldn't adversely affect other operations but I doubt it would prevent the situation I encountered. The experimentation question is as much limited by "able" as "want".

One down-side to the Holley not yet mentioned - spending more money.

I have a 4150-converted 750 VS in the garage attic. It needs inlet nuts, springs & filters, and as already mentioned, it would require an open element air cleaner. But, I don't think it would have the same secondaries-opening-during-stall problem because Holley vacuum secondaries are opened via flow through the primaries, and RPMs wouldn't be high enough to do that when stalling up.

 

i run mine a tad rich to avoid problems and I have yet to fully tune it. Plus my cam doesn't idle to well for long periods of time.

 

Id go double pumper,
I have a 750CFM DP and I still get about 21 mpg (highway), and in town well,
a lousy 11mpg, but that's probabaly cause of the 6 speed, always shifting.
My carb works great, I have excellent idle and response.
Just spend yourself about 110.00 dollars on a Proform main body, and get some Holley billet metering blocks and that's it (the Proform metering blocks are purple, go figure).
My sparkplugs come out almost white all the time, and you can actually stand bhind my car without coughing or squinting your eyes because of exhaust fumes.

I'd go DP you can tune them a lot better than a Q jet style carb.

Thats just my opinion,

Thanks
Eric....

 

Eric, you need to read the contents of this thread a little more carefully.

First, the Holley DP I'm talking about getting is a spreadbore. Proform doesn't make a mainbody for that carb.

Second, if you read my sig, you'll see that the 396 in the '57 has a Proform mainbody DP on it. No need to try to sell me on it, I sold out a long time ago (like 2003).

In addition to all that, I want to keep the choke. I don't want to have to get out to the garage 5 minutes earlier in the morning so I can warm the car up enough to drive it without a choke in order to get to work on time.

 

If you had slotted secondary AVs, you'd know it. They would tend to make the situation worse, which is why I asked.

Check out the TPS on that "Holley" installation? You could probably keep the ECM and stock HEI that way.

The metering rods would be a bit of a band-aid. Anything you might do to the vacuum signal itself (like a check valve, orifice, etc.) would probably hurt you in normal operation, too.

 

Save yourself a lot of $$$ grief and bother by just changing your driving style during staging. launch it from an idle.
By raqising the rpms against the brakes during staging you're shortening the already limited accelerator pump plunger travel creating a leanout condition during launch.
You could readjust the accelerator pump linkage to allow a full shot during launch You would have to change the starting point of the shot and the linkage arm lever point to get a full shot of fuel off the line from a initial partailly opened throttle position.
(You can do this on a holley too).

Again I'd just launch 'er from a idle. Loading 'er up against the brakes probabily adds nothing to the performance or consistancy of this car at the drags.

 

So, according to Vader and F-bird, the problem is going lean, due to your secondaries opening while standing still (and not needing the air/fuel flow?), So you aren't pulling secondary fuel yet, but you are pulling secondary air sorta thing?

A few things I can think of off the top of my head (and you probably already know these Five7, from that Roe book...):

the secondary emulsion tubes - drilling small holes in the bottom help you "smooth the transition" into your secondaries. I'm guessing that would give you more fuel earlier? That's like the accelerator pump for the secondaries.
the actual physical orifice where that shot goes, is the small hole right above the front edge of the secondary air valves. I heard it's not too hard/uncommon to plug that hole with epoxy, and simply redrill it right below the secondary air valve blades. Lets it come online a little earlier.

And of course as F-bird mentioned, the acc pump itself. I know in the Roe book it goes over great detail about modifying it for more fuel volume, as well as duration. The easy mod is to simply grind ~3/32" off the top of the pump rod. That'll give a bit more volume/duration. You get a new one in any rebuild kit, so if you screw one up, or it doesn't work, it's easy to go backwards.

The problem happened during an extremely long staging eh? I guess modifying your choke pulloff to go even slower would have it's own side effects eh?

I apologize if these are obvious ones, just thought i'd mention them in case they weren't thought of.

 

losing '57 to the Non-CC Qjet world, would be like yoda joining darth vader.

 

I beg to differ. I have tried that - a decent RT is impossible, and consistency is DOA. In bracket racing, those two things are king.

I'm going to check the pull-off tonight with the Mity-Vac. It's possible it's got a leak, which would lead to this situation. The other possibility I'm considering is mounting a vacuum gage on the dash so we can stall to a particular vacuum rather than a certain RPM. This would insure that there is sufficient vacuum to keep the pull-off pulling and keep the AV from that initial snap opening.

To be honest with you all, I haven't dug into the Roe mods because this carb simply hasn't caused me any problems. Until now. . .

 

I took a quick look at it but didn't take the time to understand what they were talking about with their "TCS". I think I now understand that you're saying the remote TPS would provide the signal the ECM wants, and the ECM wouldn't care about the lack of an MCS to drive. If so, that would be fairly simple to do, and I don't have any complaints with the EST system currently on the car.

Now, for the really hard part, I'm still trying to find an electric divorced choke conversion to use with the 6210. . .

 

Again, how much experimentation are you willing to do?

 

This one SAYS it has an electric choke:

http://www.prostreetonline.com/buy/h...rs/hly-0-9895/

I'd verify that first. I also wonder if the Holley choke conversion kits would work with this carb. If not, there are other options.

 

Fiddling time is limited. I'd probably have enough to be able to verify it doesn't bog and the EST is working prior to needing it at the track, but that's about it. No track test time would be available most likely before it counts.

The 9895 does have an electric choke, but it's also a VS carb (the pic they show on the site you linked is of the 6210). $345.95 from Summit. I can't find the electric choke pieces for it anywhere except the cap (aka thermostat). The mount is different than the standard universal Holley choke - I think - can't really tell for sure. So, if it is different, it's back to the divorced choke, which I can't find in electric model, either.

 

This outfit Carbs for Cars & Trucks says they have a remote (divorced) to electric conversion for Rochester, and the 6210 is a Rochester replacement, but they don't have an on-line catalog. I sent them an inquiry, we'll see if/how they respond.

 

Well, sign off eBay. The choke pull-off won't hold vacuum. It will pull on fully with engine vacuum, but leaks right down with the Mity-Vac.

 

so what does that mean?

 

That means it releases too soon, causing a bog when you go WOT.

 

haha, looks like you don't get a new carb after all.

Going to just use a new parts store one, stock style, or the older faster pulloff style?

 

Parts store one for now. It looks like the orifice is at the end of the tube, so I may be able to drill it out if I want to. I'll pull apart the old one to see if that's the case with it - both definitely have a very small opening at the tip of the tube.

(If one of these eBay 6210's stays low enough, I may go ahead and get one and accumulate the parts to install it. Something about the challenge of a non-CC q-jet with everything else remaining CC that is almost irresistible).

 

If it's a plastic one, and the orifice is .015", then it's the modifiable style. All parts stores ones that i've seen have a "small", .030"ish orifice at the tip, which isn't the restriction. I had to drill into the side of it, to access the restriction, as Lo-Tec mentioned in a thread, a few months ago.

Well good luck with this, hopefully that was the only problem.

 

It's a metal one, and the orifice is much smaller than .030", and I'd guess even smaller than .015". I'll try putting one of my really small bits in sometime and check.

 

I thought I might pique your interest with that one. If you have a little R&D time with the car, it could be done. It sounds like the wheels don't stay still very long, however.

 

it's definitely hard to do R&D with a daily driver.

 

Well, several 6210 auctions ended over the weekend. Winning bids went from $41.20 (I got back to bid 2 seconds late on that one) to $150 (which doesn't make a lick of sense to me for a used carb, since somebody else is offering a guarenteed fresh rebuilt for $175). A few more are still up.

Yes, it is hard to do R&D on a daily. We'll see how the car does this weekend (if I race it - my son will be out of town again this weekend). I'm fairly confident the pull-off will have fixed the immediate problem.

 

Yup. That usually makes me forget about my problems, too.

 

Now, who said anything about "forgetting" problems, huh???

Anyway, I sniped a 6210 on eBay tonight. I'll start gathering the pieces, perhaps during a racing break of a week or two I'll give it a try. The choke is the biggest hurdle, being divorced-type. But, that outfit did invite me to call their 800 # and talk about it.

 

Once you get the squirters, venturi pods, air bleeds, accellerator pump strokes, jets, power valves, and linkages set up correctly, I don't doubt that you can tune out any of the bog off the line with the Holley. I'm a little concerned for your daily driving mileage and low throttle angle mixture control, however. Time will tell.

Yes, sometimes things like that can only lead to more problems. It likely depends largely on the identities of the "puller" and "pullee."

 

you know, i've still managed decent fuel economy out of my 4150 style carb...i'd say with it tuned properly (which i have no doubt that five7kid can do that) it'd probably run the same around town, but with more throttle response.

 

The fuel economy would probably not equal what the CC q-jet can accomplish, but it would be better than a 4150, most likely.

The eBay carb arrived, looks in pretty decent shape but in need of a rebuild - which I expected, and for which a rebuild kit is on the way. While looking for something to help another TGO member, I realized the divorced-choke electric conversion was under my nose all along Rochester Carb / Quadrajet Parts Page . I still need to call and talk to the other outfit. The remote TPS is almost $50, but that's probably less than what TCC lock-up and HEI refresh would run me.

 

Oh, the replacement pull-off did fine last weekend. Made it to the finals of "Club Clash" (8th round), where I took a dive for a fellow club member who is now #1 in individual season points (I'm not registered in the class the Camaro runs in - I made it to the quarterfinals in the '57 the same night in the class I've been running it in this year).