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Discussion Starter #1 (Edited)
Because I dont think ours is opening up on our 63. I have only ever run double pumpers so this carb is new to me. We picked it up from a guy we know that said it sat for about 1 1/2 years.

My father said in all of his previous cars (70 chevelle, 66 malibu, 455HO TA) he could hear the 4 barrels open up and it felt like a new gear on all of those cars. Our 63 doesnt feel that way at all.


Happy easter everybody!
 

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You might not be able to see the secondaries open up by just blipping the gas while the car is running, parked. Without a load on the engine, the secondaries may not have the correct vacuum to open. Hopefully someone else will chime in here and give you a better explanation than I did.
Ron
 

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Discussion Starter #4
The tranny kicks down just right. We have a lokar kickdown cable on it and got it adjusted good. That aspect actually works really good.


63 Chevy II 2500 pounds
355
fully ported 2.02 double humps
lunati voodoo cam
* Advertised Duration (Int/Exh): 276/284
* Duration @ .050 (Int/Exh): 233/241
* Gross Valve Lift (Int/Exh): .504/.525
* LSA/ICL: 110/106
* Valve Lash (Int/Exh): Hyd/Hyd
* RPM Range: 2200-6400
* Includes: Cam Only
11:1 compression
TH350 trans
3000 stall converter
4.88 gears
31" tall hoosier pro street tires


I talked directly to Howard that designs lunati cams and told him my combo and he recommended this cam and said I should be looking at 400 to 425hp with that combo even with the double hump heads. He said some good 195 aluminum heads would bump us up to 450+.

Well no way is it making that kind of power. I just feels flat like the secondary's dont open. In a 2500 pound car it should get up and move out really good with that combo but it doesnt. Its not bad but not nearly what it should be. My bone stock 99 SS camaro would beat it in a race and thats only a low 13 second car thats rated at 325hp and 3500 pounds.
 

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the only way to find out is to take some where you cant test it. i would shift the trans manually though due to the fact the kickdown would come on. you may have to change the secondary spring in it ( make it easier for them to open) i was wondering why you dont put a duoble pumper back on it. i understand you will loose the kickdown. but with 4.88s and a 3000 converter in there you dont really need it imo........... imo a double pumper is easier to tune than a vac secondary carb you dont have to play with vacume with a double pumper. i do know some guys can run them and tune them very good just my 2 cents and my opinion :yes:
 

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Most of the time you can't feel them open. If they open too fast it will normally bog because the rear barrels don't have an accelerator pump. Make sure the front barrels open all the way. If they don't then the rear can't open all the way either. Then use something to mark where the rear barrels are at idle run the car against a load at full throttle. If the mark has moved then they have opened to that point. I saw it done with a bread tie in the rear slot. When the rear opened it moved the tie to the point of the greatest opening.
 

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Discussion Starter #7
Most of the time you can't feel them open. If they open too fast it will normally bog because the rear barrels don't have an accelerator pump. Make sure the front barrels open all the way. If they don't then the rear can't open all the way either. Then use something to mark where the rear barrels are at idle run the car against a load at full throttle. If the mark has moved then they have opened to that point. I saw it done with a bread tie in the rear slot. When the rear opened it moved the tie to the point of the greatest opening.
It has a slight hesitation any time you kick it hard.

I guess I will have to tinker with some different secondary springs. I wonder if the diaphram could be busted or dry rotten? Maybe I will pull it apart and take a look.
 

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If you can hear or feel the fours opening, then your carb is not tuned correctly. That feeling you feel is a hesitation, a slight one before the mixture gets right again. The power should come on smooth and evenly. You need to check to make sure the secondary's are opening al the way. But like stated above, with 4.88's and a 3000 convertor, you need to lose the vac. secondary and put a double pumper on there. Kick down cable? What's that? That's what they make a shifter for. Get rid of the cable, and when you need it, reach down and jerk that shifter back a notch.

Also, are your heads professionally ported or did someone with a grinder just hog them out. If they weren't professionally ported, they may not be any good. Heads can be turned into worthless junk pretty quickly if an inexperienced home porter gets too excited with the grinder.

Also, do you have your distributor curve set up properly? What's your total timing? At what rpm? What's your initial? How's your fuel pressure?
 

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one way to tell if the secondaries are opening is to fit a paper clip on the secondary linkage rod slid up tight under the diaphram,
make a full throttle pass, then check the paper clip to see how it's moved down the linkage, thats how far they've opened.
 

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Discussion Starter #10
If you can hear or feel the fours opening, then your carb is not tuned correctly. That feeling you feel is a hesitation, a slight one before the mixture gets right again. The power should come on smooth and evenly. You need to check to make sure the secondary's are opening al the way. But like stated above, with 4.88's and a 3000 convertor, you need to lose the vac. secondary and put a double pumper on there. Kick down cable? What's that? That's what they make a shifter for. Get rid of the cable, and when you need it, reach down and jerk that shifter back a notch.

Also, are your heads professionally ported or did someone with a grinder just hog them out. If they weren't professionally ported, they may not be any good. Heads can be turned into worthless junk pretty quickly if an inexperienced home porter gets too excited with the grinder.

Also, do you have your distributor curve set up properly? What's your total timing? At what rpm? What's your initial? How's your fuel pressure?

We actually have a full manual valvebody waiting to go in the car soon. We will eliminate the kickdown when we do that.

We have a tunnel ram at the powder coater right now and 2 holley 600's to top it off with. This will also be going on in the next few weeks. This was purchased as a combo type deal.

The heads were done by one of the best head guys around here. He told us double humps have a certain way they like to be ported and that most shops dont know the tricks to double humps. We had him completely redo the heads and set them up for the cam.

The distributor is a mallory unilite and it is set at 38* total all in by 3000. I dont remember off the top of my head what the initial timing is set to. Fuel pressure is steady at 7 pounds via the autometer on the hood.
 

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Is the transmission fresh? Sometimes they can slip a little and the car will feel fine when driving, even chirp the tires on upshift, but just not pull right.
 

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Discussion Starter #12 (Edited)
Is the transmission fresh? Sometimes they can slip a little and the car will feel fine when driving, even chirp the tires on upshift, but just not pull right.


Yeah its pretty fresh. Maybe 1000 miles on it over the last 8 years. If it was slipping it would wing up quickly but it doesnt.


Here is a short little video. This is in my parents neighborhood so I didnt hammer it 100% but that was probably 75%.




http://vimeo.com/1855218


This is the combo we bought from a friend. The same guy sold us this car. This tunnel ram was on the 327 he had in the car. VERY similar engine combo (he had double humps also and similar cam and compression) and this tunnel ram and carb setup and the car flew. I had to do a ton of stuff to it. We got it as a roller and I rebuilt the entire steering and suspension in the front. The entire brake system and I built the motor and we already had the trans. The car was tubbed already (old school tub with leaf springs) but the 9" was not cut so it had some nasty wagon wheels that were widened in the back. We cut 10 1/2" off each side and got new moser axles and new wheels and tires for the back.


 

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as stated above .. the 3310 is a very smooth transition .. usually best suited to mild street cars.. There should be no carb sound..... I doubt very much you could hear a carb over the exhaust note....unless your very stock and very quiet exhaust system...


the Classic ... BBbbbaaaawwwwwwww was from the flipped upside down air cleaner lids on the Qjets..... to create a open element type of air cleaner ........ was very common in the 70's
 

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Yeah its pretty fresh. Maybe 1000 miles on it over the last 8 years. If it was slipping it would wing up quickly but it doesnt.


Here is a short little video. This is in my parents neighborhood so I didnt hammer it 100% but that was probably 75%.




http://vimeo.com/1855218


This is the combo we bought from a friend. The same guy sold us this car. This tunnel ram was on the 327 he had in the car. VERY similar engine combo (he had double humps also and similar cam and compression) and this tunnel ram and carb setup and the car flew. I had to do a ton of stuff to it. We got it as a roller and I rebuilt the entire steering and suspension in the front. The entire brake system and I built the motor and we already had the trans. The car was tubbed already (old school tub with leaf springs) but the 9" was not cut so it had some nasty wagon wheels that were widened in the back. We cut 10 1/2" off each side and got new moser axles and new wheels and tires for the back.


umm,,those look like mechanical secondary 450's like i had,
 

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I spent a year tuning a vs holley 750 on my engine pulling 7.5-8" of vaccum and found that you need to run a 50cc fuel pump on the primaries to get rid of the hessitation, next get a quick change kit on the secondaries and take the check ball out of the diafram housing. it was hard to tell if mine was open too but i got it licked. you could also buy a rod that converts it to mechanical.
 

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imma VS fan

i like the VS carbs myself. Yes they are a lil harder to get to work , but i had a couple of them that really worked good. I never really heard the secondaries kick in , but the car just ran faster as i kept changing the springs in the vacume canister.


Its hard for any carb to live up to the reputation of a Qjet for sounding like its gonna suck the hood through the carb. A 500 holley 2 barrel has a nice roar too.

I had the same tunnel ram set up a while. Mine drank gas but it did wake it up. Looking back , i think it might have done better if they were converted to adjustable idle mixture metering blocks , and blocking the constant feed port in the secondaries
 

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Yeah those aren't on the car yet. Here is whats on it right now.


I like vac sec carbs too. Never had an issue with them. I always used the yellow spring and took out the little check valve in the diaphram. On the drivers side of the carb you can see the rod that hooks the primaries to the secondaries. Put a small bolt/nut so the linkage will force the secondaries open like a double pumper. Drive it this will show what the engine will feel like with the secondaries opened early. All that air with no air speed and no extra fuel should cause a lean condition for a moment.

P.S. nice looking engine!!! I hope that POS fram filter was only used on break in!!! Get that junk off there!
 

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Discussion Starter #19
I like vac sec carbs too. Never had an issue with them. I always used the yellow spring and took out the little check valve in the diaphram. On the drivers side of the carb you can see the rod that hooks the primaries to the secondaries. Put a small bolt/nut so the linkage will force the secondaries open like a double pumper. Drive it this will show what the engine will feel like with the secondaries opened early. All that air with no air speed and no extra fuel should cause a lean condition for a moment.

P.S. nice looking engine!!! I hope that POS fram filter was only used on break in!!! Get that junk off there!

Thanks for the tip!


HAHAHA you got it on the fram junk. Used it for break in then switched to wix. didnt want to waste a good filter on break in and I figured the fram junk would be good enough for 20 minutes. :yes:
 

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Discussion Starter #20 (Edited)
Your not going to believe this. I finally got a chance to look it over and come to find out the throttle is not opening all the way. I could have sworn when my friend and I put the motor in that we double checked that. It is only opening about 3/4 of the way.

I guess I need to get my butt back out there and try to get it adjusted and see what this thing can really do.


EDIT: Update! Jesus christ I never thought it would make THAT much difference! Got it adjusted and took it for a drive and opened her up and it screamed. It fried those big huge hoosiers an easy 400 feet before I had to let off of it! Before it would only go about 15 to 20 feet and that was it!
 
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