This winter I installed a set of Vortec 062 heads and performer intake on my new 350, and have hedman headers and exhaust, auto, and I still have the cc Qjet system. I have the primaries about tuned in, or close enough for now. The problem is, it doesnt seem to have any top end. It's just flat. From a start if I punch it, it will break the tires loose easily but once it hits about 25-3000 rpms, its just flat. I have B hanger and CK rods. Can anyone help out here, I dont see any reason why it would just fall on its face...Seems like the old swirl ports had more top end than these.....Actually, I think they did.
Timing is set at 8* advanced

Just bought a set of Bosch spark plugs for Vortec heads, I didnt realize before that I needed different ones. They're about 1/4 longer tip, going into the chamber. Those made it run a bit better.

If it's not the carb, im total timing isnt enough. I replaced the ESC module with a 350 unit, so I shouldnt be picking up false knock to retard the timing.

Suggestions???

 

215/215 single pattern cam....doesn't look like a cam that wants to pull at the top end.

 

But just falling flat? I wish I could describe it, its something youd have to drive to feel. I dont think its performing how it should. I dont think that cam should have any problem making some half decent power. Honestly, it doesnt even feel like it has as much get up and go as my brothers 305 tpi. I would almost bet hed pull on me from a stop to 70, 80, whatever. I dont think that's right.

It may jsut be me, but the exhaust note now seems lower, more of a hollow note, than before. I dont know if thats just from driving my cav all winter or what, but it kind of sounds weird now.
Anyhow, dont think that has anything to do with it tho.

 

Well I've got Protopline Vortecs and an XE 268H with 224/230 duration...and @ WOT once I hit 3500RPM the motor starts screaming....pulls to 5500+. I dunno....maybe something else is wrong....but from the specs in your sig that cam looks more like a low end torquer then a top end performer. Whats your total timing @ WOT?

 

I have no idea what WOT timing is. I've been asked this before, and I honestly don't know how to find out. Just slap a timing gun on without bypass mode and rev'er up and see where its at? Even so theres no timing marks so I dont see how that would work. Care to explain real quick, I'm very interested in knowing how, so I can at least eliminate the timing issue once I figure that out.

 

I've been told that Vortec heads like total mechanical timing around 32*...most SBCS make the best power anywhere from 32*-36* depending on compression and other factors.

Total mechanical timing = Initial timing + centrifugal timing, this is the timing you have when you are flooring the gas aka WOT

Your distributor should have a preset centrifugal advance. My distributor for example has 24* mechanical, and I am running 8* initial timing, so 8* initial + 24* centrifugal = 32* total mechanical timing.

You should find out how much centrifual advance your distributor has and put timing tape on your damper and take the engine up to 3000RPM and check.

 

Vortec's have "fast burn" chambers. This may be when they like a little less timing advance than other heads.

As for falling flat up top. Got me.

Just throwing this out here:
Almost sounds like your not getting any spark advance. The performance you describe is similar to the way my car performed with TPI when I had a rod knock that was causing the ECM to pull out the timing advance.

Hodge

 

You can get a good idea of what the WOT timing is by hooking up the timing light with everything plugged-in and warmed up. Watch the timing mark as you rev the motor from idle up to a few thousand RPM’s. In your mind, memorize the distance between zero deg and 10 deg on the timing pointer. The timing mark should be about twice this distance past 10 deg at high RPMs to be equal to 30 deg BTDC.

I think your problem is with the carb secondaries. Ether the Air Valve door is sticking closed, or the secondary butterflies are “locked out”. When the motor is warm, open the AV (mak sure its not sticking) and twist the throttle to WOT. Do the butterflies open? The choke mech will lock them out when cold. I think some carbs even lock closed the AV when cold.

 

I had a Q-jet that would fall flat every time you hit the secondaries- I adjusted air valve tension, swapped hangers and rods, still nothing.

Then I took it off and as I turned it over on the bench something fell out of it- the bakelite cam that actuated the air valve was broken and not opening the air valve at all- so all I was running on were the primaries.

Eric

 

Easy enough to determine if that's the problem. With engine off, air cleaner off, push open AV, watch hanger to see if the rods are being pulled up as the AV opens.

I've heard of at least one other person who had that problem.

 

The secondary fuel pull over tubes are nitorious for falling out of the carb top. This will starve the secondaries for fuel. You may find them laying in the bottom of the fuel bowl.

The cam is not the problem (215-215 @.050 will pull strong to 5500-5800 easy.)

I'd ditch the CC carb and distributor and get a Vacuum advance HEI and and Non cc carb. A holley 3310 or a Edelbrock 1407 will work well.

 

ehh.... i think where ben lives, they have emissions testing.

 

Seriously, thats what it feels like, is running off basically just the primaries. I think it's being starved somewhere. I've got it a little more tuned in now and it has some really good low end grunt. Just giving about 1/3 throttle from a stop, even going slow, its hard to keep the tires from spinning, and I'm running a posi rearend. I'm starting to gain some faith. When you floor it tho, it just revs but donesnt pull very hard at all. No, not like something is slipping either, just not pulling is the only way I can describe it. I'm gonna pull off the top of the carb tomorrow and take a look. I originally thought maybe I installed the secondary cam wrong and it wasnt picking up the hanger, but I checked today and they are working. Hopefully I'll find something out tomorrow when I pull it off.

Rob - Nope, no E testing here! I'm definitely not worried abou that.

F-Bird - Half of me wants to ditch it, and half of me doesnt. I kind of like the old CC carb system. My only gripe is the crappy timing curve of the system. Oh, and another thing holding me back....no money, haha. More than likely down the road I'll get a nice carb and dist. for it, but I've gotta do with this for now.

Oh, one more thing. It seems like maybe it needs a LITTLE bit more of 'go juice' when accelerating. Is it possible that I might need to increase the pump shot on it? Drilling a second hole closer to the fulcrum is not a big deal. I was thinking maybe it needed speeded up a little (I mean the plunger motion)? Any input on this?

 

What are you using for a fuel pump?
I'm not sure how far you can push a stock third gen fuel system before it becomes a restriction. Have you checked all the usual stuff like blocked fuel filters or even beter your WOT fuel pressure?

 

Dont laugh, right now I'm using a 'Purolater' from Autozone, it was cheap and I didnt have any money so I went with that. Says it puts out about 7 psi I think and is for v6 and v8 carbed cars. Havent had a problem with it so far, I think it is enough to keep the bowls full unless the car is really hammered on for a distance. Maybe when I take it to the track I might have to upgrade, but I think when you floor it from a stop it should at least have enough fuel in the bowls to go WOT for a good distance. Fuel filter is not a problem, I removed it because I thought it may be a restriction, but apparently that was not the problem. If it comes down to measuring the pressure, I'll just get a good pump and not worry about buying a gauge, that way I'll know I'm getting sufficient pressure.

 

What are you using for an air cleaner assembly?

 

Stock LG4 aircleaner with only the small lid that covers the filter from a functional cowl setup, for now. Basically an open element with K&N filter. No problem there.

 

I had a similar problem on my LG4 after putting headers on it.
It would run great on the primaries, but as soon as the secondaries opened up, it felt like I had thrown an anchor out the back. If I lifted the throttle enough to close the secondary blades, it would pick back up...until they opened again.
Experimenting one day, I put in the secondary rods out of another Q-jet (DR I believe they are) and it doesn't miss a beat now...it just keeps pulling.

 

Have you tried a test drive with the air cleaner assembly off the motor? You're probably right that its ok but it would be a simple step down that process of elimination road.

 

Yep, I've tried no aircleaner.

I was just outside today looking at it. If I rotate the throttle on the carb all the way, the secondary flaps do not open. They are sticking somewhat. Not the top butterflies, but the bottom round flaps that work directly off of the throttle. If I hold the throttle all the way open, I have to tap on the secondary lever to break them loose. Now I dont know if the vacuum would be enough to break them open un WOT conditions or not, but I'm thinking no. Right now, I'm leaning towards the secondaries not opening up under WOT, what do ya think? I dont know why they'd be sticking, when I put the carb on they worked fine.

 

Like I said before, I can rip the rearend loose no problem, but keeping them going is a problem, it just kind of dies/flattens out (not that I've tried, I'm just guessing ). I should be able to absolutely rip them in first gear for as long as I wish. So I think this would explain it, its just not getting enough gas/air, cause the flaps arent opening at all.

 

what they like as far as timing varries from engine to engine.. mine like a more normal 36*.

Start checking the basics on that motor. start with your ignition. make sure your cap and rotor are in good shape. more specifically i'd look at the coil make sure it isn't crapping out on ya.

As far as spark plugs run a set of R43LTS plugs in it and see how it goes. Vortecs need a long shank plug with extended tip..

make sure your pump can feed that sucker... fuel pump that is...

The "standard" test is to hold a cup and undo the inlet line.. should be about a pint per15 sec's of cranking.

 

There's a lock-out tab on the passenger side of the carb. It is supposed to be disengaged by the high-idle cam going off all the way. Verify that is happening.

 

Ok fellas, I see a lot of advise here, so I'll sum it up for ya.

Ignition is all brand new, I've checked over everything. Timing is set at 6* initial right now. New set of *Vortec* specific Bosch platinum plugs (cheapest one I could find at $2 apiece, some were 4,5 and 6 bucks apiece!!) These Bosch's also were short enough to clear my headers so it worked out great. I've ohmed every wire, cap and rotor are new. No problems there.

Fuel pump, lines are good. Pump is sufficient to fill a pint in 15sec I think. I had to drain about 1/4 tank with it, so guessing from that, I think it's ok.

The secondary lock-out tab has been ground off from a previous rebuild, that isn't the problem.

Now, for the good news. I'm 95% sure my previous theory on the secondaries not opening is correct. Just put $10 in midgrade in (to see how it works with the new setup so I could run a tad more timing without worrying), and took it for a spin. After finding some questionably backroad roads, I took it WOT. First time, acted same. Second time, acted same. Third time, it waited a little and then just started miraculously pulling HARD and all I could hear was the 'SHHHHHHHHHHRRRRRRROOOOOMMMMM' of air being sucked in by the 4bbl's. Tried again, no go. Tried again, no go. Tried again, they opened up. Soooo, they are being intermittent, I think holding WOT for a certain amount of time, the vacuum gets so great that it pulls the flaps open and overcomes the sticking. I took it on a different road and gave her hell, and man, when they open up that sucker pulls. Yes, I'm almost positive that this is my problem. After it kicks down when cruising aout 45, it takes a few seconds for them to open up. I'm gonna pull the bottom part of the carb off this saturday and see whats up.

Now I'm all excited! I'm liking it, if I can just get the dang thing to open up when the need arises!

 

Is this the pump you have?

This pump is not enough pump to feed your motor at high rpm. (volume)

 

Thats it.

Can anyone suggest a good (electric) pump for around 100 or less? I want one that will put out 15-5psi adjustable, or one that would have enough pressure to work with supercharging, because I want to keep that option open down the road without having to buy another pump. It will cost enough as it is. If not, what are some good options here?

 

I havn't had to much to do with Q-jets but I'd still be concerned with your secondary throttle plates sticking. The top throttle plates on the secondary side are vacuum controled but the lower are mechanicaly linked and should always open unless the choke is locking them off as five7kid pointed out.
Especially if it worked fine before you put the carb on the motor and then started sticking after that.
A couple of things you could check are the base gasket/manifold for interference or over tightening of carb hold down bolts.
Find out why its sticking!

 

Oh, I'll find out alright haha. I tried WOT 3 times on the way home from class and they didnt open. I just dont have time do it during the week. Oh well, on the brightside, I'll save some money in gas for 4 more days!

Ya, the bottom blades are the ones that are sticking, I know they should open no matter what. I had to tap on the linkage lever to break them loose, they werent glued shut, just sticking somewhat.

 

87,....

I have had that same problem the secondaries stick and well.....you know the feeling... so i carefully removed the
"secondaries" there are two tiny screws holding each one one and very carefully sanded the edges to regain clearence, taking great care to retain the stock shape , but just enough to make the buggers OPEN EVERY time , It was a royal pain to located but once i knew what was happening it was a simple and cheap fix,
good luck .......GTA

 

oops I just re read the post and noted that it was the BOTTOM ones there must be a reason for them to stick....... that is a new one to me, oh well good luck anyways'...GTA

 

That pump is way too small.
I would recommend you do not operate your car at WOT
till you replace it with one capable of higher volume.
(Possible engine damage)

Forget the $$Supercharger$$ for now. When that day comes
you can redo the fuel system to match.
(You'll need a specialized fuel system to feed a blow through supercharged motor.) there is no $100 pump that will do that.

Here are some Affordable Electric fuel pumps that will feed your motor.
Carter fuel pumps

Holley fuel pumps

Edelbrock fuel pumps

QuickFuel Tech fuel pump

You want one rated for about 100+GPH free flow.
The 6-7psi pumps do not need a regulator.
The 14+PSi pumps are more for racing and do require a regulator. (Extra cost)
You should be using a minimun 3/8" inside dia. fuel line
from tank to carb. The fuel filter goes before the electric pump.

I recommend this Carter pump.
Jegs/ Carter #180-P4600HP no regulator required.

 

Your secondary throttle problem is probabily caused by the lockout tang sticking.
The lockout tang prevents the secondaries from opening
while the choke is on. (cold engine) So it won't bog.

If either of the vacuum pull off diaphrams on the side of the carb are not working or the choke linkage is stuck, damaged etc , etc , the tang will stick causeing the secondaries to be locked shut.

See the pic...... the choke pull off diaphram is missing in this pick.

 

F-Bird'88, thanks for the advice on the pumps. I cant see or tell from the description if that Carter has a mount for it or what, but I'd like to mount it down by where the steering box would be if it were on the other side of the car. I was looking at the Holly Red, looks like it would be a good pump too. Little more tho.

About the 'tang'....haha, Its Not The Tang. It Has Been Removed On Mine Already.

 

Electric pumps go in the back near the gas tank.
Electric pumps push fuel better than they pull it.

The Carter pump comes with a adjustable mounting
bracket, rubber grommets and fuel fittings.
Its a good one.

I like the Carter pumps better. they are more reliable.
they were designed for OEM applications and
full duty continous use.

The Holley red and Blue pump have high capacity but were never designed for continous use.
I've never had good luck with them lasting more than a year. They leak, usually sooner than later.

Mount it just in front of the gas tank on the drivers side.
Over the rear axle. The fuel line is right there.
Keep all lengths of rubber fuel line very short. Use steel lines. Especially on the suction side.

 

Hey thanks again for the advise! I sure dont want to spend 95 for a 1 year deal. Carter it is.

 

the choke pull off still on that thing.. make sure that's working properly

 

Yep, I checked the pull-off. I just got home from work and I tried WOT once for a few seconds, and it was doggin. Got home and checked the secondary (bottom) flaps, and they were stuck pretty good so thats definitely it. I tried rotating the throttle by hand first and they dindt kick open. I had to tap the linkage lever pretty hard to get it free. I've found my problem.

Ordered the Carter fuel pump today that was recommended, FYI. And an aircleaner. I'm not gonna do any more WOT bursts until I know I'm capable of gettin the fuel there, I'm not gonna risk burnin somehting up here. Soooo, until this weekend, I guess we'll just have to wait and see. I'll post back and let ya'll know what it was that's holding the flaps up.

 

my 383 with vortec heads and cc 224/230 duration is droppining in next week, cant wait to see how it runs. anyone with that cam and heads (cc xe268h) pleas let me know how ur car runs, thanks guys and good luck man,,

Iroczman380

 

Zman, since then I replaced my carb with a reman. carb from I-five auto out in Cali. Carb was beautiful, everything fixed, new bushings, epoxied, etc etc. Anyhow, it runs perfect now. The motor has some *****, and even though I recently found out the true ratio of my rearend is actually 2.93:1 with posi, it still gets up and runs. I think you will not be disappointed. Oh, my cam is a single pattern 270HR, but I'll probly be swapping something better in down the road, I've read of a lot of people running the 274.

 

what the HELLL?????????

QUOTE;I've got it a little more tuned in now and it has some really good low end grunt. Just giving about 1/3 throttle from a stop, even going slow, its hard to keep the tires from spinning, and I'm running a posi rearend. I'm starting to gain some faith.


you have a higher rpm torque cam than me and you can actually break your tires loose???? AHAHAHAH I do not know what to do.
I had around 8.1:1 comp. with 76cc heads.
then I went to double humps with a total of around 9.8:1 cr with 64cc chambers and larger exhaust valves..I only have a comp cams 262h12 cam...why cant i roast the rubber??????I ll find the problem one day

 

Matt,
I'd say you should be able to roast the tires from a stop no problem (you have a 350 right?) if you wanted to. I would say you should be able to do that with any rear ratio assuming you have half decent heads and cam. Mine will break the tires loose pretty easy from a stop (I even just recently learned I actually have 2.93:1 rear ratio, not the originally-thought 3.23:1) but it doesnt spin wickedly until it gets into the cam's powerband. The secondaries just open up and it starts spinning like crazy at WOT (probably about 10-15mph is when it kicks in im guessing). I couldn't imagine driving around with something like 3.73:1, I dont think it would stay on the road, especially in the rain. Anyhow, good luck with that, you'll get it right, it just takes a while sometimes (believe me, haha).

 

ya thanks alot for the reply 87 formula 4bbl.

theoretically and according to many many people, my setup with the camel humps and 9.8:1 compression as well as the 262h12 comp cam should break the tires loose from a stop..and yes i too thought I had 3.23 but later found out i only have 2.93.

whatever for now, ill do some more research and try to find the problem, anyways I hope your setup works out for you.