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  #31 (permalink)  
Old 07-07-2019, 01:32 AM
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Hey, your gaining...both knowledge and performance. That's always a good feeling.
Let us know how it turns out.

I have found the Pink cam is often too slow a rate, even though at full stroke it maxes out a 30cc pump.....just not enough early on to cover at first throttle movement.
I've heard of relieving the fork area on the backside of the Pink and flipping it over really changes how it acts, but I've never tried it myself. Actually installing it wrong side up.

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Old 07-07-2019, 08:35 AM
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Any time I have bought a quick fuel carb and most of them come with the pink cams and I have always had issues with them never being enough of a shot and making things bog at a certain point when opening them up. I have found the orange pump cam which is about in the middle of the ground on the pump cam chart duration to be a good starting point to work with and go up or down on shooter size and then a slightly more or less pump cam to tune the pump shot circuit and 99 percent of the time the orange pump cam has worked the best for me for engine builds that pick up quick rpm fast.
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Old 07-22-2019, 08:41 AM
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New report, Now I still had the stubble at 1,300 rpm, so I said screw it and took the primary jets up to 66 and that cut the stubble in half. I didn't think that the primary jets would have anything to do with this problem at 1,300 rpm power braking bit they did. So next I put a vacuum gauge in the window and at the 1,300 rpm stubble I was at 7 to 8 on the gauge. So then I changed the power valve from a 6.5 to a 7.5 and the stubble is almost gone, so I think an 8.5 power valve will get it all the way. Now I am back up to 31 ifr's and it's back to rich in that area again so I may have to work with primary jetting and power valve's so I might be able to drop the ifr's a bit. I also played with the timing ,(up and down) and that did nothing for the stubble. Now the timing, (no vac) is at 22 initial and 34 total with the hei and a stop in it, also went back to heavy curve springs so I am at 30 at 2,700 and 34 at 3,000 rpm on up.

Thanks guy's I think I am getting close, anymore suggestions?
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  #34 (permalink)  
Old 07-22-2019, 08:46 AM
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I forgot to add my vacuum can , hooked to full vacuum , it gives another 6 degree's to the mix , Do you guys think that's enough? I will have to mod the can to get more
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Old 07-22-2019, 02:14 PM
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Quote:
Originally Posted by hirschdalechevy View Post
I forgot to add my vacuum can , hooked to full vacuum , it gives another 6 degree's to the mix , Do you guys think that's enough? I will have to mod the can to get more
Wow, only adds 6?? I have never seen one that small.
Or is that 6 at the distributor,?? which will be 12 crankshaft advance.
Motor will probably like 12-16 added by vacuum advance at the crankshaft for best cruise behavior and fuel mileage.
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Old 07-22-2019, 02:46 PM
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Quote:
Originally Posted by hirschdalechevy View Post
I forgot to add my vacuum can , hooked to full vacuum , it gives another 6 degree's to the mix , Do you guys think that's enough? I will have to mod the can to get more
Oops! Return directly to post #24! Do I think that a loss of 6 of timing can cause an off-idle stumble?? Yes I do. I also think you will need to change to centrifugal curve and initial timing if you add 6 of vacuum advance.

ALWAYS get the timing pretty much dialed in before jacking with the carb. Then finish up by varying the timing up/down 1 degree at a time.
Verify the timing marks with a piston stop.
Centrifugal advance = 14-16 base with advance starting ABOVE idle speed, and having total of 34-36 all in by 3000
Vacuum advance = 10-12 total, on manifold vacuum, all in with the vacuum that you have available at idle in drive.
This will give you 24-28 of total timing at steady idle in drive and will not drop back below the base timing when you step on it.

If you still have a stumble with timing set up like this - THEN jack with the carb. For now I recommend to put the carb back to original and start again with the correct vacuum cannister. There is something wrong there.

Maybe you should just upgrade to one of the small billet distributors that are easily configured?

Last edited by 2001Blazer4x4; 07-22-2019 at 03:14 PM.
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Old 07-23-2019, 12:06 AM
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Quote:
Originally Posted by ericnova72 View Post
Wow, only adds 6?? I have never seen one that small.
Or is that 6 at the distributor,?? which will be 12 crankshaft advance.
Motor will probably like 12-16 added by vacuum advance at the crankshaft for best cruise behavior and fuel mileage.
Yes that's all it gives , (checked it with a timing light).The can is a standard vc 302, I think I can grind out the back stop a bit and get 10 degee's. It is supposed to be 10 but it is not, but it does pull in at low vacuum. I just don't want to get to much advance with vortec heads
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  #38 (permalink)  
Old 07-23-2019, 12:12 AM
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Quote:
Originally Posted by hirschdalechevy View Post
Yes that's all it gives , (checked it with a timing light).The can is a standard vc 302, I think I can grind out the back stop a bit and get 10 degee's. It is supposed to be 10 but it is not, but it does pull in at low vacuum. I just don't want to get to much advance with vortec heads
I forgot to say I was working the vac can with a mighty vac hand pump and that is all it will give on the timing tape. It give's the same on full manifold vacuum as well.
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Old 07-23-2019, 12:37 AM
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Quote:
Originally Posted by 2001Blazer4x4 View Post
Oops! Return directly to post #24! Do I think that a loss of 6 of timing can cause an off-idle stumble?? Yes I do. I also think you will need to change to centrifugal curve and initial timing if you add 6 of vacuum advance.

ALWAYS get the timing pretty much dialed in before jacking with the carb. Then finish up by varying the timing up/down 1 degree at a time.
Verify the timing marks with a piston stop.
Centrifugal advance = 14-16 base with advance starting ABOVE idle speed, and having total of 34-36 all in by 3000
Vacuum advance = 10-12 total, on manifold vacuum, all in with the vacuum that you have available at idle in drive.
This will give you 24-28 of total timing at steady idle in drive and will not drop back below the base timing when you step on it.

If you still have a stumble with timing set up like this - THEN jack with the carb. For now I recommend to put the carb back to original and start again with the correct vacuum cannister. There is something wrong there.

Maybe you should just upgrade to one of the small billet distributors that are easily configured?
What I did was play with the timing, no vac can, ( 10 initial to 20 initial) with all different weight spring for the curve, then put a stop screw in the hei to limit the advance to 35 or less and the stubble was still there at all timing settings, ( high , low , slow curve and fast curve) at 1300 rpm at super slow power braking and the afr would go to 18 plus during stubble.

So right now I am at 22 initial , 30 at 2100rpm , 32 at 3000rpm , no vac can. With vac can I am at 28 initial and 37 to 38 at 3,000 rpm. I thought that was pretty close to where I need to be, no?

I was thinking I could add some more with the vac can if needed, like 10 or so with modding the vac can or use another one that would give more.

But the jet change and the power valve change and going up on the ifr's almost got rid of the stubble altogether. Do you think I should bring the initial timing down and start over? The extra initial timing helped me with keeping the transition slots square as well as opening the secondary blades a bit.

Do you think I am heading the right direction? or start over.
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Old 07-23-2019, 12:43 AM
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I did not check top dead center, its a gm sp/357 crate engine with all the timing marks on the balancer. Think I need to? It seems to like the more timing I give it so far.
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Old 07-23-2019, 12:48 AM
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I am almost back to what the carb came with , (68 primary , 31 ifr's , 65 power valve , 74 secondary jets) and now I am at , (66 primary , back to 31 ifr's , 75 power valve , 72 secondary jets).
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Old 07-23-2019, 09:00 AM
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Quote:
Originally Posted by hirschdalechevy View Post
I did not check top dead center, its a gm sp/357 crate engine with all the timing marks on the balancer. Think I need to? It seems to like the more timing I give it so far.
Doesn't matter where a motor comes from, true TDC needs to be verified or you'll never know if a mistake was made on assembly of he pointer or balancer. If you check it then it can be eliminated as a possible issue.

I think you're just fine with the current timing set-up and wouldn't reduce the initial. might be better with ported vacuum, as this will help with rpm drop when place in gear not being as much of a drop, but still give you the vacuum advance at cruise speeds. If you don't have any trouble with rpm drop in gearon full vacuum, then leave it that way.

From where you are at right now I think I'd try a .032-.034" IFR. Sounds like transition circuit is just too lean.

I don't know if it is the case, but you mention this carb is the Quickfuel version of the Holley Slayer....I wonder if it has some of the same problems that have been popping up about the Avenger carbs. You might read this and see if it helps:
https://www.hotrodders.com/forum/hol...ix-507033.html
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Old 07-24-2019, 08:18 AM
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Thanks guys , I am going to check tdc. this weekend then get back at tuning.
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Old 09-11-2019, 10:11 PM
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Had to out of town again , but back to tuning. I swapped the quick fuel primary metering block out with a 670 avenger block for fun and it seems to be much better, not perfect but way better all around. I was reading about the t-slots on the quick fuel carbs being to wide so I went and got a new 600 holley street warrior to check it out and the t-slots are way smaller so I was wondering if I could use the holley base plate on the quick fuel main body? I was going to get a brawler 600 but I think they are the same as what I have, (mine is just an off road slayer),anyway what do you guys think of a base plate swap?

Also on the quick fuel it has idle holes on the secondary side where as the holley base plate does not, whats up with that?

just trying to learn these holleys
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Old 09-12-2019, 11:10 AM
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The reason the quick fuel base plate on the secondary side has same size idle discharge ports like the front is because all of there carbs have a four corner idle base plate but on the slayer carbs they just set them up as a two corner idle but you can make it a four corner idle just by taking off the secondary metering plate and then changing the secondary idle air bleeds to be the same size as the front and then also put the same size idle feed restrictor in the secondary metering block to be the same as the front as with a four corner idle carb the secondary side needs to be square and the same as the front or things just won't be correct as it can be for the tune. Also the secondary metering block has to have idle mixture screws ability on them.

Yes you can use the holley base plate from a street avenger on the quick fuel carb just make sure your secondary idle air bleeds are what they were out of the box as with a carb setup as a two corner idle the holley base plate has a channel that allows the secondary fuel to be shared with the front so things don't get stale in the rear since the secondary side is not used much while driving. The quick fuel 4 corner idle base plates don't share with the front and that is one reason why they have the idle discharge port that is identical like the front and I actually have been reading about the billet or cast quick fuel base plates having wider transfer slots but in my experience it has never caused me any issues with many different builds with cams from mild to wild etc.

The street avenger metering block if it has not been messed with has a .028 ifr size out of box and a .046 power valve channel restrictor size hole. Also on your secondary metering plate it has most likely a .039 ifr size which will make for a really fat idle and pretty rich for that cam you have and I do think the secondary idle air bleeds are .039 unless they changed them. I had a quick fuel 600 slayer once on a 350 with a lunati voodoo hydraulic roller cam which was 272/276 219/[email protected] 515/530 lift with a 112 lsa and my quick fuel carb was pig rich on the idle that I could only go half a turn out on the mixture screws as anything more it would foul my plugs and I had an off idle stumble with the pink pump cam. I took the primary metering block and went down from the .033 out of box ifr down to a .031 and then I ditched the secondary metering plate and installed a holley secondary metering block that came off of a 670 street avenger that was only a two corner idle so the block has no idle mixture screws and it has a .031 ifr size. I then installed a orange pump cam and that made my idle perfect as I could get it outside of using an o2 gauge and I then could get my idle mixture screws to about a full turn plus out.

But every engine is different on what it needs but you got to make sure your timing is good for what your engine needs. I don't ever like the metering plates even the quick fuel ones that take jets and I always replace them with a metering block as for me they always are better for performance and working wise but that is my two cents.
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