Holley 450 cfm economaster troubleshoot - Page 5 - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

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post #61 of 69 (permalink) Old Feb 3rd, 12, 06:35 PM Thread Starter
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Re: Holley 450 cfm economaster troubleshoot

It's been a while but I've been working on the carb on and off. I've acquired these three holley books which would have been good to have from the start. Each one has good info about the operation of the different circuits in the carb but the one with the blue cover(foreground) is the most current and useful when it comes to suggestions for modification. The one in the background includes a comparison test between the Holley 450 Economaster, Qjet and Rochester 2 barrel on a low performance 350 from the 70's. The Economaster barely edged out the QJ on gas mileage, and had the most torque around 2800 rpms. Too bad they didn't give the exact list number or jetting for the carbs. That would have been helpful!

I got the 2 older books pretty cheap off the internet but the one in the foreground cost about $20 at Barnes and Noble.

Here's an idea that I got from one of the books. Old trick but new to me. Make a carb stand out of 4 carriage bolts and 8 nuts. Really helpful.


Here's another idea that was suggested in the newest book. Since the rebuild kit does not come with a replacement for this spring which controls the power valve, you can shim up the spring using some washers. I have some black plastic ones in place in this photo. Have not tried it yet. More on this later.


Back to the jets for a minute. I bought some jets that turned out to be too big so the car ran rich. I decided to experiment with blocking out part of the area of the jet using a rod, a la Quadrajet. In this case, I measured a bunch of wire things from guitar strings to paperclips and came up with options to emulate a smaller jet. Knowing the diameter of the jet orifice, I measured the diameter of the "rods" and calculated the area of each and subtracted the rod area from the jet area to get the resultant area. Here's a picture of a jet with a wire piece in place. I just screwed the jet back in like this and it works pretty well.

Another use for the guitar strings is to check to see if the passages in the carb are clear. Just run the string in and out, compare depth among different passages and check for residue on the guitar string when you pull it out.

Next experiment is probably going to be about that power valve spring. I have two carbs now so I can just use the top from the second carb and shim up the spring. I think the old worn spring may be causing the power valve to come in late, in other words, activating at a lower vacuum than originally intended and that could account for the whole lean spike in the primaries that I've been puzzled over all along.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #62 of 69 (permalink) Old Feb 3rd, 12, 07:12 PM
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Re: Holley 450 cfm economaster troubleshoot

Quote:
a comparison test between the Holley 450 Economaster, Qjet and Rochester 2 barrel on a low performance 350 from the 70's. The Economaster barely edged out the QJ on gas mileage, and had the most torque around 2800 rpms
I rem that bit, and since still cant find my copy, cant comment authorivly on that...But from memory I did have problems with those comparions, espec with the 2 barrel.. to do with tuning in of each of the carbs, I believed was suspect....The 2 barral should have creamed the others in the economy .....

I would suggest using small nuts rather than plastic or rubber as shims, espec if the type and resistance to modern fuels is unknown
yeah the wire thru the jet is an old trick, and yep the cross area is the way to go to get in the ball park....jets are funny things, a small chamfer on a top edge can completely change a jets charactoristics, as can a wire....
We used to use sewing needles...heat them with a cigerette lighter to bend, and a pack of sewing needles comes in heaps of different sizes/diameters.

I like the guitar strings to clear check galleries....

My Spelling is not incorrect...it is creative

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post #63 of 69 (permalink) Old Mar 17th, 12, 07:03 PM Thread Starter
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Tonight i swapped in the top off another carb that i had shimmed the power valve spring to open more quickly. What? Nice grammar... Anyhow, i'll drive it in the morning and see what effect the shimmed spring has. I expect it will cause the power valve (which feeds only the primaries) to open sooner and kill that part-throttle lean spike.


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'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #64 of 69 (permalink) Old Mar 18th, 12, 08:28 AM Thread Starter
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Re: Holley 450 cfm economaster troubleshoot

Well, I drove it this morning and the shimmed power valve spring seems to have killed the lean spike. I wish I had a way to measure the spring tension and put a number on it...will keep thinking about that. But no sign of a lean spike on the A/F meter today.

Highway driving at 70 mph and 2,550 rpms I have about 15.8:1 but fat at WOT at about 11.8 @ 70-90mph. Next, I'll be working on those secondaries to lean it down to about 12.7:1 A/F. Right now I have the original "550" secondary jets in there(about 1.80 mm). I have some smaller ones that I'll try first, 1.65 mm. I could also do the wire restrictor trick as in the previous posts but "six of one half dozen of the other" I guess. And just picked up some real small drill bits and a pin vise if I decide I need to drill any smaller ones bigger.

Kinda blows my mind that this thread has over 2,300 views at this point...when I started it I didn't think anybody would care. But now it is the most comprehensive data I have seen for these carbs on the internet.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #65 of 69 (permalink) Old May 10th, 12, 02:17 PM Thread Starter
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Re: Holley 450 cfm Economaster troubleshoot

I havenít posted on this in a while and this will likely be my final post on the subject. Iíve got the carb where I want it now so I donít think thereís anything more to gain. Funny, Iíve noticed a couple guys selling these carbs on Ebay and in their descriptions they are referring to this thread for tuning pointers!

So here are my final notes on the subject:

First, I would not have been able to get these results without my Innovate wideband A/F meter. NO way. All in all, itís a good running street carb now. I think if I put as much effort into a Holley 4150 or Qjet, Iíd get similar results. Itís more responsive than previous QJets, gas mileage comparable. Have not tried other Holleyís to compare.

Jetting: I wound up with about 130 (1.3mm) jets in the primaries (wire restriced 1.45mm) and 165 (1.65mm) jets in the secondaries. Tuning with my wideband A/F meter I get a nice high 14-15.5 on the primaries on cruise and about 12.7 A/F all in at WOT. My engine is a 327 with approx. 10:1 compression, Performer intake, 1.94 double hump 291 heads, Crane 272H10 cam 216/216 .454Ē/.454Ē I would recommend this 130/165 jetting as a good starting point for a mild performance small block.

Power valve: I shimmed the plunger spring up about 6mm using some washers and that is what ultimately killed the lean spike on the primary cruise circuit. This plunger spring is not included in the rebuild kit. I tried various methods of applying a vacuum pump and gauge to this assembly to quantify the change with a number but the results were inconsistent so I gave up. Itís pretty much trial and error if you need to shim the spring and then only if you are noticing the same lean spike situation on the primaries that I had.

Top Gasket: If you are planning to change jets, float level or tweak the power valve spring after your rebuild it is imperative that you use some chapstick or grease on the top gasket of the carb because it is coated with some extra sticky stuff and will tear once you try to remove the top again after a period of time.

Choke: I am running the divorced choke on a performer manifold. It works fine but I think it could easily be modified to be operated by a cable if you prefer. I have not seen any Economasters with electric chokes but have seen some with either a hot water or hot air activation. I think Holley makes a retrofit kit that will allow you to convert these to electric but I donít believe you can convert a divorced to electric because the mounting bosses are different or not drilled(donít remember which)

Thatís about it on the Holley 450 Economaster. Feel free to email me questions at thomasandlynne at Comcast dot net.
Happy motoring!
Melrose

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #66 of 69 (permalink) Old Jun 14th, 16, 09:55 AM Thread Starter
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Re: Holley 450 cfm economaster troubleshoot

No test is complete without a long term report.

It's been 4 years now and this carb has been on the car for most of it and is still running fine.

I removed it a couple times to experiment with others but came back to the Holley 450.

I am about to try out a Holley 4010 600cfm double pumper that I rebuilt and will be posting on that one soon. The mechanical secondaries should make it very responsive but with more torque than the Holley 450 and I think for those long highway trips I can easily disable the secondaries to preserve some MPG.

Stay tuned, we shall see.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #67 of 69 (permalink) Old Dec 27th, 16, 11:04 AM
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Re: Holley 450 cfm economaster troubleshoot

Great tips on the Holley 4360! I have a 73' Vette with this carb because a few owners ago the Q-jet was tossed. Many years ago I had rebuilt a Q-Jet on a 75' Vette and no prob. On my 73 when I stomp on the pedal the car just dies, so I'm guessing the acc pump.

Thanks,

-RAy
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post #68 of 69 (permalink) Old Jan 3rd, 17, 11:52 AM Thread Starter
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Re: Holley 450 cfm economaster troubleshoot

Quote:
Originally Posted by rpetronk View Post
Great tips on the Holley 4360! I have a 73' Vette with this carb because a few owners ago the Q-jet was tossed. Many years ago I had rebuilt a Q-Jet on a 75' Vette and no prob. On my 73 when I stomp on the pedal the car just dies, so I'm guessing the acc pump.

Thanks,

-RAy
yeah, opening all 4 barrels with no acc pump can't work very well. Good luck with it. Still running mine.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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post #69 of 69 (permalink) Old May 6th, 18, 07:50 AM Thread Starter
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Re: Holley 450 cfm economaster troubleshoot

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'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

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