Holley 1904 Economizer Replacement

[Robert Kenney]

I started a new thread to put the Holley 1904 economizer repair a home of its own(hope that is ok).

This is a very common failure on these carbs that can cause many symptoms. I am copying michael Maybens photos here for reference. The original thread should anyone wants to read it is below.
http://www.forums.IHPartsAmerica.com/carb-tech/751-1409-Holley-issue.html

I received the package from michael containing the 5 bad main wells in the photos below Monday.

I hope to start the replacement econo valve seat and poppet design next week. I will post the machining out of the old valve and the machining of the new parts here as time permits.

Robert

 

[Robert Kenney]

Well, I just finished the replacement economizer valve design.. Installation will require boring out the casting and reaming to " -.002 (.2xx0 diameter).. Them heating up the casting enough to allow the seat, poppet and, cap/guide to slip in to the correct depth. After cooling it will be locked in for good..

the seat material and cap/guide material will be beryllium/copper or phosphorus/bronze because they can be hardened to ensure a long life.. The poppet will most likely be made from 400 series or 303 strain hardened stainless steel again to give the new parts a long service life..


Robert

 

[Michael Mayben]

Dam that's impressive!!!

What's the "critical" temp for warming the zinc casting for the shrink fit??? I got no idea what that would be!

So looks like you won't have to remove the plug in the end of the feed tube? And the "cartridge" will be blank on the opposite end from the poppet and won't need to be plugged after install?

 

[Robert Kenney]

dam that's impressive!!!

What's the "critical" temp for warming the zinc casting for the shrink fit??? I got no idea what that would be!

So looks like you won't have to remove the plug in the end of the feed tube? And the "cartridge" will be blank on the opposite end from the poppet and won't need to be plugged after install?

I would need to check but 300f would be close to expand enough but that will depend on how much interference I design into it.. @.001" maybe can be simply pressed in cold? I will probably make the parts .2500 +/- .0005"(normal for a swiss screw machine) and play with the id reamed size.


It would be nice to leave well enough alone. We should be able to leave the plug in the horizontal feed tube..

The replacement parts (seat and end cap/guide) are going to be separate so I suppose they are not really a cartridge per say. There is not enough room to make it a one piece valve assembly.

Robert

 

[Robert Kenney]

Another update for the econo. Valve deal.

I have modded all of the valve locations to except the new parts.
I have also begun to machine 5 sets of valve components. I think I will machine and assemble the main bodies as it can be tricky to accomplish and maintain the bore diameter +/-.0002. Normally I would say to locally heat and expand (375f) the casting in oil but I need to see if that will work hear. May work better to simply press the parts in.
Rk

 

[Michael Mayben]

Lookin' good!

I ripped into three more 1904 mixers last nite...looking for a decent pair of cores for build. All three cores will be ok, but only one of the three had main wells that are useable.

Of the other two, one carb was fairly recent rebuild but the poppet valve was missing from the economizer segment, the spring was still there. So it was put together without a functioning economizer, ya can imagine how that one performed (and was no doubt then tossed in the scrap pile).

The other one has the "plunger" tip worn completely down so that there was no way it could actuate!

So that's two more candidates for rework.

I still have three more cores that are unknown right now. So I'll rip those apart this week to check out the main wells also. Once I got all the main wells I have sorted, then I'll send ya the rest of the units for re-work.

 

[Robert Kenney]

Got one main body all finished. Ready to install. Works great, seals off good and actuates nice and easy. I checked the emulsion tube orfices and reinstalled the plug. The so called "science experiment" has come full circle.
Now we have a viable repair for a no longer availible or servicable carburetor.

Robert

 

[RobertC]

Robert,

nice work

 

[Michael Mayben]

Fantastic!!

I've now got seven 1904 carbs in pieces, all are nice cores except for the main wells! Did two more today, one main well is useable, the other has the poppet stuck inna "mid-seat" position

two of 'em are in the dip basket now. Still have three more to gut out and check the condition.

The current version I'm doin' tonite is a 3" mount pattern (larger venturi/throttle body diameter) from a 196 of unknown vintage, got this one two sundays ago and came from michael dimock's s80 as described in this thread:

http://www.forums.IHPartsAmerica.com/I-h-s-t-o/1101-trail-report-trask-nov-2-a.html

Michael could not get it to play nice...guess what, the economizer is toast and....it was a previous "aftermarket" rebuild (glass beaded botch job) so it was put together that way and shipped...typical of the parts bizz today.

As long as wells keeps pumpin' out kits for these mixers, we can keep pumpin' out rejuvinated cores with original IH p/n's.

Can ya see a four "single barrel" down-draft setup using 1904 mixers onna stroker 152?? With a set of "visi-flo" bowls or your steampunk fuel level sight glasses?

 

[Robert Kenney]

Can ya see a four "single barrel" down-draft setup using 1904 mixers onna stroker 152?? With a set of "visi-flo" bowls or your steampunk fuel level sight glasses?

Ha, I was thinking 2 big bore units above a 4-71 blower pushing 8 pounds into a stroker 152 but maybe 4 would work better.

you know blower carbs don't want power valves so kinda defeats our main body rework. but more fun with four anyway.

Robert

 

[Michael Mayben]

Update regarding Robert's reconditioned 1904 main well/economizer system...

world class part!!!!

I built another fresh 1904 today to replace the two from my personal s80 collection I've given away recently to help out a couplea club bubbas.

Keep in mind...I've done many of these carbs and then run 'em in on my engine/rig, so I got a real good feel for how one oughta play. This is the first one I've ever done that essentially had a new economizer system though.

What a difference in drivability!

The carb core I used was a commercial "reman" from a few years ago, it had been nicely cleaned, and then re-chromated. But the bastards put a main well in that had the poppet stuck in the open position so the carb ran like it had a main jet at least 6 sizes too large.

So I built it using Robert's steampunk sight glass fuel bowl and his first "prototype" reconditioned main well. I didn't have time to run it on the exhaust gas analyzer going down the road so I could "watch" the economizer work (that will come later) but seat-of-the-pants tells me it does and the idle quality is outstanding, sure sign the newly-minted economizer system is sealing properly at idle manifold vacuum.

So right now I'm calling this a successful project! Robert and I have talked and he'll move ahead on completing all the main well cores he has now. In addition, I have three more to send him for service.

No doubt, ihon is the only source for reconditioned Holley 1904 main wells in existence! And freshly reconditioned 1904 carbs will be on the shelf soon!

Here's a shot of the main well just before installation, the new poppet is a stainless alloy.

 

[Michael Mayben]

Here's another shot of the economizer segment up close.

 

[Robert Kenney]

Michael,
did you take it for a road trip? Should really improve the afr at the higher altitudes where it would be fat any how. Mine was bad when I took it to mammothb@ 9000 feet I could see black smoke at light throttle cruise and increases in throttle at all rpm's. I fixed it and that went away. Same thing at big bear before. Not not.

before the fix I would get 12-13 mpg. Now after the trip to see Mike @ iho in Lancaster at 65-70 I got 16 mpg round trip.

Your economizer should be good for 40 more years as I made the replacement parts from hard bronze and stainless. Shoud never give you a problem again.

Robert

 

[Michael Mayben]

No extended driving on the test bed Robert! Tha rig ain't street legal quite (I only been messin' with it three years, street legal normally comes at about the five year point).

But I can say that it works perfectly. Because of the way the idle mixture adjusts in, there is no way it can be "bypassing" fuel and throttle response under load is perfect. Like I said, I gotta "test loop" I run on (always watchin' for jonnylaw) that includes variable conditions. Includes hookin' onto a 16ft. Chunk of down cedar about 30" in diameter and draggin' around. Neighbors feel sorry for me and always wanna come help. But then I keep remindin' 'em it's a dam treehugger dyno/load cell.

In fact, now them shitty engine mounts are allowing the fan to git into the shroud onna real hard pull, so those are on the list when the fresh motor goes in. Do ya know where I kin git any???

 

[Robert Kenney]

In fact, now them shitty engine mounts are allowing the fan to git into the shroud onna real hard pull, so those are on the list when the fresh motor goes in. Do ya know where I kin git any???

Hmmmmm, let me think about that.... I heard something about that.

Ahh yes... I believe ihon stocks them. the real deals, not the hard azz poly ones but oem style metal and rubber ones.

Robert

 

[Maughan]

Robert....how would one go about getting the whole rebuilt well assembly?

 

[Robert Kenney]

I do believe the store has them in stock if not michael has them. It would be best to call Jeff Monday and see.

 

[Maughan]

I just got a rebuilt main well from michael mayben I put a rebuild kit in and I can't get it to idle. Anybody have some suggestions?
It's a 1904 on a 196 Scout 800. Thanks for any help you can give.

 

[FSM]

Hate to being up an old thread but I can't find these on the website. Do I need to call? Also I have a couple of these if you guys have a core or trade or anything.

 

[ASE Doc]

Hello folks, I have to make a quick comment this excellent thread. Awesome work! The time and care taken to rebuild the eco valve and metering block for this carb is very impressive. I am always impressed by great precision machine work.

I am not an IH owner but a service professional with the rare privilege of working on a 1966 IH pick up. The truck is a slightly neglected gem with 17,000 original miles. The issues it has are typical of a vehicle that has spent way too much time sitting out in the cold wet nw weather, and not nearly enough time being enjoyed and cared for by a loving owner.

Among the other work I'm doing is refreshing the carb, which suffers mostly just from sitting with old fuel in it and a rotted out accelerator pump. A gentle cleaning and new rubber and paper is all it really needed. Fortunately, and I'm sure largely due to the low miles, the eco valve is fine. I spent a lot of time cleaning the metering block passages to be sure all the cob webs were cleared out.

I will keep this forum in my bookmarks and as future work progresses on the gem of a truck, I'll likely be back. Thank you!