Loadstar carburetor general advice needed


The workhorse

Golden Jubilee
Golden Jubilee

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Joined: Wed May 29, 2013 6:50 am

Post Sun Jan 14, 2018 10:51 pm

Loadstar carburetor general advice needed

ok everyone,
here's where I really need some advise from everyone who has had experience with Holley carbs.

I was planning on rebuilding a Holley 2300 carb, IH part number 443269-C91, list number 4308-1. This is a non-emission carb made for an early '70's 304 pickup truck. I intended to install it in my 304 V8 Loadstar. It seems like a simple carb and I have read some books on Holley carbs so I understand their theory of operation from a performance point of view much better than I did a year or two ago.

However theory is not practical experience. My situation is this: I just came across a NOS Holley 2300 carb for sale, IH part number 442-159-C91. At the moment all I know is that it was made for a 345 with exhaust emissions. This carb is new old stock, not re-manufactured.

Being 40 plus years old I know I will need to replace gaskets and seals. And probably replace jets and power valve to make it work properly on my 304. But my thinking is this - mechanically it should be like new otherwise, correct?

And my question is what other changes are there between an exhaust emission carb and a non-exhaust emission carb? How are they different other than jets or power valve differences? Can this carb be tuned to work as well or better than the other carb and be even more dependable because its not worn out? Is there any problem anyone sees in tuning this carb to work really great on a 304 without exhaust emission considerations?

The only differences I see between the two per IH parts books is the throttle plate assembly is different, the jets, power valve, accelerator cam (and possibly the accelerator discharge valve assembly) is different - all interchangeable if necessary for tuning (except for the throttle plate).

So what are your thoughts on using this NOS emission 345 carb as opposed to rebuilding the other high-mileage, junk yard pulled non-emission 304 carb? Dependability and economy are my two most important goals.
Thank you, everyone for your advice.
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Golden Jubilee
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Location: Wichita, Kansas

Post Mon Jan 15, 2018 2:50 pm

Re: Loadstar carburetor general advice needed

You know the throttle plate assembly is part of the governor, right? Are you planning to swap the throttle plate assembly to the newer carb, or just run it without a governor?

Dean
Lifelong Kansan
Grew up with red paint
Moved off the farm 33 years ago.

Golden Jubilee
Golden Jubilee

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Joined: Wed May 29, 2013 6:50 am

Post Mon Jan 15, 2018 5:13 pm

Re: Loadstar carburetor general advice needed

dean466 wrote:You know the throttle plate assembly is part of the governor, right? Are you planning to swap the throttle plate assembly to the newer carb, or just run it without a governor?

Dean

Just run without a governor. I'm the only one driving my truck so I don't need to be concerned with someone else over-revving it. There was no governor on it when I bought the truck and its carb, per the list number, is rated for a 266 v8. So that's why I initially was going to rebuild the 443269-C91, list number 4308-1 carb I got at a junk yard. But I now have a couple other questions about the two-stage power valve in this carb now. I'll quote from the service manual:
". . . during light load and part-throttle operation where manifold vacuum drops to a pre-determined level , the first stage opens to enrich the mixture slightly ..." - ok, I understand that - ". . . when the throttle plate reaches a 50* or greater opening, a hole through the throttle shaft aligns with passages in the throttle body admitting atmospheric pressure to the power valve permitting the power valve to open regardless of manifold vacuum."

I never heard of this before. Is it common to all 2300 carbs? To me that sounds like this carb is going to get horrible gas mileage. First, Holley no longer sells two-stage power valves. They recommend the single stage 125-65 power valve to replace it. Does practical experience with our engines agree with this recommendation?

Secondly, can this mechanical 50 degree throttle opening of the power valve be defeated so it responds to manifold vacuum only? What would be the ramifications and is that something I would even want to do? Or should I leave it as is? Or put a power valve in it rated such that it will only open at the 50* throttle opening? What are your thoughts?

I'm still waiting to hear on the price of the other NOS carburetor but that IH dealer is probably going to want a couple hundred dollars for it. I'm sure that's why he's never sold it in all these years - but we'll see.

Thank you.
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Golden Jubilee
Golden Jubilee

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Location: Wichita, Kansas

Post Tue Jan 16, 2018 2:21 pm

Re: Loadstar carburetor general advice needed

That power valve arrangement is interesting and not one I've come across before. It was probably used to prevent lean mixtures at full load.

Dean
Lifelong Kansan
Grew up with red paint
Moved off the farm 33 years ago.
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Rusty Driver
Rusty Driver

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Post Sat Feb 03, 2018 6:23 pm

Re: Loadstar carburetor general advice needed

The dual vacuum power valve was designed by Stromberg, and later also used by Holley. This was an attempt to produce a fuel curve with less deviation from ideal, over a wider range of vacuum values. Both Stromberg and Holley were trying to compete, unsuccessfully, with the metering rod technology designed by Carter, and also used by Rochester.

We reproduced the Stromberg dual vacuum power valves years ago, as the main bodies were a machined part. They were fairly expensive to reproduce. The Holley valve main bodies are cast, and extremely expensive to reproduce. Don't know of a current source for either, although we still have a good inventory of the Stromberg valves for our rebuilding kits.

Holley is basically saying that part throttle (mid-range vacuum) air/fuel ratios will be less than optimal with the single vacuum valve, but the carburetor will still function at WOT without issues.

Jon.
Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri

Golden Jubilee
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Post Mon Feb 05, 2018 5:17 pm

Re: Loadstar carburetor general advice needed

Very interesting, ... and thank you Jon.
I think I will be rebuilding the carb I got at a junk yard ... it doesn't seem to be that badly worn, and it was much cheaper to buy than the NOS carb I came across.
I also came across a post at a different forum suggesting that the two holes be plugged, the one as indicated shown and the other one that goes through the throttle shaft in the baseplate as it provides an unregulated air leak, a direct path for air to enter the base of the carb through the power valve cavity - anywhere from no air to a little air as the shaft rotates to more air as the shaft completely opens the throttle plates. That post suggests once those two holes are plugged,the carb can be tuned to run as smoothly as any other Holley 2300. Thoughts, anyone?
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And I found a supplier that still has a few 2-stage NOS power valves in stock for my junk-yard carb. But do I even want to use them? They're probably 30 plus years old and I doubt the diaphragm in them will hold up very long with today's gasolines. Can a Holley 2-stage power valve be rebuilt?
Thank you, everyone.

Golden Jubilee
Golden Jubilee

Posts: 338

Joined: Wed May 29, 2013 6:50 am

Post Mon Feb 05, 2018 11:40 pm

Re: Loadstar carburetor general advice needed

Just thought I'd ask another question since I have no previous experience rebuilding carburetors.
What is the best needle and seat to use for street and off-road 4x4 use?
There seems to be several different approaches.

There's the stock Holley all-steel tipped, the viton-tipped, and the titanium version. And there are other non-conventional versions such as the Datona float valve version,

https://www.daytonaparts.com/daytona-ca ... valve.html
and
https://www.youtube.com/watch?v=j3YoHOodWHc

and the Grose Jet version,

https://jimsgarage.wordpress.com/2006/0 ... grose-jet/

The Datona Float valve has a very good write-up with supporting video, and I found where they have claimed to have made thousands over the past ten years, but I don't really know how much of that is just marketing hype.

And with the Grose jet I've found some excellent testimonies how they have lasted 10 plus years with no problem, but also some testimonies stating there was a run of bad ones made that will leak from time to time. And there seems to be no company support for the Grose jet valves and I've only found one shop that claims to have any for the Holley 2300 carb in stock.

And if I go with one of the Holley versions, would the brass float or the Nitrophyl float be the best to use?

Your thoughts and comments are appreciated.

Thank you.
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Rusty Driver
Rusty Driver

Posts: 127

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Location: Eldon, Missouri USA

Post Thu Feb 08, 2018 7:53 am

Re: Loadstar carburetor general advice needed

Steve - this link may help:

http://www.thecarburetorshop.com/Fuel_valves.htm

As to rebuilding the power valves:

Anything CAN be rebuilt, but I doubt very much if these could be rebuilt economically even on a large scale (quantity). I think it would be easier to machine a new one than rebuild an original.

Jon
Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri

Golden Jubilee
Golden Jubilee

Posts: 338

Joined: Wed May 29, 2013 6:50 am

Post Sat Feb 10, 2018 10:50 pm

Re: Loadstar carburetor general advice needed

Jon, I was just looking at your web site and all I can say is . . . wow, very impressive! I don't think people appreciate the amount of work required to compile that kind of information. My hats off to you. . . very awesome.

I was looking at some of the IH 2300 repair kits, but I'm not sure what some of the numbers mean. Below, for example:

1972 . . . 8 . 266 B series . . . . . . Holley . . 2300 . . . . . . 1710 . 6 . 443250-C91 . . . 2919
1972 . . . 8 . 266 S/T. . . . . . . . . Holley . . 2300 . . . . . . 3863 . 2 . 344307-C92 . . . 3026

For example - what is a B series? - I thought a B series was a model of truck that came out in the late '50's and very early '60's, not 1972.
And does S/T mean standard transmission? And what about carbs that don't have a A/T or S/T next to the engine displacement size - are they made for both a standard or automatic trans?
And in this example is 1710 or 2919 the list number of the carb and then what is the other number?
I recognize the IH part number but what is the single digit number immediately before the part number?

I just want to fully understand all the info you have put together on your web site.

Also, I was not able to find my carburetor or its list number and rebuild kit on your web site. I probably just missed seeing it. It's a Holley 2300 IH part number 443269-C91 List 4308-1 and the number under the list number is 2363.

I have lots more questions on your rebuild kits, so please check back from time to time.

Thank you, Sir.
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Rusty Driver
Rusty Driver

Posts: 127

Joined: Mon Feb 09, 2015 7:10 pm

Location: Eldon, Missouri USA

Post Sun Feb 11, 2018 8:41 am

Re: Loadstar carburetor general advice needed

Steve - the information posted, with the exception of the number for the rebuilding kit which is our own, is taken directly from the factory Holley literature.

In the example you mention, the "6" is the engineering change status for List number 1710. List number 1710 was first assigned in 1959. Generally (not always), there is very little difference from one change to another. Example, the change of an idle jet from 0.032 inch to 0.033 inch would be considered an engineering change. Virtually always, the highest change number will be the better product.

I do not know the definition of a "B" series in 1972, again, the information directly from the Holley literature. I guess I am a good "parrot" ;)

S/T does mean standard transmission, as A/T means auto transmission. If there is no transmission specified, Holley did not include the information.

Thanks for your comments on the website. I started the database in 1967 using IBM 80 column punch-cards! There are now 92,500 plus records in the database. Information older than 1915 is challenging as much did not survive, and some was never printed. Information later than 1968 is even more challenging, as many companies became very possessive of their information trying to prevent others from copying their product.

Jon.
Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri
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