WTB...Propane induction parts

[JeffHK454]

Looking for propane mixers , regulators and fuel valves from Impco or OHG.

Need #425 or #450 mixers and L or E regulators.

Thanks, Jeff

 

[MOE]

Are you looking for base mount or updraft versions of the mixers? I may have the vaporizers as well. If not impco, I may have century.

 

[ShoerFast]

Jeff,
I never worked with a "#450" is that new?

I would have what your looking for, But not sure I could part with it, (what ya got to trade?) "E" regulator and 425 ,set up with a 51 cone and Quadrajet flange and throttle plate and the vacume operated fuel lock-out (VFF-30) as it seems they are better then electral as it seems they last a lot longer.

The parts are out there and you can find someone local from there web site:

http://www.impco-beru.nl/products_fuel.html



Master catlog

http://www.impco-beru.nl/pdf/IMPCO MASTER CATALOG 2006.pdf

I have done a few conversions and worked on a lot of systems, I liked IMPCO better then other brands, but had more exposure to them.

Kevin

 

[JeffHK454]

The OHG 450 is the bigger and better brother to the Impco 425 .

When the original CEO/head engineer of Impco quit and started a new company(OHG) his first major design was to improve on the 425 , that's where the 450 was born.

My project is a healthy BBC 454 with dual 425s on a low riser Edelbrock dual quad
intake.

Let me know if anythings for sale!

Thanks, Jeff

 

[ShoerFast]

I need to check OHG out!

I can't think what could be improved on the 425 , there usually good for about 100K if there set up right, and have a wide area of flow, like getting a 305 SB down to a 600 rpm idle if you want it, and I have set them up in Kodiak's with 454 BB's to tote 2800 gallon propane delivery tanks up and down mountain roads, thay do okay, even at 12,000 feet msl.

That sounds like a very cool set up you have going , what is the engine going into, if I may ask? With that much liquid I would think that you may want to route the heater hose from the supply side, split or "Y" - vaporiser(s) - heater - return, and use a hi-flow water-pump, it is sort of easy to freeze them up.

As far as selling my IMPCO stuff, you would need a cool trade.
It would be my bet that there are not a lot of used #450's out there?

 

[JeffHK454]

I have an ever evolving Chevy Blazer that I rock crawl, mud bog, and generally abuse that I've been considering for a propane conversion.

The improvement in the #450 is said to be the absence of a poly backed diaphragm for flow metering, don't ask me what replaces it I'm just quoting an article off the inter-web.


Trades?... not much cool stuff at my house.

I will most definitely use your recommendation for keeping the system warm using engine coolant.

Do you think I'm over fueling ? Is it possible to over-fuel ?

Thanks, Jeff

 

[MOE]

The OHG 450 is the bigger and better brother to the Impco 425 .

When the original CEO/head engineer of Impco quit and started a new company(OHG) his first major design was to improve on the 425 , that's where the 450 was born.

My project is a healthy BBC 454 with dual 425s on a low riser Edelbrock dual quad
intake.

Let me know if anythings for sale!

Thanks, Jeff

How many vaporizers are you running with that setup? I've got a 460 ford that I'm thinking of building into a high compression LP powerhouse. I'm currently pulling a couple of LP pulling tractors. Would like to see pics when you're done.

 

[MOE]

I have an ever evolving Chevy Blazer that I rock crawl, mud bog, and generally abuse that I've been considering for a propane conversion.

The improvement in the #450 is said to be the absence of a poly backed diaphragm for flow metering, don't ask me what replaces it I'm just quoting an article off the inter-web.


Trades?... not much cool stuff at my house.

I will most definitely use your recommendation for keeping the system warm using engine coolant.

Do you think I'm over fueling ? Is it possible to over-fuel ?

Thanks, Jeff

It is possible to over -fuel. LP is more fogiving than gas because it's a vapor that mixes better with the air,(that's why the idle so low and have good lug). I use a pto dyno to tune my tractors. I like to run them as rich as I can before the power starts to fall,(overfueled). This helps keep egt's down. You can tune them with an exhaust gas analyzer.

 

[JeffHK454]

I have a set-up in mind that consists of 2-Impco 425 mixers and 2-Impco model E vaporizers. They will be adapted to a low-riser dual quad intake and double Impco #30 fuel shut-offs.

I went with Impco because I lucked into a complete 425 from a neighbor for $20.

Since both of you (Moe/ShoerFast) are considerably more experienced with propane conversions I would like your opinions.

I have a BBC 454 with mild cam and milled heads and very low miles(1700) that I'm using as a foundation. I upped the C.R from 8.75-1 to 10-1 to take advantage of the octane.

Moe describe your set-ups.

Jeff

 

[ShoerFast]

Running 2 vaporizers would not need 2 ,fuel lock-outs, just "Y" the liquid lines after the lock-out, there is hardly ever a problem on the liquid delivery side.

Moe is right about hard to over-fuel, but it can happen, you may want to start out with #19 fuel-cones and go from there, Your going to want the same "lift" of the fuel ventures at a safe or near WOT, measure and just lift or push of them to see if you need more more or less pressure from regulator to the other. (as I am sure reading this sounds harder then it is, just give the carbs what they want till they match)

Propane is so fun, a single #425 can put out close to 500HP,

Here are just a couple from the "do" list.

*do tighten the gap a little on your plugs, propane just fires, but will not even need tweaking for 100K plus miles, help the coil , cap and roter a little by less spark gap. If everything works real well, your plugs will re-gap themselves in a few years. (if your running an HEI) (propane mix is a slight insulator compared to gas)

*DO run a "D.O.T tank, and test it by getting side wind of it and crack the valves open as fast as you can, it should hiss then pop closed.

*Do short out your plugs when you first set the system up, short the evens and odds , or every-other (what ever your manifold is set up for to kill one carb or the other) to match the carbs , you want the same power from each to be the same.

*DO take time setting the system up, it is unbelievable how long propane systems and engines run.

* Do run it as fat as you can propane will burn if mixed a little lean, but there is extra O2 in the burn, that O2 and hot valves are the weakest link, if you can test it, you want about 2.75% Co.

*Do tap in a O2 sensor, there cheep, and the very best place to check your tune, you want about .7 volts up hill, and about .3 volts down hill, .5 volts should give a nice idle.

 

[MOE]

I haven't built a V8 yet but have fooled around extensivly on LP tractors and pulling tractors. Shorefast spells things out very well. What I can tell you is go with high compression,(I'm running 240 lbs cyl pressure with no detonation problems). Most farm use LP is around 105 octane. You can run almost unlimited air flow as well. A carburated gasolene engine mixes microdroplets of fuel with the air. When the fuel air mix loses it's intake speed and turbulance it doesn't stay mixed as completely. This is why it's important to match heads and intake with the rpms you want to run. Big intake and big ports for high rpms, smaller ports and smaller longer intake runners for low-midrange. When LP comes out of the vaporizer it's dry vapor that mixes with air and stays mixed with less turbulance. You can run bigger intake and ports and still have good low to mid range. big valves and headers would help a lot.

 

[JeffHK454]

Would you guys think I might be better to run a single 425 rather than a dual set-up?

I know in stock form this engine was rated at 310 hp and with simple boltons it might make 330.

Thanks for the info!

Jeff

 

[MOE]

IF it is an off road, weekend fun truck, I would lean towards running the dual setup with a model E vaporiser feeding each one. My reasons are because you can buy the componants so cheap,(look at impco on ebay) and it would look cool as hell when you open the hood. Another thought: LP works great with turbos

 

[JeffHK454]

Moe I should probably avoid talking to you , we have very similar ideas.. ..

And yes dual mixers on a 2x4s manifold does push the cool factor way up!

turbos, um??

 

[JeffHK454]

Now got two Impco 425s, just won a new for $56 off e-bay!

need some E or L Impco regs.

 

[ShoerFast]

Would you guys think I might be better to run a single 425 rather than a dual set-up?

I know in stock form this engine was rated at 310 hp and with simple boltons it might make 330.

Thanks for the info!

Jeff

In all honesty, I would run a single #425 , or give it a try, one of the biggest advantages is the drivability at the bottom end, for a rock-truck that is key!

If you dint get the dual set-up perfect, a slight throttle lift, may be just more power then you want.

Take a look at what you have for fuel in the idle portion of the carb? I think you will notice that there is really not much adjustment, and to keep an engine at it's rock bottom slow, your relying mainly on that setting.
The idle setting would be twice as hard to control with 2 carbs.

Once you start to add some throttle, the venturies start to lift, if one starts before the other, your power out-put compared to demand will be not be as accurate. IWO just a little foot into it may give your just a little power, but just a scooch more may be 3-4 times what you want, dual carbs are just plain hard to get perfect. I call this phoneman "eerky-jurky"

A single set up would have just as much power as a dual , too about 80% then the dual would kick it's butt. The single setup would kick a dual setup for "usable" power, or controllable power.

Try the single first, take a lot of notes on how it runs, use the idle screw to note speeds, (like all the way in, and all the way out) take vacuum readings at different speeds, (inches hg @ say 1000 , 1500, 2000, 2500, ect to say 5K) switch carbs and set it, make it do the exact same thing, you will be just that much closer if you mount both.

A single #425 will make 330 HP in a cake-walk! Rember, propane dose not have the power as gas would, but has nothing to do with induction, if a 500HP engine on gas got 400HP on a single #425, it would at best get (just a guess) get 430hp with a dual set-up.

 

[JeffHK454]

What I've picked up so far is that the limiting factor for performance is the cfm of air that a mixer body can flow, correct?

Propane mixers get very inefficient when they reach there limits of air flow and will "over fuel" the air charge . Talked to the tech at "GotPropane" and he told me that a single 425 body just can't flow enough air to feed a 454 with 10-1cr and performer cam. Impcos web site has a chart that rates what its systems will support , a single 425 with an L or E reg are said to have a ceiling of 281 hp.

Other than synchronization there are no minuses? Could you intentionally set them up progressively for a smooth low throttle "open" and "close" and still flow big cfm at 4,000-6,000 rpm?



Ever port a mixer inlet for more flow?



I have ZERO real world propane "hands-on" , I just listen and read.

Feel free to tell me I'm all wet!

Jeff

 

[ShoerFast]

Part correct!

The limiting factor is the total amount the whole engine will flow, but not limited by the mixer. Just as there is no real limit or rating for the HP that you could get from , for a say, a Quadrajet, there is no real limit of HP from a #425 .

The mixer could flow 1000 cfm, but at a substantial lose of pressure (it would have a lot of vacuum)
If you match and tune the mixer cone, and the flow from the regulator, it won't hit too rich at the very top, but as mentioned, your going to need to check it at a safe WOT speed. Not that you can port the mixer, but you can do a lot to the regulator.

If you look at the opening in the mixer with the diaphragm pulled open to full, and compare it to the size of the throttle plate you can see that the mixer will keep up with the plates, I like using Quadrajet plates.

The biggest limiter to the performance, IMO is the cam, again you can go too big, but propane dose not need the system to revolve around a set flow as much as cams for gas engines, your "Performer" cam may be a alright, but it will feel like it is a couple sizes smaller or more "stock" then it is. If to put an idea to cams sizes, we could start with a stock cam, move into the long duration short lift "RV" or towing style cams , then into hi torque "Boat" cams and then into choppy street-rod cams , then into your full snort , can't idle race cams. Out of those, the aggressive "RV" or a hot Boat cams are a nice power.

Latuni <sp grinds a few "propane" cams that take advantage of the ease that propane will mix, and give a little more duration to the grind.

Setting up progressive carbs wouldent be needed as much with the small then big Quadrajet plates.

Here is a picture of a single mixer 700HP CSB

 

[JeffHK454]

Thanks for the tons of info , I need to put it to practical use now.

Jeff

 

[MOE]

Shoerfast spells things out very well. When he explains the needs of rock crawling the ,(low rpm and fine tuned response) the single carb makes the most sense. I disagree on the HP comparisons for gas to LP. if The engine is a stock 7:1 gas engine that's meant to run on 87 gas,it will loose some power if you switch if over to LP and do nothing else. If you have a high compression engine with good flow that needs 100+ octane to prevent detonation, I think the HP would be very close. I would give the low to mid range tourque advantage to LP. This has been my experience with high compression tractor engines. LP has always outlugged it at low rpms. LP has high octane and burns great with high compression. It does have only about 80% of the btu's per gallon that gas does. This means your economy will go down some. I'm still burning $1.21 LP out of my farm tank. As for cams, we've had good luck increasing the overlap and lift,(providing there is enough compression to work with). Call Berry cams in Lester prairie MN they have done propane grinds.
This is inspiring me to pull the 460 out of the corner and start doing something with it......maybe a 514 stroker motor.
post some pics with what you decide to do.