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DirtyComanche
08-09-2006, 09:34 PM
Every engine that I've ever seen running on propane was a 5.0L (300+ci) or bigger engine.


So, has anybody ever converted something smaller? I mean, I guess the gotpropane guys convert those piddly little toy motors. But I'd like to use junkyard parts. And DIY it.



So, I'd assume running a mixer ment for a V8 on the little renix (4.0) with a poor flowing intake would be similar to over-carbing an engine. The result being nothing working optimally.


So, should I just try it and hope for the best? I mean, my gas tank started piddling today(don't ask...), and they are RARE. So, this is a good excuse. Besides, I hate all of the wiring anyways. Although, at the same idea I'm just toying with ideas here. I can fix that tank.





I 'think' my conversion would require: (This is for an 89 4.0 Renix engine)

Junkyarding:

Propane tank
Mixer
Regulator
Assorted hoses. Ah, maybe buy them new. Probably should talk to the local impco dealer or something...

CJ/YJ intake (carbed intake), or modify the renix one? (Fill various holes)
CJ/YJ ignition, being dist, coil and god knows what else


Make:

Adapter plate for mixer.
Tank mounts, line mounts, etc. No big deal.



I have no idea what will happen when you remove the computer with the renix. I'll probably have no headlights or gauges and etc, but that's something to deal with as it happens!



Tell me I'm stupid, or set me straight or w/e.

MetalMan
08-09-2006, 09:39 PM
Just throw an alky 440 in there.

J20
08-09-2006, 09:45 PM
ya i agree you can just buy a smaller mixer and your good to go........i have seen 4.0s on prop before.......talk to Roy.......he sells a jeep kit

http://www.propaneguy.com/

ottoman
08-09-2006, 09:56 PM
i got a old 225 mixer but from what i've seen the smaller engines don't make much torque on propane

DirtyComanche
08-09-2006, 10:00 PM
How does mixer sizing work?

sj-x 500
08-09-2006, 10:02 PM
i've seen zukis on propane

m j
08-10-2006, 06:27 AM
225 is 225cfm
450 is 450cfm
I do not recall what pressure drop they are measured at

there are more mixers available for small motors then for large

DirtyComanche
08-10-2006, 08:39 AM
Well, they're out there then... What should I look for to snag the parts off from the JY? I've never noticed ANYTHING but V8 trucks, vans, and buses on propane.

fishrips
08-10-2006, 09:17 AM
I've been told that the bigger the engine, the less power you lose with a propane conversion. My dad had a V6 car (+/-3L I'm guessing) with EFI converted to propane and it lost a lot of power.... I have a 1/2 ton with a 350 on propane and it sill has awesome power. I've also heard that you can help reduce power lost by boosting compression... but yea... propane conversions are definately better on larger engines.

CORC
08-10-2006, 09:24 AM
not to steal the thread,.. but info may help both of us..
whats the difference between the 300a and the 425?
im running the 300a dual fuel, recently, went straight propane.
was thinking of replacing the 300a with the 425, will it increase power?
tourque? if anything?

ottoman
08-10-2006, 10:08 AM
i would replace it for sure. the 300a is probly only 300cfm . 425 will deliver more fuel wich = more power

DirtyComanche
08-10-2006, 12:08 PM
Hmmm, what's that formula for calculating needed air flow?



Max RPM x Displacement
-------------------
3456


And that would be assuming a 100% VE.


So, assuming a 75% VE and what I intend to rev to, I'm looking at about 280CFM.

m j
08-10-2006, 09:54 PM
some V8s are saddled with tiny 225-250 mixers on 2 barrel manifolds at the wreckers
what the previous install was on has no bearing on whether you can use the parts

DirtyComanche
08-10-2006, 10:52 PM
I assume they will have fairly easy to understand stampings on them?



Any recommendations on which brand/model is best?

m j
08-11-2006, 06:15 AM
you are not going to see too much selection in brands

Rx7_Rudy
08-11-2006, 11:25 AM
I have a 1975 monte carlo with a 400sbc on propane. I inherited it from my gramps. When he first converted it to propane in was a dog so slow. But when he got the engine rebuilt they upped the compression to 13:1( propane has an octane equivalint to 107) and did a few other minor changes, and now its screams. I think a small motor on propane without upped compression or turbocharging would leave you with very little power.

CORC
08-11-2006, 01:36 PM
as long as its done right, and the ignition is recurved shouldnt be sluggish!

m j
08-11-2006, 03:33 PM
it does depends a lot on the compression ratio
late 70s domestic motors really suck for conversions
the 351m/400 has less then 8:1 compression from the factory and are real gutless on LPG

DirtyComanche
08-11-2006, 05:18 PM
I think a small motor on propane without upped compression or turbocharging would leave you with very little power.


I will try it and see...


If not, I have one hell of a good excuse to build a 4.7.


Or, just shave the head.

jeepingpw
08-11-2006, 07:31 PM
Hers my 2 cents from what I've played with.

If you are useing a 4.0L, not much different than a 4.9L (300 -6cyl)

Had a bronco , 300 , 6cyl. took off the small mixer & put a 425cfm Imco on it, no notice in power.

400M , 3/4 ton 4x4, on propane, power wise about the same, just cheaper at the pumps & no carb prob's.

Currently have a
'93 Bronco, 351W stock, on gas, $45 to go 200 kms.
'85 F350 CC, 4x4, 35's , 460 on 425cfm propane. $32 to go 200kms.
Yeh not as much power as the old 750cfm carb,
but will still light them up in 1st (full sync. 4 speed) gear no prob.

I have a small mixer kicking around. If i can find it, you can have it.

The only reason why my Bronco is still on gas is it's easier to carry Jerry cans of gas than 20 lbs bottles of propane on my moose hunt 90kms off the hwy in PG.

DirtyComanche
08-11-2006, 08:43 PM
I have a small mixer kicking around. If i can find it, you can have it.



If you find it, I'll give you some beer! Or something else if you're so inclined (how's wine that comes in a bag sound?)


Thanks!

Torch2815
08-11-2006, 09:34 PM
I'm getting a mazda b2200 thats on propane...next weekend, You can come take a look at it if you want once I get it.pm me and let me know...

DirtyComanche
08-11-2006, 09:36 PM
I'm getting a mazda b2200 thats on propane...next weekend, You can come take a look at it if you want once I get it.pm me and let me know...


Bit of a drive!