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propane ?

Mud Rat 12

Mud Rat 12

1/2 ton status
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Jul 31, 2000
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Citrus Heights, Ca
I keep looking into this. I can get all the parts but I do not know what size parts to get.
www.gotpropane.com kit is great but $1000:screwy: is a bit much.
does anyone know what size impco propane carb or regulator to use.
I have a 350hp 400ft-lb 355ci motor.

Thanks in advance.:waytogo:
 
run dual Impco 425 mixers and Dual Model E vaps im running just 1 425 on my 355 300hp sbc and it works well but dual would make it alot nicer for CFM rating into the engine
 
I'll be setting the blazer up with Propane eventually. Gona run it on dual 425 impcos. I guess you need dual vaporizers as well. I'm wondering why not do a dual VFF30 lock off as well for trail redundancy.
 
well duals arnt really necessary 1 vff30 lockoff will be just fine for that whole setup be prepared to up ur mech timing alot im running 14def adv mech lol its awesome cause its such high octane 110 it doesnt knock but make sure you build a motor for propane the heads have to be built up or else you will pound the valves into the head and seats and mess up stuff royally also run single plane intakes cause the propane is already heated its not like gas where it needs to vaporize before hitting the cylinders
 
Yeah, I think I'm going to find a 425 and E type + lockout and run 2 10gal tanks. I have a edelbrock carb legal 600cfm now.

That should be good for a solid weekend on the trail. Rubicon is only 11 miles round trip and I trailer to and from.
 
Disciples Performance said:
well duals arnt really necessary 1 vff30 lockoff will be just fine for that whole setup be prepared to up ur mech timing alot im running 14def adv mech lol its awesome cause its such high octane 110 it doesnt knock but make sure you build a motor for propane the heads have to be built up or else you will pound the valves into the head and seats and mess up stuff royally also run single plane intakes cause the propane is already heated its not like gas where it needs to vaporize before hitting the cylinders
Click to expand...




I was thinking more for a backup I guess. Just doing some reading up on it tonight and it seems some higher cube engines aren't getting enough fuel through the lock off so its helping them. Gona build my own intake, It'll be an aluminum mid rise single plain.

Mudrat12, not trying to hijack. Seems the Propane info gets kinda scattered.
 
Not sure why people like propane so much. It makes less power, uses more "fuel" and requires a much higher compression ratio (11:1-12:1 ideally) and is harder on an engine and can't be bought everywhere and also you can't just borrow some from someone on a trail unless they have an extra tank to loan you. I just don't see any benefit to using it over going with a FI setup other than no electrics to deal with.
 
4x4high, some of the reasons you mention are some of the reasons I love mine so much. If you put propane on a stock low compression motor you are correct that it is not an ideal setup. But, if you build up the motor for propane, It is a wonderful fuel. Really all you need is high compression and stellite exhaust valves and WOW.

1. High Octain - Allows you to bump up the compression to get back the lost horsepower
2. With the exception of exhaust valves (easily remedied) a propane motor will outlast a gasoline engine quite handily as they burn ridiculously clean.
3. vaporisation - No need for trying to get gasoline to vaporise for proper burning as propane is already in that state. No fuel puddling when cold.
4. off camber situations - if you could keep oil in the pump the motor will run forever on its back.



I especially loved the vaporisation in my truck. it was converted to propane in 1974 (one year after it was bought) and the carb was hell going from sea level to 7000 feet. The carb was constantly out of tune and cold starting was almost impossible. With propane the car would sit for 3 days and cold soak down to 17 degrees. You could turn the key and the truck would start like it was a 70 degree day at sea level. No choke, no fast idle, no fuss, no muss. That was worth all the downsides. All this comes from over 30 years personal experience running a 100% propane system on my jimmy. It is a daily driven truck with over 300,000 miles.

Now, after saying all that, I agree that most of these issues are resolved with FI and I am actually switching my motor to a dual fuel setup that will run both. Given the advances of FI and computer control I can now get an engine that will run efficiently on both. I love technology and building my own FI computer. :D So many possibilities.

Now, for a person that just wants a super simple system that will run off camber with zero fuss I don't think propane can be beat especially for those that are intimidated by wiring. single wire hookup.
 
I'm sorry to say that even with a propane built engine with the higher compression it still doesn't make as much power as an engine running gas. I can understand the desire to have it start everytime no matter what elevation or outside temp but still not sure why people want something that uses more "fuel" and makes less power. Also the higher compression is alot harder on the internals of the engine than a lower compression engine.
 
I went with the 425 Stage 1 kit from propane guy (350 CI .030" over, mild cam, Edlebrock Performer manifold) for $380 shipped (US dollars). His instructions were hand written and a little hard to read but he is good about answering emails. Total cost was around $850. Some things I ran into were tank brackets, availability and use of forklift cylinders vs. a steel tank, and the fittings and hoses. Brackets cost me $41 per set vs. another guy wanting $100. I went with used steel cylinders (10 gal. aka 43 pounders - empty; about 80 full) for $40 each. I saved a lot on fittings and hose because I have a friend who works in the hydraulic and pneumatic business and he got the stuff for cost plus. Example: the hose from the cylinders to the lockout was around $3.50/ft through him and others wanted as much as $13.50 per foot.
Another thing to consider is how the 425 will mount. I was running a Q-jet so I needed an adapter plate to mount the mixer on the Q-jet throttle plate (which by the way needed rebushing of the primaries - propane hates vacuum leaks). I got the plate from Carburetion & Turbo Systems in MN(IMPCO part no. is AA3-86). Eric is real helpful (952-445-3910).
Worst problem so far centered around starting and it did not show up until recently. I had the vacuum line from the lockout teed in with the line running to the distributor. Eric helped by telling me I needed a "manifold" vacuum source so I reconnected to the two-outlet fitting that is toward the rear of the manifold and serves the tranny vacuum modulator.
I wound up with a single fuel system - nothing mechanical or electrical and I really like the way it performs. It has eliminated all stumbling/rough running and for the wheeling I do, I noticed no loss of power.
Hope this rambling helps. I only recently rejoined and got a little "wordy".
 
everyone forgot to mention that the fuel is still cheaper...it might burn faster but its almost half the price of gas around here
 
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