putputput carb'd engines on inclines - wheeling

[78Bronco]

I have a 460 carb'd engine in my 78 with a carter AFB carb. Carb is recently gone through and it runs well, but I am a little tired of worrying about the rig running on inclines. Are there any mods to help prevent stalling or is a swap the only way to go?

If I swap I'm not really leaning towards fuel injection. I've been thinking about swapping over to propane. I've never run propane, but the swap seems pretty simple, and honestly looks like an afternoon of work.

What have you done with your rig? If you run propane what kit do you run or did you put it together yourself? If you run carb what have you done to help prevent stalling? (besides flooring the pedal and yelling for everyone to MOVE.........?><:? )

School me, I'm undecided.

[fordtrucknut]

it may just be coinicdence but it seems to me that a good old 2 barrel works best off camber other than that I run a 600 edelbrock on my 460 and dont have any major problems with it on steep hills or off camber

have you got the timing high enough?
you may also wanna try going to a hotter spark plug its pretty cheap and it just might be worth a shot

[redmt79]

I think OX is running propane, maybe he will chime in.

Also, make sure you don't have your floats set too low.

[Highhorse78]

The best and cheapest alternative is to run a Quadrajet backwards. I rebuilt and modified a QJ for a buddy's 460. It ended up working far better than my old Truck Avenger. Going up and down inclines were about the same with both carbs, but the QJ never cut out over rough terrain like the TA did. The only thing holding me back from running one is the kickdown for the auto trans. Never did much looking but, you might be able to get a cable operated kickdown to work.

[J&SBroncolvrs]

you can put in spring loaded needles and seats if it doesn't have them already. Also you can take the top off and block the two passages connecting the float bowls at the back with either an epoxy or pieces of fuel line cut in half work well too. I wheel in the mountains and these mods work quite well. Oh yes, set your floats to 3/8" ( I just use a drill bit).

[fordtrucknut]

run a qjet backwards??? so that the secondaries are open all the time?

[Highhorse78]

run a qjet backwards??? so that the secondaries are open all the time?

No, it still operates the same under normal conditions. The reason for running it backwards is to prevent the primaries from fuel starvation on steep inclines. I'd also recommend running a regulator and dropping the pressure 1-2psi while wheelin.

[Gilligan]

The AFB on my '78 is modded about as much as one can be and it gets me by without too much black smoke and embarassement but...it's night and day much worse on trails compared to my rig with EFI (and compared to other guys I wheel with, including OX, who are burning propane). I see and hear statements all the time from people who say they wheel their rigs with AFBs and do OK...but that means they definitely do not wheel them like I do as far as terrain goes because I've done everything possible you can do to mod mine and it sucks in the worst stuff..

I've accumulated most everything including the multi-port intake manny to convert the 400 to EFI...plan is to get that done at the same time I replace the front and rear axles for 1-tons.

[78Bronco]

That is what I am worried about. Going to be some seriously wicked inclines this summer and I just don't want the poor bronco to embarress herself.

There has been trouble running propane? I thought that was pretty darn comparable to gas?

I'm sucking this thread up. Been reading up a little bit on running quadrajets backwards.

[Kaiza]

i run propane on my truck and i have no problems with it, i didnt do the conversion myself but it is pretty straight forward... not much to it really...

truck runs actually better on it than with gas, propane burns cleaner and more efficiently
only thing is it doesn't like the heat...

[78Bronco]

oh dang thats no good. I wheel in the south a lot. on a 460 in 90-100 degree temps it's going to get hot. As odd as it sounds to say it (since it is a gas), does it do the equivalent of vapor locking (a gas cant really vapor lock), what does it do in the heat?

[Highhorse78]

If you're looking to try the backwards QJ before dropping a load of cash on a pane setup, you can easily do it for less than $200. You should be able to pick up a late 60's to mid 70's QJ for around ~$75. The one my buddy is using was off a 72 Vette. The extra length CSR throttle cable was around ~$40, and the rebuild kit was $30. If setup right, it definitely beats the TA by price and performance off road.

If you're still considering a pane conversion, I would look into a dual-fuel setup. Most likely its going to cost a little more, but the advantage of running gas when propane isn't available would be worth the extra cost.

Heres some helpfull links:

Pane conversion- http://www.jasperengines.com/rock_crawler.htm

Dual Fuel kit (3/4 of the way down the page)- http://www.gotpropane.com/p4.html

[427pantera]

http://www.carburetorsandmore.com/predator11.jpg

Heard these work well.
Then again, heard a lot of bad reports about them too.
Very good throttle response.
They come up on e-bay, had two of them, but never had time to install.

[78Bronco]

At the risk of sounding like a complete idiot what is that? All I can find online for predator is cold air induction stuff. Nothing running on ebay currently.

Gotpropane's dual kit looks like it is similarly priced. But dang then I'd have to keep the mounted gas tank. I wonder if it can swap on the fly like a dual tank system or if the vehicle would have to be turned off and then restarted. Not really too important for an offroad only vehicle. The 78 is already on an electric fuel pump on a switch. I'm betting that could be tied into a dual system.

I'm going to try out all of the existing carb mods mentioned here and take her out in June. No reason to dump a grand now if I can make this carb work better.

[Kaiza]

i'm not sure how the heat affects the gas, but the engine runs a lil hotter i find.... so if you're putting a lot of stress on the engine you'll need some extra cooling, i have a high perf water pump as well as a non clutch high perf fan....

but i can second the dual fuel suggestion, i have a straight conversion and i definitely have to plan my routes as to where i can get a fill..... a fork lift bottle in the back is a good back up too...

[78Bronco]

Got a taurus fan wired up and run it on high in the summer. It would overheat without it. If I make a propane conversion, it would be awfully nice to just put two fork lift bottles in the back. Getting rid of the gas tank would be awful nice. I smack the thing every time I go wheeling.

[427pantera]

It's a magik box. :o) (http://www.predatorcarb.com/performance/carburetor.html)



The variable venturi design of the Predator carburetor allows it to work strictly off of the air demand of the engine and meters fuel in a direct relationship to that demand. As a result, the engine is never "under" or "over" carbureted at any engine rpm or load.

[78Bronco]

It is a magic box.

You weren't kidding about the good and bad. People either love them or hate them. If it really does it though it would be ideal. Still reading up though. Thank you

[OX1]

Propane never stalls, not once. Others had to remind me to shut it down when I rolled upside down. Getting fuel is EXPENSIVE and a PIA here in suburbia (34$ for 10 gallons), might be easier/cheaper in more rural areas that use pane in homes. Power is down, a lot more than most say, even with the timing bumped way up. Runs super clean, oil looks like I just put it in and that was 8 trips ago.

Backwards QJ rocked pretty well also. I got it from Jet Perf and they supposedly tuned it for a mild 400, but it ran rich as hell (usually my A/F guage was pegged all day long). I put a small alum wall with some JB weld in front of the primaries to keep gas in the bowl on extreme downhill. Never had any problems downhill, just did it as a just in case. Uphill was great, never died out, but did start to run super pig rich if you were pointed UP for real long periods.

I'd say bang for buck, backwards QJ would solve most peeps problems.

[Gilligan]

http://www.carburetorsandmore.com/predator11.jpg

Heard these work well.
Then again, heard a lot of bad reports about them too.
Very good throttle response.
They come up on e-bay, had two of them, but never had time to install.

We ran a Predator on one of our MX racers (351C built to the hilt) for many years and it did great. Some of the MX tracks are pretty extreme in terms of grades and jumps, moguls, etc. However, idle performance is not their strong suit (MX racing is all WOT for the most part) and so I have no clue how one of those would behave trying to crawl rough trails.

[427pantera]

Yes, the idle issue is the biggest complaint I heard about them.
Were you running with the optional idle circuit they have for them?
Just curious as both of the ones I had came with it already attached.(used off of flea-bay).
I sold one to a kid for his F-100 project and he was happy with it, just never got the chance to run one on my rig.

[Gilligan]

Yes, the idle issue is the biggest complaint I heard about them.
Were you running with the optional idle circuit they have for them?
.

Actually, no. I'm sure that would have improved things but frankly..the engine spent precious little time anywhere near idle RPM.:D In MX racing you put the skinny pedal on the floor and hold it there..engine RPM you control with the ratchet shifter.

[78Bronco]

Propane never stalls, not once. Others had to remind me to shut it down when I rolled upside down. Getting fuel is EXPENSIVE and a PIA here in suburbia (34$ for 10 gallons), might be easier/cheaper in more rural areas that use pane in homes. Power is down, a lot more than most say, even with the timing bumped way up. Runs super clean, oil looks like I just put it in and that was 8 trips ago.

Backwards QJ rocked pretty well also. I got it from Jet Perf and they supposedly tuned it for a mild 400, but it ran rich as hell (usually my A/F guage was pegged all day long). I put a small alum wall with some JB weld in front of the primaries to keep gas in the bowl on extreme downhill. Never had any problems downhill, just did it as a just in case. Uphill was great, never died out, but did start to run super pig rich if you were pointed UP for real long periods.

I'd say bang for buck, backwards QJ would solve most peeps problems.

Propane is much cheaper than you're getting it for dang. I pay $1/gallon. Is the usage mpg similar to gas?

We ran a Predator on one of our MX racers (351C built to the hilt) for many years and it did great. Some of the MX tracks are pretty extreme in terms of grades and jumps, moguls, etc. However, idle performance is not their strong suit (MX racing is all WOT for the most part) and so I have no clue how one of those would behave trying to crawl rough trails.

It would be a lot of idle time.

Yes, the idle issue is the biggest complaint I heard about them.
Were you running with the optional idle circuit they have for them?
Just curious as both of the ones I had came with it already attached.(used off of flea-bay).
I sold one to a kid for his F-100 project and he was happy with it, just never got the chance to run one on my rig.

something else to google. hmmm

[OX1]

Propane is much cheaper than you're getting it for dang. I pay $1/gallon. Is the usage mpg similar to gas?



It would be a lot of idle time.



something else to google. hmmm


I know I'm getting ripped, but Pa prices and Va prices were not much better, not sure where you are. Uses a lot more, especially since the M's are everything pane motors don't like. Hope to gain efficiency on my new 400 build with CHI heads and 12:1.

[78Bronco]

Iowa, the 460 hopefully won't hate the propane too much. I've seen a couple of systems for sale locally in a very attractive price range.