Been doing a lot of reading on here regarding dual carbs for a 235, so getting better versed on carburetors by the day. Thought I would post my plan to see if I'm understanding things right.
First off, I'm doing it for both looks and performance. The block casting date is Dec 28, 1955. The truck is a 1952 half ton. Have 4.11s now, but planning on upgrading to 3.55s.
The engine is getting modified per the following:
- Bored .06 over - Aluminum pistons - High compression 848 head - Fenton Headers (already bought) - Fenton dual carb intake manifold (already bought) - Zero decking the block - All rotating parts are to be balanced - Mild performance cam (Intake - opens 1 degree, closes 40 degrees, .405 valve lift, exhaust - opens 56.5 degrees, closes 11.5 degrees, .428 valve lift) - Ported head (per California Bill's Speed Manual - Note: I realize this may not be worth the cost, but trying it out)
I had read enough in the past to go with the 216 carbs to minimize over carbureting it, so I've already modified the intake manifold to accept the 216 carbs. My original 216 came with the Rochester carb. I bought a second, but after the reading I've done, I'm abandoning that plan. Getting a second 1950 1 1/2 ton, so I can use the rebuilt Rochester there for now.
This won't be a daily driver, but a weekend driver in the summer months. After the reading I've done I'm figuring that going with the Weber 32/36 would be the best bet to preserve drivability around town, but give a performance boost.
Right direction? Would the Carter W-1s do justice?
I am an Engineer, so I get the can't change physics bit and over carburation, but with what I've read, feels like the progressive carburetor is the way to go for my build given the looks part of my criteria. Input welcome.
"I am an Engineer"- - - - - -You have my sincere sympathy!
Stick with the 4.11 rear end gears. You will experience some severe bogging on acceleration from moderate speeds with the 3.55 due to losing virtually all your venturi velocity anytime you attempt to pass, climb a hill, or haul any kind of a load bigger than an iced-down Yeti cooler. The only solution is to keep the engine wound up above 2500 RPM or so at all times. Even with the 216 carbs, you will be WAY overcarbureted. I'd suggest using a pair of Carter carbs intended for a CJ-2 Jeep 4 cylinder. They have the same throttle body footprint as the 216 carbs, but two of them will get you into the ballpark CFM-wise and mimimize the tendency to bog down on acceleration. This discussion has been playing on an endless loop for the almost 20 years I've been on the stovebolt site, with the same results. Most people invest tons of time and money only to get a mediocre increase in performance, mostly at RPM ranges no sane driver wants to run on the street, and lots of low speed and midrange RPM gremlins to play whack-a-mole with.
However, dual carbs and a set of repop "Fenton" headers impresses the heck out of the mouth breathers at a "show and shine" who don't know any better. Good luck! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'm realizing that the 216 carbs are not the way to go. Looking at two Weber 32/36s really. The bore area of the Weber primary is 70% of the 216 Rochester. Ideally it would be 50% for two to perform as well as a single 216 carb, but that's getting closer. My engine being a 243 now, gets it even closer. Three fifths of the way there, or you know, 60/40, better 60 than 40.
But really, I should be looking at comparing it to a single 235 carb with a 1 9/16" bore. So then the Weber primary is 65% of the Rochester. Even closer.
In addition, I turned up a Datsun forum that suggests the Weber 32/36 was designed for displacements between 1200 cc to 2300 cc, so 73 to 140 cid for a single carb, or 146 to 280 cid for two, which puts it in the 235 range, or in my case 243.
Guess I shouldn't really have mentioned the two 216 carbs in my original post as I've pretty much gone away from that route. More looking for flaws in my reasoning on going with the Weber 32/36s.
My question should have been am I on the right track with the Weber 32/36? Am I thinking along the right track? The bore area discussion was mainly referring to the lower rpms.
Kinda getting into this. Thought about calculating velocity through the bore of each carb at different engine RPMs, but realized I'd have to account for the different position of the throttle plate. Too complicated for tonight.
Two carbs on an inline six with three intake ports is either one too many, or one not enough. The firing order of 1-5-3-6-2-4 means that the volume of only one cylinder at a time is being drawn through each port, three impulses for each turn of the crankshaft. The next multi-carb engine I'm planning on building will have three Keihin side draft carbs designed for a Harley Davidson EVO engine with 40-something cubic inches per cylinder, on some short home-brewed aluminum adapters bolted to each intake port. Those carbs have a "constant depression" design, with a variable venturi slide controlled by a diaphragm which prevents over-carburetion. The engine I'll be running those carbs on is a bored and stroked 261 with approximately 300 cubic inches. It would be hard to run fast enough to give me a progressive linkage Weber 2 barrel carb of any kind, having struggled to keep one working on a couple of late 1970's Datsun 4 cylinders for many years. The adapters required to fit the Weber carbs to the Fenton manifold will result in a major loss of laminar flow of the mixture and some very bad turbulence just below the throttle plates, also.
One other point, and I'll get off my soapbox for now- - - - -the geometry of the intake and exhaust ports of the stovebolt cylinder head make any so-called "improvement" of gas flow with intake and exhaust manifold modifications the equivalent of putting lipstick on a pig. It's like joining two pieces of tow chain with a paper clip. The cosmetics are impressive, but the end result will be a big, expensive disappointment. "Your mileage may vary"- - - -but the several decades of dyno testing of mild to wild engines that I've done have me convinced that the stovebolt engine has no business trying to run in the RPM range where improved intake and exhaust flow might be benefecial. The laws of physics are not "suggestions". Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The GM engineers working closely with Carter tried it out on 1953-1954 Corvettes with 3 x 1 Factory aluminum intake with 3 original Carter type YH 2066s carburetors. Wow factor, yes. Performance increase, yes a little. Street wise it was good. Put to bed by the humble 265 V8 with a 2 barrel carburetor in 1955. Talk to the classic Corvette owner's about the issues and effort they put into maintaining 3X carbs. The 235 has been carbureted to death. The next hope is possibly MPFI (see picture for 250 intake) but the "baggage" (wiring, tubes, computer etc.) get in the way of desired appearance.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
I run dual Carter W-1's on a stock 250 inline six. It was the best move I made as far as drivability, and mileage. Performance gains, maybe a little, not enough to cover the costs, but the mileage increase more then covers it. Six cylinders have terrible fuel distribution, outer cylinder run lean, inners run rich, theres no way around it with stock equipment. I have messed around with carburetors for 20 + years on my truck, and by far the Carters work best. They have plenty of adjustability and are small enough to keep air velocity high. My intake is home made with small runner diameter, this helps keep air speed up but probably hurts high rpm running which I don't do much of anyway. If you watch e-bay, you can pickup metering rods for cheap, and there are a lot different ones available. My set runs stock jets with different metering rods, the rest of the carburetor uses all stock replacement parts. Do yourself a favor and get an Air/Fuel ratio gauge, it will cut down on a lot of guess work.
Thanks for the suggested reading buoymaker. I have read the first two, and will give the second two a read.
Joe H, any of the bogging issues at low rpm that Jerry warns about? I'm assuming no by your second sentence.
The impression I've gotten from reading on this site and articles is that two carbs on a stock engine will most likely deter performance, but there are references to some benefit to two carbs on a modified engine, which is why I'm pursuing it. In the end, for me, if I get equivalent performance, or even mildly improved with two carbs, it's a win, so trying to get it right from that perspective.
One thing I've not seen referenced in the threads on two carbs is the dyno tests done in California Bill's book. He claims a 12 HP gain (if I remember the number right) over stock on the dyno, with the only change being the two carbs from stock. The carbs used were Zeniths, which I have not heard of. Is there an argument out there to rebuke the claim the book makes?
Dyno tests are usually made to determine max horsepower and torque for running at drag strips and the Salt Flats. The drivability test is measured by the two legged Dyno called a human.
In the late 40's and early 50's American roads were improving. Luxury or premium car manufacturers are competing for bragging rights. Hudson designed car engines to be able to cruise at a higher speed/rpm on the highway. They won races. Chevrolet continued to offer economical family cars and trucks with the 216/235/261 that was designed for low rpm torque (inglorious term, tractor engine) to run on slow moving crappy roads and labor all day long in a farm field. Fast forward to today. Everybody wants an AD truck but they are quickly disappointed when the drivetrain struggles at 55 mph and driving the truck is a "white knuckle" experience on modern expressways.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
I love multiple carbs on a 235 and have run them for close to 45 years.
The Carters run pretty good. I ran a pair of YFs on a Weiand intake for many years but Jon (the Carb king) and I have had a few discussions on this topic and he has suggested, with good reason, that the W-1 would be the better choice with the fully mechanical power system as opposed to the YF vacuum/mechanical power system. My YF set up always ran rich and that is why. So if I was going to do a dual 1bbl set up again, I would be using the W-1s if I could get them.
In terms of other alternatives, I also ran a pair of 1974 Ford Pinto Holley/Weber 5200 carbs with adapters on that same Weiand intake. These are progressive two bbls with a small primary and a larger secondary. I liked them and they ran really great for me, right out of the box.
I moved up to a Clifford 2X2 and ran his recommended 38/38 mm webers. Non-progressive two bbls. I did not like them and I never really grasped weber tuning. That and I never thought they ran as well as they should.
Last year I cobbled up some adapters and bolted on a pair of Holley 2300 350 cfm 2bbls (about 247 cfm as a direct comparision to a 4 bbls). Truth be told, they run really really well on my 261. Parts are easy to come by and the jetting and tuning is more familiar to me.
The 60-65 mph of my '50 is fine for me. Tall skinny tires make it easy to steer and fast enough to get where you want to go. Nobody expects me to win a drag race.
It performs perfectly for a 72 year old truck. Why would I want to pretend that it isn't 72 years old?
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
If you get the air speed right, there is no bogging or running problems. I ran dual Mono-jets for a short time, they were way to big for the engine, as one came stock on it. It ran really good, but mostly due to the super rich fuel mixture. It was so rich running, you could almost see the fuel gauge moving. I also ran three Model H Rochester for a long time, these are small Corvair carburetors. Problem with them was no mechanical metering enrichment. I could jet for more power, or for mileage, couldn't have both. As a test, I made six runs at the local dragstrip with the three carburetors and header pipes. The following week I went back with the stock intake and exhaust just as the engine came with. Both setups idle, and ran fine, I had no problem heading out for 100 mile drives with either set up. I made six runs with the stock setup. When the first six and the second six timeslips were compared, the was zero difference, mph was the same and ET was so close I could have won money bracket racing. So I gained nothing using the three carbs over stock other than it looked really cool. My track closed down or I would go and run it now with the Carters, it feels much better. My truck has a 3.08 gear with 28" tall tires, so if anything was going to bog, this thing should, yet it takes right off with no issues and pulls right up to the shift rpm. Last outing was 240 miles, mostly interstate at 65 mph, averaged 21 mpg with A/C on, the Mono-jet wouldn't even get close to that.
OlbetsysDad Hey all you engineers,when I put propane injection on my 04 GMC I ask that guy if I could install the equipment. He said engineers ask me that all the time,next he said if your a guy out in the hog-lot fixing fence with your pliers you probably can install it.Well it's been fine winning right now at these prices.
Old enough to quit trying to convince anyone of anything; however:
If I still owned a Chevrolet 235 6 cylinder, it would immediately (assuming no clearance issues) be equipped with a triple manifold and three Carter type W-0 carburetors from a Willys Jeep identification number 636s. Linkage would be straight, never progressive.
i wouldn't personally use a dual manifold on my own Chevrolet 235 6 cylinder, but if I was forced into a comparison test; I would use two Carter type W-1 (either a mix or match 483s, 574s or two matched 420s) carbs with straight linkage. Joe has proved what two Carter W-1 carbs can do.
The bottom line is: if the owner is happy with his/her set-up..................................................................then the owner is happy.
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
Jon, the old saying "My mind is made up- - - - -don't confuse me with facts!" probably applies to a lot of these discussions! Ditto for adjusting valves, setting ignition timing, and a lot of other subjects we cuss and discuss here! At least it's cheap entertainment! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jerry - you are probably correct; but at least folks are asking questions.
The internal combustion engine is remarkably adaptable.
When it comes to carburetor(s), lots of different ones will work; some will just work a LOT better than others.
Perhaps we try to be too much of perfectionists?
Repeating from my previous post:
The bottom line is: if the owner is happy with his/her set-up..................................................................then the owner is happy.
I personally have always thought engine modifications should improve something (fuel economy, power, reliability, all of these???).
Eye candy under the hood is fine for many; but to me it falls under the same category as fuzzy dice, a winking cat in the rear window, and curb feelers. Not trying to talk anyone out of it, just not my cup of tea. I would rather have some actual improvement.
Jon.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
Some people mutilate their bodies instead of their trucks. I've collected too many scars and scrapes by accident to ever consider doing any sort of "body work" on purpose, whether that might be tattoos, piercings, or making anything bigger or different-shaped than what I was born with. The ladies in particular seem to like doing that last thing- - - - -repeatedly! LOL! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'll challenge any of yous guys with 2 carbs to a race of your choice. My '50 3100 has a 235 high pressure '53 engine with a YF2100 carburetor on a stock intake/exhaust manifold. How will I beat you? A T-5 transmission, a 4.64 to 1 limited slip rear end out of a 2001 Nissan Xterra (6 lug Chevy bolt pattern), and 30 1/2 tall skinny radials. That's how. (I normally answer this multi-carb, soup up my truck question more tactfully, but I thought I'd change it up with a different strategy of bold directness to get my point across. No offence intended.)
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
The fiberglass body Excalibur roadster I've got waiting for shop space is going to have a 4.30:1 ratio Toyota Supra independent suspension rear end, and either a 230 or 250 inline six, plus a 4L-60 OD transmission. That same bell housing bolt pattern will accept about six or seven different GM engines, from a Mercruiser 4 cylinder all the way up to a big block V8. With the hood closed, I'll have the ultimate sleeper! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'll challenge any of yous guys with 2 carbs to a race of your choice. My '50 3100 has a 235 high pressure '53 engine with a YF2100 carburetor on a stock intake/exhaust manifold. How will I beat you? A T-5 transmission, a 4.64 to 1 limited slip rear end out of a 2001 Nissan Xterra (6 lug Chevy bolt pattern), and 30 1/2 tall skinny radials. That's how. (I normally answer this multi-carb, soup up my truck question more tactfully, but I thought I'd change it up with a different strategy of bold directness to get my point across. No offence intended.)
Often, the cheapest method of improving performance is more gears.
By far, the easiest and cheapest way to lose at least a second in the 1/4 on a 1964 GTO was to replace the original 2-speed A/T with a 350 turbo. Bolt in swap.
But have you chrome-plated the transmission case for eye candy?
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
Hotrod Lincoln, carbkink, Joe H and the others. Thanks for the input! I really appreciate it, whether it agrees with my direction or not.
I have kids, and this thread really reminds me of some of the things I preach to them. I always say, you can learn it the easy way (experience of others/dad's advice) or you can learn it the hard way (on your own). They usually choose the hard way. I guess it's human nature.
Compared to you guys, I'm the kid for sure (at 49! but I've owned my truck since I was 15). I don't know what it's like down in the US, but I've been to car shows with up to 2500 cars up here in Alberta. Of all the 50's Chev's I can look under the hood at I see maybe 2 inline sixes. For me it's a balance of show and performance. I want, as Jerry says, the mouth breathers to be impressed because there's nothing like that here. I also want to balance that with performance. It's the right mix for me.
So what I'm saying is, I'm going to do some learning on my own, cause who doesn't like to tinker! And I'm going to take some of the expertise given here so I can stay out of serious trouble.
Mark, I'm termpted to put a 300 cubic inch "261" with the three Harley side draft carbs in that Excalibur, but that would involve using a different bellhousing that would not be compatible with the 4 cylinders, v6's and V8's. If I'm able to destroke a Chevy 230 engine about 1/8" I'll have a 200 cubic inch inline six capable of about 7500 RPM, with NASCAR H-beam connecting rods, a bit of cylinder head work, and the proper roller cam. That would be a real attention-getter! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Quote "So what I'm saying is, I'm going to do some learning on my own, cause who doesn't like to tinker! And I'm going to take some of the expertise given here so I can stay out of serious trouble. Thanks again guys!
Mark" End quote
Experimenting oneself is the definitive answer for each individual.
Take good notes; do zero~55 times (average 3) with each set-up for comparison.
When the project is finished to your satisfaction, please post results on these forums.
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
A long uphill grade where you can run wide open throttle in high gear for a mile or more and a stopwatch makes a pretty good field expedient "dyno". Make several runs at various RPM starting points, and make ONE change at a time such as ignition timing or fuel metering, etc. Compare times and you'll be able to get a good comparison between runs. On the race engine dyno runs we did we would also try to have similar ambient temperature, atmospheric pressure, and relative humidity conditions if at all possible. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Good idea on the timed runs. Sounds like spreadsheets and graphs. Kinda my wheelhouse!
When I was 18 I took the truck to a mechanic to try get it tuned properly. I didn't have the skills, and the internet was just coming into existence. The mechanic flat out told me to go find an old farmer.
So I asked my grandfather, which I should have done in the first place. He told me it's tuned properly when I could start out in third gear. Pretty simplistic.
I'll post results when it's done, but will be about a year's time.
Good idea on the timed runs. Sounds like spreadsheets and graphs. Kinda my wheelhouse!
When I was 18 I took the truck to a mechanic to try get it tuned properly. I didn't have the skills, and the internet was just coming into existence. The mechanic flat out told me to go find an old farmer.
So I asked my grandfather, which I should have done in the first place. He told me it's tuned properly when I could start out in third gear. Pretty simplistic.
I'll post results when it's done, but will be about a year's time.
Now that is perfect "farmer logic." I like it! Woe is a man who has not spent considerable time working with a long time farmer. With what they are up against on a daily basis when time is greatly limited, miracles happen.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
My grandfather was also farmer as well as a tool and die maker during WWII.
When I was 10 years old I bought a 1946 Cadillac. It wouldn't start one day and I was pretty dejected. My grandfather told me that the car was designed and built by men. These men were no better than me and if they could build it I should be able to fix it. He instilled the "can-do" attitude of a farmer in me.
Last edited by Otto Skorzeny; 06/21/202210:34 PM.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
Otto, I was fortunate to grow up around a bunch of people with that kind of attitude. They survived the depression, won WW II, and invented things like the automatic transmission, air conditioning, supersonic airplanes, space travel, cell phones, and personal computers. Somewhere along the way, their approach to problem solving was replaced by "If at first you don't succeed, give up and cry about it!" and "There's no app for that!" Lord forbid that anyone would think outside the box on anything, or use the "I'll make it work" approach to solving a problem. That might be one of the reasons America hasn't won a war since 1945! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Olbetsysdad That is a lot to spend on what some call a tractor engine,as far as power just a garden variety accurate re-build should do what you want. I swear by propane burners but no one wants to hear that,no sludge,easy starts,never cold natured,doubt if you want to hear it either. good luck !!
What sort of fuel economy does a 216 get on propane in a stock AD? What does propane cost per gallon when you aren't buying the Blue Rhino tanks at Walmart?
Last edited by Otto Skorzeny; 06/21/202210:38 PM.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
Olbetsysdad That is a lot to spend on what some call a tractor engine,as far as power just a garden variety accurate re-build should do what you want. I swear by propane burners but no one wants to hear that,no sludge,easy starts,never cold natured,doubt if you want to hear it either. good luck !!
fixite7, this 'tractor engine' is what my Grandfather introduced me to when we pulled the truck out of the bush when I was 15. So it's not a 'tractor engine', it's a legacy for me. Although it's not the original 216 I'm playing with, it's the 235 out of the grain truck I used to play in the back of during harvest when I was a kid. 35 years later this is my vision to play with.
There's probably no words to describe my feelings towards the project except it's my vision. Just trying to carry it out in the best way possible for the goals I have in mind.
Honestly, let's face it. From what I see, I'm a younin' in this game. If guys like me don't start tinkering, there'll be no experience left for the next generation. I value every piece of advice given here, but if I can't say to someone one day, I tried that and it didn't work, then I haven't lived the way you guys have already lived.
Without a lot of other modifications, running LP gas is a giant leap backwards. The first result is around a 5% or greater reduction in power from the gas displacing some of the air voume that would normally be drawn into the carburetor. This can be offset to some extent by taking advantage of the approximate 110 octane of LP gas and raising the compression ratio of the engine to 11:1 or so. You'll also need stellite exhaust valve seats and/or stainless steel exhaust valves, so by the time you amortize the cost of building an engine that can never be run on gasoline, even in an emergency, and being restricted to areas where LP gas with road tax added to the price of the fuel is available, the engine will be worn out. To my decidedly biased point of view, that's a fool's mission.
"Propane" is a misnomer. LP (Liqufied Petroleum) gas is a mixture of Propane and Butane, and the blend is altered seasonally. Butane produces more thermal energy than Propane, but it "freezes" (stays liquid) at 32 degrees F. Propane evaporates at -70 degrees F. or so, and winter mix gas has a higher volume of Propane mixed in for easier evaporation. That doesn't matter much for cooking or home heating, or powering your back yard hot dog grill, but it makes a big difference in engine performance. "Your mileage may vary", but I choose to deal in facts, not fairy tales! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
That sounds a lot like what I found when I looked into it some years ago but I never seriously got into looking at it further. I understand the appeal of it in purpose-built engines for forklifts and other small equipment that works indoors but not for highway use.
On a related note, I'd really like to get a mid 1980s Mercedes 300D and put a vegetable oil tank in the trunk. I met a high school kid who did that about 10 years or so ago. At that time restaurants would give him the used oil for free. I think most places charge for it now since it has become more popular.
He installed a tank in the trunk that was operated by a switch under the dash. He'd start the car on diesel and then flip the switch to the used oil after the engine warmed up. All totaled the conversion only cost him about $250. He didn't have to make any modifications to the fuel system or to the oil. It went through an canister style oil filter before entering the fuel system.
The tailpipe emissions smelled like French fries (or nasty fish if he got the oil from Captain D's)
Last edited by Otto Skorzeny; 06/22/20224:53 PM.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
25 years ago (maybe longer, memory not that good), the local LP companies used LP in their delivery trucks.
Maybe 25 or so years ago, even the LP companies quit trying to use LP, and went to gasoline and diesel powered trucks.
If it is not economical for the LP companies.........................................
I have personal experience with only one vehicle that was powered by LP.
In 1981, Dad purchased a new Winnebago with factory installed dual fuel (gasoline/LP) with a Chevrolet 454 engine.
Mileage (Dad kept complete records, no guessing):
Winnebago alone: gasoline - 9.3, LP about 4 (since how full you can fill an LP tank depends on temperature, difficult to really pin it down to the tenths) Winebago pulling loaded 16 foot trailer - gasoline 6.3, LP - less than 2 on level ground (insufficient power to pull the trailer in the Missouri Ozarks).
I understand that an engine designed exclusively for LP (as Jerry discussed), will be some better than a dual fuel.
After a couple of years, Dad disconnected the system to save the $110. Missouri auxiliary tax (this in additional to the vehicle license) for using LP, only to find that the total system had to be removed, and the vehicle inspected by the Highway Patrol to remove the auxiliary tax. Dad spend several dollars (in the hundreds) to have the system removed, and put the entire system in recycling (polite word for junk!).
Jon
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
Olbetsysdad Wasn't trying to insult your project,others are often not very tolerant of idea's presented on stovebolt.Example...a lightweight AD truck on propane works fine,tyeing onto a 30,000 lb. trailer and heading off into the mountains on propane not so good !!
carbking They learned that same lesson around here trying to farm with 11 cent propane in the fifties. When your valves run red-hot under a hard pull on LP they wont last long,in a light throttle application (cruising) last a long time even without hundreds of dollars spent on modifications. At least mine do.
Otto Skorzeny An old guy in our fish eating town heated his house with cooking oil,using an oil furnace and oil the restaurants would give him. Always smelled like supper was ready when you went there.
That's funny. I saw a show on tv last week where the largest factory fishing ship in the American fleet processes every single part of the hundreds of tons of fish they catch.
After processing all the filets and edible stuff, the rest gets turned into fish oil and is used to run the diesel engines on the ship!
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
