In my quest to acquire Rochester 2GC small base 2 barrels, I came across marine carburetors with the side fuel inlets. Not being a boat person, I have no idea what the differences may be. Anyone know what the differences may be? And why? Coast Guard regulations? Inquiring minds...
Don't know, but as boats often have the engines enclosed it may relate to where fuel may get out of it if it overfills. You really don't want a puddle of fuel in the bottom of the boat, unlike a car it stays there until dried up or a spark lights it up.
The bowl vent goes back into the carb rather than into the bilge. Spark arrestor rather than air cleaner. Mike
So basically the bowl vent might be set up to dump into the carburetor with minimal chance to dump into the bilge. Functionality would probably not be different. From the pictures of the marine versions, I couldn't see any visible differences. Here's the reason why I ask: there are a couple of sources for replacement carburetors for marinized Chevy engines, and they have the side fuel inlets. I'm ***uming that the castings are Pacific rim sourced, one company claims US ***embled, and modern fuels compatibility. I'm willing to take a chance on one to see about the quality and suitability. All new parts has some appeal. If anyone has used one, either for a boat or car, let me know. I'm still going to acquire a few used ones regardless. Thanks
In addition to the bowl vent, there are other internal differences; including gaskets; typically, because of the gaskets, marine carbs require different rebuilding kits. Functionally, marine carbs (at least those manufactured 50 years ago in THIS country) work great on car engines. We have sold lots of marine 4-barrels for p***enger application, and never had an issue. Have not had a lot of marine 2-barrels. Because of the venting, it would be quite possible for stalling issues in hot city driving, but so far no one has reported this with the 4-barrels we have sold. I would suggest before pulling the trigger on the off-shore stuff, check with the vendor for repair parts. Anyone can get a tank of bad fuel, and need to clean the carbs. Chances are that rebuilding kits produced for USA carburetors are NOT going to fit. See if the vendor supplies a line of rebuilding kits AND floats. The solder used to solder the halves of the floats together seems to give issues in ethanol fuel. What about calibration parts, ie jets? I haven't been to any swap meets for awhile, are the 2-barrel Rochesters with side inlets REALLY sufficiently scarce to consider off-shore stuff? Jon
Not sure on 2bbl, but quadrajets are set up for continuous load. Only light load is at idle so load can be fairly high under cruise. Jon's post is the only one I have ever seen that said they work good on the road(not doubting his experience) Would guess it would take some amout of recalibrating to use a marine unit in a car and/or vise versa. Jon, what changes would you see to set up a marine unit for auto usage?
In a different lifetime, we bought a LOT of Rochester 4-G carbs originally used on a performance 345 CID Palmer Marine. These were new leftovers. Dis***embled one to examine, and the circuitry was the same as a p***enger 4-GC except manual choke. This was early 1970's, way before Mr. Gore invented the internet and there were a number of "hustlers" on the street; many of them running "283 small blocks". These Rochesters were the 700 CID version, and ran like a scalded dog on a hot 350! "Hey kid, wanna race your wheels against my 283"? "Of course its a 283, just look at that tiny Rochester truck 4-barrel, look at that manual choke". Some jetting changes were all that was required. I remember buying 50; just checked the inventory and only have 3 left. In the day, we called these cars "street sleepers". Jon
Thanks for the input Jon. Not scarce, just getting spendy. And I don't get to many swap meets these days. Searching the internet popped up the marine links. BTW, looking at some old Hot Rod magazine articles I noticed that back in the early days of the small block, the Edelbrock 3-2 manifolds would take the early front fuel feed Rochesters, the pre fuel filter models. That's the style on the 58 283 out in the garage. Which begs the question did the later manifolds move the carburetors closer together?
I've had a few of the marine Rochester 4 jets; they look like they should flow about the same as the 340hp 409 Rochesters.
When I did my first McCulloch supercharger as a blow thru with an F code bonnet the Studebaker guys told me to use the Edelbrock/Carter clone and fit the Marine rated accelerator pump. That was a Coast Guard rated part. It was sealed. No other mod required for up to 12lbs boost (had to be tuned of course). Ran for years at 5lbs.
Someone else is going to have to answer the manifold question. I don't know. I have always built tri-powers ONLY for vehicles that came from the factory handicapped with the tripower. For non-factory installations, at least on an 8 cylinder, have always tried to steer the customer who wanted multiple carburetors toward dual quad set-ups. I rebuilt my first carburetor in 1959, when folks were looking for performance from their modifications, not just looks, and they often hid their modifications. If you look at my previous post about "street sleepers", folks I knew didn't have chrome valve covers, they didn't have chrome air cleaners, have actually seen some factory air cleaners with factory chome lids that were painted black! So other than factory tripowers: https://www.thecarburetorshop.com/Multiplecarbmanifolds.htm I don't know one tripower manifold from another. Jon
I don't believe so. People just bought small br*** 90 degree fittings that screwed into the front inlets. Something that every parts store used to have in their br*** cabinets, but not any more.
You guys are right! I'm officially crazy! The only non-Holley 4 barrel I've ever used in a performance build was a Carter AFB. It was on a 327 I acquired when I was 16. Don't ask how many decades ago that was... And I used either a Holley or a Predator on my friend's hillclimb special. Still have a gasoline one in the ba*****t, the alcohol Predator is long gone. I preferred Hilborns on the modifieds. So much easier to tune once I learned how to. And SUs on the Mini, until I got sick of them and put a 45 DCOE on it. How I wish I could make the old Tillotson carburetors from my snowmobile days work on a V-8. Of course that would require a full brace of them. And a manifold that would support them. Or I could go with Weber downdrafts. Or just be sensible, and put a, yawn, Holley on it! I've got a 650 cfm and an original Edelbrock Torquer manifold. They had good midrange torque without killing the top end, or being so soggy off idle, that I'd destroy clutches. Hoo boy, I keep opening up cans of worms, don't I?
The Edelbrock, Offy and other SBC tri power intakes for the small bore Rochester 2 Jet were all 5.5” carb center spacing. Front and side inlets work, although with front inlets you end up with a 90* fitting right at the inlet, which is why people favor the side inlets.
@carbking "If you look at my previous post about "street sleepers", folks I knew didn't have chrome valve covers, they didn't have chrome air cleaners, have actually seen some factory air cleaners with factory chome lids that were painted black!" Stock 1958 Impala set up with large air cleaner for three carbs came black from the factory. Then as money came into our pockets, just the top lid to the all black air filter cover got chromed. The chrome top only was enough to give the dark engine compartment some contrast. We also saw a fully chromed, large air cleaner for the 3 carbs in a car show and that looked too shiny and not so high performance. And then, finally, chromed valve covers with Moon Aluminum breathers. No finned aluminum covers at the time. It was just enough contrast to give it a little shiny parts to go along with the race factor... IOHO The best description is: “A non-marine carburetor will allow this fuel to seep out of the throttle shaft ends and onto the manifold. This is not allowed on a marine carburetor because normally the engine is situated in an enclosed bilge where potentially deadly gasoline fuel fumes can ac***ulate.” Most inboard motors on sailboats or even on cabin cruisers have the motors located near the sleeping quarters of the water craft. Also, it is only steps away from gathering spot inside of the cabin where the kitchen, navigation table and the usual place where food is served. So, any gas smell is not the best for the people on board. The safest place for any motor, whether efficient or gaudy in appearance is at the outside of the rear end away from all occupants. My wife’s dad had a cabin cruiser with a single Chevy v8 motor. It was powerful enough to raise the front end while cruising in open waters towards the Catalina channel. But, he had a starting procedure, just in case. He opened the engine compartment lid and the v8 motor sat there in all of its engine glory. After a spell, now he hit the starter ****on and the motor coughed to life. With no smell in place or fumes floating around, the v8 motor was now running well. The dangerous place to be sitting in any cabin cruiser with a rear located motor is at the rear transom. It looks like a great place to sit and enjoy the blue water zipping by, but the notorious CO smoke comes swirling out and over the transom to attack the deck occupants. Despite the forward motion of the cabin cruiser, the smoke swirls out, then up, then gets ****ed over the transom toward the unsuspecting occupants in their deck chairs, while the motor is running. We can’t smell CO, but together with other exhaust smoke components, if we smell something, it is bad. Most motor compartments are cramped into a small space below the main deck, next to various compartments for storage or sleeping. The compartments are sealed tightly and vented to the outside, but if it does leak, the odor is definitely noticeable. Jnaki Our experience sailing was after we shut off the motor and now the only sound was the wind in the sails. Afterwards, the motor got started to come back into the different harbor docking space(s). So, for us, there was never a smell or leak in any of the inboard motors of our different sailboats. YRMV
There is another difference between some marine carbs and standard car carbs. The needle and seat are frequently what off-roaders refer to as off-road needle and seats. Due to the swells and the pitch and roll of the boats carbs can flood out. The needle and seats allow for greater pitch and roll angles which is why we used to install them in 4 wheelers. Fuel injection is making that a thing of the past, but Edelbrock used to sell the kits for their carbs (not sure if they still do).
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