Thread: Rochester jet size ?

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I have a small v-6 approx 225 cubic inches...basically stock with headers.

Carb is a rochester 2 barrel 2 jet..........no running info on the engine, rebuilding the carb now, not sure if the carb is stock to this motor or not., rebuild is because it was super rich at idle, hesitated,black smoked and was seeping/leaking thru the gaskets.


Current jet size that was in the carb are 52`s....I am not super familiar with carb jetting so I have no idea if this is middle of the road, way too small or way oversized for my application.......

Thought I might as well change them if needed while it is apart.....

I kow the only way to know for sure is readig the plugs,vac readings etc........just wanted to get in the ballpark to start with.

Any advice appreciated, thanks

You have any idea what Model Carb it is? I ran 52s in my dual one barrel Rochs on my OHV sixer with great success.

meller

Should be close on the jet. Rochester's like to run fat, keep the float on the low side of the setting on the carb overhaul sheet.

Originally Posted by MelloYello

You have any idea what Model Carb it is? I ran 52s in my dual one barrel Rochs on my OHV sixer with great success.

meller

I believe it is a 2g.........no model number, it is a pre stamped one that the tag is missing for the actuall number.....it is one of the 2g/2gv/2gc models with manual choke, making it a 2g.......unfortunatly thats all I know, other than 2 barrel 2 jet.....thanks

Originally Posted by Dave Severson

Should be close on the jet. Rochester's like to run fat, keep the float on the load side of the setting on the carb overhaul sheet.

Not sure what load side means, but I am sure I will when the kit arrives with the spec sheet...........thanks

Ahhhh my favorite carburetor......everybody should run at least 3 of them

If the carb is equipped with the fiber float be sure to replace it.

With today's crap gas I normally set the float slightly lower than the recommended setting (which I think is the same thing Dave is saying), as it helps prevent boil over during hot summer days.

As the float is set with the lid inverted that would actually mean raising the float slightly over the factory setting.

As far as jetting, 52s sounds a bit fat for a 225. My experience is that factory jetting is normally 50s for 283s and 305s, 52-54s in 327s and 350s. If you can lay your hands on a pair, I think I'd start with a pair of 48s if you can find them.


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Thanks everyone!

I ordered a new set of 48`s and a set of 50`s to go with the current 52`s........I think that will give me a good coverage.......to get started.

Also ordered a new set of idle mixture screws as these looked like someone used a cheater bar to seat them........


Hopefully this will clear up the black plugs problem and the loading at idle and the black smoke issue............

Installed a new set of plugs and just waiting on the parts kit now.

Ignition seemed fine....even with the black plugs I removed it fired right up like a new engine....actually started quicker than my 93 mustang does and it is in excellet runing condition.

Thanks

Carb kit part 1 came in today, all new gaskets,accel pump,float, needle and seat etc........waiting on idle mixture screws and jets to arrive now.

Going to get a bucket of carb /parts cleaner and a can or 2 of carb cleaner and brake cleaner and get everything soaking today.

Will post up some pictures of the carb in its current state and the new parts kit and do a kind of step by step picture information thread.....with questions.


Question..........should I worry about coating the carb on the outside and making it look like new......any pluses or minuses to doing it/ not doing it.......?

Thanks

hi shawn been thinking I played your video a few times and I don't remember my buddys jeep sounding like that and maybe somebody has put an even fire dist in here or maybe the had the dist out and put it back in out of faze at any rate the cyl. firing spacing is not evenly spaced on that eng. so either way that makes 3 cyl. in time and 3 that are out of time that's my thought I may be wrong I have been before any way it's worth checking out btw. as dave said the only manes that I can think of is Kenny bell who I don't know and lt'l john buttera and was at his shop a few times with a friend but I really didn't know him he has passed on now hope this helps....ted

Originally Posted by shawnlee28

Question..........should I worry about coating the carb on the outside and making it look like new......any pluses or minuses to doing it/ not doing it.......?
Thanks

Why of course - - - get you some fine steel wool (remembering to keep the dust out of the carb) and shine her up, if nothing else but for ONE BRAGGING PIC to save for posterity or whatever. Your call of course !

Originally Posted by ted dehaan

hi shawn been thinking I played your video a few times and I don't remember my buddys jeep sounding like that and maybe somebody has put an even fire dist in here or maybe the had the dist out and put it back in out of faze at any rate the cyl. firing spacing is not evenly spaced on that eng. so either way that makes 3 cyl. in time and 3 that are out of time that's my thought I may be wrong I have been before any way it's worth checking out btw. as dave said the only manes that I can think of is Kenny bell who I don't know and lt'l john buttera and was at his shop a few times with a friend but I really didn't know him he has passed on now hope this helps....ted

Thats not my jeep.....but exactly how it sounds....lots and lots of youtube videos with that same sound..........including my jeep........I thought it had problems as I have never heard anything like it before, maybe it is the full length headers as almost all the ones I heard that had that soud had headers.

That sound is what made me investage the carb and ignition on mine....still not thru with the ignition investigation, but after hearing a lot of jeep videos where they sound like that , I am less concerned now.

Definatly does not sound right or the way any engine I have ever heard sounded....but untill I got the jeep I had never heard of a oddfire motor before.

But just because others sound like it does not mean I will not make sure mine is correct, because it sounds unatural to me.....I like the sound, but who knows what has been changed since 1963.....as this engine did not come in a 63 jeep originally....very well could have the wrong cap or be 180 out...definatly will confirm what is going on after the carb is back on.

It did fire right up like a new engine....maybe these do not crank funny when 180 out or mis wired....we will see.......thanks

“...........Question..........should I worry about coating the carb on the outside and making it look like new......any pluses or minuses to doing it/ not doing it.......?”

That’s a good question and one I wrestled with when my grandson and I rebuilt the carburetors on the Tri-Power setup a couple weeks ago.


Let me say this first……..how the carburetor looks on the outside will make absolutely NO difference on how it will work when it’s bolted on the engine. The important part is that it is internally clean (especially the internal passages) properly assembled and adjusted.

In the case of the Tri-Power, I’m shooting for a close to show quality engine when all is said and done. I was starting out with 3 carburetors that had “aged” differently (the end carbs are 40 years old and the center is 28 years old). The finish on each of the carbs was a bit different and it really showed up when you bolted all three to a single manifold.

The original finish on the carbs was Chromate which is a “dip” process. As far as I’m concerned it is really probably the only acceptable way to truly restore the original finish. The problem from what I’ve read is it’s somewhat complicated/time consuming to do at home, and the results are not always consistent…..which can be a problem when trying to match 3 units.

Restoring chromate finishes on carburetors | The Old Car Blog

An option would be to send out the carburetors to be re-chromated, but then you have the down time with shipping and the prices I saw ran in the $100 per carb range…..much more than I wanted to spend.

The second thing I researched was the carburetor Paint that Eastwood sells (both silver and bronze). I’ve read where people like the durability of it and I actually ordered a can of the bronze color. The problem is at anything other than a cursory glance at a distance, the carburetor looks just like what it is…….a painted carburetor. The silver may not look so bad, but at $16 (plus shipping) per small can, I’ll pass on trying any other colors.

Another option that I will be trying at some point (but not on the Tri-Power carbs) is powder coating. I’ve seen carburetors done in red and black with this process and they do look pretty good. According to Eastwood’s site, a 50/50 mix of their translucent Green and Gold Powders produces a finish that is very close to original. The powder coater up the street is going to be getting those powders in at some point and when they do I’ll be sending them a couple of sample pieces to do to see how it turns out. The one caution on the process, is that the internal passages MUST be sealed off to prevent any of the powder getting into the passages. The price I was quoted is about $35-40 per carb.

What we ended up doing on the Tri-Power carbs is actually an intermediate for most processes listed above. That is Bead Blasting the body and top. The key to bead blasting is keeping the media out of the inside of the carb. How I accomplished this was removing all the internal parts, screwing on a “junk” base plate (so I didn’t have to worry about the idle passages), then stuffed the inside tightly with balled up masking tape (which would catch media that seeped thru), then screwed the top back on and plugged EVERY hole and external passage/vacuum line. After the blasting was done, I took everything back apart and flushed everything with a can of spray carb cleaner and compressed air.

When I got done with the blasting and cleaning I was so happy with the results that I decided to leave them just as they are (the bases were just painted black). I realize the finish will eventually darken but I think I can live with that.





One last tip that comes to mind for when you assemble the carb. In the kit you should find 2 check balls. They will be different sizes, but it’s a little hard to tell without actually measuring them. In the case of the kits I’ve been getting one ball (the larger) is polished and shiny while the smaller one is not so polished looking. The smaller ball goes in the accelerator pump well. If you happen to just drop the bigger ball into the well, it can jam in the port and be a real PIA to remove. The larger ball goes under the small spring and “T” shaped retainer under the venturi assembly.

Anyway hope this helps a bit.



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Originally Posted by MelloYello

Why of course - - - get you some fine steel wool (remembering to keep the dust out of the carb) and shine her up, if nothing else but for ONE BRAGGING PIC to save for posterity or whatever. Your call of course !

Yeah, it is hard for me to leave aluminum alone........just looks soo nice all polished up.......I know sometimes with heat, polished helps and sometimes it hurts with heat transfer or reflectivity...or at least that is what I have heard or read some where.......might only relate to the combustion chamber...not sure.

I might just get the funny yellow spray stuff....zinc chromate or whatever the stuff is called.....once I start polishing it is hard to find a stop point and then I start replacing good parts I can not polish .......I am trying to avoid that on this build....probably not going to happen, but at least I have intentions or trying to curb my illness

Probably end up like the last engine in my avatar......I just can`t help myself

Thanks

Thanks mike!

I decided to just clean the outside up and focus on the inside......and just as I suspected with all the "form a engine" under the base plate....we have a bolt/stud broke off in the intake carb mounting flange...

Good news is the carbs back together and I happy with it...no real issues to speak of with it, all went pretty smooth, installed the 48 mains to start with.

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No hi-jack intended here but I did my dual Roch one barrels with fine steel wool and kept them that way with just the steel wool every now and then. I'm sure there are better ways but I'm lazy and always take a similar approach.