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One to two barrels.
https://www.slantsix.org/forum/viewtopic.php?t=39565		 Page 1 of 2
Author:  carlherrnstein [ Thu Mar 25, 2010 7:02 pm ]
Post subject:  One to two barrels.
I am considering modifying my one barrel intake into a two barrel so I can get away from my junk re manufactured 1920. I work in a machine shop and can run a mill, also can weld aluminum. What sort of things should i consider like....should i have a plenum divider, which direction to mount the carb etc. I plan to use a carter BBD or a new holley 2280 with the air cleaner from a 318.
thanks for any help
Author:  Reed [ Thu Mar 25, 2010 7:03 pm ]
Post subject: 
I would mount the carb with the throttle bores parallel to the engine and run a plenum divider. Post pictures of your work!
Author:  carlherrnstein [ Thu Mar 25, 2010 7:11 pm ]
Post subject: 
I thought that would give better fuel distribution than side to side, what (if any thing) does a plenum divider do ? I'm shur it divides the plenum.
Author:  DusterIdiot [ Thu Mar 25, 2010 7:20 pm ]
Post subject:  It divides the plenum...
Quote:
what (if any thing) does a plenum divider do ?
It might not have much affect/effect on a "stocker plenum"...

It would allow you to adjust the mix kind of like a V-8, except you are tuning 1-2-3, and 4-5-6.

On big plenum intakes it changes the amount of plenum each barrel has to "feed", or how many cylinders the carb "sees"...which can change the amount of reversion in the plenum if you have exhaust pulses running up the intake runners (not much if you have a stocker cam/valves). It also changes your "sweet spot" for torque/power (on a hyperpak, this brings the torque range in to a more "useable" to a street car, than a race car...)
I'd do it if you considered a hyperpak intake or even a clifford shorty intake, not "necessary" for the "Stock" intake, just isn't enough plenum to make a change to the power band, but it might be nicer to tune the engine, one "side" at a time.

-D.Idiot





-D.Idiot
Author:  carlherrnstein [ Thu Mar 25, 2010 7:35 pm ]
Post subject: 
So the plenum divider separates the intake all the way internally?
Author:  DusterIdiot [ Thu Mar 25, 2010 9:07 pm ]
Post subject:  Yep.
Quote:
So the plenum divider separates the intake all the way internally?
Mine does...

-D.Idiot
Author:  valiant1966 [ Sun Mar 28, 2010 6:08 pm ]
Post subject: 
I am currently building one of these myself. I spent this weekend grinding the one barrel boss off the manifold and laying out my aluminum plate for the carb adapter. Gonna take it to work tomorrow and mill the manifold flat and drill out the aluminum plate.

Whatever your plans are, note that the area that the carb sits on is not level(front to back) and you should maintain that same angle for you new setup.

I am using this carb. http://cgi.ebay.com/ebaymotors/ws/eBayI ... &viewitem=
Author:  carlherrnstein [ Sun Mar 28, 2010 7:19 pm ]
Post subject: 
I've read that some where before, I imagine that keeps the carb level on both axises. I wonder how critical the angle is. My plans were to set it up on a mill and get the one barrel mounting pad level, mill it off flat, cut out the materiel inside the plenum, modify a Mr.Gasket 1937 adapter, position adapter and weld it in place. If for some reason I can't weld the to together i will JB weld it :( Then paint it with epoxy paint after blasting it with walnut hull. As for the carb i would like to use a holley 2280, with air filter assembly off a 318. If anyone has helpful suggestions I'm all ears.


P.S. Thats the carb I'm looking at, does it seem to be of good quality? How easy/hard was it to order?

thanks for the input :D
Author:  valiant1966 [ Mon Mar 29, 2010 2:24 am ]
Post subject: 
Thats a good plan. I don't think the angle too critical. After all, remember how we used to jack up the rear end of our cars with air shocks to get clearance for huge tires? Didn't seem to be too devastating back then and the way I saw some of them jacked up, the carb had to be level or worse. I'm pretty sure it has to do with the float in the carb.

I can weld but am not a welder but I am pretty sure you can't weld aluminum to cast iron so plan on using JB Weld. I plan on using the existing carb mounting holes plus JB Weld to secure my adaptor. I can post a pic of my adapter plate or at least a drawing of it tonight after I get in if you like. Simple to make.

That particular carb may be sold out. Better check. It's a good deal. They are new, not rebuilt. SSDan put me on to them. Thanks Dan. I'm not sure how the linkage is gonna hook up though. I know I can do it, just don't know specifically what I'm gonna do yet. If you are interested in one and it isn't available, my friend ordered one too and isn't sure if he is gonna use it(thinking about a Weber) so it might be available. It's still untouched in the box.
Author:  carlherrnstein [ Mon Mar 29, 2010 3:00 pm ]
Post subject: 
I think my intake is aluminum,but I've never tried a magnet on it i will try one after a bit. If you don't mind posting a drawing of your adapter, I would like to see it. That's a good idea of using the mounting bolts to hold it down. If your friend doesn't use that carb I would be interested in it.

thanks valiant1966 :D
Author:  valiant1966 [ Mon Mar 29, 2010 4:57 pm ]
Post subject: 
Well, I hope a picture is worth a thousand words because I walked off and left my drawing at work. Gonna try to post some pics for ya but not sure if I got it right.

If this don't work, PM me with an email address and I'll send them to you. I WILL have the drawing tomorrow!

http://s968.photobucket.com/albums/ae17 ... g&newest=1

I have a lot of pics so if this works, I will post some more.
Author:  carlherrnstein [ Mon Mar 29, 2010 6:21 pm ]
Post subject: 
I really like that, I've just had a thought, when I do this I will use a plenum divider and possibly make a couple plates to be interchangeable, just in case i don't like the way the two barrel does. The gasket between the manifold and adapter will be neoprene or buna rubber. I have decided not to weld it on because I think that the cast aluminum will have junk in in that will not weld pretty.

dumb question: What is the hole in the heat exchange area?
Author:  SlantSixDan [ Mon Mar 29, 2010 6:29 pm ]
Post subject: 
EGR. Exhaust gas recirculation. The EGR valve mounts to the outboard face of the intake manifold. When it opens, exhaust passes into the intake tract via that hole.
Author:  carlherrnstein [ Mon Mar 29, 2010 7:47 pm ]
Post subject: 
I'm sure it's there for a reason but what is the idea behind the EGR valve. Is it increasing fuel efficiency? Or one of the things that are there to "clean up" the exhaust. :mrgreen:
Author:  Reed [ Mon Mar 29, 2010 9:43 pm ]
Post subject: 
Quote:
I'm sure it's there for a reason but what is the idea behind the EGR valve. Is it increasing fuel efficiency? Or one of the things that are there to "clean up" the exhaust. :mrgreen:
Both, actually. The recycled exhaust gases (a) get reburned so are cleaner when they go out the tailpipe, and (b) lower cylinder head temperatures and, therefore, reduces the formation of NOx and acts as a preignition suppressant which, in turn, permits you to potentially run a more aggressive spark advance curve for increased power and fuel economy. In later fuel injected vehicles the EGR system is a vital component to how the motor runs. The computer presumes a certain amount of exhaust gases being introduced into the intake and calibrates the spark advance accordingly.

However, the EGR systems on our old slant sixes are rather primitive and often hurt performance more than they help it. Plus they are leak prone and it is getting hards to find parts for them.

See the WikipaediaEGR article.
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