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Need distributor vacuum can recommendation and source
https://slantsix.org/forum/viewtopic.php?t=55042		 Page 1 of 1
Author:  Reed [ Sat Apr 05, 2014 4:23 pm ]
Post subject:  Need distributor vacuum can recommendation and source
I had the opportunity to drive my brother's 83 Dodge van a bit last week and I am not 100% happy with how the engine is performing. Manily I am not liking the low vacuum readings and the lack of power and accelration at highway cruising RPMs.

DETAILS:

1983 Dodge van, stock rebuilt 1973 904, 225 with .06 overbore (232?), stock 1983 hydraulic lifter cam and valve train, 1972 198 head with Ford 300 valves, no known porting (yeah, yeah, I know), Super Six intake with a stock Holley 2280, rear axle is 3.2 gears. Overall it is a very mild motor.

The van will cruise at 60-70 around 2500 RPM, which is fine, but it pulls around 9-12 inches of mercury when it does so. The instant I touch the gas pedal the vacuum reading nose dives down to around 5 inches until the van is allowed to cruise at VERY light throttle again. At very light throttle the vacuum will start at around 11-12 inches and if the flat straightaway is long enough it may climb as high as 15 inches.

I no longer remember what springs I put in the distributor the last time I was in there tuning it. I know I used some of the springs from the Bigslantsixfan spring kit. The mechanical advance feels pretty good, it just feels like I am not seeing any vacuum advance except for the rare long flat straightaways.

At idle the engine pulls a strong 19-21 inches of mercury. This is a big heavy (4000+ pounds, not including the trailer it pulls) brick with less than optimal rear gears (I would prefer 3.5s, at least in this application). I believe in this application I need to have mechnical spark that starts coming in quick around 900 RPM and that is pretty much all in by 2800, and I need vacuum advance that will start working at very low vacuum levels, like around 5 inches.

So, I am looking for a vacuum advance can that starts coming on around 5-7 inches of mercury since that is what the engine sees during most highway driving. Can anyone recommend a part number and/or supplier? I thought someone, somewhere, put together a matrix of vacuum cans and specs, but now I can't find it.

Thanks.
Author:  xjarhead [ Sat Apr 05, 2014 4:31 pm ]
Post subject: 
Here it was under the electrical Faq's section http://www.slantsix.org/forum/viewtopic.php?t=13198
I thought i read somewhere that the spec's on the can's were suspect as of recently.
So make sure you double check them when you get them.

Dave
Author:  Aggressive Ted [ Sat Apr 05, 2014 5:07 pm ]
Post subject: 
Reed,

PM sent for your email so I can send you all the distributor goodies in one file. Lot of good information! :D :D :D
Author:  Reed [ Sat Apr 05, 2014 5:28 pm ]
Post subject: 
D'OH! Of course I did't look in the obvious place! Sorry about that. I'l go do my homework and order a can now. :oops:
Author:  xjarhead [ Sat Apr 05, 2014 5:35 pm ]
Post subject: 
Quote:
Reed,

PM sent for your email so I can send you all the distributor goodies in one file. Lot of good information! :D :D :D
Can I get a copy of that info too please.
Does it include the curve you are running now?
PM sent.
Thanks Ted

Dave
Author:  Aggressive Ted [ Sat Apr 05, 2014 5:51 pm ]
Post subject: 
Dave,
Quote:
Does it include the curve you are running now?
Yes! both summer and winter curves. In the winter curve I snuck in a few more degrees of initial to hit a full 60 degrees. I just love the feel (spunk) in the corners on the back roads....
Author:  xjarhead [ Sat Apr 05, 2014 7:05 pm ]
Post subject: 
Thank you very much.

Dave
Author:  DusterIdiot [ Sat Apr 05, 2014 8:57 pm ]
Post subject:  Yep...
Quote:
I thought i read somewhere that the spec's on the can's were suspect as of recently.
Yep...VC-239 is no longer produced as an 11x can like the original super six cans were, it is now only produced as an 8.5x can like the VC-184/185... Even in this configuration, it is still very useful in most conservative applications, and used to be $1-2 cheaper per unit

With a grossly underpowered van or truck I shoot for a total advance (base+mech+vacc) at 44 to start, and 47 max as a safe window. You might get a little more if the engine and drivetrain is vastly improved (4 barrel, 270 torque cam, 10:1 SCR...lots of low end with nice 4.X gears).

-D.Idiot
Author:  Reed [ Sat Apr 05, 2014 9:19 pm ]
Post subject: 
Thanks Rob! Ted sent me a bunch of info that I need to read through to refresh my memory on distributor curve tuning. It has been a few years since I played this game and I am rusty. I am hoping to get a spare distributor mocked up so I can just pop it in the next time I get my hands on the van.
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