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Need help setting up dist for max torque d150 lean burn conv
https://www.slantsix.org/forum/viewtopic.php?t=37360		 Page 1 of 1
Author:  radarsonwheels [ Sat Oct 03, 2009 11:52 am ]
Post subject:  Need help setting up dist for max torque d150 lean burn conv
Howdy

Please help me sort out my truck!

*Background*
I just got a 1987 /6 d150. I love it and it drove great for about a week. Thats when I had to replace the rear brake lines. No biggie, just maintainance, right? Then the lean burn pooped out on me. I put in an MSD 6a triggered by an old points distributor with a new set of points. The motor felt stronger and smoother, but without computer control the carb isn't acting right. Starts hard b/c the choke isn't working. She pings past 1/3 throttle and knocks past 1/2 throttle. Even with the vac. advance disabled and the timing at around 0btdc.

I ordered a new holley one barrel from ss Dan. I think his stuff is drop shipped from the midwest? Anyway, that is only one part of the puzzle, and hopefully gets me going much better. Of course when I put it on I will be making sure there are no pesky vacuum leaks.

The biggest problem with the truck is getting moving from a stop. Its not too bad on level ground, but uphill- fuhgeddaboudit! I am tearing up the clutch and knocking and all that bad stuff. Once she's moving the power (or lack thereof) is plenty. This is with an 833od, so the first gear is real short, like 3.09 I think!

*Question*
While I'm waiting for the carb I want to figure out the distributor. I need to know what a good initial setting is, and a good total mechanical advance. Also, how much vacuum advance do I want? Again, this is for a relatively heavy truck, not the A-body I'm used to...

Thanks
radar
Author:  DusterIdiot [ Sat Oct 03, 2009 12:40 pm ]
Post subject:  Keeping the points right?
If you are keeping the points you are locked into an 11.5 governor, so 23 degrees mechanical advance. A little more initial is fine but you are driving a brick so you will have to have little initial since the load on the engine will be high with low rpms until it moves... You also will be limited on your vaccuum advance because the truck is going to place a lot of demand on the smaller engine... I would set at 5 btdc max + 23 if the advance mechanism actually will max out... so 28 degrees...the stock point vacc. pod is a 6.5, so 13 more degrees at cruise...for a total of 41...which should be OK...if this were a EI distributor I'd try to replicate the mopar truck distributor as best as possible, they used low initial, a 13R governor, heavy springs and rotating the lugs out so the springs catch sooner to slow down the advance...and an 8.5 vacc can like the 1973-1974 cars did...

Check the rear-end ratio...yor truck may have a 3.21, or 3.55 rear ratio...which are great for cars, but a bit much on a heavy truck with the OD...a set of 3.91's would make it a bit easier...also check to make sure the clutch is adjusted right and you have the fluid topped up in the tranny and rear end....

-D.Idiot
Author:  radarsonwheels [ Sat Oct 03, 2009 1:48 pm ]
Post subject:  thanks awesome answer! Where can I find more info?
Where can I read more about different governors etc.? I never saw this information before.

Do you think I would be much better off with the magnetic pickup setup instead of points? Its only triggering the msd, so I figured the wear issues associated with points would not be an issue. It would be really easy to switch to a two wire hookup to the msd instead of the one. Are you saying that the EI distributors had more advance built in?

This isn't my first rodeo with distributors- it's my second :razz: :roll:
My 408 smallblock ended up wanting 25 initial 35 total. Before that I only knew how to set initial and hope the curve would work. I know a little about welding up the slots, changing the springs, etc. but I never did it. I took the easy way out with the v8 and bought a pro-billet. For the truck I definitely want the benefits of vac. advance and Dan says the carb I'm waiting on has ported vacuum for my distributor :cool:

If it's the way to go I'm sure somebody here could come up with a decent dizzy to fiddle with. I don't know if that will be necessary since the numbers don't seem too far off if all is as you say in my points setup?

Dang lean burn!

Thanks again- you know a lot for an idiot!
Author:  Aggressive Ted [ Sat Oct 03, 2009 1:55 pm ]
Post subject: 
Do a search on recurving distributors......lots of good info and pictures of the different governors.
Quote:
Are you saying that the EI distributors had more advance built in?

Yes, the the 73-74 EI distributors have longer slots for more advance. Try and find one for some good tuning options.

DI is right on.... :)
Author:  radarsonwheels [ Sat Oct 03, 2009 2:57 pm ]
Post subject:  Didn't get much searching here, but look here:
http://www.potentialtech.com/pmoran/dist-9-22-05.pdf

Pretty cool article.

I didn't realize when you said governor you were just talking about the plate with the slots in it!

Now I got a good handle on it. I think I will remove/ clean/ modify my dist. this week.

Thanks everybody this site rocks!

radar
Author:  DusterIdiot [ Sat Oct 03, 2009 4:59 pm ]
Post subject:  Good luck.
Hopefully it works out for you. If you get into a bind, Midi has sent me a mid-70's EI Truck dizzy and it has the 13R plate so you can run a little initial and still let the spring slow down your "ramp up"... I haven't taken it apart yet to recondition and map the curve yet.

-D.Idiot
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