Thread: retard vac distributor

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i have a 225slantsix race car,with 4-71 blower. i am trying to make a distributor that will leave the line at full advance then when boost comes on retard timing by 5degs, i have put together the mechanical adv parts from 225dist the gives me 25degs total timing at 2500rpms and i then installed the pickup coil and plate with vac canister from a 440bb and hooked it to port vac at the carbs. it is working but the vac side is pulling out to much timing and at to low rpms, idle 1200 rpms 10degs/ 2500rpms 25degs/3000rpms 20lbs vac 10degs,is there anyway i can reduce vac at port fitting on carb or delay it for higher rpms,i have tried screwing the adjuster nut in the vac canister it help a little but i need more delay.any help would be appreciated

hi to ya way east from the flat oil country
would something like this work for ya ? someone has to make a low output one of these. just a reverse regulator for vacume, it would be able to let you tune the advance exactly where you want it to kick in
http://www.airtechonline.com/Airtech...0&ProductID=26

Would sure be a lot more easier, and better adjustability to use an electronic retard box like MSD sells....

your right dave you can dial in anything you almost want on them

Nothings free and few things are cheap... this one works very well with an MSD box...

Brand: MSD Ignition
Product Line: MSD Three Stage Retard Controls
Part Type: Timing Controllers, Electronic
Circuitry: Analog
Controls Ignition Advance: No
Controls Ignition Retard: Yes
Use with Locked Distributor: No
Controller Activation: Programmable
Adjustable: Yes
Adjustment Style: Pills
Ignition Box Required: Yes
Compatible with Multiple Coil Ignitions: No
Quantity: Sold individually.

Timing Controller, Three Stage Retard, Analog, Programmable, Each

* Check to make sure this part fits your application

Retard your ignition timing in three different stages.
These MSD Three Stage retard controls allow you to retard your ignition timing in three different stages. You can activate one retard for a nitrous stage, and another at top-end in high gear for more mph, and still have another module left over for dual-stage nitrous systems. When activated together, the retard amounts are cumulative, so you get the total of the three. For example, if you pull 2 degrees, then 4 degrees on the second stage, and another 2 degrees at top-end, the total retard is 8 degrees (2+4+2=8). In addition to the individual retard stages, the Three Stage retard controls have an optional start retard function that retards the timing 10 or 25 degrees while cranking the engine. This makes starting high-compression engines with locked-out timing, such as crank trigger systems, much easier. These units easily connect to your MSD Ignition and can be triggered from points, electronic ignitions, crank triggers, or magnetic pickup distributors. They're supplied with a 2, 3, and 4 degree module, and must be used with an MSD 6, SCI, 7, 8, or 10 Series ignition.

If you want a cheap hobby, try whittling!!!!!

Don't know how he wanted to do it!!!! But then I don't know why someone would want to run a blower on a slant six either!!!!! What I do know is that a 3 stage retard box and a good ignition that is compatible with it is a lot more accurate and tuneable then a $39.00 vacuum chamber!!!!! Not my car, and I'm not buying the parts, guess he'll do whatever he wants.... As we all know, cheaper is not necessarily better......just cheaper....

Yup,. if it's a mild boost pressure, the dual canister distributor would work excellent, used one on a nitrous assisted small block once, worked great. But if it's up their on the edge with boost pressure, then a more tunable retard would be essential!!!!

thanks for the feed back , i not rich nor drag`n the ditches to find part. i like to find ways of making things like the first drag racer who couldn`t go to local speed shop and put the cash on the table and say i need this order it.as for my problem i just want to try taking some timing away at full boost(only 5lbs at 5700) i haven`t had the car to the track with this dist yet but it seems to idle and rev find in the garage,i will find out when i get to the track. as for the comment about not understanding why someone would put a blower on a slant/6 it`s like any motor, just to see what you will achieve, i will try some way of increasing the spring tension on the vac/canister untill i slow the timing retard to a righer rpms.