Hello Buick Fans! Thank you for all your comments on my last posting, "When does it need a girdle?". I have the motor back together and very carefully followed the suggestions that were offered in most instances. Which bring me to my question. When I degreed the camshaft at the intake lifter the measurements indicated that the camshaft was 2 degrees retarded. This surprised me since it was ground at 4 degree advance built. The dual roller chain had a little slop maybe 3/8 inch back and forth midway between the sprockets. When I changed the camshaft to 1 1/2 degrees advance at the lifter measurement and reassembled the motor I lost 3 to 4 inches of vacuum at idle (You know what this does to your brakes). It was 12 to 13 inches previously and is now 8 to 9 inches jumping to 15 inches as I flash the motor to 2500 / 3000 rpm . Is this normal or is my vaccum gauge correct in telling me I have an Intake maniold leak? POINT two - I installed the MSD digital 6 ignition system. To this point my motor has a locked down vaccum ignition and total lead on the mechanical is 30 degrees. The car runs best at this setting according to the electric timer an MPH at the strip. Question - Should I reset the timing to 34 for streetability and set the high RPM retard to back this down to 30 degrees. Would it be better to reinstall the vacuum an limit the advance to 34 or 36 for streetability? Compression ratio has been calculated @ 10.50 and it has been had on the gear reduction starter at startups, this is part of the reason for the dual retard ignition system. I await your input with anticipation of even more stellar advise. Weekender
Weekender, If gas mileage is at all important to you. Install the vacuum advance, and limit it to 8-10* As soon as you get on it, the vacuum will drop, and the vacuum degrees will go away. At light throttle the motor will handle 40* or so. You can experiment with the high speed retard on the Digital 6. I have it hooked up, and I have about 34-36* all in by 2500 RPM, and back it down 4-6* at about 4200 RPM and up. Have you hooked up the high speed retard? You do know you have to buy some other items from MSD to make it work.
Larry I bought the digital 6 in favor of the MSD al6 unit because there are no other units needed to achieve the 2 rev limiters and 2 retards levels. These adjustments are activated by switches and can be adjusted by soft touch adjustment dials on the end of the box. I think I will try the Vacuum hook up for gas mileage, we need to do our part for the ecology and the environmental cause. Do they have a dashpot that has a advance limiter built into it? I have both rev limiters and both retards activated. The Off line rev limiter does work very well since I could start the engine with just the flex plate. I won't be able to try the top end rev limiter or the high speed retard it for a few days. My transmission still at the Doctors since the PAE convert failure. Any thoughts on loosing 4 inches of vacuum after I degreed the cam? Larry (Weekender)
Larry, I see you haven't really read through the directions that come with the Digital 6. The high speed retard is adjustable, at the box, for the amount of degrees desired. BUT, it needs to be triggered by the pink wire. When that wire sees 12 volts, it retards the ignition by the amount dialed into the box. Same for the secondary rev limit. When the blue wire receives 12 volts, it switches on the secondary rev limiter. You can rig up 2 switches to activate these 2 functions, but then it isn't automatic, and gives you one more thing to do while driving. I have done it in a much better, and versatile way. I bought an MSD 8950 (RPM activated switch), an MSD 8670 (RPM module selector, and a 12 volt automotive relay. I wired the RPM switch to ground the relay when it sees the RPM dialed into the module selector. The relay energizes the pink wire and the ignition retards by the specified amount. The module selecter adjusts between 3000 and 5200 RPM in increments of 200 RPM. Now you can retard the ignition at the RPM you want. To energize the secondary rev limiter for my burnout, I wired the blue wire into the switched side of my line lock. As far as limiting your vacuum degrees, the best way is to modify your vacuum advance cannister like in this picture. As far as I know, advancing your cam timing builds low end power. I would think you wqould get an increase in vacuum.o No:
Larry I read more than you thought, I have the pink wire connected to the Trans Kick down switch for lack of a better mode of operation, which you have now shared with me. I love this site and appreciate your help. This trial and error bit was getting old and expensive. The vacuum limiter photo is great. Thanks again. I hope to get some photos of my efforts on this site soon. I'm not sure how to accomlish this as of yet, oh my, another learning curve! Are you using jpeg images to attach the photos? Larry (Weekender)
Larry, Yes, I'm using jpeg photos. You need to have the photos stored on your hard drive or CD ROM, or other storage device. Then when you post, at the bottom you will see a button labelled "Browse". Use that to locate your photo. Then double click on the photo, and "Submit Reply". The photo can be no more than 163 Kb, and about 800X600 pixels or so. Wiring the pink wire to the kickdown will work, but you may leave alot of power on the table that way. I looked to see where my tach dropped to on the 2-3 shift, and retarded it there. The engine is under the most load there at WOT, and pulling in high gear. Retarding the spark some there, wards off detonation, and the engine pulls better. My way, it's adjustable for RPM. Unfortunately, it's more expensive(100.00), but worth it IMHO.
