HEI redneck blueprinting LOL
- Thread starter turtlevette
- Start date
big2bird
Charter Member, Founder Bird-Run, Cruise-In Bird-R
If it's a good unit, change the cam and weights.
OR, if it's iffy, or worn, order a new unit from DUI, built with a 20* Chevy power book curve.
http://www.performancedistributors.com/
OR, if it's iffy, or worn, order a new unit from DUI, built with a 20* Chevy power book curve.
http://www.performancedistributors.com/
Your worn set was an aftermarket set. Don't know how much mileage you had on them but the OEM won't wear like that, just on the pins and swing holes.
If you must use the aftermarket, use the centerpiece too and check the complete curve with a dial back lite or tape. You may have to adjust the centerpiece for your needs. They won't last nearly as long as OEM. Problems arise when people try to mix and match the new and oem. Make sure they return completely at your idle and you have no advance at idle.
If the 75 advance was seized, then the weights and pins should not be worn, clean them up and see.
Best bet is to hit an old time junk yard and just strip the dist advance parts.
Gene
The post size changed in the very late 70s when the powdered weights were used.
Talk to your welder buddy about repairing the original small post weights. You can add the plastic bushings. He's got the tools.
clutchdust
Millionaire Playboy
Sounds to me like you're fixing the wrong problem. Replace the balancer with a new one, better yet, get something like the Streetdampr where the ring can't slip and it's marked out to 45* from TDC. Then set the base timing per Lars' paper and fine tune from there.
turtlevette
The Turdle
That's the same problem i was having. If you look carefully at my weights you can see the wear preventing it from advancing the full 20deg. The other big thing that gets more advance is using those wimpy gold springs. The stock springs are so stiff i doubt you see 20deg until it hits 6 grand.
I've got a balancer cover i bought years ago and never put on. Its a plastic shell that bolts between the balancer and pulleys with all the markings. The balancer ring is free to slip below the cover. The cover is indexed based on the 3 pully bolts.
I've done timing tape before and it lasted about a week.
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DC3
Well-known member
I went through some of these same gyrations trying to get more mechanical advance from the junkyard HEI the previous owner installed in my '73. After playing with various combinations of weights and springs and even sourcing some original GM parts from a buddy, I had accomplished diddly squat. Ending up taking the distributor apart and found it so gunked up inside that I completely disassembled it. The shaft had so much old gunk on it that I literally had to scrape and file it to get it smooth. Cleaned everything, lubed as needed, put it back together and the difference was remarkable.
DC
DC
1Michel
Well-known member
Is this the settings you were talking about with me last time Jeff?
big2bird
Charter Member, Founder Bird-Run, Cruise-In Bird-R
turtlevette
The Turdle
pictures of the redneck mod as promised. The flat section of the weight that limits advance has been ground off, so it just keeps advancing until the weights hit the inside of the rotor.
don't try this at home. You guys know i'm out of my gord.
The weights i pulled off of my spare dist do not have plastic bushings and fit loose on the posts of this dist. I'll have to drill them out to accept the plastic busings. They are much thicker and heavier than the other weights and are stamped 60.
I was looking around and found that MSD now has a 20 amp coil and module.
don't try this at home. You guys know i'm out of my gord.
The weights i pulled off of my spare dist do not have plastic bushings and fit loose on the posts of this dist. I'll have to drill them out to accept the plastic busings. They are much thicker and heavier than the other weights and are stamped 60.
I was looking around and found that MSD now has a 20 amp coil and module.
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mrvette
Phantom of the Opera
pictures of the redneck mod as promised. The flat section of the weight that limits advance has been ground off, so it just keeps advancing until the weights hit the inside of the rotor.
don't try this at home. You guys know i'm out of my gord.
The weights i pulled off of my spare dist do not have plastic bushings and fit loose on the posts of this dist. I'll have to drill them out to accept the plastic busings. They are much thicker and heavier than the other weights and are stamped 60.
I was looking around and found that MSD now has a 20 amp coil and module.
Jim, that's what I was talking about, you have Poncho/other weights on the Chebby posts there, that's what I found with this motor home dizzy, when having to fix it...I worked the poncho studs loose and used them on the chebby shaft/plate....in your pix above, you cut off that long beak from the weights, but I see no stud sticking through a hole/slot in the plates and that is what limits advance on many dizzys I dunno why the changes....anyone??
OH, edit, I have never ever seen one of those green circuit cards in a HEI, always the TPI type or the old black OEM sending chips....WTF is that for??
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turtlevette
The Turdle
That's an MSD analog module. You match that with an MSD coil for a hotter spark with better high rpm performance. A stock coil will overheat and burn up after a few months use.
There is also a digital version that uses a micorprocessor and has a variable rev limiter.
i just found out There is a 3rd digital version that gives a super hot spark. It draws 20amps where the frist 2 draw 7.5 amps. The 20 amp version requires a different coil, special high dielectric cap and rotor.
turtlevette
The Turdle
Most say 3000. Close enough. I'd leave it be. Is it pinging?
SmokinBBC
Well-known member
My DUI is all in at 3000.
big2bird
Charter Member, Founder Bird-Run, Cruise-In Bird-R
If it will take it, it's fine. Some engines can take full advance at 2800, and most like it about 3000.