I bought a date coded original tach drive for my 72. It is in pretty rough condition and will need to be rebuilt. I'll likely go with an electronic ignition set-up versus points.

Any advice or word of wisdom on rebuilding the mechanical portion of the distributor?

 

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Hello Big2Bird

I have a similar situation. Can you send me any rebuild papers if you have any.

Thank you
kdf

 

I will post my thoughts: You need to do this job correctly. The cam drive gear has a drill mark on it, that aligns with the distributor rotor blade, make sure you dont re-install it 180degrees off. Remove the tach drive gear bronze bushing (threaded coupling with a slot in it) and gear assembly looking for worn holes and broken gear teeth. Then you can remove the distributor mainshaft by pressing out the drive pin from the cam gear, sand the distributor shaft and deburr the oil pump drive key before trying to remove the shaft from the housing. Pull the shaft out of the distributor body and inspect the bushings looking fo worn mainshaft bushings (usually the lower bushing takes the beating.) remove the advance weights and springs from the centrifical advance plate and seperate the pints cam from the mainshaft (you did check for a good tach drive gear on the shaft alread didn't you?) Remove the snap ring holding the breaker plate onto the housing and now CAREFULLY remove the oil seal below the breaker plate. Make sure the breaker plate grounding wire is in good shape and not broken or brittle. Remove the vacuum advance unit and tape up the distributor housing for bead blasting for a fresh coat of semi-gloss Black paint. Paint and let dry. Clean all the old grease out of the upper well of the housing and replace with moly based grease of moly based camshaft breakin paste. Reassemble the housing starting with the vacuum can, after checking to see if it is still functional (I get my parts from NAPA if it is bad.) There should have ben a felt washer above the oil seal at the top of the housing, use a 50/50 mix of Molly Paste and Motor Oil and soak the felt washer then coat the upper bushing with molly paste, re-install the points plate, install the retainer ring. Make sure the breaker cam/upper shaft is clean and pack the upper grooves of the mainshaft with Molly Paste, lube the advance plates with paste, reassemble the shaft into the housing and add a mix of Molly/Oil above the lower bushing. Re-install the drive gear making sure the drill mark lines up with the rotor blade. Pack the cross gear housing with grease and install the coupling and crossgear (I forgot to mention you need to check the crossgear thrust surface foe wear and chang the plastic or bronze plate inside the cross gear well. Install a Pertronix Ignitor and route the wires so they wont chafe and go out of th epoints ground wire hole below the breaker plate. Install the new distributor into your motor with the rotor pointing the same direction as the one you removed. Wire it up, bump the motor to #1 cylinder on compression stroke, set crank about 10 degrees before TDC, turn the ignition key on, turn the housing with the coil wire disconnected looking for the spark and light the motor off! Or you could have bought a re-production Distributor for around $275, go the date correct tag from Paragon and skipped most of what I have laid out and been on your way (a few omissions possibly.) I'm a cheap guy, with access to a machine shop and do my own work, that is probably why my LT-1 runs low 12's with a Delco Distributor in it (NO MSD for me!)

 

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Don't do the electronic conversion. Set it up with a good set of points (like a set of CS-786's) - it will run very well.

 

Pertronix not necessary, nor that desirable.

 

Hello Big2Bird

Can you send me any rebuild papers also?

Thank you!

 

PM sent

 

Good information. Have any of you replaced your distributor bushings? The shaft in mine is pretty well chewed up and I thought I should replace the bushings at the same time. Is that something I can do with a press or should I just send it out to a machine shop?

 

Good to get some feed back on point verus electronic. Now that I think about it, I installed a Mallory Unilite in a GM single point on a 70 Z-28 that I had ages ago and it did not make a big difference.

 

Awesome step by step instructions. I'll likely do the work myself and this will help. It's always good to have info from others that have the experience. Thanks!

 

Where can I get a set of these?

 

Napa

 

Theres a fella on Ebay selling BW A-112 HP points which are the 28-32 oz HP for cheap. His Ebay name is "Black Schnauzer Antiques". He is selling them in lots of 10 for $56 which includes shipping.