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Distributor Overhaul 101 by Jeff at Advanced

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Brosky

Brosky

Great Pumpkin
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This is the before and after of my ebay distributor adventure.

Before:

dirty1 (Custom).jpg


And after:

finaldistributor (Custom).jpg


And this is the link to everything, step by step, so I don't tie up space here:

https://www.74tr6.com/distributor.htm
 
Well done, Paul, I liked your site. One question; who took the photos? I'm assuming your distributor man took them.... I'll definetly consider a winter distributor rebuild, now. Any thoughts on price?
 
Good documentation. Did I miss it or did they not replace the bushing for the shaft?

I realize the typical wear/wobble here is not such a big problem when using the Pertronix but would have thought this was SOP for a rebuild.
 
Hi Geo,If the main shaft bushing [Bearing} is not excessively worn there is no need to replace it,given that the Pertronix is the primary unit while points remain as the back up.On The Otherhand,in the case of the 25D Dizzy it is a major machining operation to rebuild/replace the main bearing.---Keoke
 
Yes, Jeff did take the photos.

The bushings in the case were fine.

I did not include the photo checking the total indicated run out of the shaft. Here is that photo:

checkrunout (Custom).jpg
 
Email Jeff for a quote to get accurate numbers. His contact email is on his site, which is linked in my page, as I'm sure you noticed.

My job included a lot of extras, like the point plate with new parts, tachometer drive gear, ground repair, polishing, complete new (Moss) vacuum advance (retard) and the Euro spec recurve. I would not want to give any numbers that could prove to be inaccurate when compared to another case.
 
I always check the shaft-to-bushing clearances on a standard rebuild, but more often than not they are within .0005" of the original specs. The replacement bushings that are currently offered (by only one supplier nationally) have greater clearances than most slightly worn original bushings. In the TR6 distributor, as Keoke stated, it can be a major machining process to replace the bushing, or I can install a 2-piece bushing as the factory did in some models (to clear the tach drive gear.) In Paul's case, the shaft bushing had almost .001" tighter clearances than the replacement bushings. I could have custom made a bushing that fit .0005" tighter, but you have to ask why? It wasn't cost effective or necessary, even with points!

At this point I am shopping around to have better fitting bushings made in bulk. I think I found a great supplier, but have to be worked into their schedule for a small parts run (less than 10,000.)

By the way, most rebuilds can be done for $79 including new springs, so automatically replacing a good shaft bushing wouldn't be fair to customers. I'd have to raise EVERYONE'S costs, whether it was necessary or not. This way each part is evaluated on a case-by-case basis.
Jeff
 
The rebuild documentation is great. My observations of TR6 dizzy’s are limited but the problems I have encounter center around the shaft bushing and the internal wiring. The most common problem I have observed is the lockup of the advance mechanism because the lubrication process (one drop of motor oil on the screw head that is accessible when the rotor is removed) is just too crude to be true.

My question is how does the main bush get any lubrication? I have seen the replacement bush priced at near $100 (part only).
 
<font color="green"> Hi vettedog,

have you ever considered using this one? No probs anymore, no points, no waggling advance mechanism, spare parts (cap and rotor) are standard Bosch items and you benefit from a really smooth running engine due to spark balancing. Plus you have 16 different advance curves to select from.

For more info look here .

Lots of financial interests, as I'm selling them. /ubbthreads/images/graemlins/smile.gif

123_bosch_blk.jpg
</font>
 
And where is the tach drive? None of your examples show one.
 
That's true, Paul, and that's the reason why somewhere is stated that you have to check for the necessity of a mechanical tach drive.

But there are 2 workarounds. First one, you can convert your tach to electronical by yourself (this is for an MGA but can be assigned to a Triumph as well) or the usual suspects thus making the presence of a tach drive needless.

Secondly your distributor or a core unit could be converted internally to the 123ignition specs.
 
OK, so what is the price for a 74TR6 for a complete unit as well as to convert a core to the 123 system?
 
Vettedog72, on assembly I lubricate the shaft & oil impregnated bushing with a coating of Mobil1 synthetic grease and "special" high rpm motor oil. The weights and advance assembly get only a slight amount of the grease mixed with oil for a slick lubrication that resists drying and sticking. From my experience it lasts longer than camshaft lube, which is also a good assembly lube.

For bushing replacements, I charge $50 for the 22D distributor as I use a 2 piece (top and bottom) bearing. The more expensive option of a machined 1 piece bearing shows no longer life expectancy.
 
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