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Discussion Starter #1
I have been having a difficult time removing the old Bosch distributor rotor on my Alfa spider. I've read that they are sometimes glued down. Can someone tell me the best way to remove the rotor? Hit it with a hammer? :)
 

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But Mad North-Northwest
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For the glued rotor the procedure is in TSB 05.90.04 if you have the service manual. You're supposed to grip the neck of the rotor with vise grips to carefully break it free.

I don't think the L-Jet cars were glued down from the factory so maybe yours is just stuck, or perhaps someone glued a new one on.
 

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Just removed mine yesterday. Used vise grips, wiggled and pulled as straight up as possible. The side of the rotor broke and the rest of it broke free! I replaced with a new rotor which was my reason for removing the old one.
 

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Discussion Starter #4
Removing old distributor

Thanks for those that replied. I did manage to remove the old rotor as directed, in pieces, and install the new one. Unfortunately, it wasn't the solution to the problem of an engine that seems to not be hitting on all cylinders. I'm going to replace the spark plug wires now.
 

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What's the consensus on whether to glue them back on or not?
 

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Discussion Starter #6
gluing the rotor

I decided not to glue it down. The engine starts quickly and seems to run a bit better, but definitely didn't fix the problem. I plan to leave the rotor unglued and see what happens.
 

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Welcome to the board.

If you have a problem don't hesitate in asking for help.
There's some really good people here that really know their sh...
 

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But Mad North-Northwest
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Alfa says to glue it down, but as far as I know most people don't bother.
 

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Actually, the instruction to glue the rotor comes from an Alfa issued TSB containing the information as supplied by Bosch.

But what do the manufacturers known. :rolleyes:
 

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They know not to make window crank handles out of plastic, but do anyway.
They know not to use poor quality seals on doors and windows, but they do anyway.
They know they need to use X gauge wire for best electrical performance, but go as small as possible anyway.
They know that rust can occur in various places, but do nothing to help initally alleviate it.
They know the 12V automotive electrical system has been pretty much obsolete for many years now, but use it still anyway.

But what they know best of all is how to save a dime, and they'll do everything they can to accomplish that anyway regardless of the amount of things they should know better than to do :)
 

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Well, let's see.

Plastic door handles don't rust or pit. And they weigh less.
Just exactly how long are door seals supposed to last anyway? 5 months? 5 decades?
The wire gauge used is designed carry the load that the powered device requires plus factors to include temperature and conductor length plus a safety factor plus a fuse rating lower than all the above factors add up to. For example, switching from a 1.0mm wire (12 amp capacity) to a 0.5mm wire to power, say, a tail light circuit that requires only 1 amp means that more vehicles can be built using the same amount of material, space savings from a smaller harness and less copper means less weight.
Tri-metal phosphating (zinc, nickle & manganese) and electrocoating the substrate prior to top coat are quite common these days (with Volvo leading the way, IMO) resulting in perforation/rust through warranties that didn't even exist a decade ago. One would wonder then why use metal door handles.
The 12 volt system was very gradually taxed to the limit by the addition of more and more electrical devices over many, many years. It will take just as long to convert to a different system.
Might I add that I was not aware that Bosch made door handles, door gaskets, or either wired or rust proofed motor vehicles.

Back to the Bosch distributor rotor. The manufacturer recommends this cost increasing procedure for a reason. Ignoring it would be akin to tossing out every service manual ever printed for anything since the design and operational parameters set forth by the manufacturer are, by the end users choice, irrelevant.
 

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But Mad North-Northwest
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A valid point, Jim. That being said, the Motronic distributor rotor isn't significantly different from the earlier non-glued L-Jet (or, hell, any other non-glued distributor for that matter). If it's snug on the shaft and keyed to keep it from rotating I can't see any reason that not gluing it's going to be an issue.

If it makes you feel better, easy enough to glue it on. Personally I think someone at Bosch was just feeling paranoid one day. But hey, we've got a test case now in Pete :D
 

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When Ford did it for a short period of time a few decades back it was due to rotors not being in spec resulting in them 'walking' up the shaft during use and breaking the dizzy cap.

They glued them for a while, (since they likely had a million on the shelf they weren't going to just throw them away, so gluing was cheaper) then as stock depleted they got newly manufactured ones that were in spec under a new p#, and didn't glue them again during manufacturing or when that new part was used as a replacement for the original loose one.

I imagine deep down the reasoning is simular in regard to the rotors in question. (or conversely, the dizzy shafts could have been turned undersize. Either way, something likely didn't fit right from the manufacturer and they came up with gluing as a workaround that was cheaper than outright replacing)
If that is the case, then gluing is still likely moot as they prolly ran out of the ill fitting ones a long, long time ago.
Granted, gluing it won't hurt regardless, but in the grander scheme of things it's likely not the neccesity it was way back when unless its the shaft thats small rather than the rotor being big. (by now the rotors have prolly long since been corrected, but if the dizzy was the issue and is still the factory original the engine came with then the shaft is still small regardless)
 

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Sure. If one assumes that it's a design/manufacturing flaw. One could equally assume that it's glued on by design.

But neither Bosch or Alfa say why it should be glued down.
Bosch doesn't say why fuel pressure needs to be x PSI or Alfa that the clutch master pushrod length needs to be 134mm either. Lack of a reason does not mean lack of importance.
 

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Lack of a reason does not mean lack of importance.
Whats'a matter Jim - the local grocery store run out of prunes?

I think we can figure out why the fuel pressure needs to be at a specific pressure or the clutch operating rod needs to be set to a specific length. (actually it would've made sense to simply make the rod the required length) But I can only guess as to why the rotor should be glued on. Enquiring minds and all that.
 
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