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Hi - a new to me 1990 RRC came to me in pieces recently. In sussing out spark issues, it appears that the PO threw a bunch of parts at the problem, without diagnosis. I have read a number of threads here, but am seeing some conflicting information.

My first question relates to the mechanical advance on the distributor. This list of information provided by someone in the community references testing the mechanical advance by turning the rotor counter-clockwise to test the spring action. I am seeing that the rotor only turns clockwise, with counter-clockwise return action bringing it back to a home position. In taking apart the distributor it does not appear that it can be reassembled to allow for the reverse of this scenario. Is the reference to turning the rotor counter-clockwise incorrect?

Also, the tophat is completely missing on this distributor - how critical is that piece?

Thanks - and I appreciate this community being here for us newbies. I am part of other vehicle support groups (Landcruisers, VW Vanagons and vintage Triumphs) and it is so great to have the resources available.

Chris -
SW Colorado
 

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Its correct as you describe, it turns (gentle pressure on rotor arm) clockwise 10 or so degree then springs back to its original position from fairly light spring action.
It's only the amount the centrifugal bob weights allow to give mech advance to timing.

Tophat, is that the clear plastic shield that fits just under the rotor that screens the HT from triggering components ? They run without ok but longer term with varying humidity can run into problems as far as I'm aware. I always keep them fitted.

Welcome to forum, which Triumphs interest you?
 

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Discussion Starter #3
Thanks for the reply. As far as triumphs go I presently have an early TR4 (CT2165) short bubble. Body is off presently - and I am attending to various insults from historic damage, rust, 6 layers of paint - etc..
 

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Discussion Starter #4
So in working through the tests in the electrical section of the Manual (Section 86, page 20) - I pass test 1 and 2 as described in the manual.
Test 3: With the ignition off, I am getting 12v between the Positive (+) battery terminal and the Negative (-) post on the coil - manual says I should have zero volts.

I'll dig into that next and try to better understand how the coil is making ground. Any direction is appreciated.
 

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Replace the tophat piece. The distributor is fairly simple to work on, just make sure you mark and reinstall to the same position on the drive gear. Here is a link to notes from my distributor rebuild - Distributor Rebuild (4.2L)

Regards,
Tom P.
[h=2][/h]
 

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Discussion Starter #6
Thanks Tom - your thread was about the only one I found that had solid information - I like the tiny wrench application.

I have cleaned and re-assembled the distributor. Started at square one on the distributor reinstall because I was not convinced the PO had done this correctly. I think I successfully reinstalled following the manual - with crank at TDC, and cyl #1 at the top of its stroke I reinserted the distributor so that the rotor is pointed at the #1 lead on the distributor cap - i have ample movement of the distributor to advance/retard beyond the #1 position. Trying to find that magic piece of plastic to set the air-gap to the recommended width (.2-.35 mm).
 

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Discussion Starter #7
OK - I take back what I said about Test 3 and having 12v between the positive terminal on the battery and the negative terminal on the coil. I just went outside this morning and checked it again and I have zero volts with the ignition turned off.
 

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Discussion Starter #8
...actually, I take back my take back. Shouldn't have tested before fist cup of coffee. Negative kill switch was turned off. When kill was turned back on I do have 12v between positive terminal on Battery and negative terminal on coil with ignition off. As I saw yesterday.

...I'm really not this flaky usually. :)
 

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Trying to find that magic piece of plastic to set the air-gap to the recommended width (.2-.35 mm).
Easy, cut strips from a few single-use water/drink bottles, and check thickness with calipers. These are typically all different wall thicknesses so you should find one that works. Added bonus - they are also non-magnetic.
 

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...actually, I take back my take back. Shouldn't have tested before fist cup of coffee. Negative kill switch was turned off. When kill was turned back on I do have 12v between positive terminal on Battery and negative terminal on coil with ignition off. As I saw yesterday.

...I'm really not this flaky usually. :)

It's Test 3 that's flaky.
 

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95classiclwb - 100% correct. However I ran up to the only old-school garage I thought would know about non-magnetic/non-ferrous feeler gauges. He had some, but searched and couldn't find them. I had a small window to get the motor running so I improvised. This time it worked perfect.
 

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There's a standard calibration we use in case of no dedicated tools. You'll have to excuse the terminology as it has different connotations away from UK.

It's a *** paper for setting points, just put it between the contacts and pull it to set timing, releases at point of opening.Top of a *** packet to set air gap, the cardboard bit that is.
And all brief design innovations are described as "back of a *** packet" as they fit on such a carton.

All instances of *** should be substituted for cigarette in translation ;)

I think we got it from the Romans, but still in use today.

Very nice car TR4, there seem to be a higher percentage of total range that are collectable and interesting in Triumph vehicles than many others.
 

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Discussion Starter #15
Thanks for the lesson - will look for opportunities to use *** in the future.

I have steel feeler gauges, so I tried to match thickness with some plastic - I'll mess with that some more.

Failing test 6: spark from HT wire coil to Rotor top. Replace Rotor and tophat? Also, was there a condenser near the coil and how was that wired in - I found a dried up bracket/grommet assembly with a lead going in one side.

thanks for your replies.
 

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Failing test 6: spark from HT wire coil to Rotor top. Replace Rotor and tophat?
Get new, good plug wires. I chased a few dead-ends only to discover the HT coil-to-dist wire was bad.
 

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Discussion Starter #17
Yes, probably good advice. I was surprised how much voltage was making its way through the insulation of the HT wire - pliers with rubberized handles were no match for the excess charge that passed into my hand holding that HT lead above the rotor head.
 

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Excuse my ignorance but why the special feeler gauges, I used to work on these in the seventy’s and ordinary steel gauges worked fine
That HT wire you are talking about (coil-to-dist)is the LT wire, about 400v
 

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Excuse my ignorance but why the special feeler gauges, I used to work on these in the seventy’s and ordinary steel gauges worked fine
That HT wire you are talking about (coil-to-dist)is the LT wire, about 400v
non ferrous feeler gauges are best to accurate measure the gap at the coil pick up and trigger wheel magnet, ferrous gauges stick to the magnet thus to inexperienced mechanic it will give a sense of false reading due to the drag.
 

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thanks 95, i am not Familiar with this system, it before my time, or should I say after my time
i Misread his comments about the HT wire also, not my day
 
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