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Discussion Starter #1
Could someone point me in the right direction to learn about recurving distributors? I have a good idea what I want the curve to look like, but just don't know how to get there.

Thanks in advance,

-Travis
 

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You replace the springs and/or counter weights for the centrifugal advance inside the distributor. Since these are Bosch distributors, you can go to the junk yard and get a pile of springs and counter weights from a variety of VWs and other cars with Bosch point type distributors.

The way the "pros" do it is to put in springs/counter weights and then put the distributor on a machine that spins the distributor and measures the advance through the RPM range.

You can do the same thing on your car. You'll need a timing light with one of the dials so you can see how much advance there is at each RPM. Put a set of springs/counter weights into the distributor, and then run the engine through the RPM range and write down the advance for every RPM point you are interested in. Keep changing springs and counter-weights until you get the curve you are looking for.

A couple of things to remember:
1. A heavier counter weight is the same as a lighter spring.
2. No matter what you do with a centrifugal advance, the change in rpm will give about the same change in advance. I.E. If you go from 1500 RPM to 2500 RPM and get 10 degrees advance, then when you go from 2500 RPM to 3500 RPM you will still get about 10 degrees more. In other words, a centrifugal advance gives you a straight line, not a "curve". The only way you can get a true curve is with a computer.
3. If you are still running a "Vac" advance, then it will give you advance in the first 3000 RPM, but none after that. So with the centrifugal advance and the "Vac advance, you will get one advance rate for the first 3000 RPM (centrifugal + vac) and a diferent rate after 3000 RPM (centrifugal only)... I guess that is sort of a curve, since it has a "kink" in the middle

If you do it yourself, it's a lot of work, trial and error. But once it is done, it will last just about forever.
 

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RallyCarLessBob:)

Since the distributor advance info you posted is part of the technical reference library I cannot reply to it. So I'll do it here.

Does the mechanical advance of the 69-70 and the 71-74 distributors have the same curve up to 32 degress?

Also, could you give a quick description of your adjustable total mechanical advance mod?

Thanks is advance

-Travis
 

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Travis said:
RallyCarLessBob:)

*****Sure, everyone's a comedian;) But my WRX is more of a rallycar than your GT is a racecar at the moment, right? And I finished all the cagework but my seat mount on the ITB car this weekend. So nyaaa....

Does the mechanical advance of the 69-70 and the 71-74 distributors have the same curve up to 32 degress?

*****No, the automatics all came in sooner, and there are definitely different springs in the early vs/ late distributors.

Also, could you give a quick description of your adjustable total mechanical advance mod?

*****No. Can I ever give a 'quick' description of anything? Later model distributors are easy, just bend the tabs limiting the distance the weights fly out. Early ones are more involved, but IMO this is worth it. I make them adjustable externally, but this cannot be described in this forum, photos would certainly be necessary to get the idea across. Alas, I have no photos to show, the only ones I have are 35 mm prints and I have no scanner.

Thanks is advance

-Travis
*****You're welcome.

Bob
 

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Discussion Starter #5
On the distributor from my '70(standard) one of the advance springs is loose and doesn't provide tension until roughly half way through the mechanical advance range. The coils of the spring are tight so it hasn't stretched. Compared to the other spring the wire diameter is slightly larger and has fewer coils.

Any thoughts?

-Travis
 

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This is normal. Use two standard 'light' springs from two distributors to maintain tension, or the advance will 'creep' at idle.

Bob
 

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Discussion Starter #7
Here's a pic of my distributor which now has adjustable total timing advance. The nut is stood on end and soldered in place on three sides. I tinned the brass nut with and iron and the distributor with a torch before assembly. I used Locktite on the threads to keep the screw from falling out since it's not getting stretched. It's not quite straight but should work

I used a degree wheel connected to the rotor to set the amount of advance on the bench. Mine is set to 7 degrees on the wheel(14 crank degrees).

BTW, this is based on info from RallyBob. Thanks again!

-Travis
 

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Travis,

Does it matter what side you attached the nut to? Then if I am following what you di dyou can adjust the wieght by screwing the bolt in further or less as needed correct? and you plates are rivered together so they don't move correct?

thanks,
C


you don't know the year, mechanical, vacuum and total advance of a distibutor with the number 0 231176 038 do you? it is not on any of the lists.

Does anyone know what the year, mechanical, vacuum and total advance
is on Bosch distributor 0 231 167 038?

With manual trans the last 3 numbers


68 is oo1
69 is 005
70-71 is 007 up to here 3231 167 ---
72 is o11 till 74 0 231 176 ---
73-74 is 012
75 is 140 75 is a bit different 0 231 170 140


With out any vacuum advance hooked up I subtract 4-9 degrees. Is that
correct????

Right now the car idle wanders I will set it at around 1000 at 18-
degrees initial advance and after a moment it will jump 800-900 rpms on its own and the timing is then at around 26 advance at 2000 rpm. (The engine is modified 1.9 to 2.4 30 over 305 flat top pistons with around 10.5.1 compression and a 486 lift 236 @50 302 108 sep, mildly ported, 1.84 exhaust 150 intake


To the to keep the base plates from moving is drilling out (just to
clean the metal) the extra hole on the top plate and soldering the
hole so the solder hits the lower plate an acceptable way to keep the plate from moving or rivet then together?

Futzing with the weber's DCOE 40ies doesn't seem make that much difference, even if I set them by the book and the way on the redline.com sight the idle speed screw has to really be moved to make a difference. Right now the idle jets are 55 so I should go up a step to 60ies...right?
-----------------------------

Thanks,
Calvin

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From: "Calvin" <[email protected]>
Date: Thu Jun 19, 2003 8:20 pm
Subject: bosch distributer 0 231 176 038 is what year? not in bob's lists



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Does anyone know what the year, mechanical, vacuum and total advance
is on Bosch distributor 0 231 167 038?

With manual trans the last 3 numbers


68 is oo1
69 is 005
70-71 is 007 up to here 3231 167 ---
72 is o11 till 74 0 231 176 ---
73-74 is 012
75 is 140 75 is a bit different 0 231 170 140


With out any vacuum advance hooked up I subtract 4-9 degrees. Is that
correct????

Right now the car idle wanders I will set it at around 1000 at 18-
degrees initial advance and after a moment it will jump 800-900 rpms
on its own and the timing is then at around 26 advance at 2000 rpm.
(The engine is modified 1.9 to 2.4 30 over 305 flat top pistons with
around 10.5.1 compression and a 486 lift 236 @50 302 108 sep, mildly
ported, 1.84 exhaust 150 intake


To the to keep the base plates from moving is drilling out (just to
clean the metal) the extra hole on the top plate and soldering the
hole so the solder hits the lower plate an acceptable way to keep the
plate from moving or rivet then together?

Futzing with the weber's DCOE 40ies doesn't seem make that much
difference, even if I set them by the book and the way on the
redline.com sight the idle speed screw has to really be moved to make
a difference. Right now the idle jets are 55 so I should go up a step
to 60ies...right?
-----------------------------

Thanks,
Calvin

Bob's list below
1968 - 32-36.5 mechanical advance
19.5-22.5 vacuum advance
51.5-59 degrees total

1969 - 32-36 mechanical advance
11.5-14.5 vacuum
43.5-50.5 degrees total

1970 - 32-36 mechanical advance
11.5-14.5 vacuum
43.5-50.5 degrees total

1971 - 28-32 mechanical advance
7-10 vacuum
35-42 degrees total

1972 - 28-32 mechanical advance
7-10 vacuum
35-42 degrees total

1973 - 28-32 mechanical advance
1-5 vacuum
29-37 degrees total

1974 - 28-32 mechanical advance
1-3 vacuum
29-35 degrees total

1975 - 25 mechanical advance
5 degrees static timing
No vacuum advance unit
30 degrees total
 

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Discussion Starter #9
calvin said:
Travis,

Does it matter what side you attached the nut to? Then if I am following what you di dyou can adjust the wieght by screwing the bolt in further or less as needed correct? and you plates are rivered together so they don't move correct?
It shouldn't matter which side the nut is on. The nut isn't really adjusting the weight but rather how much the weights and rotor are allowed to move. Do you have a distributor that is out of the car? If yes, try moving the piece the rotor sits on to full advance. You'll notice that it moves until it hits one of the spring mount pins. I have installed the nut and screw such that the screw hits the pin BEFORE it would have normally. Now you can adjust the screw to determine exactly how much it is allowed to move. This will only allow you to set the amount of maximum advance. It will not affect how quickly the advance comes in.

You may also need to adjust how quickly the advance comes in. I didn't have an extra 'soft' spring so I was unable to take the route that RallyBob reccomends(two soft springs). I used a stiff spring from a '73 distributor as I had accidently damaged the spring that came with the distributor I was using '70. I would expect you could also use this method with the original spring but I don't know for sure. The stiffer springs have some slop in them when installed. I reshaped the end of the spring with the slop to remove it and to provide some pre-load. I then installed the spring and assembled the distributor in the car. Using an advance timing light I was able to determine at what rpm max advance was happening. For me, it was coming in to soon. So, I bent the mount of the spring(not the pin end) and retested. It took me a few tries to get it where I wanted it. Be carefull that you don't bend the mount too much or it'll hit the housing of the distributor. I ended up just installing the fuel pump with one bolt as I was installing and uninstalling it so often.

BTW, I went through this process a few more times then I really needed to. It turned out that the leads of my timing light are very sensitive to my new CD ignition and we're screwing with the results. It can pay to be really anal about these things.

I actually welded my plates together. It was more convenient to me than rivets. If you think you can get a good solder joint it should be fine as there's not much force here. However, it could be a challenge to get a good joint down in the bottom of the hole.

I hope you can follow this. Let me know if you have questions or need further clarification...

-Travis
 

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1) add the soft spring. (I have three or 4 old battered up distributors that I have been practicing taking apart).

2). Weld plates together... safer than soldering ok…….. does it matter what position when they are welded they are in as the move? Dumb question maybe but it might make a difference.

I thought you used the bolt as a weight .Now I see that it has to hit the tab and I begin to understand.

Any idea on the mech./total advance of that distributor? Opelbits had a parts #book that said it was a 71-72 automatic so judging by a 72 with a manual Trans does 28-32 with 7-10 vacuum sound reasonable?

So I 1). Weld the plates 2). weld the nut and add bolt 3. Disconnect the vacuum advance totally (as I have the dual cannon intakes with no place to feed it).

So I will shoot for 18 degrees advance at idle and 3600 at 4000 rpm.

If the total advance is more that 3600 tighten the bolt limiting the spread of the weight and thus the advance, if it is less than 3600 then loosen the bolt allowing the weight to swing out a bit more.

Find the sweet spot, count threads and apply lots of locktight to hold it steady!


Thanks I hope this works as you have made it a lot clearer.


Thank you thank you!
C
 

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Calvin,

I was looking at some extra distributors I have. One has the same #'s you said 0 231 167 038 and cast down near the base on the opposite side is 71

I also have a 0 231 167 037 with a 70 cast as the year.
Both of these are JFU4 distributors taken from Opels engines.
I don't know what models or if auto or manual.

Tom C.
 

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well the radiator shop failed to attach the nut by solder or braising so i ended up doing it myself...it is a very very ugly soldering job but seems to be holding. I am starting by taking out 1/3 of the play which I figure is about 12 degrees. (give or take 6)a sthe 71-72 list 28-32 for advance.


I only had time for on try by the time I got it all back together then i realized that I forgot to put the springs on and the breaker plate is ass backwards.... oh well will try again in the AM.. even like that I didn't get spark so i bet i put the pickup on backwards too.

I will see how the thing held up to after it has been cranked... this part is worse than changing the cluth cable (three times) and adjusting it around the welded up exhaust and i did't think anything could have been worse than that nightmere....

on the bright side I heard that this is the kind of Roger's opel engineering will undertake if i totally mess it up.

Cal

Opelbits say that his manual says that it is an automatic distributor froma 71-72 but doesn't know the total advance
 

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Discussion Starter #13
Calvin,

The total advance can be set up on the bench, no need to guess. Here's what I did.

Download timing wheel off 'net. Someone posted a link recently. Otherwise use google. Print timing wheel and cut out. Attach to a round piece of cardboard of the same size. Lightly clamp housing of distributor in bench vice. Install rotor on distributor. Lightly tape degree wheel to the top of the rotor, trying to get it as concentric as possible. Get an old metal coat hanger from the closet and straighten. Use a file or grinder to form a sharp point on one end. Wedge the other end of the coat hanger under a heavy object placed next to the bench vice. Bend coat hanger such that the point is just over the degree marks on the degree wheel. Around the outside of the degree wheel will be a bunch of little lines, one for each degree. The inner end of all these lines will form an imaginary circle. Rotate the distributor shaft watching the distance between this imaginary circle and the end of the pointer. When you can rotate the distributor shaft one full rotation and the distance between the imaginary circle and the pointer is consistant, you'll know the wheel is concentric with the shaft. Adjust the wheel as needed until this happens. Then gently add some more tape to hold things together. Gently remove distributor from vice, being carefull not to bump the wheel. Mount the distributor shaft in the vice. Adjust coat hanger so that the pointer is once again over the little lines. Make note of what degree is indicated. Now advance the distributor by rotating the rotor or the piece the rotor is attached to. Do NOT rotate by pulling on the wheel. Make note of the max advance indicated on the wheel. The difference between this number and the number noted earlier is 1/2 the advance of the crank. Remeber that the distributor rotates at 1/2 the speed of the crank.

Lets say you wanted 18 degrees initial advance and 34 degrees total advance. This would be 16 degrees of mechanical advance. You will want the advance measured above to be 1/2 of this (8 degrees).

I know this is lengthy and likely best described with some pictures but I think you'll get the idea....

-Travis
 

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Changing the subject slightly, I just installed the Bosch RPM limiter rotor. It is basically a centrifugal switch built into the rotor. I got the 6500 model and, believe it or not, it cut out right at 6500 on my old tach. Protection for $23----sweet!
James
 

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for the more mechanically challenged like me.

Finally got it today. I used the smallest 5/32 brass nut I could find and a short bolt that I chopped the head off of. On the 038 distributor that I had I ended putting the nut fairly close in about where it is at its narrowest point in front of the post that holds the spring.

First I used super glue (just a tiny amount) under the nut then I soldered it. I blocked out about a little more than a third of the allowed movement.


Go here for your downloadable degree wheel
http://www.tavia.com/free_degree_wheel.html

Save to disk and then paste it into MSWord. You can now grab the corner of the pasted picture and drag it till it is the exact size of the distributor. (I forgot the size but I will edit this) line up zero with the notch (put the rotor on it is easier) make sure you have the distributor in with the weights showing and the car is exactly at TDC. Check TDC on your flywheel not the hap-hazzard marks you made last week... Twist it clockwise and measure how far it goes. Do the math with the distributor that you are using and adjust your bolt till it is right. Count threads, now pull the bolt out and put lock tight on it and put it back. Double-check it quickly. Reassemble your distributor.

Put it all back and the car should start. Double check with it at idle and then at 4000 rpm..

Now that car runs and is in time and you can move on to getting the carbs to run right

NOTE
If you take your vacuum advance off like I did be sure to cover the hole (and any other holes) where it went not to let light through or you will end up like me, very frustrated and wondering why your car won't start for 2 days because there is too much light and its messing up the optical unit.
 
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