1850 distributor springs. Any interest ?

[MIG Wielder]

The springs on the A.C. Delco distributor on my 1850 are not what they should be. They are getting weak through old age. I have seen a pair of replacement ones from a supplier and they are too long, so I had a look through the various catalogues and I have found an item that is very similar.
So how much interest would there be in a pair of these ?
I intend to (try) to get some free samples first to actually evaluate in a car.
So who would like to volunteer to try some out ?
Now when it comes to cost I have the following price breaks.
1 - 19 = £6:80
20 - 49 = £3:92
50 - 99 = £2:06
100 - 199 = £1:28
At these breaks it is cheaper to get 50 than 19
There again I don't think we are going to be in big numbers for these.

TBH nearly £7 for a spring sounds expensive. Is this what industry expects to pay please ?
Thanks Tony.

[soe8m]

I can't imagen these are two identical springs because the curve is not linear. Multiply costs x2 for two different springs. The one too long can actually be the right type in combination with a shorter one.

Jeroen

[xvivalve]

Would the TR7 share the same spring and give a potential economy of scale, or might the TR7 guys have already sourced something?

[MIG Wielder]

If you go to the very early 1972 ,1850 parts manual they actually supplied individual parts for the A.C Delco dizzy.
One advance spring plus one advance weight was supplied under part no 520208.
Both were identical.
Which tends to be supported by the advance curve I plotted here. Its vaguely linear.
viewtopic.php?f=4&t=30681&hilit=distrib ... t&start=15

(Look for the graphs about 2/3 rds the way down.)
I can't find any evidence of any change on these parts.

And yes, the TR7 Distributor is also an A.C. Delco unit and the advance springs are quoted as RTC1863. ( 2 per unit ) which suggests each spring is the same on the TR7. Are the weights the same ?

How do these differ from the 1850 unit ?????
I have seen 1 specimen of RTC1863 and it is too long for my 1850 dizzy.
Ta,
Tony.

[MIG Wielder]

Well I got some samples today. And they are very close to the originals.
I've just done a trial fit on my spare distributor and they are a perfect fit.
You do have to select them though for the correct end loop termination as the termination is quoted as "random" but in practice most are within a few degrees of being parallel.
http://www.leespring.com/downloads/uk/2 ... Series.pdf

... is the supplier and the part number is LEM 110BB 01

Now for an actual fit,
Tony.

[georgethompson730]

Tony, Without anything to compare them to how do you tell if your springs are not what they should be? Having said that I don't believe mine have ever been changed.
George

[soe8m]

Tony, Without anything to compare them to how do you tell if your springs are not what they should be? Having said that I don't believe mine have ever been changed.
George

You can't. The only way to determine the original springs are not good is on an distributor tester to check the advance at different revs and draw a curve from the results. These new springs probably cause a curve that doesn't match at all. One coil more, slightly different diameter or wire thickness and you end up having a totally different strenght. That will create a fantasy curve.

Jeroen

[MIG Wielder]

Tony, Without anything to compare them to how do you tell if your springs are not what they should be? Having said that I don't believe mine have ever been changed.
George

Hi George, Thanks for that. 2 things to try. ( This is for the 1850 A.C. Delco unit ) If you take the dizzy cap and rotor arm off ( 2 screws ) you'll find the springs underneath. The first question is... if you rotate the outer co-axial bit of the distributor shaft by hand and release it does it return by itself to the static position with a slight click. If so , that is a good start. If it flops about and settles in all sorts of random positions when released then the springs have gone weak. First thing to do is remove the weights & springs, clean them and re-assemble with a tiny smear of lubricant.
Put the cap back on.
For a dynamic test use a strobe timing light. I have a really nice Gunson's unit with a calibrated degree setting.
Disconnect the vacuum advance pipe at the dizzy. At a slow idle < 650 rpm measure the static timing. This should be the book figure of 11 deg BTDC.
Now note the exact timing figure you get in degrees BTDC.
Increase the engine RPM to 1500 rpm. You should get static + 7 to 11 degrees. ( 18 to 22 degrees if static set correctly )
At 2400 rpm you should get static + 10 to 14 degrees ( 21 to 25 degrees actual )
At 3500rpm you should get static + 13 to 17 degrees ( 24 to 28 degrees )

If your timing figures are in these limits then your dizzy advance springs are working fine, and no rectification is needed.
Re-connect the vacuum advance pipe.

Yes I know I promised to write up the results of the springs I obtained but unfortunatly I have a more urgent "project" to manage right now.
HTH,
Tony.

[georgethompson730]

Thanks Tony, I will have a look at them next weekend. I don't have a strobe gun; unbelievably I never had the need but I do use a digital dwel meeter, which I always found gave me smooth running when setting points up. Timing was always a bit of adjust and try. Recently, despite checking all I can, I've started to get hesitation under light acceleration and was thinking it could be the weights not being kept under control by the springs.
George