72 350SL Resistors should I replace

[afmcorp]

hello folks

i've been having some trouble starting this car. long story... however i'm wondering about what my books say on the 2 resisters at the coil "they should be changed if not in spec".

ok... here is my question the silver one should have a resistence of 0.6 so my trusty vom tells me the silver one is running 1.2 and the blue one is running at 0.9 to 1.0 (the blue shows a spec of 0.4) so that one is also hi.

so if they have twice the resistence would this cause much or any problems in the ignition? and should this cause a voltage problem to the dist and to the plugs.

also does any know for sure what the numbers mean when they say .4 or .6 ohms. i take this to mean 400 and 600.

any comments or suggestions is appreciated.

ps: on the pass side between the battery and the expansion tank on the bracket that holds the expansion tank is a connector block and there is a cylinderical piece with an adjustment screw. i haven't been able to identify that item. does anybody know what it is?
tks much
craig

[Rasputin]

The resistor with 0.4 OHM has now been superceeded (no longer available) and both resistor are now 0.6 OHM. Yours are definitely shot creating very high resistance to the coil. The ceramic body tends to crack underneath (thinest part).

The connection block you refer to seems to be (a black box) the connection point (with two fuses) for the auxiliary fan.

[erubin]

Your and my 72 350SL originally came with a transistorized switch gear (under the fender). It works along with the ballast resistors you described. When my system went bad it was bypassed and became a conventional breaker system. To do this requires changing the coil. The points will wear out quicker in theory but it really was not a problem for me. I change them at the same time as my plugs, every 12K.

A few days ago I decided to order the Pertronix breakerless ignition (Hall affect, not optical) to upgrade my distributor. It costs ~$70 and should improve performance as the dwell is no longer controlled by a worn out distributor cam. In your case this would eliminate the need for your resistors and the archaic/primitive transistorized switch gear.

Here is the info i got from a Pertronix reseller:

Elliot,
We have the 1885 Ignitor in stock, $69.95, free shipping, no handling charge. We ship via First Class Mail which takes 3 days to California. You can use your credit card on line to order. Please see this page:

http://www.vintageperformance.com/retrorockets/credit.htm

Thanks for your inquiry.

Carl
Retro Rockets

Elliot wrote:

Carl,
I would like to order a new 1885 Pertronix Ignitor. $69.95 which includes S&H. Do you accept credit cards? When can I receive the kit?
Best regards,
Elliot
----- Original Message -----
From: carl dudash
To: Elliot
Sent: Wednesday, July 09, 2003 8:41 AM
Subject: Re: 450SL ignition
Elliot,
You can use your stock coil with the 1885. If you have an aftermarket coil be sure it has at least 1.5 ohms resistance which is what is required for the Ignitor. Stock coils will have this resistance. Stock rotor, cap and wires are fine as long as they are in good condition.

The proper distributor is critical. The 0 231 403 007 would be the stock distributor so if you know that it's original you won't have a problem. The number is sometimes stamped on the outside rim of the housing that gets covered by the cap so the cap must be removed to see it.

Thanks for your correspondence.

Carl
Retro Rockets

Elliot wrote:

Carl, Thanks for your response. for the 1885 can I use the same coil as I now have with my stock system? Ant other pats needed such as rotor,etc? I don't see a P/N on my distributor. Is it critical that i identify it as 0 231403 007? Thanks,Elliot
----- Original Message -----
From: carl dudash
To: Elliot
Sent: Tuesday, July 08, 2003 9:23 AM
Subject: Re: 450SL ignition
Elliot,
My notes show the '72 450SL to have distributor number 0 231 403 007. If this is what you have it will take the 1885 Ignitor ($69.95) or the 91885 high performance Ignitor II ($101.45). For stock engines we recommend the 1885. Free shipping, no handling charge, both in stock.

The Ignitor is more tolerasnt of a little shaft wobble than points. If it's less than say .025" you shouldn't have a problem. The distributor should be rebushed if the wobble is excessive.

Thanks for your email.

Carl
Retro Rockets

Elliot wrote:

Hi, I own a Mercedes 1972 450SL. The ignbition system is with points. please advise which to get of yours and the cost. Do i need to restorre the distributor as well, it has some (not too bad) play on the shaft. Best regards,Elliot