DDK - Die Deutschen Klassiker

Dear all,

I do suspect that on my ´71 911T one of the ignition cables is faulty (the copper contact which enters the Distributor cap is corroded, i.e. green), as the engine is not running on all cylinders, so I´d like to exchange the presumed faulty cable with one from my ´83 SC - will this work? will I risk any damage to the 911T?

many thanks for your expertise!!

Stefan

You'll be fine trying that but if your leads are old a new set can make a world of difference.

Fresh leads for sure, £68 +vat etc from Type911 + a cap. Change the lot.

http://type911shop.co.uk/epages/de867ca ... oducts/653

RetroGuy wrote:Dear all,

I do suspect that on my ´71 911T one of the ignition cables is faulty (the copper contact which enters the Distributor cap is corroded, i.e. green), as the engine is not running on all cylinders, so I´d like to exchange the presumed faulty cable with one from my ´83 SC - will this work? will I risk any damage to the 911T?

many thanks for your expertise!!

Stefan

Nothing wrong with buying fresh leads but you could clean it up using a fiber pen. Then also cut a 1/8 off each cable to expose some fresh cooper and reconnect the socket? Also are you sure it's the leads problem? Try having the Mrs crank the engine while holding the plug near the sheet metal or swap with another lead?

As a slight aside, I've had corrosion in one/two of the plug tops that catch water from the engine grill.

many thanks for all of your replies!

In the mean time my "layman´s diagnosis" has progressed a bit: Obviously all cylinders of the left cylinder bank fire, all of the right bank DO NOT (I verified this by pulling the ignition leads one after the other, where a disconnection of any of the right bank´s did not change the engine´s running sound at all). Also, to be noted, even if running only on the left hand side the engine idles quite stable at around 1.000 rpm (being normal for my engine when cold).

Am I therefore assuming correctly that I should next check whether the right bank might work by (first taking off the air filter housing) spraying a bit of starting fluid in the trumpets of the right hand side (Zenith) carb, and do I further understand correctly that if the engine then runs (probably only briefly) there´s a problem with the fuel line leading to the right hand side carb? If not, something might be wrong with the carb? I also read on another forum that one could look inside the trumpets and pull the gas cable and one should see fuel being squirted in - nonsense or good advice?

Any precautions to be taken before attempting all of this?

again, many thanks!

Stefan

when you rev it, does it sound like its on all 6?

if its only at idle, that your having probs with the carb, then it could be low float level, dirt/debris in carb - more than likely in the idle circuit, to verify your accelerator pumps, ignition on (FP running), engine NOT running, air cleaner off, pull accelerator, and watch fuel squirt. If you do this with the engine running, then you could get a backfire in your face.

Although it sounds like you should delve into the carb, i would always do fuel related diagnosis last, and do the following below first. Recently my sc had loads of problems with running and starting, i messed around with the fuel and fuel injection for ages ages, before concluding it had pulled studs, and low compression on one side of cylinders. That reminded me to always go through a set procedure (see below) from now on. And that was a low mileage, with recent "work" engine...give me a gun

So start with :

• Valve Adjustment (you dont have to change the oil, just jack one side at a time, engine stone cold)
  Compression/Leak Down Test
  Adjust Ignition Dwell
  Adjust timing, check distributor advance
  In your exact case, verify you have spark on the side you are having problems with (use a spark plug, turn the engine off and on each time you do this)

Now start playing with the carbs set up/rebuild etc.

I'm currently fiddling with my 2.4 zeniths, having been through the above. I have noticed that one of my carbs is leaking fuel constantly, either from over pressure, or incorrect float height/etc, so thats my next step (well if my clutch hadn't failed yesterday).

Luke

thank you very much for your Elaborate answer!

I am now a bit further in my "diagnosis":

- I have good spark on all six spark plugs, in addition I put in new spark plugs on the right side cylinder bank (being the one which does not fire) - the old spark plugs looked okay, btw

- when I take off the air cleaner box and pull the accelerator I see fuel being squirted in

- when I start the engine and then pull the plugs of the left cylinder bank they are wet

So, as ignition seems ok und fuel delivery too, there seems to be bigger problem lurking?!?

I fear that I have to deliver the car to a specialist shop...

thanks!

Strictly wrote:when you rev it, does it sound like its on all 6?

if its only at idle, that your having probs with the carb, then it could be low float level, dirt/debris in carb - more than likely in the idle circuit, to verify your accelerator pumps, ignition on (FP running), engine NOT running, air cleaner off, pull accelerator, and watch fuel squirt. If you do this with the engine running, then you could get a backfire in your face.

Although it sounds like you should delve into the carb, i would always do fuel related diagnosis last, and do the following below first. Recently my sc had loads of problems with running and starting, i messed around with the fuel and fuel injection for ages ages, before concluding it had pulled studs, and low compression on one side of cylinders. That reminded me to always go through a set procedure (see below) from now on. And that was a low mileage, with recent "work" engine...give me a gun

So start with :

• Valve Adjustment (you dont have to change the oil, just jack one side at a time, engine stone cold)
  Compression/Leak Down Test
  Adjust Ignition Dwell
  Adjust timing, check distributor advance
  In your exact case, verify you have spark on the side you are having problems with (use a spark plug, turn the engine off and on each time you do this)

Now start playing with the carbs set up/rebuild etc.

I'm currently fiddling with my 2.4 zeniths, having been through the above. I have noticed that one of my carbs is leaking fuel constantly, either from over pressure, or incorrect float height/etc, so thats my next step (well if my clutch hadn't failed yesterday).

Luke

sorry, it should read

"- when I start the engine and then pull the plugs of the RIGHT cylinder bank (i.e. cylinders 4-5-6) they are wet"

thanks!

Stefan