Tuning issues ? 1968 911L

[nucleonic]

i was hoping the group might be able to offer some advice on my 1968 911L. When I bought it it wasn't running quite right as it had sat for almost a year without much driving. I took it to the shop here that services my 356 for a tune up etc. they suggested a cdi perma tune unit and cited that 68 and 67 cars basically will never run right without a cd. I didn't do the cd because there wasn't any in town and I didnt have time plus I thought surely it can run correctly on on points etc. they tuned it, adjusted valves, new plugs (old ones were fouled) etc and it runs a bit better but, now is small popping back firing on de acceleration and still isn't running they way it should.... Almost kind of like it has turbo lag.

Should I do the cdi or maybe seek more of a guru 911 tuner who maybe more adequately suited to meet the needs of servicing the car ? Maybe the carbs need attention. Dunno. All I know is that currently my 356 is quicker with steady acceleration and more fun to drive than the 911 and somehow that doesnt seem quite right based on engine size and out put etc !

penny for your thoughts.

Thank you !

[gulf908]

Hi

Yes be all means install the cdi and correct coil.
However it sounds if you have more than one problem from lack of maintenance.
Is the car a US delivered ?
Do you still have the small air injection pump on the LHS of the motor ?
I believe this 1968 US only emissions arrangement was not a success in the day and is still not.
Others may want to give chapter and verse for this model which is great when running well.
Welcome to the Early 911 slippery slope !

Cheers
Dennis.

[nucleonic]

thanks ! The engine was rebuilt 4k miles ago to high standards. The smog equipment was removed. Car is a USA model. When installing cdi, where can it be placed so it doesn't look out of place ? Currently the engine compartment looks like new as it was detailed at time of rebuild. Would prefer to mount a cdi in a discreet location if it is necessary to go that route.

[vicrola]

If you do CDI, make sure that your box matches the coil (same manufacturer)...it does make a difference. I hid my box on the firewall behind the air cleaner.
Vic

[Fritz A. Ficke]

CDI is very nice and was a great advantage especially on the S model cars at the time. But your problem sounds more like dirty Carbs and will not be fixed with a CDI, may be masked over some but not fixed.

[Fritz A. Ficke]

Here is a picture of my CDI unit that was installed in 1968 on my 1968 911S, note it is aftermarket as the Bosch units were not common, as Porsche did not use them until later.

[nucleonic]

thank you. I have contacted "partsklassik" for suggestions on a complete ensemble for cdi. If it is just the carbs, I asked the shop to look at them as suspects, so I would hope they determined the carbs wasnt the problem but you never know I suppose.

[JT912]

Who is the shop that you are using? I have a shop in Eugene that just dialed in my '68 and it runs very well without a CDI.

[nucleonic]

thank you. Eugene is a bit too far from PDX for me to try to get a car serviced there. I'd rather not say which shop I took it to for diplomatic reasons, though it is a shop that has years of experience with porsche etc.

[RSTarga]

apart from the carbs, is your distributor working properly? Check the advance mechanism. Have they done a leak down test to make sure all is right?