Ignition/Compression on '77 Euro Carrera 3.0
02-11-2003, 04:10 AM
#1
Instructor
Thread Starter
Ignition/Compression on '77 Euro Carrera 3.0
Hi Folks - have a tough question for you here.
I have a '77 Porsche 911. It went into service in Europe, and came to the US in the mid 80's. I am the third owner. The vehicle is a European 3.0 flat six, first year of the 3.0.
The engine is still strong, but I am having a problem with the timing. If I advance the distributor too much, she starts to ping. I can stop the pinging by retarding the distributor, almost to its limit. Unfortunately, at that point, she is slow off the line. Her acceleration is mild until the RPM's go above 3250, and only then does she start to take off.
Here lies the problem - I want her to be more lively, but each time I move the distribtor forward, she pings above 3750 rpm. Her acceleration is much more lively, but I know the pinging will kill her sooner than later.
My mechanic mentioned that this a drawback to having a European 3.0, that they have higher compression since they run on higher octane gas over there, and that there is not much that can be done about it. I am pretty sure the car was originally made to run on leaded fuel, as well.
I am interested in a second opinion. I do not want to tear down the entire engine, but I really like the extra power in the lower RPM's.
Any advice would be GREATLY appreciated.
Thanks -
Rob
I have a '77 Porsche 911. It went into service in Europe, and came to the US in the mid 80's. I am the third owner. The vehicle is a European 3.0 flat six, first year of the 3.0.
The engine is still strong, but I am having a problem with the timing. If I advance the distributor too much, she starts to ping. I can stop the pinging by retarding the distributor, almost to its limit. Unfortunately, at that point, she is slow off the line. Her acceleration is mild until the RPM's go above 3250, and only then does she start to take off.
Here lies the problem - I want her to be more lively, but each time I move the distribtor forward, she pings above 3750 rpm. Her acceleration is much more lively, but I know the pinging will kill her sooner than later.
My mechanic mentioned that this a drawback to having a European 3.0, that they have higher compression since they run on higher octane gas over there, and that there is not much that can be done about it. I am pretty sure the car was originally made to run on leaded fuel, as well.
I am interested in a second opinion. I do not want to tear down the entire engine, but I really like the extra power in the lower RPM's.
Any advice would be GREATLY appreciated.
Thanks -
Rob
02-11-2003, 01:18 PM
#2
RL Technical Advisor
Hi Rob:
Sorry to to hear of your troubles and I'd like to offer some suggestions.
Ignition timing is VERY critical on 911's and your Carrera 3.0 is no exception. You are correct; letting it ping is very dangerous to your pocketbook and must be avoided at all costs.
Make sure that you set the timing at 5 deg ATDC with all vacuum hoses connected. This is done at 900 RPM.
Check CO to make sure that its not too lean. This should be 1.5-2.0 %.
These engines have a compression ratio of 8.5:1 so it should run OK on any premium fuel, 91 or better.
Sorry to to hear of your troubles and I'd like to offer some suggestions.
Ignition timing is VERY critical on 911's and your Carrera 3.0 is no exception. You are correct; letting it ping is very dangerous to your pocketbook and must be avoided at all costs.
Make sure that you set the timing at 5 deg ATDC with all vacuum hoses connected. This is done at 900 RPM.
Check CO to make sure that its not too lean. This should be 1.5-2.0 %.
These engines have a compression ratio of 8.5:1 so it should run OK on any premium fuel, 91 or better.
