'74 engine vibration
04-15-2007, 01:09 PM
#1
Nordschleife Master
Thread Starter
'74 engine vibration
I'm posting this question for a person who is not a part or rennlist. He's a friend of my father who heard I "knew people". Anyway here is his email....
" I have a 1974 Porsche 911 that I bought new. I have kept it up very well over the years, or I should say expensive shops have kept it up well, and I drive it most every day. However, in the last three months a problem developed that nobody can find an answer for including myself, Gabriel at Alpina Car Center and my son, who is a mechanical engineer and car nut. One cold morning when I started it Everything was normal for about 15 seconds until an engine vibration started that lasted for about five minutes and stopped. It has done it every day since then. It vibrates the whole car very noticeably. It doesn't have to be in gear or have the clutch in or out. Alpina replaced all the injectors and spark plugs. It runs extremely well with good power with no other bad indications. So, perhaps there is someone in your group that has an idea of what it could be. Gabriel says the motor mounts seem just fine, however, my son does say it is possible it is the motor mounts in some way that are causing an harmonic. The vibration is most active at about 1200 RPM. Have any of your cohorts had any similar problem?"
" I have a 1974 Porsche 911 that I bought new. I have kept it up very well over the years, or I should say expensive shops have kept it up well, and I drive it most every day. However, in the last three months a problem developed that nobody can find an answer for including myself, Gabriel at Alpina Car Center and my son, who is a mechanical engineer and car nut. One cold morning when I started it Everything was normal for about 15 seconds until an engine vibration started that lasted for about five minutes and stopped. It has done it every day since then. It vibrates the whole car very noticeably. It doesn't have to be in gear or have the clutch in or out. Alpina replaced all the injectors and spark plugs. It runs extremely well with good power with no other bad indications. So, perhaps there is someone in your group that has an idea of what it could be. Gabriel says the motor mounts seem just fine, however, my son does say it is possible it is the motor mounts in some way that are causing an harmonic. The vibration is most active at about 1200 RPM. Have any of your cohorts had any similar problem?"
