"typical" early 911 behavior..
10-03-2006, 01:28 AM
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"typical" early 911 behavior..
After 5 years of being off the road my purple monster is back in business with a fresh motor. Since arguably, I've never owned a 911 with a healthy motor before, I have some questions regarding typical early 911 behavior.
First, starting the car when it is cold takes a couple tries. When it does start there is sometimes a small backfire. Is this typical for an early MFI car?
Second, once it is running, the motor is very smooth from idle on up. It pulls strong and feels like I always knew it could. The exhaust, however, has an oily smell to it. There is no smoke to speak of other than the puff of blue when it first starts after sitting overnight. From what I hear, that is normal. It's to early to tell if it is using oil as this is only the second day I've driven it. Is the oily exhaust smell a concern? Do 911s consume more oil than a "normal" car?
On an unrelated note, I wish to extend my thanks to all of those who offered help and advice this summer as I struggled through putting all the pieces back together. Now I only wish I had more than a few weeks left to drive it before it goes away for the winter!
Scott
First, starting the car when it is cold takes a couple tries. When it does start there is sometimes a small backfire. Is this typical for an early MFI car?
Second, once it is running, the motor is very smooth from idle on up. It pulls strong and feels like I always knew it could. The exhaust, however, has an oily smell to it. There is no smoke to speak of other than the puff of blue when it first starts after sitting overnight. From what I hear, that is normal. It's to early to tell if it is using oil as this is only the second day I've driven it. Is the oily exhaust smell a concern? Do 911s consume more oil than a "normal" car?
On an unrelated note, I wish to extend my thanks to all of those who offered help and advice this summer as I struggled through putting all the pieces back together. Now I only wish I had more than a few weeks left to drive it before it goes away for the winter!
Scott
10-03-2006, 02:38 AM
#2
Three Wheelin'
Use the hand throttle when you start the car, do NOT pump the gas pedal like in a carb'd car. The hand throttle activates the cold start which allows extra fuel to help the car start. If everything is working as it should, this should help your cold starts. You can also use the hand throttle for a fast idle to help warm the car up and since it doesn't idle well w/out it when cold anyway, and then close it when car is warm. A little popping/backfiring right after startup seems to be normal on the MFI cars in my experience.
You are correct that a small puff of smoke is OK on 911's at startup after sitting a couple days, it is after all a horizontally opposed engine and a bit of oil can leak past the rings and into the combustion chamber. As for your "oily" smell, I am not sure if this is just after startup or all the time or what. If it is not oil that is burning in the combustion chamber, maybe it is a small oil leak onto the exhaust itself. Most 911s seem to have a slight burned oil smell to em! Porsche says that oil comsumption of 1qt/1000 miles is the normal limit. I'd be ok w/ 1 qt per 1,200 or 1,500. If this is a new engine, change the oil and filter after the first 1,000 miles and readjust the valves, and then if everything is OK you can resume normal intervals, making sure that you monitor oil consumption to make sure that you're not using too much oil. Use the dipstick not the gauge!
Also, make sure that when you drive the car, DRIVE THE CAR! Let it warm up well, don't romp on it till you've reached normal oil temperature, and take it for a spirited drive! These cars were designed to be driven. Not abused, obviously but the worst thing that you can do is putter around town and lots of short trips and cold starts. Too bad you live in a place where you have to put her away for the winter. That's why I live in CA! Good luck w/ your toy!
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Chris Andropoulos
Schneider Autohaus
Santa Barbara, CA
You are correct that a small puff of smoke is OK on 911's at startup after sitting a couple days, it is after all a horizontally opposed engine and a bit of oil can leak past the rings and into the combustion chamber. As for your "oily" smell, I am not sure if this is just after startup or all the time or what. If it is not oil that is burning in the combustion chamber, maybe it is a small oil leak onto the exhaust itself. Most 911s seem to have a slight burned oil smell to em! Porsche says that oil comsumption of 1qt/1000 miles is the normal limit. I'd be ok w/ 1 qt per 1,200 or 1,500. If this is a new engine, change the oil and filter after the first 1,000 miles and readjust the valves, and then if everything is OK you can resume normal intervals, making sure that you monitor oil consumption to make sure that you're not using too much oil. Use the dipstick not the gauge!
Also, make sure that when you drive the car, DRIVE THE CAR! Let it warm up well, don't romp on it till you've reached normal oil temperature, and take it for a spirited drive! These cars were designed to be driven. Not abused, obviously but the worst thing that you can do is putter around town and lots of short trips and cold starts. Too bad you live in a place where you have to put her away for the winter. That's why I live in CA! Good luck w/ your toy!
---
Chris Andropoulos
Schneider Autohaus
Santa Barbara, CA
10-03-2006, 02:50 AM
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Thanks, Chris! That helps put mind at ease a bit. I have been using the hand throttle like you say but the nights have been getting a bit cold here lately. I'm sure that doesn't help.
Scott
Scott
10-03-2006, 12:11 PM
#4
Rennlist Member
Scott: In addition to what Chris wrote, try your best to get that engine broken in before it has to go into hibernation, even if you have to drive it a few hundred miles this weekend. Another thought regarding the exhaust smell - this is usually from the heat exchangers being filthy before the engine was disassembled. No matter how hard you try, or how "clean" you get them, they will still stink for a while. Oil consumption can be high pre-break in (maybe a quart the first hundred miles), or very low post-break in (a quart per 3-4,000 miles). MFI can be a bit cranky in cold weather, but it would probably be good to verify your fuel mixture after you get a few hundred miles on the engine. So there is no confusion, Porsche does not recommend a garage warm-up - as soon as the car is running smooth enough to pull into traffic safely get out and go!
Pete
Pete
10-03-2006, 12:29 PM
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Thanks, Pete! Your remark about the heat exchangers is something I never thought about. Makes sense though as things were pretty grim in the final days of the old motor. I'm doing my best to complete break in before I put the car away but I'll only drive it on fair weather days for now. All the rubber seals on the car have seen better days (next year's project) so I don't want to risk it getting too wet. If the weather is nice this weekend, I'll tell my wife I'll be gone for a few hours to protect my investment!
Thanks again!
Scott
Thanks again!
Scott
