I had a top end rebuild done about 5,000 miles ago and the car is running very well ... but I still use about 1 liter of oil every 550 miles. This seems a little excessive based on what I've read about other cars on this board. Does this rate of consumption sound reasonable to the experts out there.

On the subject of engine temperature, the advice seems to be not to exceed 4k rpm until the engine is fully warmed up. Does this correspond to the first hash mark on the temp gauge?

Also, the recent threads on gas fumes have been very helpful. I'll try the new cap fix and also check the lines under the hood for leaks.

 

Hi Michael:

Although its tough for me to tell from here from the information you've provided, I'd guess that your rings (if they were replaced) are not yet seated. If they are the same ones, there is a bigger problem.

 

Thanks for your reply Steve. My mechanic also said that the rings would take a while to seat and oil consumption should improve. Regarding details of the rebuild, the car is an '87 Carrera that had about 92,000 miles on it. I brought it to a guy in Switzerland that has an excellent reputation for preparing Porsche for the track. He changed my piston/cylinders to Euro spec. (with new rings), changed my camshaft to a 964 model, dropped the cat, and remapped my chip. The car was dynoed at his shop with an increase of about 25 hp over stock with, if I remember correctly, about a 20 nm increase in peak torque. Other mods were turbo tie rods, camber bar, and clutch replacement. When I brought the car to him it was pretty tired and consuming 1 liter every 250 miles.

 

if you are correctly adding oil to 1/2 way between the high/low marks on your dip stick, and your not leaking oil Steve answered your question.. and 5k miles is plenty long for rings to break in.. ring break-in vs millage is not a linear curve.. perhaps 90% of the break-in should happen within the 1st 100 miles... it's not unusual for your ring situation to occur.. not common, but not unusual. there is a technique for ring break-in. If you can get a re-ring come back here with a new Post..............Ron

 

Thanks Ronin. I'm keeping the oil between the high/low marks and notice that the car smokes less on start up if it's lower than halfway between the marks. Of course reringing would involve dropping the engine .... so is it important enough with the consumption I mentioned to force the issue? If I'm not mistaken 500 miles/liter is within Porsche specification so that would weaken my case.

 

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by RoninLB:
<strong>.... 5k miles is plenty long for rings to break in.. ring break-in vs millage is not a linear curve.. perhaps 90% of the break-in should happen within the 1st 100 miles... there is a technique for ring break-in. </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Good points.
Many owners make the mistake of "babying" a new motor.
Wrong! Doing so increases the risk of the piston rings not seating, with the resultant oil burning later in life.

The "technique for ring break-in"?
Drive it like you stole it!

 

OK Michael... I'm not a pro, but if I wanted another shot at seating the rings.. I'd flip your oil for straight 30w non-synthetic non-detergent oil.. drive it to circulate the 30w w/your present oil left in at the oil change.. then change to the non-detergent 30w again.. then constantly load the rings by rocking the car with the gas pedal.. maybe never use 5th gear.. better in 4th at 65mph than 5th.. always rock.. floor it then take your foot up.. keep doing it for 500mi. it may work, no garantee.. I think it's your only chance now.............Ron

 

As I understand it the consequences of leaving as is or not being able to seat the rings properly are:

some initial smoke at a cold start-up
higher than normal oil consumption 500 mi/liter

Is there any downside to leaving it as is or should I push to have it reringed?