Can I get a second opinion?
 

I have a 190K mile SC with a stock CIS 3 liter except for, SSIs, and 20/21 cams.

The car runs great. The only puff of blue smoke is on start up after siting for a few days and big temp. changes day to night.
If the temps are mild there is very little smoke after being left a few days. Takes a a week or longer to get the puff of blue smoke at start up if the temps are mild. No smoke orther than blue a starts as noted.

I recently had a compresion test and a leak down done.

Compression was 145 across the board. Down from 160s 30K miles ago and from the 150s 16K miles ago.

Leak down was 8, 10, 6, 6, 12, 12 which is causing me some
concern. Down from 6, 4, 6, 5, 5, 6 @ 174K miles.

As far as I can tell the car goes through a quart of oil every 600 miles. But it is hard to be very accurate, it could be slightly more. I try to keep the dip stick at half way between the marks. Half a quart at every fill up pretty much covers it.

I have a short gear box (4 new gears and a 127 top end) and I drive the car briskly. Little to no around town stuff and usually keep it above 4K and redline 3/4/5 on most every trip. Track days once a month where the oil consumption goes up accordingly.

Recent dyno showed a good torgue (168) curve and 182 at the wheels.

Are the leak down and oil consumption something to worry about or just keep an eye on?

Rebuild now or drive it another 50K?

Thanks for any insights and opinions. I am feeling like a worry wart looking at the oil and miles but wanted to hear some informed opinions.

Thanks for the help!

Sounds good to me. All the tests are only useful when used as pieces to create a complete picture. You can probably drive it for a while more without worrying about it. It's getting tired, but it's not undriveable yet...

-Wayne

When I freshened up the top-end of my 3.0 at (only) 80k, there was negligible wear on the pistons and cylinders. I did find 2 oil rings were broken, however. Luckily, they stayed in their grooves and did not damage anything. Who knows how long they were broken!

Anyway, at the time of the rebuild, my motor was using about 1/2 qt. of oil every 2000 miles. I'd say a quart in 600 is excessive. You are probably looking at rings and valve guides. And how much consumption is due to leakage??

Hmm, you're right doug - I missed that quart thing - I thought he said 1/2 a quart for some reason. That does seem high. I would take care to measure the oil consumption a bit more.

See here:

http://www.pelicanparts.com/techarticles/mult_Engine_Rebuild/mult_engine_rebuild-1.htm

-Wayne

I have one other question, do you have any oil leaking? Any spots on the ground after driving? You might want to verify oil consumption versus leakage. FWIW

Thank you gentlemen for the insights.

Wayne I spent the night rereading your book again. Good stuff, thanks!

I had the engine pulled and case resealed a short time ago. It does have a single oil leak that has been problematic. The tube that is manufactured in the case, what ever that is called . Leaks enough that I am getting oil on my plate and bumper. But last time it wasn't leaking I was @ 1 quart every 600/700 miles during long distance, moderate, highway driving. I try to keep the oil midway between the lines on the stick. Takes a bit to get the engine to temp with a BB cooler up front so that has made consistant measurement a little more difficult. Car is running right at 170F after 30/45 minutes.

Week in the garage undriven and I have a quarter to half dollar size spot on the floor.

I suspect without the oil consumption I would be a happy 911 driver. But the oil consumption has me thinking rebuild. Once the heads are off I'll know more. But making that decision to pull the engine is bugging me.

One wrench says don't pull the engine till the oil consumption goes past where it's at now.

The other wrench says he suspects the rings are bad at minimum and it's time just to avoid a lost engine.

They both know how I use the car and its history.

Can you give me any more insights from this? TIA

Have you spoken to John Walker about this?
I'd do whatever he suggested.
You can't go wrong listening to someone with his experience.

i would agree with wayne, that it seems to be hanging in there at the moment. a quart in 600 is pretty normal for an engine with 190K. has it ever had a valve grind? most need one around the 125K mark, due to the guides being worn out. the occasional smoking thing may be indicative of worn rings and guides that you would expect to see at 190K. when the guides wear out, the valves wobble around and contact the seat erratically, and basically beat the hell out of it, until the seat is no longer round and precise. that's where a lot of the high leakdown readings come from. loose guides and poor seats are not good for valves, because valves conduct their heat into them, and when they can't, they burn, or drop their head off. you are kind of living on the edge, but i've seen them go a lot longer than 190K without any work to speak of. personally, i would drive it a bit easier than you describe. 4K all day long, and redlining all the gears is hard on an older engine.

Again, thank you gentlemen for the comments.

Funny enough this engine is now apart. Still running good when it was pulled from the car.

It also has three bent values and broken rings in one cylinder with some good scoring on that cylinder wall.

Engine had the original Ausil cylinders and the original '79 head studs.
Dynoed the week or so before I pulled the engine was 182 at the rear wheels on a Dynojet machine. The other SCs that dynoed at the same time where a good deal less.

Says a lot for a new or renewed Porsche flat 6!