salukijac

I'm looking for signs when a 87-89 911 need a top end or at what mileage, etc. I did a search for older posts and I didn't find what I was looking for.

old man neri

Oil consumption.

Amber Gramps

Matt is right on. Oil consumption down in the 1qt. per 500 mile range and you are overdue. Ask me how I know.

salukijac

In Peter's book he says 1 qt per 1000 miles is normal consumption and recommends a top end when it gets down to 300.

So Doug I'm interested in your story.

And how fast does it go from 1k to 500? Months, years, thousands of miles??

Amber Gramps

No you're not, trust me. The story is way too long....

radvan

Presumably the 'normal consumption' figure of 1qt /1000miles applies to 'normal' driving. What about track use? I rarely drive hundreds miles between DE events so can't easily use that metric. At DEs I tend to use 0.75qt per 2 day event. Anyone have data points for DE oil consumption - particularly for a mid 80's 911 needing a refreshed top end?

rusnak

I think if you have high oil consumption while street driving, then that is a clue to do a leakdown test. DE or more high speed driving will consume more oil no matter what.

jakeflyer

So what is a top end???? Rings, valve grind, guides maybe. That assumes that there is a good seal between the jugs, heads, and cases, and head studs are good. Static compression will give you an idea about rings and valve sealing------ maybe hot and cold. Excess oil burn will be shown on the spark plugs, due to oil entry into the burn chamber----- maybe thru valve guides or rings.

1. check the plugs for oil burn
2. check compression

Norske

Also, smoke on deceleration is a good sign of valve guide wear.

porsche930dude

a quart every 300 miles lol It would be smoking like a diesel

BlackPearl

My '83 SC has over 170K miles, and I duel-use the vehicle on street and track.

On the street I go through about 1/2 to 3/4 US quart of oilevery 600 miles, driving it "tamely."

As for the track: uh, well ... not so good on oil consumption. For a Time Trial/DE event where I drive 5 to 6 sessions at 25 minutes per session HARD, I'll go through 1 quart of oil per driver per day. (That's 2.03 hours of full throttle driving per driver per day.)

As examples: I shared my car with a buddy at Buttonwillow for a two day event. On the first day we burned through 2 whole quarts of 10-50 Royal Purple Syn Oil driving 2.5 hours of track time each. (Says a lot about how durable the SC's are.) So 1 quart for 2.5 hours of hard track driving (Approx. 150-miles of near full to full-throttle track time on the big loop.)This month, my wife and I shared my SC at Streets of Willow (a smaller, taimer track by many measures). We burned through 1.25 to 1.5 quarts of same type oil on the shorter, more tame track sharing the car.

As for my SC: My car smokes at start-up, and when initiating decellerating hard at track events ( in other words, a quick puff of blue ). To the best of my knowledge, the top-end is original equipment ... and probably a little tired. Compression is good across the bank (only 5-psi difference from cyl. 1 through 6 at 170 psi - 175 psi), so no leak-down has been done since the compression is good.

I've heard others in '78 to '83 SC's, '84-89 Carrera's and 964's and 993's use up to a quart of oil a day at TT/DE events so I'm not panicking yet.

It might be disputed, but I've heard from more than one professional wrench-turner that Porsche was not super-concerned or "tight" about tolerances for valve-guide construction in the '74 to '98 cars. I've heard quite a few horror stories from owners of 964 and 993 models about valve-guide (and valve spring) issues and failures in '78 to '98 cars (ie; "check engine" fault light signal and smog test failers in 964's and 993's, etc).

Personally, if I were in your shoes (and owning an '83, I kinda am) I'd be vigilant about tune-ups and valve adjustments. I'd have my heads re-torqued every year, or every valve adjustment; whichever comes first, I'd watch my oil consumption and tailpipe "sooting" for signs of "excessive" oil burning, I'd listen for unusual valve tapping between cold and warm engine conditions, I'd note repetitive backfire/pop-off valve occurances, and check for detonation when the car gets to running temps or hotter.

In other words ... I'd be a Porsche owner.

Of course, a compression and leak-down test would never hurt, either.

Just my opinions....

Happy Driving!

HarryD

300 miles/quart, worn seats, 12 worn valves:

umfan866

This is something I've worried about a lot when looking at cars.
I'm trying to find one with a top-end already done.
You'll want to read these threads:

How certain is valve guide failure in 3.2s?
http://forums.pelicanparts.com/showthread.php?t=316430

Which years are the worst for valve guides
http://forums.pelicanparts.com/showthread.php?t=364730

JamesR

MY 88 CARRERA,WITH 119K,WAS USING THE QUART/500 MILE ROUTINE.
OWNER SINCE 01. SWITCHED TO VALVOLINE VR-1 LAST FALL. 500 MILES
& JUST A SLIGHT ANOUNT OF USAGE. NOT A PROMO. JRS

g-50cab

At 56k miles I was down to 400 miles per qt and dropping fast. The best my car did (when I first got it was 1,000 miles per Qt - at 44,000 miles) it went down in a hurry. Castrol GTX oil. The PO was pretty religious about oil changes, always with castrol GTX - but the car was definitely a low mile example (has 64,000 miles now).

When I opened it up - The case was stained amber, the cams were pitted, 8 of the rocker arms were worn beyond spec, layshaft bearings were showing copper and all six exhaust valves were worn beyond spec and had to be replaced.

It's all good now though...