CalvinC4S

PCNA in Reno,Nv trained us to fill by level and temp gauge as they work together.

geolab

In my case I use the car until oil goes down to minimum on dipstick, and if/when it does, I give it half a liter
Oil consumption is primarily on each start of engine....
You HAVE to use the original porsche updated small engine filter, or else you would see puffs of smoke from exhaust from time to time.

Even the dipstick is not accurate at all...
As proof that the dipstick is not accurate,
-run engine until warm
-park car steady for 30-45 seconds and read dipstick level, lets say its at half...
-step on the gas pedal and raise the rpm to 6500 rpm 3 or 4 times, or wot in first gear and second gear if you are out.
- park car steady for 30-45 seconds, dipstick level will read 3/4 full and not 1/2

geolab

I know I am going to be hammered , but why not, I trust the community gents here will do their best , so for debate purposes....
I woke up less "politically correct" today, so here is what I am thinking...

A valve stem seal role is to control the amount of oil that flows between the valve stems and valve guides,
its role is NOT = to prevent oil from passing, but calibrating.
That's how I understand it.
In the 993, I think a lot of buzz biz, generated concerning the guides.
There is concrete evidence through P TSB that the small oil filter default, resulted in different cavity pressures and oil seepage with oil fumes through exhaust, in the turbo engine, AND the NA engine....
Whenever there were fumes from exhaust, everybody yells its the guides.
In my personal opinion, the issue with the guides was exaggerated.
What would you tell an owner when his low mile engine is ripped apart in front of you ? the guides are still in tolerance ?
The guides that showed weakness on a high mileage 993 engine were mostly the exhaust guides.
and weak exhaust valve guides make the engine fume, but the oil does not enter to the cylinders through the exhaust guides
It is not the guide material, the culprit, in my opinion today, tomorrow it might change.
Its the heat.
This is why the turbo and the RS engines have Na exhaust valves.
there is a 0.03 mm oil film between the valve stems and guides, no reason for the guides to wear.
over-heat and less oil, creates a friction between metal to metal (the stems against guides)
but this scenario was not eluded by Porsche, because in my opinion it is not true. At least not more
than in a subaro or a honda.
The response to this by pros is a bronze - mag - ph. guide???????
because if the stem has friction with the phosphorus whatever guide, it won't wear ????
I was at RUF in germany a few years back, and I discussed the guides issue there..
Their opinion is that the guide material was purposely chosen like this, for the engines to last 200k km or more.
Do not be impressed by the word RUF, I wasn't, but its an opinion
but that's just me.
I'm changing, boring honing my guides soon
Steve jobs said "stay hungry, stay foolish" I agree

.

Quadcammer

I would most certainly NOT free rev the car in neutral to 6500 rpm ever, much less every time you check the oil.

vincer77

First time I have seen mention of a redesigned filter. Do you have the TSB reference?

NP993

+993. Not smart.

Steve Weiner-Rennsport Systems

That's correct,..

Based on personal experience from doing all of our machine work in-house over the past 30+ years, I'd kindly disagree.

The Turbo's engine mounted oil filter contains an anti-drainback feature not found on the N/A engine filter and thats to help prevent oil backup in the turbochargers. Using the N/A filter on a TT results in some excess smoking.

The root cause is two-fold: soft guide material and poor fitment. I've see far too many low-mileage heads with tolerances way past factory specs. Some came here with under 3K miles that were honed and assembled beyond the factory specs! Heat does add to the wear and that's why we advocate measures such as additional oil coolers and removal of engine undertrays.

993/907

My '95 uses oil, about a quart/500 miles.
I figure oil is cheap, the car runs just fine, and $5k+ is a lot to spend to fix a problem that isn't a problem.
What am I missing here, why the fuss over oil consumption?

Gordo

Quadcammer

Gordo,
Your car doesn't run just fine. Well, in comparison to a 4 cylinder camry it might, but compared to a healthy 993, it won't. You will be down on power, and all that oil is now clogging your cats.

That oil reduces octane, mucks up the combustion chamber, and will eventually damage the cats and 02 sensors.

Given this is a gradual process, you probably don't notice the decrease in performance, but I can almost guarantee that you will be down on power.

993/907

You may be right Quad; mine is a DD so I rarely get a chance to nail it hard.

Quadcammer

As far as I know, you also live in alaska, so your oil consumption may also be higher because your car spends so much time warming up, during which oil consumption is also higher

geolab

I have honestly no scruples revving the engine in neutral or in gear to 6500 rpm for a few seconds in neutral, or for an hour in gear.
I have visited 4 engine factories and personally saw what they did to new engines on benches, before they went in new cars.
At Porsche in Leipzig, every carrera gt engine went on a bench, was fed hot 90* celcius oil, run for a few seconds at idle and directly at 8000 rpm until the computer saved all the givens. At that time, the heat exchangers are liquid red.
THEN, comes the vibration test. The computer shoots the engine from idle to 8000 rpm and back to idle like 30 times up and down. Attended the sessions of two engines.
At AMG , 20 minutes from stuttgart. SLR engines were tested up to 6500 rpm.
Each engine was built by one mechanic, who himself installs engine on bench.
As well, they made the engines scream.
Saw that at RUF and at Renault f1 as well.
There are youtube videos of renault f1 engines singing at high revs in neutral
In my opinion, the engine risks nothing zero ziltch nada

any substance added to gasoline and is less flammable than gasoline or not flammable at all, like water, increases octane. Lower octane is better gasoline, purer, which is prone to ignite at a certain pressure. Add to it anything that obstructs this gasoline ignition at the same pressure, but ignites at a higher pressure, renders the octane level higher (of course on condition that the gasoline and substance mix still ignites) think of it that way.

geolab

My respects My main man. How are you, hope all is well.
Thank you for your participation.
I have in my possession 44 used valves all out of 993 RS engines, half intake half exhaust. (they came from racing schools)
To my surprise, all intake valve stems are out of tolerance, and all exhaust valves are in tolerance. When I asked about the health of the RS heads at porsche, they said all the heads had In-tolerance Intake valve guides, and out of tolerance Exhaust guides. But they claim it is normal wear.
I mean how come many many engines live miles and miles, with the same valve guides that everybody point at ? The original valve guides are not good ? I find it hard to believe, but thats just me.
Now you have answered my question by stating that you have witnessed out of tolerance valve guides from factory, now that would be a cupid reason for me.
Now I understand better.

I do kindly disagree
The filter is the same for NA and Turbo, always been, but original 99310720300 concept was defective
I have done all possible, some time ago, to gather the 993 TSB's for our community. And whilst doing that, I had to read all the TSB's to class them in folders etc etc.
A lot of the TSB's were general, and some specific.
One of the general TSB's was the one handling the small oil filter, and it applies to both turbo and NA 993.
Since then, I had spare knecht, Mahle oil filters, and all aftermarket filters made my car puff a cloud of smoke after a long sit in a garage.
I have then only put original porsche small filter and never had that puff anymore.
I know for a fact, I could initiate the puff now, if I put an aftermarket oil filter.
the famous TSB:

http://www.pcarworkshop.com/images/3...0395geolab.pdf

Quadcammer

1. In general, these engine tests are done on engine dynos, which apply load to the engine.

The F1 engine revving: 1. you have a porsche street car, not an f1 race engine. 2) If you've seen the clutch and transmission assemblies on f1 cars, there is little load on the engines anyway so the engine is designed in such a manner; 3) Do they rev to redline or do they rev to 10k or so.

2. There is still no point in revving the car to 6500rpm before checking the oil.

3. Its your car. You can rev it to 12k rpm if you really want to. Not my engine, not my checkbook, so have at it.

4. I'm just curious, what do you think the purpose of that is?


5. Oil has an octane level of about 40. You think adding this to a 4 stroke engine is somehow A) increasing the octane level; and b) good for the car somehow?

plymouthcolt

On my 1988 it puffed on startup but did not smoke on any type of acceleration or deacceleration test. It did burn oil-one quart every 500 or 600 miles. It was determined the valves guides were worn. Are you noticing any oiling fouling on your plugs?