IcemanG17

Well after reviewing the video from "Sears Pointless" a couple weeks ago, it clearly shows the oil pressure and temp gauges..... Oil used was Amsoil 15-50 racing and had 18 hours of run time on it at the end of the race....1984 928 S automatic

The modifications to the oil pan are:

1: Retrograde to early style pan with plastic insert-mesh screen-pickup
2: 3/8th inch pan spacer

that's it....not even an oil cooler....

During my stint oil temps were consistently 240F and pressure varied with RPM between 75-100+psi.....in all types of corners at over 1G (trackmate data) it held pressure......sometimes I would downshift to a 2nd gear mid corner if traffic was bad and guess what...OIL PRESSURE WENT UP WITH RPM's...... never saw less than 50psi and that was off throttle at turn in at about 2500rpm.... never ever saw under 75psi on throttle...with RPM's of at least 3000.....

It burned about 6 qts over the weekend due to a bad leak at the rear of the pan spacer.....

When I drained the oil the magnet was perfect....just 1 tiny spec on it....cut open the oil filter and its also perfect.....no metal at all.... oil analysis should be back later this week....I expect it to be near perfect, especially considering the time on the oil....

I think a "retograde" oil pan might be a cost effective solution for 928 owners who track their cars!!!

GregBBRD

Mark Anderson had a much different description of what the temps and pressures were, during his driving stint, when I talked to him.

I guess he drove first and was pretty much convinced, even before the start flag dropped, that this was going to be a very "short" day. The engine was overheated and steam was coming out, before the race even started, according to him. He said that anytime he "pushed" harder on the car, it overheated and steam would come out.

He was absolutely flabergasted when the thing ran the entire race.

I think he might be a new "Amsoil" convert!

IcemanG17

Greg
The overheating problem was caused by two "issues"

1: A certain namelss rocket scientist installed the seal on the thermostat wrong...that was fixed on Saturday
2: The car was overheating a bit on Sunday for the middle stints because the fan was OFF....oops...so the fact that it ran even remotely cool with NO FAN at all...is pretty impressive.....

After watching the video of Marks Sunday stint....he was floating between 2nd white line and red on water and the oil was between 240F-280F.... with the fan OFF (you can see it)....I went out right after him.....water was 2nd line and oil was 240-250F the whole time.....

Given how spectacularly the engine grenaded last time I was a bit concerned about this engine lasting.....but it did and still runs GREAT!!!

mark kibort

I was watching everything during my last stint on Saturday and first on sunday. pressures and temps were good, the only concern was water, going just to the second white line for the entire 2 hour to 2.5hour stint I ran. More rocket scientist action: no fan, or a meaningless fan (i.e. the ac fan as the only fan) with a proper fan, the temps will be fine. I could overheat any of the cars I have even during street driving, without the fans properly working. on the track, you NEED the big puller fan on the inside or you are out of luck! (yes, even at average tracks speeds of over 80mph)

mk

IcemanG17

MK
Which is why I think the radiator must be fine.....since the car ran for over 2 hours with NO FAN AT ALL & was only slightly overheating!!! The new puller fan in place of the stock belt driven fan will fix it!!

GlenL

I seized the 2 and 6 rod bearings with that setup and with the Amsoil racing oil. This is not a solution.

mark kibort

and Ive raced full seasons for over 10 years without it, so I tend to agree with you Glen.

I think its oil level, a good engine to start, and smart operation.

hacker-pschorr

Was that with or without the scraper?

GlenL

This was with a partial scraper set-up. It had side-drains and a scraper. Hard to describe it all but the latest I-J system, that I've got installed, is about 3x as complicated. There was no screen or trap doors, to start with.

I'm planning to track my beast this year and I'll post observations. I'm going to do oil tests, too.

GregBBRD

Seems like if you add something, it would be...different.

GregBBRD

No matter, still an impressive result given any of those oil temps!

mark kibort

my temps are always in the 250 to 260 range, depending on the ambient temp of the day. water is always running at the middle of the gauge, usually between the two lines. ONLY when the fan fails does it creep up to the 2nd white line during a race. (happened twice. fuse failure, switched to aux fan, and then forgot to turn on the fans, and fixed that just as I noticed the temp creep.)

as a note, i tried to do a calibration of the temp guage I use, and when it was submerged into boiling water. (4 seconds from the stove) it regestered a 185 temp, so its quite possible, my temps are higher than 260F)

as another note, generally, my oil temps are about 10 degrees cooler with the built in S4 radiator oil cooler, as my prior S engine, with near 100 less hp would run just slightly hotter. interesting that the water temp is still in the same range. However, hood venting, and all the stuff in front of the radiator is removed

IcemanG17

Glen
Interesting........maybe the pan spacer makes a huge difference? Getting the oil away from the crank is always a good idea & not running "under" full to do it is even better.....

In my experience with track driven 928's.....the FASTEST way to drop oil pressure in corners is to have LOW oil.....both times I drove a track 928 (S4) at 1 qt down it dropped pressure far faster than when its full......one was a stock S4 setup (widow) and the other has an IJ Scraper but is otherwise stock (seans 87 S4)....& we keep the lemons racer just under the full mark....even with the pan spacer....so in theory is "over" full.....

As I have said before...I am NOT an engineer...& only speak from my experience driving 928's on track..... One thing I DO believe in is you must drive within the "limits" of your car....in our case that means keeping the RPM's down in high G turns....so instead of taking that corner at 5000-5500rpm in third gear...take it at 3500rpm in 4th.....another bonus to the lower RPM is the reduced volume the oil pump flows......for example lets say the stock 928 oil pan will starve out @ 1G & 6000 rpm in 2.6 seconds....holding the same G load but dropping to 3000rpm increases the time until starvation to 5.2 seconds....

Its all about finding a way to keep our engines alive while still having fun on track!!! In can be done.....& I'm just trying to find a setup that is repeatable by anyone..... maybe the oil baffle and spacer is it.....only time and more testing will know for sure!!!

Mike Simard

I don't know if this is helpful but here's what I found doing similar things:

Plan A-Racing a stock 4.5 engine, the oil pressure would be awful, dropping to zero before long and eventually staying there when pulling into the paddock with lifters clanging away. Running more or less oil didn't seem to make a difference.

Plan B-Girdle (3/8 spacer), louvered windage shields and a later style pickup tube with the screen portion of the early setup in place to keep oil in the sump.

That was hugely better but I could still see the pressure drop a bit during turns.

I wonder if that clover leaf thing is the hot ticket and would have made plan B a better setup if I'd used it? Hmm...

GlenL

I think the pan spacer is an excellent idea. Give more space between the crank and pan for mist and drops to settle and get the liquid oil in the pan away from the crank.

Something I'd like to see is a wedge-shaped spacer so the pan slopes more steeply towards the front. The lightly-sloped pan with a front sump is not a good design for repeated, hard and long forwards acceleration.

A number of guys, including myself, have run with the oil intentionally 1/2 quart low. This was because the first 1/2 quart seemed to get burned/ejected/ingested almost immediately. After a 25 minute DE session I'd be 3/4 qt low starting full or a half quart down.