mark kibort

I suspect that warm up and some other little things really help with this issue. All I know is that I have not seen any issues, or even hints of issues. I certainly would like to understand more about the failure modes, but as we all know, there are many variables.

What oil are you using and what tempurature and oil pressure readings do you see during track activity?

Yeah, whats up with those bozos in the paddock running cold engines, vrooom, vrooom, vroom!!!!??????? I treat mine like a baby until I see 180F oil temps and then the hammer comes down and the RPM go up!

mk

slate blue

Not exactly on topic but as for oil pressure, I plan on lowering mine on my stroker. I am aiming for between 65 to 70 psi. That oil pressure will be from around 6000 rpms upwards. Having 120 psi oil pressure costs power wastes fuel, there is reasons for having it in standard engines. If the reasons for needing such high oil pressure are removed, power can be gained. I will have a dry sump with a very good oil cooler heat exchanger system i.e Laminova.

I have also decided to use 20w/50 oil I was looking at lower or lesser grades for the reasons of reducing extra drag/friction. Have decided given some Nascar guys still run 20w/50 I will do the same as there is not doubt it will provide extra protection plus the increased clearances will probably require a thicker oil to get decent oil pressure at idle. Also on the oil control side of things I have determined that I will not use squirters in this engine, with a higher output 4V engine i.e more than 600 crank hp I would employ them as a necessity.

Greg

928SS

running torco synthetic 20-50, per doc brown's recommendations. seems to work fine. hardly uses any at the streets of willow in 100F temps w/continous laps - maybe 1/2 qt all day max.

oil pressures are stockish, but there is a pan spacer, lowered pickup, windage tray and the usual gts oil control and stroker stuff.

it used to flicker on some turns w/the stock motor, no more now and its driven a lot more aggressively.

warm up is key for sure, imo. but I suspect you are a smooth driver in terms of keeping revs under control, cornering etc too... just happens w/enough track time as one learns how to put the adrenaline in check to some extent, focus on being in the right place at the right time at the right rpms, etc...

mark A and joe F seem to keep their stuff together for a long time too.

still think a decent dry sump would be the best solution though. cooler oil temps, pull some vacume for some extra HP, and zero foaming/cavitation, etc...

IcemanG17

[QUOTE=928SS;6571714
oil pressures are stockish, but there is a pan spacer, lowered pickup, windage tray and the usual gts oil control and stroker stuff.

mark A and joe F seem to keep their stuff together for a long time too.

still think a decent dry sump would be the best solution though. cooler oil temps, pull some vacume for some extra HP, and zero foaming/cavitation, etc...[/QUOTE]

Rob
I have the full Doc brown setup on the widow verison 2.0....same as you with the pan spacer & windage + GTS baffle & taylor drilled crank (probably the same as your moldex) & an accusump just in case..... However I do plan on data logging the accsump to see how much I'm using it....

928SS

did yours blow up recently? did I misunderstand/miss something? or is it ok?

Stan.Shaw@Excell.Net

I believe that was the previous motor.

IcemanG17

Rob
the widow was showing some scary oil pressure drops on track, that turned out to be a dead #6 rod bearing.....but I caught it early enough to minimize the damage

Rob Edwards

In my case of #2 rod bearing failure, the oil pressure gauge was yelling at me for several miles to pull over and shut the damn car off and tow it home, but did I listen? No..........

928SS

holy tar pits brian! sounds like your sharp eye helped dodge a bullet!! good call!

did that happen before greg's magic parts or after?

I've been flogging mine hard lately, and haven't seen any flutters, but sometimes it's hard to watch that and course at the same time... some kind of logging or trigger/alarms might be cool I suppose.

don't feel bad rob, I might have done the same. always takes me a minute to decide if the gauge is playing games or is for real... sometimes that's all you have.

IcemanG17

Rob
Of course I don't know the condition of the rod bearings when I bought the car....chances are they were fairly worn since the car had a tic over 93k on it.... I put 6 track days totalling about 10 hours of on track time....starting at about my 2-3rd track day I noticed the pressure starting to drop in hard left hand turns...but only briefly...but as I drove the car harder and harder and the temps were increasing (since I started tracking in January) the pressure would drop more and more to 2 bar hot in that same turn..which was freaking me out..BUT as soon as the car was nearly straight the pressure would go back up to pegged at 5+bar....

All of this damage-issues was with a stock 89 S4 engine...no mods, bone stock with only amsoil....

All of the improvements are in engine version 2.0..which should be installed soon! I think all of upgrades will significantly improve the oiling system...since basically I am running a near clone of the system in Joe Fans race 928...

IcemanG17

Rob
I didn't want to say THAT.....but 3 bar at easy freeway driving....I would have PARKED IT......that would freak me out something horrible!!

What I found in mine was the #6 dies 1st, followed quickly by the #2...since the oil flows through the #2 to get to the #6....I was lucky that there wasn't that much metal and it appeared the #6 was just into the copper backing, & the #2 was worn, but still in the silver as were ALL of the other bearings...

One thing I am having done on the new rod bearings is taking very precise clearance measurements.....I do not want any rod bearing tighter than .002" Ideally .0025" since these are the measurements Doc shoots for when he replaces rod bearings....

Cheburator

Let me throw some oil into the fire...

Just returned from the Nurburgring where I was lucky enough to see the original Probst & Menthel 928S compete in the ADAC 24h Classic 3hrs race where it came 13th out of 39 cars.

The car weighs at 1180kg ready for the road and is powered by the original standard S lump with 3000 race kilometers on the odo. KW3 custom suspension, GTS brakes and 17 wheels with slicks. It was lapping the circuit in 10m:30secs, which was on par with the Aston Martin N24. Yes, the brand new 450bhp, $150,000 racer from Aston which competed in the 24hrs race for modern cars later on the day. BTW, the 928 could go quicker - I speak from experience...

The point I am trying to get to is that the driver never observed oil pressure drops and all was fine... No dry sump, no accusump. Please explain...

Stan.Shaw@Excell.Net

What year motor? You mention S, so perhaps something 85 or older Euro? So pre 5L?

mark kibort

Maybe you have heard of the Holbert racer? 95 degree temps this weekend for its 15th race day (about 1 hour of racing per day) always 5 bar, a little over 1200Kg, 305x335 dot slicks, and oil temp around 260F. no cooler, no accusump, no breather system, no scraper, spacer, nothing. burned .5 quart of oil per 30min race, and no smoke from blowby. Just use Amsoil and thats it. shifts are 4500rpm to 6500rpm.

1:37.7 at laguna
1:59.8 at Thunderhill
1:47.7 at Sears

Go figure!

mk

Benton

Mark,
Regardless of what your original crankshaft was like, did they install a chevy-drilled crankshaft in your stroker? Have you dyno'ed it yet?