mark kibort

Ill check the wires again. and also check the responsiveness of the system.
I agree with you Jim, it could be something wiring related. just because it wasnt obvious, doesnt mean its not there. so. stand by and Ill check it out.

Randy V

Ban?

John D?

Sound familiar?

You may be headed back onto the same path you were on before.

Be careful.

That is all.

Carry on.

76FJ55

So just out of curiosity if you where to rotate the gage in the bezel so the right hand G loading where to pull the needle to the high temp range would phenomenon shift to right hand corner high temps?

mark kibort

So Randy,
tell me how racial obsenities relates to spirited discussion again? Your losing me. What are you talking about? what path am i headed and why. can you be a little more clear? Others here are wondering as well.

mark kibort

There was a loose wire on the main ground. i wonder if it slowly breaking connection could do this under left turns? Ive fixed it with a new connection and it might be more than coincidence that i lost all oil temp on the start of the race and had a broken wire found at home yesterday.

Ill see if it goes full scale if the connection breaks. if so false theory folks!

James Bailey

Glad you found the source of the "readings".

Cheburator

Mark, I don't mean to come across as condencending, but if you read what both Nick and I have said in our numerous posts regarding the topic of oil starvation/dry sumping you would see that the oil pressure drops during BOTH left and right corners. This was observed in a 1990 GT and a 1995 GTS with race suspension, but on street tyres. Oil pressure drops were observed during left and right S uphill bend and a RIGHT hairpin preceeded by a long uphill straight where the car would see in excess of 130mph. With sticky rubber the drops were even more pronounced. Brand new engines in both cases at the time.

Gregs idea about scavenging the heads is good, but nothing new - pretty much anything race European with a high rev-limit had additional lines connecting the head(s) with the sump on top of the standard breather/oil return channels in the block/heads. Heck, my family wagon has 2 electric pumps which are ECU controlled and scavenge the heads above certain rpm/g load

rad_951

Cheburator,

Is the head scavenging system on your M5?

Cheburator

Yep, it also has two sumps - the proper one at the back as this is where oil stays for most of the time and a smaller one at the front, which collects oil under braking and acts as a reservoir for the bigger one. The oil pump can suck oil from different areas of the sump as it has solenoid valves, which control the flow. On top of that you have the two electric scavenge pumps for the heads - the E39 M5 introduced the system, the E60/61 M5 improved on it.

heinrich

Funny. My old 911SC took 10.5qt but it all went into a drysump. You could literally see the oil level drop as the engine revved up, and oil was fed into the engine. The 928 takes 9qt but it all sits sloshing around a massive crank. And you can literally see the oil level drop as the engine revs up, and oil is fed AWAY FROM THE OIL PICKUP!

James Bailey

I wonder.....since the same heads are in use from the Holbert engine if it has the oil flow restrictors like the 944S ??? Not so great for idling around the shopping mall but reduces the flow at high rpm.....Maybe it is more than just "good luck". I have to think they spent a lot of time at Nardo at speed. Perhaps they learned something.

mark kibort

dont worry, not condecending at all. Its all observations at this point.
Im on race tires running 108% of GT3 supercup times just for refernce. on street tires, (real street tires) times go down near 6 seconds a lap. this is a huge difference in cornering force. add to that , the fact that Im running 12-13" slicks and you see that the g forces generated will be quite a bit higher. better brakes (race pads) and more HP, (370+rwhp). not just 2 race cars, only tested for ths phenom on the track, but over 5 race cars. right turns saw no fluctuation to oil pressure and that sending system is pretty good. Brian put on a aftermarke version and saw the same results. The speeds and up hill, down hill observations I see on a regular basis and have seen them for over 15years of racing now. the recent thunderhil video has us at 135mph on the main straight going into a 80mph left, and then a 80mph, 7 second hairpin. (very high gs). also, 130mph straights into hard right hairpins. Laguna, Sears point, give even more car attitude and speed situations.

I just dont see an issue, not burning any oil, not smoking at all, (I have rear view camera video to prove this for the race). keep in mind, my RPM is NEVER below 4500rpm for 30min, i certainly think that my observation was flawed by the good chance that I had a g force related electrical connection issue.

the main thing here is to determine, is there an issue. certainly my results and observatations show there is no issue. if there was a pumping of the oil in the heads to the point where those Huge return paths were not large enough and numerous enough, to return the oil in response to the volume flow of the pump i would see a problem. if it is marginal, and 5000rpm, not 4500rpm, sustained for over 1 min with out relief is the magic period then that is when the system needs assistnace .

GB also mentioned, he doesnt have any tests with Amsoil as well. its anti foaming characteristics, plus its more stable viscosity at tempuratures might also change the myriad of factors present in this topic.

remember, i did test a few times, mobil 1 in the race cars (3 of them) and all of them had the oil pressure fall on its face in the 240+ oil temp range. to the point of the oil pressure warning light coming on as well in certain turns.
with better oils, redline racing included this never happened again.

I dont think i have a magic engine but it would be interesting to see what is really happening in there. maybe we can use the level sensor and make it more sensitive and produce a analog signal to reallly see what is happening.

I also suspenct on the dyno,freeway, etc, i can load the engien slightly, run 5000rpm for a minute and see if my oil pressure starts to drop. I would be willing to run an number of tests given that I still street my 928 and can do these kids of tests.

mk

mark kibort

as i showed in the pictures, the crank is pretty high above the oil level . its not sitting in the bath of oil in otherwords and especially in turns the level moves even farther away from the crank. the return paths try and direct oil away from the crank at the sides too.

mark kibort

I just helped a friend rebuld 2 M5 engines. the heads have real tiny return paths for the oil. the entire engine is pretty strange with the pistons sharing common cylinder walls , only 5mm thick! but, they rock and put out huge power for a 5 liter.(mostly due to the intake and cam designs).
compared to the 928 heads, they are very tiny in every way.

mark kibort

could be, but doubtful. they look stock comparing to other heads we were looking at side by siide. dont know about the restrictor ports, but you never know. that could be different.