Accusumps (and a warning about oil starvation)

[whitney]

Well, after rebuilding the bottom end on my 89 325is this winter AND adding a baffled oil pan, I am still having the (little known) left-hand oil starvation problems on track.

Anyone on the board here have experience plumbing one into an E30 M20? I have seen one installation, but I'm looking for some first-hand advice on location, part numbers, good sources for parts (planning to go to RPW). Of course, if someone has one they would like to sell... Looking for a 2 qt.

Any info would be appreciated.

The warning: No matter what you drive -- if you've got a suspension and sticky tires, and drive on track often, put in an oil pressure gauge and check it (or have a passenger check it) on both left and right turns. If you see a drop in pressure, you have an oil starvation problem that needs to be fixed before the motor goes bye-bye.

My car lasted about 20 days on track before the rod bearing spun. Can you say "exceeded the design parameters of the factory lubrication system"?

Here are some gory pictures:
http://www.nogumracing.com/whitney/p...w/Image89.html
http://www.nogumracing.com/whitney/p...w/Image90.html

[JamesM3M5]

This is common in the E30 M3. You can easily put an electric Accusump in there either in place of the windshield washer tank or find a place in the passenger compartment or trunk. A 2qt unit is pretty big. The adapter plate spins on in place of your oil filter and you then spin the filter onto the plate. Plumb with Earls or Aeroquip. Do you still have the stock oil cooler/filter head in there?

How much do you overfill the oil? You should run at least 1/2qt over full. What brand and weight oil do you use?

The oil pickup is toward the right side of the engine, so right turns with sticky tires will quickly starve the oil pickup. I haven't heard of this problem on M20 or M30 motors at all.

JamesM

[whitney]

Originally posted by JamesM3M5
This is common in the E30 M3.

Yup. Common in RIGHT corners, and good replacement pans are available. Too bad no one talks much about the M20 left-hand problems.

You can easily put an electric Accusump in there either in place of the windshield washer tank or find a place in the passenger compartment or trunk.

Actually, I believe the 2 qt unit will fit on the front vestigal battery tray, if a 90 degree fitting is used.

A 2qt unit is pretty big.

Actually, it's the smallest one available that I have seen. Most people say "be sure to use the 3qt unit".

Do you still have the stock oil cooler/filter head in there?

Yes.

How much do you overfill the oil? You should run at least 1/2qt over full. What brand and weight oil do you use?

Here's a data point for all you E30 325is track junkies:

February 23rd: Mobil 1 15-50, GC suspension, Toyo RA-1 tires, custom baffled oil pan, 1qt overfilled, VIR turn 3, 3rd gear @ about 5k RPM. I have seen cornerning forces in excess of 1.1G on a G-tech. Oil pressure starts at 60 PSI at turn-in, drops to 30 PSI by track-out.

At this point I actually think that the starvation is *not* caused by the oil climbing the wall, but I think the oil is pumped up in the head, and the incline (right tilt) of the engine + the high g-forces are keeping it from draining fast enough back to the pan. This is why an Accusump would cure these transient situations.

I haven't heard of this problem on M20 or M30 motors at all.

Neither had I, till I killed the motor. Since then I have heard of at least 3 other people who have rather unexpectedly spun rod bearings as well. It's a well documented, but not widely known, fact.

Hence the reason for my warning. Just 'cause it's not talked about, doesn't mean it doesn't happen.

Thanks for the input!

[JamesM3M5]

OH! LEFT turns. Guess I didn't read carefully.

I meant that a 2-qt unit was big physically. If you're going to take the time to insatll one, install the biggest you can afford.

Your suspicions are probably correct. The oil only has one port to drain back into the pan, and it probably doesn't return fast enough when you're turning 5000RPM.

Turn 3 is the first left-hander, isn't it? What happens on turn 4? Boom?

JamesM

[Don Stevens]

Whitney,

Looked at your photos and relatively speaking, they did not look bad. I have spun them worse than that.

A spun bearing is never good but I am wondering, how did you know you spun the bearing. Could you hear it banging with this little wear?

Don

[whitney]

Originally posted by Don Stevens
Whitney,

Looked at your photos and relatively speaking, they did not look bad. I have spun them worse than that.

A spun bearing is never good but I am wondering, how did you know you spun the bearing. Could you hear it banging with this little wear?

Don

Your questions are very insightful! In fact I did not know the bearing was spun -- I had pulled the pan to replace the bearings, since I merely suspected they were worn. #1-4 were OK, #5 didn't look good, but it wasn't spun, and the #6 bearing had the tabs broken off, and there was wear/galling on the rod and rod cap surfaces from it going roundy-round.

I was pretty bummed, since that meant the head needed to come off to pull the piston and have the rod end machined. I did all the work for under $200 -- I don't expect it to last, kind of a "ghetto" engine rebuild. I have a spare block that I'll be doing a real 0.040 over build on in my spare time.

Want the rest of the story? In November at a Time Trial at CMP, the oil light began to flicker at the end of T11 (loooong 2nd gear left hander). Then I started watching the oil pressure gauge, and I saw that it was dropping to ZERO on lefties. Funny thing is, I had watched the gauge many times before, but only on right corners, which are the most common! Never thought to check left corners

It was still running and driving fine, no weird noises, good power, but the water temp was running high and oil pressure was a bit low. I figured the bearings were wearing, and I was probably losing oil pressure due to the increased clearance. Drove home, did an autocross the following weekend, then put her up on stands for the winter. Imagine my surprise when I saw the tabs broken off of the #6 bearing.

[whitney]

Originally posted by JamesM3M5
Your suspicions are probably correct. The oil only has one port to drain back into the pan,

Actually, aren't there more like 4 oil return ports, one in between each piston, on the right hand side of the block? Still not enough! Maybe if I air-pressurized the head?

You can see one in the top of this picture:
http://www.nogumracing.com/whitney/p..._crank1-3H.jpg

Turn 3 is the first left-hander, isn't it? What happens on turn 4? Boom?

Not quite "boom". More like "rattle rattle rattle. Buh. Jujujujuju (sound of starter motor). 'Damn!' Cha-ching!"

T1 and T2 are rights, then there's "noname", then T3-left (aka Nascar). Short straight then 4 (Left Hook). The noname-T3 combination is probably like 10 seconds of 3rd gear high-rpm high-G left. The oil pressure returns to normal on the short straight, then T4 is a short time duration and at low RPMs (in 3rd in my car), so it's not a problem there.

James -- black M5? I think we've met a few times at VIR. I have the red 325is -- chased you and your friend in the M50-powered maroon 325 around north course last year?

[///MikeL]

Question on the Accusump, maybe a dumb one. I know that E36 M3s can be overfilled with up to 1.5 quarts without harming anything, but I have heard that on the E30 M3s you can blow oil seals with as little as 1 quart over. Taking this into consideration, if you are running a 3 quart Accusump, and your motor can get 60 to 70psi when revving, what happens when you drop to 20 at idle? Doesnt the accusump bleed off its pressure by forcing oil into the system, which could essentially fill your motor with 2 extra quarts of oil? There must be a saftey system to avoid that, but from what I know of the Accusump, that is how it works.

Anyone know the anwer?

Thanks,

Mike - buying an E30 M3 race car sans Accusump, at least for now.