URG8RB8

Actually your previous comment about an external electric oil pump used as a pre-oiler prior to start up is an idea I have been toying around with for years. This is off subject, but a very good idea for engine longevity, as nearly all wear is generated during startup.

LUCKY DAVE

I would add to that
"Proper bearing clearances matched to oil viscosity!"

AL951

how about running another oil pump on the back of a modified balancing shaft to drive it. that would be cool!. It may seem far fetch, but with some R & D it could be done. it could became a dry sump. you could even leave the OEM pump as a scanning pump , used the new one for pressure only. any thoughts?

Regards,
AL

refresh951

Very good post by Jet951:

https://rennlist.com/forums/9295250-post68.html

Rogue_Ant

Yes - our pump starts cavitation at ~4800rpm (in an ideal situation).

I am working out more details, and testing. Hopefully, we can come up with a final solution to fix the 951/944 oiling system - since we now know what is wrong with it...
I will post more info, as I prepare and confirm our findings.

V2Rocket

Eliminating the B-shafts altogether might help with oil supply, provided the pickup tube is reinforced to deal with the vibration change. One/two less places (depending how much oil a turbo needs vs just an upper BS) for oil to have to flow means more for the rest of the system. I did some googling and found a handful of Mustang guys are using old truck air pumps of some sort to pull crankcase vacuum, either dumping it to intake or to atmosphere. Minimize air in the crankcase = minimize foaming...

Adker

We have been competing 951's ( 944 turbo's) in either 2.5L single cam engines or 3.0L twin cam ( custom of our design)turbo engines( 440+HP) for years on the race track with NO crank ( connecting rod failures at all ).
With two Drivers Championships and two Motorkahana Championships in the bag along with countless lap records & a heap of customer 944 & 944S2 & 951's with class winning & Championship results with no crank/ connecting failures at all

The reason & answer/ Clue is simple ( its in the owners manual that came with the car )
Oil Viscosity & in turn oil film strength , in other words in the owners manual( oil vis page) it states( for road use of say a 944/ 944S / 944S2 / 951 / 968/ 928, from minus ten deg cel to Unlimited high ambient temps use a 20w-50 engine oil ( shaded look at me section )
This is a last century oil viscosity for a last century engine design , nothing wrong with that at all , its just a fact .

Here is my check list:
- Use a large oil cooler and keep oil temps below 260F
- Keep the oil clean and full
- Use the proper oil Viscosity

bebbetufs

Reading Jet951s post he mentions the importance of a custom crank breather setup but does not give any clues as to what should be done. Any clues?

Laust Pedersen

Something like this?



The positive displacement Mocal electric oil pump also does pre-lubrication at 3bar and was bought at Batinc (http://97.74.32.155/files/pump.pdf).
Unfortunately it is noisy and annoying enough, that I typically am running without the pre-lubrication feature.

Laust

V2Rocket

Does the el-oil pump supplement the mechanical one while the car is running? Think the it can push enough volume to knock out any.bubbles coming from the mech pump?

George D

This issue is usually during conering hard at full tilt. If I remember correctly, it's when you are moving hard on boost on a left turn. Gravity and the issues with the pickup tube without full oil seems to be an issue. The spring plate hinged door mod on the later oil sump pans is a proven bandaid. The later 951 oil sump pans were deeper than the earlier pans. Picking up a used late model pan with the spring door mod helps, as long as you change out your pick-up tube to accomodate the deeper valley within the later pans.

Lart should have a few in his inventory. A street driven 944 turbo shouldn't ever see enough forces to cause issues as long as you check your stick daily. I used to check my oil level when I was about to start the car. Waiting for your oil light to shine RED in many cases is too late.

This issue is usually a motor that likes oil, and it's not checked with tenacity. Some of these older motors burn oil, and it needs to be filled to the upper mark on the stick fairly often. I used to keep two quarts in the wheel well compartments. Now I have subs there, and I keep it in the seat delete doors under where the stock seats used to live.

A few of the folks that used to be in the business and raced, actually added another .5 quart showing a bit above the top of the stick.

Dry sump is the best option, but this costs a few bucks and not necessary for those just wanting some fun on track days.

George

George D

I didn't read all the posts till a few minutes ago. Great link. Thanks.

George D

Experience shared tells much towards the original question. Thanks for the link, it helps me, and hopefully the original OP.

Regards,

George

Laust Pedersen

Yes, if the oil pressure is below 2 bar or the temperature is high enough to warrant flow to the oil cooler.

The el-pump’s flow capacity is maybe 1/3 of the mechanical pump’s capacity at idle, so it can only assist intermittently. Air bubbles result in reduced (fluctuating) pressure and that’s where the el-pump is supposed to fill in. The two pumps do pick up oil at different locations in the sump.

Essentially I substituted the OE cam driven pump dedicated for oil cooler duty with an electrical pump and thought it worthwhile adding the longevity and safety features to the installation.

Laust

AL951

has anyone try to supply more oil to the #2 rod with a external oil supply line?......... I wounder if a pic of the oiling system for M44 engine is available

Regards,
AL