M758

I never said there was NOT a problem, just that there is No solution that most racers are aware of short of a dry sump.

The reason you need to replace bearings on these cars is to keep the oil at the bearings. Since the system is marginal you need to keep tighter tolerances to maintain the oiling. This means more bearing changes most cars.

951 S

I see your point. sence this is a form of open opinions, I am led to beleive that if the oil going to bearings is plauged with air or froth, then the bearings would have poor lubrication causing contact with the crankshaft. Having newer bearings might prolong the destruction of the bearings.

Sufnituning

Try www.Accusump.com

Danno

"Do a search on rod bearings and you will find lots of theories and little concrete evidence."

I agree with M758 here. No one has yet to explain why it's just the #2 rod-bearing that gets munched... If it was oil-frothing, it would affect all the rod-bearings equally. If it was low-oil pressure, like sucking in air at the pick-up, it would affect all the rod-bearings equally.

Also all the solutions presented are imperical fixes for the symptoms of the problem without ever addressing what the real problem is to begin with. But as long as it works, who cares why.

One thing that's been left out are scrapers.

m42racer

951S,

I'm really interested in the Air/Oil Seperator. How many fittings go to it. I looked at their picture, and can only see 2 from the photo angle. How is it plumbed?

951 S

M42,
The set up is not to hard to install. It comes with all the fiittings and lines to hook it up. I think I paid extra for the satraub front mount oil cooler, not sure if the kit comes with it anymore. This is how the lines run: Out of the oil filter housing to the air/oil sep unit. From the sep. unit down to the oil cooler. Then back up to the oil filter housing. The only tricky part is the placement of the separator unit. You have to take out the washer fluid container and then bolt the separator unit to the inner splash well. Here are some pics....
Danno, Your point is well taken. I wish I knew why the #2 rod bearing is more affected than the other bearings if air is present in the oil. What I can say is that I have blown 2 #2 rod bearings in 2 years sence I have been tracking 951's. My current car has way more HP and I have been runing this set up problem free for 3 years.

951 S

Another pic....

Sam Lin

I've got a similar-looking air/oil separator on my racecar.

Sam

alexands

This is a great thread as I'm in the process of rebuilding my 951 motor because of #2 bearing failure. The costs to repair it (re-sleeve, new pistons, crank grinding, etc) are adding up REAL quick. I plan to do the oil pan mod from Lindsey.

Keep us posted on your dry sump adventure.

alexands

How much for the Kokeln air/oil seperator?

951 S

I hear ya Alex. I spent a ton rebuilding my motor correctly. The serarator kit is about $1000.00 from Kokeln. Do the oil pan and pick up mod. and have the crank cross drilled also. All of it together is really working for me.....

J Chen

Hi Guys,
While on the topic on bearing failures,
would it be possible to run full groove
bearing shells instead of the half groove
ones ? Maybe that might help a little

mark944turbo

There is a reason why #2 fails first. When air gets sucked into the oil gallery, the first place for it to go is to #1. But, the mass ratio of oil to air causes #1 to get mostly oil even when air is being sucked up. Then the air goes to #2. I have seen #3 fail, but never #4. This is because #2 fails first, there is never time for the air to make it to #3 and 4, even when a lot is present. Actually, even if the air is making it to 3 and 4, it will always have been getting to #2 longer.

Im still working on ideas, but i will post back when i have pics.

m42racer

951S,

Many thanks. I have one question. If this part is a Oil and Air Seperator, where does the seperated air go? It appears what you have actually purcahsed is a very expensive Oil Filter. If the picture is correct, there is a hinged opening at one end and a conical filter element inside. Even Oil tanks which have swirl systems built into them, allow for the air to be vented thro' the breather. Air Oil seperators are usually built into Dry Sump Pumps as an extra stage. Inside there is a impeller driven by the Gear Shafts, which throws the Oil outwards and the air been lighter is vented from the center off to the Oil tank or breather.

It struck me from the picture that this part looked like a Filter.

David Floyd

Danno, Got a source on scrapers for our cars ? I found one for 924 but not 944.

http://www.crank-scrapers.com/products/porsche.html