Engine Bearing Failure - Page 7

Cam · #91 08-12-2010, 11:00 AM

So in jack's motor, did he experience any overheating problems at or below 7000 rpm? Was his cooling system stock?

dynomatt · #92 08-12-2010, 09:25 PM

It's been posted elsewhere, that he did have overheating problems...made a change to an electric pump and improved (but didn't fix) the problem.

M

Dessertrunner · #93 08-19-2010, 12:24 AM

I don't want to sound like a total idiot but could some one please post what are the benfits of a dry sump. I was of the understanding that it was all about keeping the crank etc from splashing in oil, like I say I have no idea.
Tony

1986nate · #94 08-19-2010, 12:55 AM

Quote:

Originally Posted by Dessertrunner

I don't want to sound like a total idiot but could some one please post what are the benfits of a dry sump. I was of the understanding that it was all about keeping the crank etc from splashing in oil, like I say I have no idea.
Tony

The major benefit is for under high "G" turns, the oil gets "pushed"/"gathered" on the sides of the oil pan. This, possibly could cause a loss of oiling due to the pickup not having any or enough oil since its all on the side of the pan due to (some physics term I can't remember right now). It can also be solved by the use of the modified oil pans with baffles that I have seen Rallybob post pictures of his work.

Good god I hope that makes any sense to you guys...

TomsSVX · #95 08-19-2010, 05:03 AM

Dry sumps are for cars that see long duration high forces g's. Heavy accel, heavy braking and hard turning will cause the oil to climb the wall of the oil pan and allow air to get sucked up into the oil system. The pump loses its prime and obviously oil doesn't lube anything for extended periods of time of hard driving.

Nate has got it right here but I doubt any SVX has had this issue

Tom

SilverSpear · #96 08-19-2010, 06:26 AM

How do we translate the engine bearing failure then?

Just throwing an idea here, but what if we shrink the design of the SVX pan, this way when G forces are there, the oil will still touch the pump inlet and reaches the bearings and pistons?

Assuming you keep the same volume of oil... and that (pressure) doesn't mess your gaskets and seals

sicksubie · #97 08-19-2010, 06:31 AM

No, if anything you want a larger pan like the one that Rallybob made that also had the internal baffles...

1986nate · #98 08-19-2010, 03:26 PM

Quote:

Originally Posted by sicksubie

No, if anything you want a larger pan like the one that Rallybob made that also had the internal baffles...

Oh yeah, that's who made it. I couldn't remember...

Dessertrunner · #99 08-19-2010, 04:15 PM

You can only slush oil when the sump is not full. Kind of have this alternative plan in my head that is hatching.
FWIW years ago I had a 1400 subaru engine that was used in the early subaru rally cars. The sump was seperated from the engine by the fact that the underside of the crank case was nearly all closed in. They argueed at the time it enable the engine to rev higher due to the oil not hitting the crank.

I not sure what that all means but its food for thought.
Tony

dynomatt · #**100** 08-19-2010, 04:28 PM

Have a look at the bottom of the EG33 and in fact any boxer engine and the same occurs. The crank is miles away from the oil.

One advantage of a dry sump system would be a redesign (in effect) of the oil system, meaning equal pressure could be pumped into new locations (read bearings), fixing our reliance on the Subaru oil journals and distances. THis of course assumes that failures are related to loss of pressure over distance.

I'm struggling with this though...look at an inline six like an M3...how do they oil? Surely they would have more trouble with oil getting further away from the the pump? Unless it's in the middle of the engine?

M

TomsSVX · #**101** 08-19-2010, 04:41 PM

The EG33 runs low pressure in the oil system. Esp. one with larger oil clearances on the bearings. An electric oil pump might not be a bad idea...

Example... A lot of built motors run low pressure at idle when hot. Many below 10psi. 2500rpm makes 25 psi and usually relieves at 40-45psi.

My S62 engine has 20psi at a 500rpm idle when the oil is 215*F. 2500 RPM, has 65psi... relief valve kicks around 75psi which it maintains as it winds out.

When it comes to oil, higher pressure is not always what you want but if you are increasing oil clearances and thus enlarging the amount of run-off you have from your bearings... You will need a pump to keep up. The EG33 pump is the same as a lot of high HP Subies run on 4cyl... Yet the oiling system is 30% larger with 30% more run off... It needs a more capable pump IMHO

Tom

Dessertrunner · #**102** 08-19-2010, 05:11 PM

What pressure is our relief valves set at?

I think the point made earlier that the temp of the oil can kill a engine faster then anything needs to be taken into account.
Tony

Boxersix · #**103** 08-19-2010, 08:40 PM

5w-30 weight oil warmed up to about 80C will dump at about 43psi on the Sti's. The Eg33 and EJ series motors use the same springs, OPRV, and shims. Verified this first hand just weeks ago.

There are more benefits to a dry sump system than just as a preventative measure for sucking off a, pardon the pun, a "dry sump". Zero oil aeration, case vacuum, etc, etc.

I do agree that the EG needs a better pump as Tom said. We're using the 12mm rotor as an upgrade for the EG's, and for now it suffices for most setups on those up to about 9K rpm. EG uses a 12mm rotor stock.

One must also not that you do not necessary have to run a full dry sump system to use a different pump. There are externally mounted wet sump pumps that could be used(in conjunction with a modified/gutted OE pump housing) It's just typical fashion for most going through with the trouble of running and external pump, to go the extra steps towards a DS system

SilverSpear · #**104** 09-24-2010, 03:58 AM

Bumpinitupnottobeforgotten...

Dessertrunner · #**105** 05-15-2012, 04:45 PM

The guy that I posted the link to in the other forum has issues with the oil flow to the engine so we may have to revist this issue again.

I have a question has anyone measured or looked at how much space a sump full of oil takes up. In other words if the oil was less then 50% of the sump volume then of course it will cause the pipe to suck dry.
Tony