Oil pump (crankshaft front) oil seal failures

[JamieP]

I just spoke with Pete and the spring was in place each time.

[b_have]

As odd as it may seem, this additional pipe length offered enough restriction to double the crankcase depression on part throttle, and halve it at WOT.

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What were the numbers Digsy?

[dandan]

Where was the WOT breather plumbed to Digsy and what sort of depression figures are you talking about?

[JamieP]

Just emptied the catch can and it was half full of this shit, im now going to strip the hoses out and clean everything through, replumb it keeping the hose lenth short as possible.

 

http://media.putfile.com/catch-can

[Digsy]

The WOT breather was plumbed into the intake pre-turbo. Figures as follows:

 

5000RPM / 4bar BMEP (part throttle).

Without catch can: -0.3kPa (3mbar)

With catch can: -0.6kPa (6mbar)

 

5000RPM / 12bar BMEP (WOT)

Without catch can: -2.1kPa (21mbar)

With catch can: -1.1kPa (11mbar)

[Pete]

So is it only catch tank users that have this problem?

[Wez]

So is it only catch tank users that have this problem?

 

 

Good question, should be easy enough to find out if motors that failed have catch tanks.

[Sharpie]

I will go and look at the new pump on peter Sharps engine, he was asking why it was taking so long for me to put the sump on it, now I hope he knows why i have been hanging fire

 

[Tricky-Ricky]

Looking at the seal in front of me, it doesn't look physically possible for the spring to come off if its sucked in, as the lip on the inside of the ledge that the spring sits on would become higher as the seal lips move inward, however the spring will come off pretty easy if pushed outward.

 

As for crankcase depression caused by a catch tank, all three times that my seal has failed i have had a catch tank in place, but the first time the tank was vented to atmosphere, and the second an third time it was plumbed back into the std breather points, i had also renewed the one way valve of the part throttle breather,

I have also never had any oil vapour in the can or in the pipework, or water vapour.

[Chris Wilson]

Mike-Macs car had stock PCV system, and that lost the seal spring. What was amazing was the shear volume and speed of the oil loss, even at idle it was flowing fast.

[Chris Wilson]

 

The new pump on yours is the later type, with the extra bolt hole. What do you want me to do? Go ahead as is, or try putting the internals in an earlier casing?

[gregsupra4]

Yes jamie you are correct, the spring was always in place.

 

OK food for thought, on Jamies car there is no drip on idle or when you rev the car standing still even up to 4k, the seal only starts to pass oil once the engine is under load and has had some boost put through it.

 

As stated the engine is a brand new short block from Toyota and was put together with new HKS 2mm head gasket and jamie's old head which has done less than 5000 miles since his rebuild.

 

So after two new seals we still have the leak.

 

Im sure each time its failed the spring was inplace, maybe greg can check this with Pete though.

[Digsy]

If you can recreate these problems in a garage with the car stationary then will somone please rig up a proper manometer on the dipstick tube or oil filler cap and measure the crankcase depression accurately on an affected engine?

[Chris Wilson]

Seal failure info, but nothing leaps out and smacks me on the forehead I'm afraid

 

http://www.simritna.com/catalog/RSS/failuredefinitions.htm

[b_have]

Chemical incompatibility between two lubricants (for example, synthetic oil at the sealing lip and mineral grease between the dust lip and the sealing lip - the mineral grease can cause removal of additives form the synthetic oil. The elastomer can then be attacked by the concentration of additives in the grease and by the lack of antioxidants in the oil). Figures 10 to 13

 

Didn't know that. I always use a white lithium grease on seals.

[Chris Wilson]

I have always lubed them with whatever medium they are supposed to be sealing. Seems OK according to that. I doubt it's a lube chemistry problem, surely other seals would go, too?

[b_have]

The more I think about this, the more I think its a Hydraulic problem.

I build racing two strokes which rely on high crankcase compression and never experience seal failures like this. Even with blowby, I cant imagine the crankcases seeing more than a few psi with the camcover breathers we use.

[Chris Wilson]

I would agree. The only way you'd see high crankcase pressures on the set ups I have seen is if the PCV valve opened under boost, then things would get REALLY nasty. But even if this did (bizzarely) happen, why doesn't any other seal leak, or even pop out? The back main seal, or a camshaft seal, for example?

 

I am still in favour of the excess leakage from the rotor pack overwhelming the small drain down hole in the pump casting, or even the drain hole getting blocked by sealant, grundge, et cetera.

[Digsy]

But what about increased vacuum?

 

Some interesting info here that pretty much confirms that overpressure won't be an issue, but it doesn't mention anything about vacuum. What it does say is that the oil film under the lip seal is critical to sealing. What if you started sucking air past this?

[Alex]

I would agree. The only way you'd see high crankcase pressures on the set ups I have seen is if the PCV valve opened under boost, then things would get REALLY nasty. But even if this did (bizzarely) happen, why doesn't any other seal leak, or even pop out? The back main seal, or a camshaft seal, for example?

 

I am still in favour of the excess leakage from the rotor pack overwhelming the small drain down hole in the pump casting, or even the drain hole getting blocked by sealant, grundge, et cetera.

 

Jamie's car has a modified breather system, with bigger diameter fittings on the cam covers....could this be a factor? Could the PCV valve's operation have been affected?

 

Might be worth putting a pair of stock cam covers on??

[JamieP]

I dont think this is a crancase pressure or vacum problem, the engine dont breath heavy when reving with the oil cap off, simlar i cant see vacuum being a probem either, B'have runs his with the exhaust vacum breather and i remember him saying that there was so much vacum that he had trouble undoing the oil cap with the engine running and his FMS is fine.

 

At the moment im going with the contaminated oil idea ( see link for pics ) being it a brand new engine and ive read things about this before, the car is going back in monday the 4th for engine flush out, new oil pump fitting.

 

http://www.mkivsupra.net/vbb/showthread.php?p=1113594#post1113594

[b_have]

But what about increased vacuum?

 

Some interesting info here that pretty much confirms that overpressure won't be an issue, but it doesn't mention anything about vacuum. What it does say is that the oil film under the lip seal is critical to sealing. What if you started sucking air past this?

 

 

Maybe worth testing without a pcv in the system ( I know Dimitri scraps it on modded cars )

[JamieP]

Maybe worth testing without a pcv in the system ( I know Dimitri scraps it on modded cars )

 

 

 

I dont have a pcv in my breather system, its vacumed via the turbo/ airfilter inlet pipe.

[Digsy]

If you want any part throttle breathing at all on a turbo car you need a PCV or a one-way valve with a restrictor.

 

I take it that when you say you dont have a PCV, you've routed both sides of your camcover to the intake pipe?

[dandan]

If you want any part throttle breathing at all on a turbo car you need a PCV or a one-way valve with a restrictor.

 

Or an exhaust scavenge system.