Command CH18 Oil Past Breather Gasket
 

My Command V-twin is blowing oil past a brand new gasket for the breather cover. I've isolated it to the oil pressure switch oil galley. I plugged off the pressure switch hole to eliminate that variable. breather hole area is not the problem, Flapper on breather verified working.

It seems that the pressure is too high? when cranking the engine, I can see where oil comes in through one hole, but I don't know if it drains out? I see other holes, but the oil doesn't drain back.

Can anyone verify where the oil passages go for the oil pressure switch? Someone said "replace the breather cover and gasket as a kit and all will be fixed." <-- any truth to that, or do I have a blocked passage?

if the oil galley had a drain there would be no oil psi

If there was no drain, then how would you change the oil that gets into it?

I will clarify; which holes slowly drain off oil when the machine is shut off?

I think you are using improper terminology.
There are oil passages for lubrication that work under oil pump pressure,
then there are crankcase areas that there is no pressure relatively speaking
and are vented to outside or intake manifold for emission reasons.:bigthink:

This is the breather for a CH

https://lh3.googleusercontent.com/pw...-no?authuser=0

I highlighted the area in red, which supplies oil to the item circled in red.

I suspect you have a positive crankcase pressure instead of a slight negative pressure and it is forcing the oil out.

Worn piston rings, blown head gasket, leaking crankshaft seals, leaking dip stick seal?

Or maybe I don't understand what you are talking about?

The breather valve is operating correctly. The breather cover deals with two separate parts; breather valve, and oil pressure switch. The OPS has a passage where oil is pumped up to it by the oil pump.


Extra info: All new head gaskets on the engine, new shaft seals, no visible leaks in those areas.

So I'm going to try the new cover/gasket and spin the oil pump. If it still leaks, then I need to open the block up, find those passages and see what's blocked.

Wouldn't a blown head gasket, leaking crankshaft seals, or leaking dip stick seal vent pressure not build it?

Yes,
but thinking it is a OHV( not familar) and if the head gasket leaks into a crankcase area where the pushrod gallery is, it is possible to push compression into it.
(again not familar unless I do some research and i'm too lazy) :bigthink:

No!!!!!!!!!!!!!!!!!

Hmm, good point George, did not consider OHV head.
I'll agree with that, but the rest are vents.
:beerchug::beerchug:

I put the new cover and gasket on, put oil in the engine, and spun it over without starting. Doesn't appear to be leaking from the gasket area anymore.
https://lh3.googleusercontent.com/pw...-no?authuser=0

I'm going to reinstall the engine tomorrow and fire it up for a final shakedown.
Fingers crossed!

I’m getting ready to install a CH18 that had a “leak” from the left head gasket that let compression into the cavity between the cylinders where the lifters are. Engine sounded great and was running quite smoothly but was blowing oil past full plug, when I unscrewed the full plug the compression in the valve cover blew it to the garage ceiling. Head bolts were loose on that head.

For those following along, the new oem gasket and cover stopped the leak. The 1863 is running great with no leaks anywhere.

Now onto steering adjustment and refurbing the 54" deck.