Vanguard question

[ihcc1]

Hello to all!

I haven't been on in quite awhile but haven't stopped using and working on Cubs. I recently picked up an HDS 3165 that is powered by a B&S Vanguard 16hp engine. I don't have a lot of experience with these and have a few questions.

#1: The left valve cover has a "vent tube" that has a hose attached. The hose is about 14" long and just hangs down in the engine compartment with no fitting on the end and nowhere to attach it to. Is this normal? If this is normal, why does it need a crank case breather and this vent tube? Isn't this usually ran back to the carb? Seems weird that there is an opening for contamination to potentially get into the engine.

#2: The crank case breather (sits between the 2 cylinders, under the carb) seems to pass a lot of oil through to the carb. Oil is at the correct level. This breather has a reed to allow pressure/oil out of the crank case but prevents air/oil from reentering. Like a PCV valve except I don't recall one passing this much oil. When I remove the breather and turn it upside down, an ounce of oil pours out. Is this normal? If not what could be causing this oil to pass through.

Engine seems to run well but couldn't run it much due to a very bad leaky front seal. Thanks in advance!

[Leadslingingdaddy]

Question 1 Yes... Sam is the expert on the Vanguards.... He may chime in...

#2 You may have excess blow by creating an increase in crankcase pressure causing oil to be push up through the breather at an increased rate... Do a compression test and see what you come up with....

[Sam Mac]

Only hose I have seen on a Vanguard valve cover was for the vacuum supply for the fuel pump. #2 in this pic

[ihcc1]

Lead & Sam

Thanks for the quick response! Sam, that is exactly how the right valve cover looks. The left has a brass elbow fitting that screws into the valve cover and the other end is barbed for a hose connection.

Was this an "after market" set up?

[Sam Mac]

That is not factory. That is something a previous owner added. If I had to bet my guess is that it has a bad head gasket and that the PO added that to try to direct the blow by away from the air filter. Vanguards do not tolerate over heating very well. Plan on pulling the engine out, removing the blower housing and tins and giving it a good cleaning. You'll probably find the cooling fins plugged up. What I do to test an engine to see if it has a bad head gasket is to pull the valve cover, remove the push rods and spark plug then I hook up an adapter so that I can use my shop air to pressurize the cylinder. If you have a bad head gasket or piston problem you'll hear air escaping into the the push rod area or oil return, a bad exhaust valve and air will come out the exhaust, bad intake and the air comes out the intake. This one puke the head gasket and it blew into the oil return.

[ihcc1]

That leaking seal caused a lot of oil to be blown up and all over the #1(?) cylinder fins and it's baked on so I wondered if it over heated. I have cleaned it but the engine cooling fins were very clogged up. I pressurized (100 psi) the cylinders last night, by spinning the crank slowly with a wrench until everything sealed up. It held with no noticeable leaking but I was alone and could only hold it steady for a few seconds. I bought a leak down contraption today and your suggestion about removing the push rods sounds a lot easier to perform the test. I'll try this and remove heads with any sign of leakage!

Thanks

[Sam Mac]

If you have a leak down tester use that. I don't have one so I pull the push rods that way it don't have to worry if the valves are closed or try to hold it from rotating.

[Leadslingingdaddy]

Yea that would have been good info to have off the start.....

[ihcc1]

#2 cylinder had very slight leakage at the intake valve. I will relap that valve and check it again.

[ihcc1]

I'm having to test this cold. Both cylinders have slight leakage into crank case "blow by". At 100 psi I here a slight hiss from inside the case. Shouldn't there be slight ring leakage on a cold engine? I don't mind replacing rings but don't want to repair a none problem.

I have up to 145 psi. I think I will turn the regulator up and try listening again. This is new to me so I'm having to feel my way through it.

The leak down tester I bought was from harbor freight and the gauge thats supposed to give a status reading was defective out of the box. I'll have to return it and try again.