Oil in intake runners....why ??

[1TONY1]

When I had my intake off there was a substantial amount of oil sitting, standing might be a better word, on top of the intake valves. The pvc valve does seem to have a leak when blown through. This was on about every closed valve. The engine has 50k, could all the valve stem seals be shot ? I don't mean there was an oily residue, there was liquid oil sitting there. I have not noticed oil consumtion or oil smoke. Spark plugs looked normal. tnx, Tony

 

[Tom F&L GoR]

The "Positive Crankcase Ventilation" (PCV) valve has a spring in it, so it is a check valve that should essentially close when sucking on it. Not sure if you can blow through it and say it's working or not.

Engine supercharged? A little pressure in the crankcase could push oil past valve guides.

Using aftermarket fuel additives? They are heavier than fuel and will look like an oil sheen. If you wipe the valve, how much oil is really on it, or is it just wet looking?

Sounds like the runners are dry and clean? Bad PCV valve would wet the intake also.

 

[1TONY1]

I don't think you should be able to blow or **** through the pcv valve. Not supercharged. No additives, there was standing liquid oil on the valve. Probably about 5-6 drops worth. There was oil residue in the runners, I haven't looked behind the throttle bodies to see if there was any oil in the two large runners.

edit: The intake was standing throttle bodies up and ther were puddles of oil at the bottom end. I believe it was a bad pcv.

 

[GTS Bruce]

Blow and ****.I am sure this topic will end up on that other Viper Board. Bruce

 

[Tom Welch]

Tony,

The oil that you see in the runners is perfectly normal. A small amount of oil flows from your valve covers through vacuum tubes into your airbox and is sucked into the intake during the normal intake stroke (suction) cycle. The amount is very small and should not be considered a problem.

Why is the intake off?? Thermostat change?

Tom

 

[1TONY1]

Yes Tom thermostat change and a few other shiny items from Sean. Also after a few months of testing we will be talking propane

There was about 5 or so drops of oil on top of each closed intake valve and the filters didn't look that bad.Thanks for the info. Tony

 

[WESTCOAST JASON]

Where have you found a PCV valve on the Viper? Both mine have been just vented from the valve cover through a 'T' and then to the intake (via airbox)

That is one way that oil can make it to the runners. Especially on older engines with some blow-by. It puts a positive pressure in the valve cover which then blows through the above described lines, back into the intake and voila. Oil. It got pretty bad on my 97 Venom 650R so I bought little valve cover vents from a boat store. They are common on jet boats and so forth. Then plugged the factory vents in the valve cover with vaccum caps. No more oil in the intake. The venom did not use much oil or smoke, but oil does make detonation easier.<P>

 

[1TONY1]

Hey Jason, the pvc valve is under the intake just behind and to the passenger side of the thermostat housing with the hose from it going toward the front of the car.

 

[RedGTS]

I was talking to Vipermed the other day about the whole PCV issue, and he has just done away with the hoses to the airbox, etc. and capped the vacuum outlets on both his '97 and '01 (both Roe sc'd). I would like to do the same thing, mainly for aesthetic reasons (to get rid of the crappy looking hoses). Does anyone know of any reason not to junk the PCV system on an '01?

 

[WESTCOAST JASON]

I have just torn my manual apart looking for a PCV valve, still can't find it. Driving me nuts! Is it a standard check style PCV valve? Would you happen to know where in the manual it talks about it? Thanks

 

[1TONY1]

Jason, Maybe they changed since 96. Check the hoses that connect the front of the valve covers, from that gob of plastic hoses see if there is a soft hose that goes beside the passenger side of the thermostat housing heading under the intake.

 

[Vipermed 97.01]

nothing has changed,look in between #1 and #2 intake runner directly under them is your PCV valve all you will see is a rubber gromlet with a 6AN hose going to it youve hit paydirt

 

[Doug Supercharged Vipers]

Jason -
You won't find a PCV (positive crankcase ventilation valve) on a '98 GTS. The hose tees off directly into the crankcase behind the thermostat housing into a plastic grommet. The '96 GTS does have a PCV located in the same grommet where the '98 doesn't have one.

Regards,
Doug

 

[HP]

Has anyone out there thought of using a power-vent type setup,
which involves plugging all crankcase/valve-cover vents(except 1), and attaching a one-way valve to the unplugged vent.
This setup has solved a lot of problems with V-twin(Harley)
motors that are notorious for crankcase pressure problems - due
to 2 large cylinders and almost no reservoir vent area.
The 'power-vent valve' allows excess pressure to be vented, but
'saves' vacuum pulses by its one way action. The cost is
around $75 for the unit.

 

[WESTCOAST JASON]

Now that is an interesting idea! Are those online so I can see a picture of them?

 

[HP]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jasontarnutzer:
Now that is an interesting idea! Are those online so I can see a picture of them?

<HR></BLOCKQUOTE>

There are 2 designs - one is a diaphragm or reed valve type and
goes by the brand name Krank-Vent. It looks like a small metal
gas line filter. The other type, which I have used,
is a precision piece of billet aluminum that has a movable, spring-loaded piston inside that acts as a one way valve.
It is about 3" long and 1" diameter, and is fitted with a 3/8" ID ****** for connecting to vent on motor, the other end can
be fitted with a mini-filter. Both types are available thru
aftermarket motorcycle suppliers. All other vent holes on the
motor have to be plugged, so the dipstick/hole would have
to be modified to seal properly. They are advertised to keep
crankcase pressure constant and lowered, helping to rings to
seal better and preventing oil leaks caused by high crankcase pressure.

 

[GTS Dean]

I think that in '97 or '98, they changed from a conventional (poppet) PCV valve to an Orifice type. I have never examined an orifice PCV valve.