Timing Belt Need replacment?

[series8217]

It doesn't matter whether they are hooked up to open air or the intake tubing; It's the same thing! The intake tubing does not pull a vacuum on them, therefore it does not make a difference! The reason you get oil coming out of there is because the baffle design SUCKS and the situation worsened if your engine has excessive blowby.
You must be confused, the 3.1 is NOT set up stock to have vacuum on the valve covers and crank case.

[SappySE107]

The 3.1 has the PCV on the rear valve cover directly to the plenum. How is that blowing air into the valve cover like your picture shows? A vacuum fed sand blasting setup uses a similar setup as the lines to the intake tube right before the throttlebody. Again, i don't understand how you are saying its sucking air in at the valve cover. If it does get fresh air from the vacuum line, wonderful. That means there is a vacuum inside the valve covers instead of pressure like my 3.1 had.

Again, I never said shit about imploding the motor from this. Little extreme. I did notice a difference on my car but like I said, it was pretty fucked up when I got it. If you don't have oil coming out the top where your breathers are, I guess its doing good. My 3.1 probably had some excessive blowby, who knows. I just know I am sticking with the stock setup minus I want catch can in line before the plenum.

[series8217]

The 3.1 has the PCV on the rear valve cover directly to the plenum. How is that blowing air into the valve cover like your picture shows? A vacuum fed sand blasting setup uses a similar setup as the lines to the intake tube right before the throttlebody. Again, i don't understand how you are saying its sucking air in at the valve cover. If it does get fresh air from the vacuum line, wonderful. That means there is a vacuum inside the valve covers instead of pressure like my 3.1 had.

You're contradicting yourself:

This follows the exact same setup for stock having vacuum on the valve covers and the crank case.

Which is it? Is just the valve cover hooked up to the plenum or are the valve covers AND crank case hooked up?

[SappySE107]

How is that contradicting myself. I was stating 3.1 in the one and 3.4 DOHC in the other. The 3.1 has the front valve cover hooked up to the intake tubing and the rear valve cover hooked up to the plenum direct with PCV. On the 3.1, I don't recall any direct crankcase plug so I assume it goes through the rear valve cover where the PCV is hooked up.

On the 3.4 DOHC, I think its been stated several times and im kinda tired of repeating myself. Either you get it or you don't, but im done. I obviously don't explain shit well enough for people.

[series8217]

How is that contradicting myself. I was stating 3.1 in the one and 3.4 DOHC in the other.

On no wet sump motors do all of the openings to the motor have a vacuum pulled on them. On the 3.4 DOHC the crankcase vent has a vacuum pulled on it and fresh air enters the crankcase through the valve covers. On the 3.1 apparently there is no direct crankcase vent due to all the stuff in the lifter valley, so a vacuum is pulled off of one valve cover to evacuate the gases, while the other valve cover supplies fresh air.
You pull a vacuum from one spot (through a PCV valve preferably so you dont blow out your oil seals if you backfire through the intake) and allow fresh air to enter through the other openings to the motor.
The point is, there's no difference between hooking up to the intake tubing (post air filter, but pre throttle blade) or to just a little breather filter like WhiteMonteZZZ.

[SappySE107]

I was wondering where it would get fresh air but makes no sense for it to get it from the intake tube since that will have a vacuum source (motor) on it. Pull the line off the intake and stick your finger over the hole. Now apply some throttle.

I take it vacuum from the crank case will cause the pressure in the valve cover to overcome the vacuum from the motor. Why don't they just use a filter stock vs running it to the intake tubing? Thats another servicable part for them to mark up insanely and make money on. Heh, ok, well ill just assume that there must be something wrong with my old 3.1 for it to be blowing oil out the filter I had put up front, and that the valve covers overcome the depression inside the intake tube via the vacuum from the plenum.

[series8217]

I was wondering where it would get fresh air but makes no sense for it to get it from the intake tube since that will have a vacuum source (motor) on it. Pull the line off the intake and stick your finger over the hole. Now apply some throttle.

Try this: Pull one of your post-throttle blade vacuum lines off and stick your figner over the hole. Apply some throttle. There's more vacuum because the throttle blade is a restriction. So you still get positive pressure at the breathers compared to whats connected through the PCV valve.

Why don't they just use a filter stock vs running it to the intake tubing?

Actually, they have a really good reason for it. On older motors you get a lot of blowby, probably enough to completely overcome the PCV system especially at WOT at high rpm. The gas ends up coming OUT of the breather lines (which may be why you get oil splashing out, if its not just because GM sucks at making baffles). In the spirit of emissions control (and making our lives harder) they are required to run these blowby gases back through the intake somehow. So with old motors that have crappy ring seal, the blowby gases that overcome the PCV system still end up in the intake tract and get burnt up in the combustion process to prevent it from entering the atmosphere. It also keeps gases from entering the atmosphere after the motor is shut down. Theoretically the gases inside should cool down and condense, but after that happens if there was unburnt fuel vapor in the motor it could drift out as its quite volatile.
Thats why you only see the connection to the intake tubing appear in the 80's. If you look at an old SBC they just have a breather can on one valve cover and they pull vacuum through the other or a crankcase vent.

[SappySE107]

Ill give that a shot the next time its not freezing out. Thanks for clearing that up, I learned something

[Juglenaut]

The Manifold pressure is less than pressure in the intake tube. As rpms increase the the ratio of manifold pressure to intake pressure evens up some but there is always more vac on the manifold side of the throttle body.
So in a sense using breathers will allow the PCV system to ventalate more air, also it may drop the positive pressure in the crank case because it is now an open air system that might have less restriction. Since manifold pressure to atomosheric pressure is a different curve than if the valve covers where connected to the intake. One more thing that it may cause is more frothyness of the oil for the same reason as less positive pressure, the bubbles tend to adhere more so the closer the crankcase is to barometric pressure.

Blowby happens when the their is less vac in the crank versus the intake, like when ramping to wot, that is why there is a PCV valve (s).
If you're getting lots of blow by you need new pcv valves. Sometimes these valves are on the valve cover. Without the pcv valves pressure can actually build in the crank mometarily. PCV valves are sort of a safty device, but having no PCV valve may leave the engine more prone to damage during a backfire, but is unlikely that a backfire will blow out oil seals.
Remember this is air and not oil as a back fire would have to be a really nasty one to push enough force to make oil press out a seal, even then the backfire would have to travel though a tube that will only allow a certain amount of air through it when unrestricted. I would say that the pressure would be relieved just as fast as it entered the manifold or crank for that matter. If you have that bad of a backfire chances are something else is more damaged or wrongly modded than the oil seals would be damaged from that same backfire..

[WhiteMonteZZZ]

So in a sense using breathers will allow the PCV system to ventalate more air, also it may drop the positive pressure in the crank case because it is now an open air system that might have less restriction. Since manifold pressure to atomosheric pressure is a different curve than if the valve covers where connected to the intake. One more thing that it may cause is more frothyness of the oil for the same reason as less positive pressure, the bubbles tend to adhere more so the closer the crankcase is to barometric pressure.

So if I have this right, I'm actually venting MORE air than if I ran the stock setup? Thus, being safer? the only drawback being frothier oil? My oil is changed every 3k, IF that, so no worries there.

To recap this huge post I need my timing belt and accys replaced in about 1k miles or so, and the breathers are safe?

WMZZZ

[series8217]

Blowby happens when the their is less vac in the crank versus the intake, like when ramping to wot, that is why there is a PCV valve (s).
If you're getting lots of blow by you need new pcv valves.

Or new piston rings..

Sometimes these valves are on the valve cover. Without the pcv valves pressure can actually build in the crank mometarily. PCV valves are sort of a safty device, but having no PCV valve may leave the engine more prone to damage during a backfire, but is unlikely that a backfire will blow out oil seals.
Remember this is air and not oil as a back fire would have to be a really nasty one to push enough force to make oil press out a seal, even then the backfire would have to travel though a tube that will only allow a certain amount of air through it when unrestricted. I would say that the pressure would be relieved just as fast as it entered the manifold or crank for that matter. If you have that bad of a backfire chances are something else is more damaged or wrongly modded than the oil seals would be damaged from that same backfire..

Good point; its not like the breathers get sealed off during a backfire. I would hate to see someone damage their new motor the first time they try to start it because the cam timing is off though. You could get major intake backfires that way.


Ben, I just remembered now having the same problem you do (did?) on the 3.1. The first time I hooked up my PCV system I had the valve backwards; it would close when vacuum was applied so it wasnt doing anything. If you're running the stock setup I doubt its backwards but thats something to check. If I recall correctly, the fat end should be facing AWAY from the vacuum port on the throttle body.

[SappySE107]

That 3.1 is long gone. It was on right and replaced often though. There was only 1 way to put it in honestly so im a bit confused as to how you got it backwards. Big end sticks into the valve cover grommet.

[series8217]

That 3.1 is long gone. It was on right and replaced often though. There was only 1 way to put it in honestly so im a bit confused as to how you got it backwards. Big end sticks into the valve cover grommet.

This was on a 3.4, so it didnt stick into a grommet. I didnt have the factory lines and just had a brain fart as I was hooking up my own hoses