DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstick!

[jblackburn]

The Volvo diagram shows clamps on the bottom "hose", but I thought this is just an adapter that gets wedged between the trap and block. Is it just a mistake on the diagram?

The original system came with a short little bit of hose there. Every replacement kit I have seen has had that little "adapter" thing, so no need for clamps there.

There would be a need for 6 clamps total - the hose that attaches to the side of the canister, then the 2 hoses that attach to the top @ each end. I suspect the screw clamps would be easier to work with on one of the hoses (perhaps the one at the turbo, and the other at the top of the valve cover).

I've seen DIYs where the fuel rail is disconnected but left on the manifold and others where it's not disconnected, but pulled off the manifold. Which is easier and has less of a chance of breaking an expensive part (which I'm quite good at!).

If you've got one where you can just disconnect the line feeding the fuel rail, do that, and leave the injectors attached. Swing the whole thing up as one piece.

And the last question- For hoses- URO=bad, but for the trap, URO=OK, correct? Or should I go all OEM?

Avoid URO whatsoever.

For the cam seals I'm going AMA and using and Elring replacement. It's the good one with a red ID and gray OD. I've used them on VW and they have a nice tight garter.

The Elring seals suck & will blow out again in a short time. I've replaced far too many cam seals on this dang car.

[erikv11]

+1, the Elring cam seals are terrible, the rubber rots out.

[precopster]

I don't know about any rot on the seal but I can confirm that an Elring cam seal blew out on my wife's 850 afew weeks ago.....darn oil spewed out of the engine and all over the road. There's a trail of oil consisting of 6 litres of Nulon synthetic on Melbourne's roads. I told the wife to top it up and continue driving. The seal had 40,000kms and 5 years on it.

Of course the blocked PCV in her car has nothing to do with it.

[jblackburn]

I don't know about any rot on the seal but I can confirm that an Elring cam seal blew out on my wife's 850 afew weeks ago.....darn oil spewed out of the engine and all over the road. There's a trail of oil consisting of 6 litres of Nulon synthetic on Melbourne's roads. I told the wife to top it up and continue driving. The seal had 40,000kms and 5 years on it.

Of course the blocked PCV in her car has nothing to do with it.

Mine lasted a whole year and a half before doing the same.

And no PCV issues there

[OldSkoolMadSkilz]

Got the message. Pep boys has the SKF seals for a bit under $10. I saw them on ebay for less, but who knows if they are copies. I found a nice blue 5/8 fuel line hose. Should dress it up a bit!

And I am going OEM on the rest.

[OldSkoolMadSkilz]

Just did this fix and it works great. I used blue Parker push-lok 836-10 hose. Looks great and is tolerant to oil and gas vapor. It's expensive at industrial supply stores, but there's an ebay seller that has it for $4 per foot. Just search for "10 AN Push Lok". Buy 3 feet and you'll use pretty much all of it. Think I had about 6 inches left over after I trimmed it. I reused the hard line for the vacuum connection, but the ends were totally rotten. I replaced them with 7/32 vacuum hose and clamped it tight to the vacuum hose with Oetiker clamps. That same hose works for other large vac lines in the system.

One suggestion for the DIY. The OP disconnected the fuel rail at the inlet and swung the evap line to the side. I found this pretty much impossible. Maybe it's something different with the line routing in my car. What I found easier is to just pull the injectors right from the manifold. There are two line clamps- one on top and one in the back. Once removed, the whole rail will swing to the fender.

Also, this is a perfect time to clean the throttle body. Just get a gasket. I also changed the dipstick tube seal, dipstick o-ring, and oil cap seal.

Car was parked in my brother in laws back yard for a couple months. Engine compartment was filled with 20 pounds of pecan shells. They were everywhere! Good thing squirrels don't like the taste of hoses.

[cn90]

...Now this is the time to get rid of factory 3/8” pipe and replace with 5/8” Heater Hose. This will increase the flow by a factor of 2.77...

This is what I wrote 2 years ago, which may be wrong.

Spoke to a scientific friend of mine about blood vessel flow rate, who says the vascular system in the human body works like this: the flow of blood is increased by a factor of 4 when you change the radius of the blood vessel!
http://www.cvphysiology.com/Hemodynamics/H003.htm

That is called Poiseuille's equation for the records (don't you love the French scientist?).
That equation is for fluid flow rate, but probably true for gas too (any scientist in forum?).

So, if the diameter is increased from 3/8" ---> 5/8", the radius is increased by a factor of 1.6667.
Now 1.6667^4 = 7.7165. In other words, the flow rate is increased by 7.7165 times!!!

PS: Re heater hose vs oil, I immersed the heater hose in a jar full of engine oil 2 years ago to prove that heater hose will be fine for this application (PCV combustion vapor). The heater hose is still good after 2 years. I will post some photos later...

[OldSkoolMadSkilz]

Room temperature oil is different than hot oil and blow by vapors. Three feet of the Parker 836-10 push-lok hose can be had for $12 shipped on ebay. It's about twice as much as heater hose, but much safer. Still lots cheaper than the factory hose.

[j-dawg]

I would argue that the flow rate is not the big improvement here so much as the increased resistance to clogging.

Flow through the stock hoses is adequate - until all the crap caked up on the walls reduces the diameter. At 3/8 in, a small reduction in diameter has a dramatic effect on the capacity of the hose, for the same reason you've stated. With a significantly larger hose, the same reduction in diameter (a) takes longer to occur, owing to the greater wall area, and (b) has a smaller effect, for the reasons you've stated.

[mecheng]

...Now this is the time to get rid of factory 3/8” pipe and replace with 5/8” Heater Hose. This will increase the flow by a factor of 2.77...

This is what I wrote 2 years ago, which may be wrong.

Spoke to a scientific friend of mine about blood vessel flow rate, who says the vascular system in the human body works like this: the flow of blood is increased by a factor of 4 when you change the radius of the blood vessel!
http://www.cvphysiology.com/Hemodynamics/H003.htm

That is called Poiseuille's equation for the records (don't you love the French scientist?).
That equation is for fluid flow rate, but probably true for gas too (any scientist in forum?).

So, if the diameter is increased from 3/8" ---> 5/8", the radius is increased by a factor of 1.6667.
Now 1.6667^4 = 7.7165. In other words, the flow rate is increased by 7.7165 times!!!

PS: Re heater hose vs oil, I immersed the heater hose in a jar full of engine oil 2 years ago to prove that heater hose will be fine for this application (PCV combustion vapor). The heater hose is still good after 2 years. I will post some photos later...

Flow-equation.JPG

CN90: yes you are on the right track.
For laminer flow, the flow rate is Q = (delta P * pi * Radius^4 )/ (8 * u * L)
P is pressure, u viscosity, L length of pipe
Double the pipe size and you increase the flow by a factor of 16

For turbulent flow, the formuale is different a doubling the pipe size decreases the pressure loss by a factor of 27

To determine whether it is laminar or turbulent flow you have to calculate the renyolds number.
If the velocity of the vapour is above 3.32m/s, it is turbulent flow. For my calculation
I used pure air as the vapour at 100°C (it is not pure air). Is the flow faster or slower than 3.32m/s??... who knows but it was a good Fluid Mechanics refresher for me.

And yes, I neglected pipe smoothness which you can do for laminar flow. That is a whole other calculation. Ahhhhhh isn't science fun