Advice on PCV setup

[martymil]

The vacuum realief valve will fix the issue but you have to adjust it and possibly trim the spring, you will have to use a vacuum gauge on the valve cover to see how much your inhg your pulling, you should set it to 5 to 6 but like most Ive seen that start to whistle is around 2 to 3 stock is less than 0.5 inhg

 

[ShocknAwe]

When does this vac relief valve become necessary or even beneficial?

First I've seen it.

 

[Torgus]

Amazon.com: Moroso 22637 3/4-16" Vacuum Relief Valve : Automotive

Buy Moroso 22637 3/4-16" Vacuum Relief Valve: Vacuum Valves - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

The VTT vac relief is either a knock off(most likely) or private labeled from Moroso. instructions and product is identical. Moroso make a number of versions NPT AN etc.

There are a number of these on the market: https://www.gzmotorsports.com/relief-valves.html & https://www.amazon.com/JEGS-23630-Adjustable-Vacuum-Relief/dp/B078WHWPMY for example.

I agree with @Cruizinmax I think you are pulling too much vac.

 

[Tzaks]

I will wait for my adaptor pipe to arrive and fit the VTT vacuum relief valve straight to the head.
Will update soon!

 

[ShocknAwe]

What adapter pipe did you get?

 

[Cruizinmax]

The vacuum relief will solve your issue. One way you can test prior is open you oil cap a little when it's whistling. Just enough to allow air in and see if it stops.

Also I don't believe the vacuum relief valve is appropriate for a street car that sees very many miles. You are essentially letting unfiltered air in your crankcase along with all the dust and dirt it contains.

 

[martymil]

Put a sponge unfilter sponge on it if your worried

 

[Tzaks]

This is what I used. It came here about an hour ago. Its an10 to an10 with a switchable extension in between. Used a copper o-ring between the block and the fitting to seal properly.

I'm still pulling too much vacuum, the engine has occasional hiccups and it even turned off once. I removed the VTT vacuum relief valve to allow more flow inside the crankcase, it still runs a bit rough, it's intermittent but I can feel that it doesn't have that linear smoothness.

Does it matter where I'm installing the one-way check valve for the low side? Saw people using both (between crankcase and OCC) / (between OCC and Intake manifold) with good results.

 

[fmorelli]

Suggest if you decide to keep that, to zip tie the "switch" to keep it from going anywhere.

 

[ShocknAwe]

Is there not a way to put a small filter on the valve?

 

[Tzaks]

Can probably fit a small filter where the holes are, after I solve my problem I will try to DIY something and update.

I will remove the restriction on the low side hose and run another test.

 

[martymil]

The hiccup you have is your pulling too much vacuum from the manifold.

You have to restrict the flow some how.

I run an-4 line from the manifold to the catch can or put a adjustable valve on the catch can to limit the flow of vacuum on the manifold side.

 

[Tzaks]

I did a few more tests that I will outline and describe the best I can below:

1. Test setup one
* I blocked the pipe from the intake manifold but still left the Nylon lines in. This setup works fine or at least that's the first impression but when checking vacuum in the crankcase, vacuum seems be non-existent. The end of this hose is blocked.

2. Test setup two
* I removed the restriction, there's way too much vacuum applied to the crankcase which results in a whistling sound as air passes through the VC gasket.

3. Test setup three
* I installed a nut with a very small opening on the hose between the OCC and the Intake Manifold. Used a clamp on the outside of the hose so no air can go around this nut, only through. This improved the situation however, the vacuum applied to the crankcase is still too much. Please see picture below, USB stick for size reference.

Conclusion:
It seems that even the smallest opening will still allow too much flow and create a lot of vacuum in the crankcase. I believe that due to the spring in the PCV valve and the way the valve is designed, it acts as an airflow restriction because of the path the air has to take and no simple hole can achieve that.

The VTT Vacuum relief valve seems to be doing precisely nothing. Not sure if it's not allowing enough flow through inside the engine or if the spring is too hard. According to their website, they provide 3 shims with it.
No shim = 10inHG
1 shim = 12
2 = 14
3 = 16

From my testing, I can't tell if it's opening or not, tried with no shims, or with 1 shim. If I blow through it with some mouth action, it does open so perhaps it's not letting enough airflow through. The weather over here is crap as always and it's too windy to actually tell if it's sucking anything else than my energy. I will try with a vape pen to blow some smoke on it when it's not as windy to see if it's actually doing anything.

Action:
I have purchased a 2JZ PCV valve which according to @Panzerfaust and his post it should be a perfect fit for the an8 hose. Will update afterwards.

 

[martymil]

If your pulling to much vacuum with shims removed you need a pair of really sharp side cutters and trim the spring in the vacuum relief valve half a turn of the coil at a time to reach your desired amount of vacuum.

So for if the coil has 5 turns trim to 4.5 turns, if you go a little to much don't worry as you can use the shims to bring it back up.

Be patient and don't trim to much first go and reinstall and test after every trim.

 

[Tzaks]

@martymil
I received my 2JZ PCV valve but I can hear something inside the PCV valve rattling when I'm shaking it and it's not fully sealing the reverse way. It's a small, small, air leak on the way it's supposed to be blocked. Was yours the same? The seller is trying to convince me that this is how it's supposed to be

.

 

[martymil]

It should fully seal under boost, if it doesnt its stuffed.

 

[Tzaks]

This looks faulty to me: https://1drv.ms/v/s!Ah-fc7L4KlMLj_s5-jGRQJvaOs7okQ
Tested with the vacuum gun and it doesn't seem to seal properly.

 

[martymil]

100% faulty

 

[Heyfred]

Are still using the same PCV design as in your first post and venting to atmosphere on the high side?

Would you update your drawing, if not the same, so I can see what you are system is ?

 

[Tzaks]

Crankcase > 1way Check valve > OCC (no filter) > rear inlet -AN10 tubing, no OE flapper
Crankcase > OCC > flow restriction on the hose > 1way check valve > manifold

I plan to replace the 1 way check valve and restriction with a PCV valve that will sit between CC and OCC.