Tech Advice needed: Modifying Valve Cover with -12AN fittings, does this look right? - Honda Prelude Forum

prepreludesh · 05-15-2010, 10:45 PM

Hello everyone,

It's been a while since I've been on here it seems, or at least looked around and commented/posted much.

Recently, my dad and I have been having a debate on this new breather system that I want put on my engine. But first, some background...

As most of you know, the car has the Jackson Racing supercharger on it. This is currently how the PCV valve and regular breather valve look on the valve cover:

If you can follow along, this is what the PCV tube is doing: It is running into a T-fitting that goes somewhere to before or after the throttle body (don't really know for sure, I'm not home to look at it). The breather valve is simply a long rubber hose that goes down to an area pointing directly at the ground where it can just blow into the open elements. Environmentally friendly? No. But not blowing hot gases/oil into the intake? Yes.

Before I deployed, I had my old Rising Sun valve cover fitted with two -12AN bungs welded into the front of it. The old location for the PCV valve was welded shut and the same goes for the breather valve location. Here is a quick glimpse of the ongoing project while everything is being "shaved" and before it gets powdercoated.

The reason I am having this done is because while on the dyno in 2008, at high RPM, the oil dipstick would blow out of the oil tube. The general concensus was that there was too much pressure in the crankcase due to the engine being F/I now and not having enough/large enough openings to let the crankcase pressure escape. The dipstick blowing out could've been a much worse scenario if maybe the pressure had started to try and go through the piston rings, not a good thing! The goal with these two -12AN fittings is to run in these Earl's black braided lines I have to a Moroso Crankcase breather apparatus I have that is enormous. The pressure will be vented through a large top-mounted filter.

So we've all seen others run these AN fittings on others' valve covers before, but my question to anyone with knowledge of these things out there:

Do you need to have a PCV valve after you F/I a previously N/A car?

I argue that you do not have to, and that all lines on the JRSC that were being fed off of this PCV hose should just be sealed off (black rubber nipple covers come to mind).

My dad argues that he should tap the valve cover and put in a brass fitting that could potentially be used to fit a future PCV valve if we find out we need one. He wants to do it before the valve cover is powdercoated so that we wouldn't have to try and drill thru the powdercoating later on.

My problem with that is that if I'll never need a PCV valve again, adding a brass fitting somewhere on the valve cover is going to look ugly and be unneccessary on the theme I'm trying to go with on this shaved valve cover.

Thanks for any advice or previous knowledge in this matter.

bouckarooo · 05-15-2010, 11:10 PM

In this situation, with my experience i would agree with your dad. However, i think if the placement is correct and done before powder coating you can minimize the effect. Ideally if you could drill a hole through where the old one was, then put threads in that hole. Have two fittings for it, one that can screw in and hold a PCV valve (if necessary), and the another that is a cap, completly blocking it off. Take the valve cover to get powder coated and have the cap done to match as well, then if you need it you can remove the cap and have it.

prepreludesh · 05-16-2010, 09:50 AM

Can you expand on your experience for the PVC valve being needed more?

bouckarooo · 05-16-2010, 11:51 AM

My experience comes from having the same type of issue with a turbo charged b18. I had ended up porting two holes in the front of the VC (just like you have) and install a signal japan catch can. Using a skunk 2 intake manifold, i had just capped off the nipple for the PCV(at the valve cover i plug the orfice with a rubber stopper). Assuming the lines i ran would decrease the crankcase pressure and make up for the lack of PCV. After doing this i had gained an erronius idle, taken care of the cc pressure but now had a surging idle. After many hours of research and consultation i decided to reinstall the PCV valve to see if it would even out the idle. It did. . Honestly i am not to sure if you are goin to need the PCV but i would hate to see you go through all that work then need to go back and reengineer it all.

The solution i had offered in the other post i think is the best way of trying to maintain both worlds. If you dont need the pcv then you have it blocked off and color matched, if you need it sometime then you can just unscrew the plug and continue on.

prepreludesh · 05-16-2010, 04:10 PM

ttt

chubbs · 03-29-2011, 01:02 PM

Did this ever get finished?

prepreludesh · 03-29-2011, 02:13 PM

No it hasn't, it still looks the same as it did. It will get finished someday soon (shooting for this summer), and I'll show it to you all when I get the car back and put some "finishing touches" on it.