Carbon canister and hoses.

Carbon canister and hoses.

Author
Discussion

LenChim

Original Poster:

225 posts

154 months

Thursday 16th February 2017
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Well I am back with a 4.5li Chim, having sold my 4li and my Wedge. It seems that I bought a car with a lot more problems than I thought. Having taken the radiator out as it was not fitted properly I found resting in the nose a pair of horns, wired & working, the air filter, the washer bottle fitted but no piping in site not even sure were it goes through the body and of course the Carbon Canister. Looking in the book it mentions a electronically controlled valve. As you can see from the attached pic's there seem to be something missing from the top of my can, the pipes were just jammed on the "tank" connection and the "air" connection the other connection and the little box are missing.
So the question is do I really need it? If I do can I buy the the little box on the top? And is the little box on the top a valve and is it wired to anything?

LenChim

Original Poster:

225 posts

154 months

Thursday 16th February 2017
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caduceus

6,069 posts

265 months

Thursday 16th February 2017
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If your car is decatted and you intend keeping it that way, it's my understanding from info on here that you don't need it. I've taken mine off.

N7GTX

7,823 posts

142 months

Thursday 16th February 2017
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LenChim

Original Poster:

225 posts

154 months

Thursday 16th February 2017
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caduceus said:
If your car is decatted and you intend keeping it that way, it's my understanding from info on here that you don't need it. I've taken mine off.
If you have taken it off bearing in mind that mine is just laying in the nose cone with the pipes apparently in the wrong places did you notice any wires going to it? As people keep saying that the ECU knows when to open the valve, where is the valve? and the wiring?

TwinKam

2,937 posts

94 months

Thursday 16th February 2017
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caduceus said:
If your car is decatted and you intend keeping it that way, it's my understanding from info on here that you don't need it. I've taken mine off.
It has nothing to do with whether the car has a Cat or not, it's an environmental thing to stop petrol fumes from the tank venting to atmosphere, they're stored in the carbon-filled canister until the engine is running and warm, the solenoid purge valve then opens and they're drawn in by inlet vacuum... so much better for the planet to burn them instead! rolleyeslaugh
It's probably illegal to remove inasmuch as it was a compulsory fit by manufacturers after a certain date (possibly coinciding with compulsory Cats from 1991?) but it's not part of the MoT Test and not easily detectable anyway.

LenChim

Original Poster:

225 posts

154 months

Friday 17th February 2017
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Ok guys now I know that there should be a solenoid on the top (I have found the wires and connector) but it seems that I still can't buy one. Has anyone got any ideas were one might be obtained or a substitute item that could be used?

OleVix

1,438 posts

147 months

Friday 17th February 2017
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Throw it away. Save weight.Let the petrol tank vent to air behind the diff. Put a small filter on the vent hose.

LenChim

Original Poster:

225 posts

154 months

Friday 17th February 2017
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OleVix said:
Throw it away. Save weight.Let the petrol tank vent to air behind the diff. Put a small filter on the vent hose.
Do you just bung up the hole in the plenum chamber then?

ProjectChimaera

197 posts

112 months

Friday 17th February 2017
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OleVix said:
Throw it away. Save weight.Let the petrol tank vent to air behind the diff. Put a small filter on the vent hose.
Ditto!

The thread mentioned earlier was initiated by me and the answers are comprehensive in what to get rid of and venting the tank etc.

OleVix

1,438 posts

147 months

Saturday 18th February 2017
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LenChim said:
Do you just bung up the hole in the plenum chamber then?
yep smile

ChimpOnGas

9,637 posts

178 months

Sunday 19th February 2017
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I fitted a Crown Automotive J3234216 PCV Valve from a 79-81 V8 Jeep CJ.



I used it to stop the strong closed throttle plenum vacuum (used for crank case ventilation) from acting on the plenum ported vacuum port at the throttle body, this proper PCV valve helped improve idle quality and my tank vent pipe fits to the small diameter 'T' part of the valve to allow the engine to draw away any unwanted tank fumes .

The whole system works perfectly, no idle manifold vacuum acting on the throttle body helps idle quality while the valve ensures perfect crankcase ventilation management is maintained (shuttles between idle & open throttle), and as I've removed my carbon canister it also allowed me to completely eliminate my occasional petrol fume smells.

LenChim

Original Poster:

225 posts

154 months

Monday 20th February 2017
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OK I have ordered the aforementioned Valve. So what pipe goes were? One from the petrol tank (vent pipe), one that goes back to the plenum chamber.
3 options:- 1) small nozzle, 2) Nozzle closest to the small nozzle 3) Nozzle furthest from the small nozzle.

ChimpOnGas

9,637 posts

178 months

Wednesday 22nd February 2017
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LenChim said:
OK I have ordered the aforementioned Valve. So what pipe goes were? One from the petrol tank (vent pipe), one that goes back to the plenum chamber.
3 options:- 1) small nozzle, 2) Nozzle closest to the small nozzle 3) Nozzle furthest from the small nozzle.
The valve goes in the 'J' shaped crankcase vent pipe between the 'T' joiner and the throttle body, you then fit your existing tank vent pipe that originally went to your carbon canister to the small pipe that protrudes from the valve body at a right angle.

It may help now to understand the function of the standard crankcase ventilation system used on our cars.

When the throttle is closed or mostly closed vacuum is high in the plenum, so at idle, low load cruise, when you momentarily snap the throttle shut during gear changes or during heavy deceleration the crankcase gasses are drawn from the O/S rocker cover through the flame trap into the plenum.

When vacuum is low in the plenum during acceleration and part throttle openings the ported vacuum source at the throttle body takes over drawing the crankcase gasses past the throttle butterfly to be reburnt by the engine exactly as with the closed throttle operation... it just takes a different path.

The valve I'm using allows our crankcase ventilation system to function as normal, but has the added advantage of separating the strong plenum vacuum source at idle from the throttle body. All crankcase ventilation systems are in effect just controlled vacuum leaks, and any vacuum leak controlled or otherwise is bad for engine behaviour.

In the case of our standard unvalved crankcase ventilation system it's a rather poorly managed vacuum leak allowing the engine to either pull crankcase gasses through the flame trap... or in certain circumstances momentarily draw air through ported vacuum port at the throttle body... which trust me is a bad thing for drivbility and idle quality.

When the manifold vacuum in the plenum is lost the ported vacuum source will take over the job of pulling crankcase gasses through the flame trap but it sill remains an open unvalved connection to the plenum, without a valve the change over from manifold vacuum at the plenum to the ported vacuum at the throttle butterfly is an uncontrolled process.

Basically its not a great design especially when you consider our cars use a singe plane inlet manifold which is well known for promoting undesirable reverse pressure pulses through the inlet tracts on a V8 engine. I have found adding this simple valve and fitting hose clips where none were used previously improves idle quality and helps to mitigate shunting.

There's a bunch of other tricks I've learnt along the way to make my Chimaera substantially smoother to drive, these include running more advance at idle (25 degrees), increasing the throttle butterfly resting air gap, and then winding the base idle screw all the way home to eliminate that controlled vacuum leak too.

Basically what I've found is you ideally want as much of the air being drawn into the engine to enter via the throttle butterfly, setting the engine up so the idle valve (stepper motor) is required to add as little air as possible definitely also improves idle quality and makes for a far smoother drive at small throttle openings especially during urban driving.

The PCV valve I describe is just one part in a range of strategies that can transform how your Chimaera or Griff RV8 engine behaves, the real solution of course would be to do what Land Rover eventually did and fit the separate runner type (Thor) inlet manifold wink



Edited by ChimpOnGas on Wednesday 22 February 22:10

LenChim

Original Poster:

225 posts

154 months

Wednesday 1st March 2017
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Ok I have the part and have read the text but the description of the "J" shaped pipe, is this the one you mean?


If so which side of the "T" should it go and in which direction should the NRV face. The ignition coil, oil filler end?

ChimpOnGas

9,637 posts

178 months

Thursday 2nd March 2017
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As I said...

ChimpOnGas said:
The valve goes in the 'J' shaped crankcase vent pipe between the 'T' joiner and the throttle body.
I cant really be any more clear than that, but here's an image if you're still not grasping it.



Three important points before you progress:

1. You need to understand how the standard PCV system works which I've also explained very clearly above

2. You need to understand the theory behind fitting the valve you've bought, to explain once more... the idea behind fitting the Jeep PCV valve is to separate the plenum from the throttle body, this is to stop strong manifold vacuum at the plenum from drawing air through the throttle body

3. You need to be 100% happy yourself with the act of fitting the valve, the PCV system we have isn't very clever but it does work, any valve you fit will be a restriction and if that means the system can no longer effectively manage crankcase pressure the pressure will find a different path. This will likely be your rear main seal or sump gasket so please proceed with caution, I hold no responsibility if you fit the valve and you find it promotes oil leaks, you have been warned!

Once you've fully absorbed the above three points and you feel confident and happy to progress, by all means fit the valve, it has worked for me, I enjoyed a crisper throttle response when pulling away in 1st and or during slow speed manoeuvring, a smoother idle and less propensity to stumble between 1,600rpm and 1,850rpm during low load light trailing throttle applications.

Please be aware I run a Canems engine management system which allows me to run 25 degrees of timing at idle and a much richer idle air fuel ratio than the excessively lean 14.7:1 delivered by the 14CUX at idle. I run no restrictive catalytic converters whatsoever and have also made other changes as described in my previous post, all of which help to smooth out low speed engine behaviour. Therefore as my setup is likely to very different to yours I can not guarantee you'll enjoy the same benefit from the Jeep valve as I did.

The orientation of the valve will be obvious once you've properly understood how the standard PCV system works and what you're trying to achieve by fitting it. Suck on the valve to get a feel for how it works, you will also need to sleeve one end of it so it snugly fits in 'J' pipe, always used hose clips to completely eliminate any tiny vacuum leaks.

Finally (and for fear of repeating myself) you absolutely must satisfy yourself you are not creating a restriction in your current PCV system, you need to be 100% happy that with the valve fitted the engine can still draw a sufficient volume of blow-by gasses so as not to create an over pressure situation in your crankcase or you will definitely end up with oil leaks.

Please proceed with caution, personally I have had no oil leak issues since fitting the valve and it definitely worked for me, but each car will be different so the responsibility for any undesirable consequences associated with this mod are all yours.

I hope this helps?

Edited by ChimpOnGas on Thursday 2nd March 11:08

LenChim

Original Poster:

225 posts

154 months

Tuesday 14th March 2017
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Well thanks for the info, it is now fitted but I have not been able to run the car yet due to other problems.

andy43

9,548 posts

253 months

Tuesday 21st March 2017
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Quick question - does anybody know what thread the plenum tapping is please - I'm binning my carbon pipework and rather than an allen bolt stuffed in the hole with some insulating tape to stop it falling out I'm considering going high tech and investing in the correct bolt smile

LenChim

Original Poster:

225 posts

154 months

Thursday 23rd March 2017
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Well I fitter the valve and the car seems to run ok.
Many thanks.

StuVT

79 posts

110 months

Thursday 25th January 2018
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IN case it helps. I've been reading up on the PCV situation on the RV8 and from what I can see the engine was originally designed to run a PCV system.

I've seen reference to, and soon to try a GM PCV valve which has been used to good effect on other RV8 forums.

Its a BYFV184 available from Real Steel in Uxbridge. Its less than £3. I've purchased and and will be testing it soon.