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My 86 32v crankcase vent setup

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Old 05-04-2012 | 12:11 PM
  #16  
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Originally Posted by ramcram
Yes, that does the rising rate fuel pressure. Not happy with it yet. It starts well cold, although it runs very lean during cruising until the temp gauge starts to move. The AFR needle jumps up where it should if I accellerate. Once the engine is warm it sits around the 14.7 and shoots up on accelleration. But warm, the engine sometimes needs the slightest amount of throttle to get is to stay running for the first few seconds, then it behaves perfectly. Strangely, when it wants help to start and I don't do it, it hunts, suggesting to me a rich mixture but the AFR gauge says lean. Acts as if the cold start map is not working. It only does this for a few seconds, so I'm living with it for now.
Everthing else is stock at the moment and may/may not stay like it.
I want to run it on the dyno and get the tuning correct but first want to alter the cooling and get the engine temp and volt meters to behave as they should. I fitted a 130 Amp alternator and all new engine sensors but I'm not confident in their accuracy, so some checking has to be done. 26 year old wiring connections I suspect. I have had the cluster out and sent it to an instrument shop for servicing and calibration.
Did you remove the stock FPR and replace it with the BEGI or are you running both?
Old 05-04-2012 | 02:50 PM
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Originally Posted by ramcram
The issue that compounds most of us is crankcase compression. Some deal with it by fitting a vacuum pump where the emmissions air pump was, to 'suck out' the sump. The sump is a sealed unit except for an allowance for 'blow by' to escape. Porsche vented it from 1 restricted cam cover elbow, the top bottom of the filler neck.
You are right about a designed vacuum leak. This is managed by the 'Idle Control Valve'. When the throttle butterfly is closed at idle, air enters the inlet manifold through the sump vent system and the idle control valve. the idle setting procedure sets the amount by which this will be adjusted to achieve the 680RPM.
The restricted cam cover elbow is not intended to be a 'venting port'... It is supposed to draw fresh air into the crank case.... It's just that more often than not the venting system becomes overwhelmed at high rpm, and crankcase gases are ejected here...
At idle/partial throttle Crankcase gases are supposed to be drawn into the intake via the restricted outlet on the oil fill, which connects to the base of the manifold (s4 anyway) and at higher rpm via the hose that runs from the base of the oil fil neck to the MAF boot.
Fresh air should be drawn into the camcover elbow at idle to prevent a large vacuum being drawn on the crankcase... The throttling of this elbow is presumably what Porsche figured out gives a 'reasonable' level of vacuum.

Which provent did you use? Is it one with a vacuum limiting valve in it? Did you bypass this valve?
Old 05-04-2012 | 02:57 PM
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Originally Posted by Imo000
You didn't aswer my question and I was actually serious.
I cannot answer that question, he could have other issues causing it or a combination. My comment about not playing guessing games was serious. There are methods to trace down problems like this, starting with any known issues.........

The only known issue (that I'm aware of) here is the engine tune, so start there and if the blow-by is still excessive, time for a compression / leak-down test or other diagnostic measures like smoking the crankcase.

Originally Posted by ramcram
I'm keen to find out if Porken's modified chips would give any advantages to this setup?
That would make it worse.

Ken's chips have been carefully designed to give maximum safe performance for a non-boosted engine. The changes he makes to the timing map are the totally opposite what you need with your boosted car.

When I first fired up my 81 with LH 2.2 and EZF I took out 20+ degrees of timing across the board in the EZF map for all areas under boost. Was that excessive? Yes, but I don't like blowing engines. No, my chips will not work for you since I have a different MAP sensor in my EZF. This isn't necessary but my goal is over 20psi. I'm maxed out at 17 right now.
Old 05-04-2012 | 03:26 PM
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I have LH/EZF chips that were specially designed by Ken and myself for my boosted 85. Basically I have timing progressively removed above 4500 rpm and additional timing removed depending on intake temps with a maximum of 6 deg removed with intake temps above 145F.

Your ROW 32V I think is lower compression then mine, which is better for boost but I have no idea what the stock EZF/LH mapping is like. They may have put more timing advance in the map to compensate for the lower compression. I am not sure if the chips I have will work for your car.

Anyway back to the original topic. Getting oil out of your intake is definitely a good thing! Why didn't you just vent the Provent to the atmosphere? It is a lot less complicated.
Old 05-04-2012 | 04:26 PM
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Originally Posted by Cosmo Kramer
I have LH/EZF chips that were specially designed by Ken and myself for my boosted 85.
Ok, those would work
Old 05-04-2012 | 04:52 PM
  #21  
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Originally Posted by Hacker-Pschorr
Ok, those would work
On a low compression 32V? I wonder if the EZF and LH are mapped the same?

Either way, I guess with his lower compression motor it would even be more safe then it is on mine.

Ramcram: I have pretty much the identical system as you and my car runs like a champ, no surging, no hesitating etc. and pulls like a freight train. I have some ideas to help you, you can shoot me a PM or search some of my old threads if you like.
Old 05-04-2012 | 05:12 PM
  #22  
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Originally Posted by Cosmo Kramer
On a low compression 32V? I wonder if the EZF and LH are mapped the same?
Just thinking if he went to Ken for chips, he would know what chips work where, so what you did in theory would be an improvement.

No replacement for a proper tune, but you have to start somewhere.
Old 05-05-2012 | 01:15 AM
  #23  
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Originally Posted by Cosmo Kramer
Did you remove the stock FPR and replace it with the BEGI or are you running both?
Runing both. Under vacuum, the RRFPR is suposed to be out of the equation, letting the stock one do its job.
Old 05-05-2012 | 01:50 AM
  #24  
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Originally Posted by Cosmo Kramer
I have LH/EZF chips that were specially designed by Ken and myself for my boosted 85. Basically I have timing progressively removed above 4500 rpm and additional timing removed depending on intake temps with a maximum of 6 deg removed with intake temps above 145F.

Your ROW 32V I think is lower compression then mine, which is better for boost but I have no idea what the stock EZF/LH mapping is like. They may have put more timing advance in the map to compensate for the lower compression. I am not sure if the chips I have will work for your car.

Anyway back to the original topic. Getting oil out of your intake is definitely a good thing! Why didn't you just vent the Provent to the atmosphere? It is a lot less complicated.
Oh boy, those chips sound VERY interesting indeed. If they'd work in mine I'd be wrapped!
Yes, the ROW is only 9.3:1 CR. Lower HP higher tourque to achieve the same 0-100kpm as the 4.7s of that era.
I followed a SC 928 on a run once and got oil mist all over my window because he vented straigh to atmosphere, besides it's illegal and well, it just felt like cheating.
I'm not sure where I went wrong but I seem to have given this thread the notion that my 86 ROW had/has excessive blow by or crankcase breathing problems and I'm just playing catch up.
This is not the case. Having removed all the inlet system twice since I've owned the car and finding oil inside it but not as much as I've heard some describe, or as much as I've seem in photos, I thought it prudent to work on improving it. Especially adding a SC which has to agravate the problem.
So my efforts are really an automotive excercise by an old bloke with too much time to waste.
As I said at the outset, I don't want to race the car just want to improve its drivability, stretch my brain waves a bit, address a few known issues with these beauties, have some technical fun. Done the same with oil cooling and intercooler as well but that's definitely another story.
Old 05-05-2012 | 04:01 AM
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Did that SC car infront of you had any kind of oil seperator or, he just wented one of the bubes straight into the atmoshere?
Old 05-05-2012 | 04:04 AM
  #26  
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Originally Posted by Imo000
or he just vented one of the tubes straight into the atmoshere?
I guess so, I didn't look at it.
Old 05-05-2012 | 12:08 PM
  #27  
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Originally Posted by Imo000
Did that SC car infront of you had any kind of oil seperator or, he just wented one of the bubes straight into the atmoshere?
The way these cars can barf oil you want the vent into a can or separator. This lets you judge it and/or control it. I'd expect some truly hard running and there's be oil all over the engine bay.

Originally Posted by rad_951
Are you sure the one way valve to the sump is needed? The OBs have a tube from the oil filler to the sump without a one way valve.
Nope. OBs (78-79) have a different tube. Starting in '80 they got a filler tube that extended down into the oil pan and below the surface of the oil. This provides a lock against blow-by running up the tube. That is, until the oil level lowers due to use, windage or vehicle acceleration. Then blow-by will go up that and mess up the operation of the separator can.

I wonder at what point they added that big filler/separator. Speaks to me that they spotted oil ejection problems early on and applied a fix to the symptoms.
Old 05-05-2012 | 07:24 PM
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Originally Posted by FUSE69
The restricted cam cover elbow is not intended to be a 'venting port'... It is supposed to draw fresh air into the crank case....
I think Porsche expected it to also vent there whenever blow-by was more than the otherwise small (resticted) intake vacuum ports could handle... You'd have to assume that since there is nowhere much else for it to go.

Now obviously the cam elbow isn't sufficiently sized to vent very well anyway and since there is no separation before it enters the MAF boot its far from ideal. Especially since the high RMP/turn crankcase oil misting and passenger cam cover filling issues are well known - so that is actually a particularly bad place to be venting from.

Converting that cam vent to air in only (check valve) and T'ing to a bigger out only vent (check valve) from the top of the oil filler would have seemed the easiest way to address that issue without adding a specific seperator (provent like) - I wonder if anyone has ever done just that (its pretty easy plumbing). Not clear how much entrained oil would make it up the oil filler - but its pretty easy to suff scrubbies down there for some degree of vertical stack oil separation.

Alan
Old 05-06-2012 | 07:07 AM
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Originally Posted by Alan
I think Porsche expected it to also vent there whenever blow-by was more than the otherwise small (resticted) intake vacuum ports could handle... You'd have to assume that since there is nowhere much else for it to go.

Now obviously the cam elbow isn't sufficiently sized to vent very well anyway and since there is no separation before it enters the MAF boot its far from ideal. Especially since the high RMP/turn crankcase oil misting and passenger cam cover filling issues are well known - so that is actually a particularly bad place to be venting from.

Converting that cam vent to air in only (check valve) and T'ing to a bigger out only vent (check valve) from the top of the oil filler would have seemed the easiest way to address that issue without adding a specific seperator (provent like) - I wonder if anyone has ever done just that (its pretty easy plumbing). Not clear how much entrained oil would make it up the oil filler - but its pretty easy to suff scrubbies down there for some degree of vertical stack oil separation.

Alan

True... Porsche would have known about the venting at the elbow, probably why there is the shroud attached there... But the as I see it, the system isn't designed specifically to vent there, as so many who are redesigning the system seem to do.
By only drawing in air at the cam cover you assist in pulling the oil in the heads back to the crankcase... An issue that GB has well documented and I'm sure Porsche engineers knew about.

I have mine set up pretty much as you describe, but with the provent and an additional elbow on the drivers cover...
I'm working on a solution to increase the diameter of the hose running from the provent back to the MAF at the moment.

Can post a diagram later, when I'm back at my laptop...
Old 05-06-2012 | 09:08 AM
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Originally Posted by FUSE69
TI'm working on a solution to increase the diameter of the hose running from the provent back to the MAF at the moment.


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