High crankcase pressure help.
Discussion
Hi Peeps..Its been noticed that since i have had the supercharger intake pipe remade to the correct bore the crankcase pressure is forcing oil up and out of the dipstick tube..Im going to see if a different type of dipstick with a bung fitting rather than a metal cap over would be better.
If this doesnt sort it does any have knowledge of an engine vacuum pump or any other way of containing the pressure, I have checked the PCV valve and that seems to be free and not sticking.. I just hope its not failing rings...Cheers...Ziga
If this doesnt sort it does any have knowledge of an engine vacuum pump or any other way of containing the pressure, I have checked the PCV valve and that seems to be free and not sticking.. I just hope its not failing rings...Cheers...Ziga
Zigs how dose the V6 crank breath, on the v8 there is a small filter on the left rear of the left rocker and a flame trap on the front right with the pipe running into the throtal at the plenum and burned in the engine, i installed an oil catch tank and ran the two rockers onto a tank with a 10mm pipe with filter breather on the top and i dont have any crank breathing issues, you may just need to let more air move around your block now you have the suppercharger up and running at full boost.
Hope its not the rings or the head gasget
Cambelt
Hope its not the rings or the head gasget
Cambelt
mrzigazaga said:
Hi Peeps..Its been noticed that since i have had the supercharger intake pipe remade to the correct bore the crankcase pressure is forcing oil up and out of the dipstick tube..Im going to see if a different type of dipstick with a bung fitting rather than a metal cap over would be better.
If this doesnt sort it does any have knowledge of an engine vacuum pump or any other way of containing the pressure, I have checked the PCV valve and that seems to be free and not sticking.. I just hope its not failing rings...Cheers...Ziga
Probably don't want to contain the pressure, might blow crankshaft seals. If this doesnt sort it does any have knowledge of an engine vacuum pump or any other way of containing the pressure, I have checked the PCV valve and that seems to be free and not sticking.. I just hope its not failing rings...Cheers...Ziga
Have you been through the existing crankcase ventilation arrangements? Including cleaning out all valves and pipes?
Increased combustion chamber pressures might be causing ring blow-by. I can't recall if you had thicker head gaskets fitted to reduce compression ratio.
Is this a problem with other supercharged Cologne engines? Has anyone else modified the crankcase ventilation arrangements on another engine? Increase the vacuum? Be careful though!
Cheers chaps..The V6 breathes via the plenum being connected to the rocker cover via a PCV valve which i have changed and replaced with a new one and i have changed the rocker cover seal that the valve goes into, The oil filler cap originally was an atmospheric breather and i have a different one with a pipe going to the floor now, The dipstick wasnt the best fit in the world and i managed to break it today so i have put a pipe over the tube and capped it with a bolt...Until i can get another tuesday.
I was thinking about a catch tank but only if there really is a problem...I am a bit concerned as there is oil coming from the front of the crank so i wonder if the seals are failing..Apparently the engine was rebuilt a few years ago.
I dont think there is problems with the cologne as a rule but obviously the blower makes a difference...Ziga
I was thinking about a catch tank but only if there really is a problem...I am a bit concerned as there is oil coming from the front of the crank so i wonder if the seals are failing..Apparently the engine was rebuilt a few years ago.
I dont think there is problems with the cologne as a rule but obviously the blower makes a difference...Ziga
red tasman said:
Looking at the first video on your other posting, looks like quite a bit of blue smoke on acceleration.
Hi Mate..That was smoke was caused by oil coming out of the dipstick tube and burning on the manifolds..After i returned to the lay-by where we were filming from i could see the smoke still coming from under the bonnet which prompted further investigation, The plug lead nearest to the dipstick was wet with oil but there does seem to be some at the back of the inlet manifold, However this is a prone place for leaks and i suppose it is made worst by the blower upping the pressure.The compression was lowered in the heads and payen gaskets were used..When a compression test was done each cylinder came out at 120 instead of an average of 175-180.
I had a blast out earlier and didnt see any smoke or smell any oil burning...Cheers...Ziga
PS:The blower is running low-mid boost = 4-6psi.
Edited by mrzigazaga on Monday 26th August 00:02
Mark,
Assume you are aware lower CCP should always be a tad negative.
You have to look at what you plumbed in .....and where!
When you apply pressure it is not directional, pressure is pressure.
Emmision vent systems allow/pull unburnt stuff back to intake to be reburnt.
Your blower is almost certainly blowing harder than your system would prefer
Solution may be a to put in a one way valve similar to a pcv in the return hose.
ETA Do not run car with lower CC blocked, you WILL blow something.
Assume you are aware lower CCP should always be a tad negative.
You have to look at what you plumbed in .....and where!
When you apply pressure it is not directional, pressure is pressure.
Emmision vent systems allow/pull unburnt stuff back to intake to be reburnt.
Your blower is almost certainly blowing harder than your system would prefer
Solution may be a to put in a one way valve similar to a pcv in the return hose.
ETA Do not run car with lower CC blocked, you WILL blow something.
mrzigazaga said:
Cheers chaps..The V6 breathes via the plenum
If the original design relies on the vacuum created in the plenum to create negative crankcase pressure, is the supercharger now pressurising the plenum, thus pressurising the crankcase?Not tried this on a Cologne, but as a rough test, find a known good normally aspirated Cologne, remove the oil filler cap with the engine idling (watch out for oil spray, if it's excessive then abort). Place hand over filler, is there suction? Now try the same with the supercharged Cologne. If that is the problem then it's likely it has occurred on other installs.
V8 Fettler said:
If the original design relies on the vacuum created in the plenum to create negative crankcase pressure, is the supercharger now pressurising the plenum, thus pressurising the crankcase?
Thanks for the help guys..The system is a closed crankcase ventilation system/PCV..Positive crankcase ventilation, It does say that if the "Blow-by" exceeds the capacity of the PCV valve then the fumes are fed back through the air box pre filter..I have seen on some colognes a pipe coming from the oil filler cap and going onto the airbox, unfortunately mine cant do that because my airbox has been modified..Initially i had a non airbox fed type on mine.There is a dual outlet manifold next to the PCV pipe that the distributor vacuum diaphragm is connected to in order to read the boost...So with that in mind the blower is creating some pressure for it to read, Is it enough to push past the PCV valve?..
At the moment i have a filler cap with a pipe coming off of it and going to the floor, I have seen fumes coming out of it and thats why it faces the floor.
V8 Fettler said:
Not tried this on a Cologne, but as a rough test, find a known good normally aspirated Cologne, remove the oil filler cap with the engine idling (watch out for oil spray, if it's excessive then abort). Place hand over filler, is there suction? Now try the same with the supercharged Cologne.
No suction...This does also indicate a leaking inlet manifold.PCV Valve:
I fitted this pipe over the dipstick tube for now and capped it off with a bolt, Its not completely air tight and tomorrow i will hopefully replace it with the correct type.
Here is the oil filler cap with a breather pipe coming off and going to the floor..I would of thought this would of helped alleviate any undue pressure?
mrzigazaga said:
No suction...This does also indicate a leaking inlet manifold.
Someone with a norm asp Cologne needs to do the same check. Bonus points if someone with an SC Cologne can test.mrzigazaga said:
Here is the oil filler cap with a breather pipe coming off and going to the floor..I would of thought this would of helped alleviate any undue pressure?
Cheers for the advice, Its a little over my head though TBH, Unless i was to know what the CCP should be and then test with relevant gauges..I know that the set-up i have as regards to the blower fitment is as it was designed by Power engineering on the sierra 2.8i 4x4..The whole principal was that it would run on a stock bog standard V6 cologne with only a modified fuel pressure reg..A distributor with a boost vacuum diaphragm and slightly different spark plugs, All of which i have fitted, Im hoping that i may be worrying over nothing as the dipstick..(Rodney) was leaking as the metal cap had snapped off its fixing and was rattling about and i had to put some fuel hose over the metal puller to keep the cap near to where it should be..I was going to see if i could find the type that was in the later sierra's which had a rubber type bung fitment..Or get one made similar to the one that a rather nice blue 280i had at this years fest...I will investigate it a little further though as tomorrow i will be able to test what you suggested with a non modded cologne against mine..Cheers...Ziga
Edited by mrzigazaga on Monday 26th August 22:23
When you are running part throttle openings you'll be below atmosperic on the plenum for sure.
For example mine only starts giving any boost at all above maybe 80% open and there is significant drop in boost below 95% open.
So if your crankcase breather is still being fed to the plenum, for most of the time it'll be negative. The only problem comes under full power acceleration the boost will push the plenum positive, so maybe you could try a one-way valve in between?
On the V8 versions there's a breather tube going to near the throttle butterfly but before the blower, which avoids this problem, that might be another way out?
For example mine only starts giving any boost at all above maybe 80% open and there is significant drop in boost below 95% open.
So if your crankcase breather is still being fed to the plenum, for most of the time it'll be negative. The only problem comes under full power acceleration the boost will push the plenum positive, so maybe you could try a one-way valve in between?
On the V8 versions there's a breather tube going to near the throttle butterfly but before the blower, which avoids this problem, that might be another way out?
Mark,
You do not need a guage.
You need to re route the hose to intake side on your new air set up.
A PCV cannot release excess pressure if it has a higher pressure on the the other side.
Non supercharged/non turbo.
Basically the excess CCP is released into the intake side where there is normally a vacuum which assists the PCV. That's how it works!
Your blower is running at a postive pressure (obviously)and keeping the PCV closed, BUT on the other side of the blower there will be a vacuum........That is where you must route your hose from the PCV (intake side)
You have to give your PCV a sporting chance
As stated before.....DO NOT run the car with the CCP blocked.
Or of course you could go the whole hog and fit a scavenger pump (I'm gonna regret suggesting that)
You do not need a guage.
You need to re route the hose to intake side on your new air set up.
A PCV cannot release excess pressure if it has a higher pressure on the the other side.
Non supercharged/non turbo.
Basically the excess CCP is released into the intake side where there is normally a vacuum which assists the PCV. That's how it works!
Your blower is running at a postive pressure (obviously)and keeping the PCV closed, BUT on the other side of the blower there will be a vacuum........That is where you must route your hose from the PCV (intake side)
You have to give your PCV a sporting chance
As stated before.....DO NOT run the car with the CCP blocked.
Or of course you could go the whole hog and fit a scavenger pump (I'm gonna regret suggesting that)
So could i run the oil filler cap breather to the airbox?..I have a fitting that was fitted to do just this but it means that the oily warm air is after the air filter and will be going through the supercharger pre-plenum..
The oil filler breather pipe was due to me changing the cap to that type and wasnt originally set up that way..The original airbox didnt have this function.
Its the soft looking silicone pipe with the elbow inserted which is capped off.
The supercharger was designed to run on an atmospheric breather according to Power engineering..The ford garage connected the breather from the cap to the airbox and when the engine was revved blue smoke came out of the N/S tailpipe, It was subsequently routed to the floor.
Have i a problem or is it just where the dipstick was not sealing properly and letting oil passed..I dont want to start messing about with the routing of CCP if i dont need to??...Cheers...Ziga
The oil filler breather pipe was due to me changing the cap to that type and wasnt originally set up that way..The original airbox didnt have this function.
Its the soft looking silicone pipe with the elbow inserted which is capped off.
The supercharger was designed to run on an atmospheric breather according to Power engineering..The ford garage connected the breather from the cap to the airbox and when the engine was revved blue smoke came out of the N/S tailpipe, It was subsequently routed to the floor.
Have i a problem or is it just where the dipstick was not sealing properly and letting oil passed..I dont want to start messing about with the routing of CCP if i dont need to??...Cheers...Ziga
Normally aspirated car.
The plenum will be negative pressure.
Your plenum will be positive pressure due to blower pushing in 4 or 5 psi.
Your neg pressure will be before the supercharger.
Your piston ring blow by should not be excessive with your low rate of push.
So.... a regular 280 has two breathers
from the back of the A bank to the plenum and one from the B side to Atmosphere in your case South London.
The flow goes from Atmosphere to B then to A and out. (Back to be re burnt) either direct to plenum or via a restrictor valve and maybe even thru a carbon canister but eventually it will get back to the plenum.
You should not have any pipe or hose from the A side going to your plenum because your plenum has postive pressure because you have a supercharger.
I think your car is early so I don't know exactly what you have, also US and UK cars do differ but the basic theory of lower crankcase pressure is the same.
So...the A side hose needs to be removed from the plenum. Plenum hole blocked. That hose is "the out" from the crankcase.
Routing this somewhere "early" in the intake system would not cause smoke from one bank or one exhaust because your plenum serves both banks equally.
That is another issue, although it could be related, possibly higher upper pressure on one side due to incorrect flow in emission vent system.
I'm not sure I have explained this well
, but try to understand how it works sans supercharger then it will very quickly become apparent why it cannot breath now.
The plenum will be negative pressure.
Your plenum will be positive pressure due to blower pushing in 4 or 5 psi.
Your neg pressure will be before the supercharger.
Your piston ring blow by should not be excessive with your low rate of push.
So.... a regular 280 has two breathers
from the back of the A bank to the plenum and one from the B side to Atmosphere in your case South London.
The flow goes from Atmosphere to B then to A and out. (Back to be re burnt) either direct to plenum or via a restrictor valve and maybe even thru a carbon canister but eventually it will get back to the plenum.
You should not have any pipe or hose from the A side going to your plenum because your plenum has postive pressure because you have a supercharger.
I think your car is early so I don't know exactly what you have, also US and UK cars do differ but the basic theory of lower crankcase pressure is the same.
So...the A side hose needs to be removed from the plenum. Plenum hole blocked. That hose is "the out" from the crankcase.
Routing this somewhere "early" in the intake system would not cause smoke from one bank or one exhaust because your plenum serves both banks equally.
That is another issue, although it could be related, possibly higher upper pressure on one side due to incorrect flow in emission vent system.
I'm not sure I have explained this well
, but try to understand how it works sans supercharger then it will very quickly become apparent why it cannot breath now.Hi Jeff..Thanks for that..So i need to blank off the PCV valve pipe from the plenum..And then re-route the feed to the intake..i:e the airbox even if it is post K&N?..Do i leave the PCV valve on the other end in the grommet of the O/S rocker cover..(UK)...Cheers..Ziga
Could i use a catch tank?
Could i use a catch tank?
On the V6 Essex turbo, the PCV is just the shell with no internals, and both rocker feed back into the turbo intake under the air filter...that said, early versions with 3.45 differentials have the problem of oil spraying around the crank case and this feeds up the dip stick onto the exhaust at high RPM and the only cure is a re design of the sump baffles or diff ratio change.
Adrian@
Adrian@
Adrian@ said:
On the V6 Essex turbo, the PCV is just the shell with no internals, and both rocker feed back into the turbo intake under the air filter...that said, early versions with 3.45 differentials have the problem of oil spraying around the crank case and this feeds up the dip stick onto the exhaust at high RPM and the only cure is a re design of the sump baffles or diff ratio change.
Adrian@
Cheers for that bit of info, It was suggested as regards to the turbo technics that thats how the crankcase breathing was re-routed however it has been suggested that it would be best after the throttle body or use a filtered catch tank...ZigaAdrian@
V8 Fettler said:
Zig, any info from power engineering? If you do tap into the atmosphere side of the supercharger then need to ensure that the vacuum is not too great, risk of drawing engine oil into inlet (lots of smoke!).
Hi Mate..I spoke to power engineering this morning and they said a catch tank would probably be better and just keep an eye on how much it collects which shouldnt be much as it should only be an oily mist..It was suggested that i use a bailey's motorsport catch tank and plumb the feed from the rocker into one end and the breather from the filler cap to the other, It needs to scavenge..I had an old 1000cc harley that had a scavenger type system, Looks like its come back to haunt me..lol...It does make more sense now...Cheers..ZigaGassing Station | Wedges | Top of Page | What's New | My Stuff