Negative crankcase pressure ?
#1
Too many posts.. I need a life!!
Thread Starter
Negative crankcase pressure ?
I Know ive mentioned this before,,whats everyone's opinion on this.
Has anyone ever done this to a yb or any other engine.I've been told its nothing but benificial to do.It can give you more bhp(apparently),and stop those nigily oil leaks,and stop oil from seeping down the guides.
The reason it interests me ,is the guides side of it,my engine tilts slightly forward,and the oil sits at the front of the head,and is finding its way into the inlet after a long while of ticking over,mot a major problem,but it bugs me.
I await your comments,good or bad
Has anyone ever done this to a yb or any other engine.I've been told its nothing but benificial to do.It can give you more bhp(apparently),and stop those nigily oil leaks,and stop oil from seeping down the guides.
The reason it interests me ,is the guides side of it,my engine tilts slightly forward,and the oil sits at the front of the head,and is finding its way into the inlet after a long while of ticking over,mot a major problem,but it bugs me.
I await your comments,good or bad
#2
PassionFord Regular
Isn`t the only way you can do this dry sumping?
I`m going dry sump on my YB powered Westfield. It`s not cheap at Circa 3K though but the way I look at it it`s an insurance.
I`m going dry sump on my YB powered Westfield. It`s not cheap at Circa 3K though but the way I look at it it`s an insurance.
#3
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#4
PassionFord Regular
That`s a very valid point Mark! ECU is/will be Motec M400 so I presume, without talking to engine builder that can be done easily on an oil pressure switch/sender.
When you try and solve one problem, three more arise!
#5
PassionFord Post Whore!!
Mark
#6
PassionFord Regular
Thanks Mark, always helpful.
This engine build can be measured by ice age, I`ve told myself I`ll not be getting it back until next summer now.
#8
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#9
PassionFord Regular
Probably not, both would lunch an engine.
But you'd just continue driving if the dry sump pump belt came off at high revs because you wouldn't hear a buzzer/be able to stop in time to save the engine.
Why not have a safety built in if its easy to do?
But you'd just continue driving if the dry sump pump belt came off at high revs because you wouldn't hear a buzzer/be able to stop in time to save the engine.
Why not have a safety built in if its easy to do?
#11
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Mark
#12
I've found that life I needed.. It's HERE!!
Snapped belt are rare unless you twist it to check tension which can snap the cords inside
Or a bit of engine goes through it then the belt goes and takes all the blame for one mangled engine
Belts jumping off is mainly due to poorly aligned pump
In relation to pulleys
But most kits have one pulley with belt rings
Oil presure cut off and start up is a must
But start up does not need to be as high as the cut off
Negative presure is a good thing and helps in a few ways
You will always get blow by on a turbo engine while it's on boost
But that said when you are at lower revs or off boost neg presure will be
Helping
For neg presure you need to sort the breathers to work
Or it will be as usefull as a fart in a thunder storm
Or a bit of engine goes through it then the belt goes and takes all the blame for one mangled engine
Belts jumping off is mainly due to poorly aligned pump
In relation to pulleys
But most kits have one pulley with belt rings
Oil presure cut off and start up is a must
But start up does not need to be as high as the cut off
Negative presure is a good thing and helps in a few ways
You will always get blow by on a turbo engine while it's on boost
But that said when you are at lower revs or off boost neg presure will be
Helping
For neg presure you need to sort the breathers to work
Or it will be as usefull as a fart in a thunder storm
#13
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Negative crankcase pressure ?
Don't want to sound daft but what is negative pressure your all
Talking about? Being a mechanic I thought I may have heard about it before but never heard of it before
Talking about? Being a mechanic I thought I may have heard about it before but never heard of it before
#15
Too many posts.. I need a life!!
Thread Starter
#16
Too many posts.. I need a life!!
Thread Starter
I was thinking of using a smog pump or maybe a brake servo pump,but I would probably have to control the vacuum somehow with the servo pump .
#19
Belt failures will be rare with a good dry sump, but when it's so easy to add a safety it's just stupid not to.
Belt failures with cam drives are rare...but if they fail, the engine will stop anyway. There's fuck all you can do about that. No comparison really.
You do not need a dry sump to achieve vacuum in the crankcase. But if you want it when the engine is under load, you will need a vacuum pump and proper oil/air separation systems.
OEM will use a system that achieves some airflow/vac in the crankcase under light loads...ie the PCV system. It will be very light vac at best, but they like fresh air moving through the crankcase via this setup, which in turn gets drawn into the inlet and burnt.
If oil is gather in part of the head due to poor installation angles, there is maybe some way you can grind relief channels to allow the oil to drain away from these areas
And new valve stem oil seals might help
Belt failures with cam drives are rare...but if they fail, the engine will stop anyway. There's fuck all you can do about that. No comparison really.
You do not need a dry sump to achieve vacuum in the crankcase. But if you want it when the engine is under load, you will need a vacuum pump and proper oil/air separation systems.
OEM will use a system that achieves some airflow/vac in the crankcase under light loads...ie the PCV system. It will be very light vac at best, but they like fresh air moving through the crankcase via this setup, which in turn gets drawn into the inlet and burnt.
If oil is gather in part of the head due to poor installation angles, there is maybe some way you can grind relief channels to allow the oil to drain away from these areas
And new valve stem oil seals might help
Last edited by stevieturbo; 31-07-2015 at 12:08 PM.
#20
Advanced PassionFord User
Stick your finger over the dipstick tube and if it sucks it on it's got negative crankcase pressure. The way I understand it, blow by from the rings pressurises the sump/crankcase. On a newer engine you have very little blowby and this combined with a good breather system gives you negative crankcase pressure because the suction on the inlet side of the breather system overcomes any build up of crankcase pressure. As an engine slowly wears crankcase pressure increases and you slowly go from negative to positive (ie pressurised) pressure. On a very worn engine (or one with a blocked breather system) you can start blowing the dipstick out.
#22
Too many posts.. I need a life!!
Thread Starter
Belt failures will be rare with a good dry sump, but when it's so easy to add a safety it's just stupid not to.
Belt failures with cam drives are rare...but if they fail, the engine will stop anyway. There's fuck all you can do about that. No comparison really.
You do not need a dry sump to achieve vacuum in the crankcase. But if you want it when the engine is under load, you will need a vacuum pump and proper oil/air separation systems.
OEM will use a system that achieves some airflow/vac in the crankcase under light loads...ie the PCV system. It will be very light vac at best, but they like fresh air moving through the crankcase via this setup, which in turn gets drawn into the inlet and burnt.
If oil is gather in part of the head due to poor installation angles, there is maybe some way you can grind relief channels to allow the oil to drain away from these areas
And new valve stem oil seals might help
Belt failures with cam drives are rare...but if they fail, the engine will stop anyway. There's fuck all you can do about that. No comparison really.
You do not need a dry sump to achieve vacuum in the crankcase. But if you want it when the engine is under load, you will need a vacuum pump and proper oil/air separation systems.
OEM will use a system that achieves some airflow/vac in the crankcase under light loads...ie the PCV system. It will be very light vac at best, but they like fresh air moving through the crankcase via this setup, which in turn gets drawn into the inlet and burnt.
If oil is gather in part of the head due to poor installation angles, there is maybe some way you can grind relief channels to allow the oil to drain away from these areas
And new valve stem oil seals might help
Ive tried new stem seals.I was looking at getting a drain welded into the front of the head,going through the water jacket,but i'm getting fed up with taking the thing apart.
To be honest,its not really causing any problem,it just bugs me its not 100% right.
I'm want to go on a 5000 mile spanish tour next year and i want it right.
I've been looking at brake servo pumps,driven of the engine,and basically linking it up with a bailey breather setup,and an extra separater,but i'm not sure how the air/vapour would affect the pump,the rover one i'm looking at looks like it has a rubber diaphram,and i think it would perish it over time.
Last edited by mattman1234; 01-08-2015 at 09:39 AM.
#25
I think its bad design,the way the diff is mounted,to align the prop flanges the engine has to be tilted slightly forwards.
Ive tried new stem seals.I was looking at getting a drain welded into the front of the head,going through the water jacket,but i'm getting fed up with taking the thing apart.
To be honest,its not really causing any problem,it just bugs me its not 100% right.
I'm want to go on a 5000 mile spanish tour next year and i want it right.
I've been looking at brake servo pumps,driven of the engine,and basically linking it up with a bailey breather setup,and an extra separater,but i'm not sure how the air/vapour would affect the pump,the rover one i'm looking at looks like it has a rubber diaphram,and i think it would perish it over time.
Ive tried new stem seals.I was looking at getting a drain welded into the front of the head,going through the water jacket,but i'm getting fed up with taking the thing apart.
To be honest,its not really causing any problem,it just bugs me its not 100% right.
I'm want to go on a 5000 mile spanish tour next year and i want it right.
I've been looking at brake servo pumps,driven of the engine,and basically linking it up with a bailey breather setup,and an extra separater,but i'm not sure how the air/vapour would affect the pump,the rover one i'm looking at looks like it has a rubber diaphram,and i think it would perish it over time.
But as said, you need to have proper oil/air separation systems in place so you dont suck oil out too
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