Engin PCV System and Induction systems

[Malfunction]

Howdie all,

Just thought i would pop up this info i have just gleamed last night and tried. I have a focus type Induction kit fitted to my sei and think it is ace and love the noise and look but suffer from the common problem of the engine running hot sometimes. After a bit of investigation i have found the common problem for this and it is the Engine PCV system!

Never even herd of it till last night after a chat with a very clued up tuner. :worship:

Basically i like most removed the standard oil breather from the rocker cover and piped in a straight pip from the breather to the inlet pip on the focus kit. Then made a short pip from the intake manifold nipple to the hole in the focus kit 90% bend.

This however means that the blow by caused by induction in every engine is not sucked out correctly by the inlet manifold. Then the carbon in the blow bye creates excess heat in the engine and drops the carbon deposits in it also into your engine oil!

I have replaced the standard breather pip now fitted correctly to the inlet manifold ( Blocked off hole in 90% bend with a bolt) and add an extra bit of larger pip to reach the focus kit.

Hay i tell you now it does make a difference the engine is running smoother and cooler, but the focus kit does not make as much of a roar now but ho hum i can live with that if the engine is working better and i am no longer damaging it basically.:slayer:

Apparently this affects the map sensor also as not all the gases are now being passed through it by induction? :bang:
Hence possibly the better running as my friend recons the old setup would cause the CDI to over fuel the system which will also cause over heating ? :bang:

Just thought i would share this info as not seen anything about the PCV system on here, if it is apologies i missed it and this is a repeat.

 

[Eklipze3k]

It's because we don't call it PCV, we call it crankcase breather, that's why you couldn't find anything.

 

[Malfunction]

It's because we don't call it PCV, we call it crankcase breather, that's why you couldn't find anything.

I have looked at everything that had crankcase breather or induction kit on it an non mentioned you need to keep the inlet manifold connection and why? One even said it was ok to just block it off?

Oh well sorted now

 

[fingers99]

Howdie all,

Just thought i would pop up this info i have just gleamed last night and tried. I have a focus type Induction kit fitted to my sei and think it is ace and love the noise and look but suffer from the common problem of the engine running hot sometimes. After a bit of investigation i have found the common problem for this and it is the Engine PCV system!

The Sei does not, and never did, have a PCV (Positive Crancase Ventilation) system. A quick look up on Google will reveal as much, let alone consulting the Seicento Technical Manual in the Downloads section.

Never even herd of it till last night after a chat with a very clued up tuner. :worship:

Well, not that clued up if he thinks that a Sei has a PVC system!

Basically i like most removed the standard oil breather from the rocker cover and piped in a straight pip from the breather to the inlet pip on the focus kit. Then made a short pip from the intake manifold nipple to the hole in the focus kit 90% bend.

I don't understand this bit!

This however means that the blow by caused by induction in every engine is not sucked out correctly by the inlet manifold. Then the carbon in the blow bye creates excess heat in the engine and drops the carbon deposits in it also into your engine oil!

There isn't carbon in the sense you mean in the blow-by gasses, which are not caused by induction(?) anyway. Blow by gases are the result of an imperfect seal between the piston rings and cylinder bore. They're made up of moisture, unburnt petrol, and oil, all as vapour. Sure, there's carbon in there, but then, petrol and oil are hydrocarbons. You contain a fair bit of carbon, too.

I have replaced the standard breather pip now fitted correctly to the inlet manifold ( Blocked off hole in 90% bend with a bolt) and add an extra bit of larger pip to reach the focus kit.

I don't understand this bit either.

Hay i tell you now it does make a difference the engine is running smoother and cooler, but the focus kit does not make as much of a roar now but ho hum i can live with that if the engine is working better and i am no longer damaging it basically.:slayer:

And the evidence that the engine is running cooler is? If blow by gases are excessive, chances are the rings are shot. This can cause detonation in highly tuned (and especially turbocharged) engines, and might lead to rough running.

Apparently this affects the map sensor also as not all the gases are now being passed through it by induction? :bang:

One of you is confusing a MAP sensor with a MAF sensor. The Sei uses a MAP sensor which measures pressure, the MAF sensor measures airflow. Air which doesn't go through a MAF sensor means that the MAF can't "count" it so the engine may run rich. This doesn't affect MAP sensors at all.

Hence possibly the better running as my friend recons the old setup would cause the CDI to over fuel the system which will also cause over heating ? :bang:

The Sei does not use CDI (Capacitor Discharge Ignition). Overfuelling generally causes an engine to run cooler, rather than hotter (unburnt fuel acts as a coolant) -- Alfa Romeo used this to good (but expensive) effect in their supercharged GP cars in the early 50s.

One, or both, of you has got it so completely wrong that I had to correct it. There's a lot of misinformation out there, but it's rare to see so much of it heaped together in one bite!

 

[Malfunction]

Fingers99 wow thanks for the above looks like i am way off

Can you advise what the pipe to the inlet manifold from the rocker breather is for then?

 

[fingers99]

Put up a picture and I'll do my best.

Good read on most of this stuff are any of the A Graham Bell 4 stroke books, although they don't deal specifically with the Sei.

 

[Malfunction]

Put up a picture and I'll do my best.

Good read on most of this stuff are any of the A Graham Bell 4 stroke books, although they don't deal specifically with the Sei.

Finger99 found this which explains it better also

The Sce would appear to have the straight suction pipe directly into the inlet manifold like in the very bottom section under Alternatives. And you are quite correct no PCV valve fitted.

Every days a school day as they say

am going to leave the standard pipe on now till i get an oil catch can fitted to catch all the gunk that was building up inside the breather pipe, then just blank off the inlet manifold breather intake as it must weaken the fuel air mix as stated above.