Tappet Pressure how much is too much ?

[Mr Multivalve]

I have a 94 Bluebird as a runaround family car, about 8 months ago I had to get my dizzy replaced because the nissan one died.
That was replaced and about 2 months ago that one died.
I replaced my pcv valve and after the dizzy died the 2nd time I replaced my tappet cover gasket as well. As I was told that oil leaking from the tappet cover had gotten into the replacement dizzy and killed it.

The auto elec that replaced my dizzy said he thought I had too much pressure building up under my tapped cover, he said when he took the oil lid off oil would squirt up. So he said I must have some other problem with the motor causing it to build up too much pressure under the tappet cover, then causing oil to be forced through my distributor seal. There that being the cause for my first dizzy to die apart from old age.
I would think that oil would definitely squirt up as when the motor is running and you take the oil lid off their are cam shafts spinning thousands of time per minute that would throw oil around abit underneath their anyway.
My bluebird has been reliable, motor is strong, blows no smoke so I am not sure what he is on about.

My question is:
Is there a pressure build up under your tappet cover when you are running your motor? If so what is an acceptable limit?
One thing that is confusing to me is that the tappet cover actually has a breather pipe that vents air back into the intake, this being the case how could excess pressure be building up if their is a breather pipe that releases any pressure, if it is theoretically building up.

I quized my mechanic about this and he said it sounded like the auto elec was a wanker and spoke a bit of shit, which after dealing with him I can only agree.

Sorry for the long rant just my bluebird has now once again started to behave irratically and I am pretty sure it has something to do with the spark whether it is the dizzy dying again or one of the leads. And I will be pretty pissed off if the dizzy dies again on me.

Thanks, any ideas or personal experiences would be appreciated.

P.S. Isn't it funny how the week after I am made redundant the family car starts to misbehave, my dvd burner only 18months old just dies, and my brass button clutch on my 1G Corona is playing up. *sigh* Could be worse I guess...

[love ke70]

the breather comes from the crank doesnt it?
just passes up thru the head cam cover but is seperate?
i thought so anyway
there should be oil, but there shouldnt be pressure

[Mr Multivalve]

There is a pcv (positive crankcase ventilation) valve which stops pressure build up, and also a breather pipe on the tappet cover. Can't remember if the pcv valve releases it into the head or somewhere else. Had the schematic diagram for it somewhere.

[30psi 4agte]

Whats the engine cond like?

Excess crank case pressure can be from worn rings and the combustion gases escaping past the rings into the crank case pressure.

May pay to give it a comp test to rule this cause out.

[oldcorollas]

and clean out the breather pipes and PCV valve.

[Mr Multivalve]

The engine appears to be in good nick, never had any major trouble with it, blows no smoke and does not miss a beat, appart from the electrical trouble.

I had and pcv valve replaced and the breather pipe was checked and is clear.

Goes to the mechanic tomorrow, could be a clogged fuel filter

Hopefully it is a cheap problem.

I was planning on going to the auctions this week as well darn it

[30psi 4agte]

The PCV is around the right way????

[kingmick]

you could find its chocked up with oil crud inside the rocker covers!

[slide86]

Goes to the mechanic tomorrow, could be a clogged fuel filter

i dont think a blocked fuel filter will cause crank case build up.....

If the pressure gets too great, its likely to blow the dipstick out or something similar. really if the PCV is working correctly then you shouldnt get a build up in pressure that great. 30 pound has a good point tho.....is the PCV round the right way. It may be working correctly when its outta the car, but if you put it in backwards, then it wont let any gas back into the inlet!

[Mr Multivalve]

I certainly hope that the pvc valve is around the right way, I paid a qualified mechanic to put it in there, I could always ask the mechanic to check for me.
The dipstick has not blown out or anything like it, I am just trying to think of how I could find out for sure that it is building up pressure, as it seems to be a very uncommon problem. Any mechanics I have spoken to have said it is very unlikely

I checked under the tappet cover when I had it off to replace the tappet cover gasket and it look ok to me.

I was not stating that a fuel filter blockage could be causing the pressure build up but that it may be the cause of my car starting to run rough, after I got fuel I noticed it was running worse but cannot be sure untill it gets diagnosed.
I am just hoping it is something cheap to fix

Thanks

[love ke70]

have you actually taken the oil cap filler thingy out with the engine running?
i seriously doubt oil pisses out when you open it :S

[Mr Multivalve]

Well when I unscrew the cap when the motor is running some oil does spit out but it seems to be, from the cams spinning like buggery. I would have thought this was normal

[love ke70]

my 1g doesnt do it. but i spose it depends on where the hole is. i wouldnt say there is anything wrong in that regard

[bansheebuzz]

did you put a new dizzy in or 2nd hand from the wreckers? That model nissan has a common problem with the dizzys filling up with oil due to dizzy seal failure. There is no way known i would put a 2nd hand one in a car.

I have had numerous of these cars come into my shop with that problem

[Mr Multivalve]

I spent the money and got a aftermarket one, a brand new one, the wreckers wanted close to what one of those cost anyways $500+

I did some research on it as well and it happens alot to the yank version of the bluebird the Altima.

Mechanic had a look at it today and said it appeared that the no spark was getting to no.4 cylinder from the dizzy.
Too it to the autoelec who said I could try cleaning under the dizzy cap and gently emryboard the contacts which I did and funnily enough it seems to be running spot on now But it even started running a bit better after the mechanic looked at it, a bit weird I reckon.
Maybe my bluebird is a female and needed to feel like someone was paying it attention then wala it stopped it's complaining. Darn I better buy it some makeup and put it on(I guess that to a car would be called wash'n'wax)

Well I guess I had better not knock it now that it is running great.