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DannyR34

Oil dipstick question

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why is it after every spirited drive, I come home and find the dipstick has popped up?

I am using a catch can off the rocker cover, then the other side of catch can is simply vented to air via filter (not plumbed into air box)

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Could also possibly be blow by/shot valve stem seals, mine used to do it but never bothered doing any investigating, just put a spring off the bracket to the dipstick so it could pop up to relieve pressure but not stay up and spray oil everywhere

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#1 reason is you have no vacuume source to suck the crank case pressure into your catch can. #2 reason is the "o" ring on your dipstick is old and has compressed/shrunk making it easier to pop out.

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Replaced your PCV?

no I haven't touched it.

 

#1 reason is you have no vacuume source to suck the crank case pressure into your catch can. #2 reason is the "o" ring on your dipstick is old and has compressed/shrunk making it easier to pop out.

 

It could be the "o" ring.

Otherwise I do have a vac source through the catch can via the filter.

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It gets its vac source from the intake plenum correct?

which is hooked up correctly etc.

 

I should add the problem only arise after tuning

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the idea is for your intake pipe to suck the pressure out, which from your pic it doesn't look like you're doing, correct me if im wrong

 

i dont use a catch can cos ive never seen oil come out of that t-piece on the rocker cover ever

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Vented catch can = no vacuum.

 

Vacuum source is from the intake...

 

Otherwise maybe your tuner set your injector duty cycle to blow, instead of vacuum. Probably not though.

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the idea is for your intake pipe to suck the pressure out, which from your pic it doesn't look like you're doing, correct me if im wrong

 

i dont use a catch can cos ive never seen oil come out of that t-piece on the rocker cover ever

 

Correct, I'm not doing that because oil does come out of that T piece, very small amours and I don't want that oil going into my intake...

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I thought air path is intake into rocker cover, through PVC into intake manifold.

 

However with catch can not plumbed to intake it won't have as much vacuum as normal in the crank case. However flow path is not affected. Also you are getting unmetered air into the intake.

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It gets its vac source from the intake plenum correct?

which is hooked up correctly etc.

 

I should add the problem only arise after tuning

 

only when the engine is under light load or a vacuum state once its loaded and making boost and pcv valve is shut all the crankcase pressure exits through one fitting on the passenger side of the rocker

 

the final stages of the while we were ironing out the few small humps in the afrs and atfer 30 + ramp tests the dip stick remained in place

 

you had your catch can connected to one end on the T on the rocker and the other hose from the can to the back of the engine block which wasn't really doing anything

the other end off the T that usually goes to the intake of the turbo was just vented to the atmosphere and the dipstick was happy

 

so if you are now running that to the catch can and one fitting on the catch can venting to atmosphere and the dip stick pops up it means your new configuration is to restrictive and those cheap generic cans usually have small fittings

 

A 20 year old engine with mods and boost will naturally have some blow by

 

I suspect the problem came about once changes were made

 

if we make a custom can with the right shape to fit in the bay

 

Ideally -10 fittings and the rocker would need to be modified

 

I wouldn't send those oil fumes back into the engines intake as it can lead to detonation and putting a hook over the dipstick will keep it in place but you now have a crankcase with positive pressure with a 20 year old engine that pressure will certainly push excessive oil up past the rings once again causing detonation

 

either turn boost down or alleviate pressure with mods to rocker and catch can

 

I've been through this with customers cars and even my own cars those are the 2 affordable options

 

more expensive options are vacuum pumps or exhaust driven venturi nozzle fittings

 

I 'm experimenting with the vibrant exhaust driven vacuum nozzle , angle and placement has to be perfect for maximum evacuation(suction)they are reported to work well with N/A engines but I'm skeptical whether it will be sufficient when being used on a turbo engine.

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I had this problem as well on my sr. Ended up being the worn o ring and because the tube is mounted to the coolant neck it will naturally vibrate itself out! I used heatshrink over the o ring makin it firm but not too tight and no problems anymore! Upping the boost an playing with your afr's could cause more crank pressure and thus help loosen that dipstick

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