Could a blown head gasket causes engine blowby?

[lancerevo]

Hello.

I have a b3 engine efi. And recently this week, I noticed that the engine seems not as usual. And it will stall easily. Also, checked the engine and seems that it has blowby. and in the radiator there are air bubbles. Probably a blown head gasket. (recently rebuilt about 5 months ago. New pistons, new rings, new head gasket and valves oil seals etc). My question is could a blown head gasket causes engine blowby from the top cover?

Thank you.

[91_festy_Gl]

Was the head re worked the last time you rebuilt it? Bubbles in the coolant is a deff sign of HG problems though...

[lancerevo]

I admit, I forgot to shave the head, but I cleaned it very well. But could a blown head gasket causes engine blowby? Also to know, I have a vacuum gauge and it shows no effect of a blown head gasket. If it was shot it will fluctuate every time the leak occurs. So the leak is not in the combustion chamber I think. It never overheated also.

[91_festy_Gl]

Hmmm... When you say blow by from the top cover I assume you mean the valve cover? If so are you sure the gasket isnt in need of replaced? Can you tell where the exact point of blow by is comming from?

[lancerevo]

The blow by can only come out of the valve cover (top cover) from the pcv or from the hole of the engine oil cap. The blowby is coming from the valve cover. I can't understand how that happened.

[91_festy_Gl]

Unless the gasket is bad or the rubber garmet the pcv goes into is worn out. Check the valve cover bolts and see if there tight. Most people forget to go back through and check bolts after a rebuild. My BP was using oil until I went through and found my oil pan bolts were loose.

[lancerevo]

There is some chocolate color on the oil filler cap.

[lancerevo]

Any one can answer my question? Could a blown head gasket causes engine blowby from the valve cover?

[perucho]

I guess it is possible. If your head gasket is not sealing the combustion chamber properly, pressurized gases can escape into the block or head (they are connected internally after all). If your engine is not properly vented and your PCV valve is not working, you could end up with built up pressure and nasty deposits indie your engine.
In any case, blowby is from the combustion chamber, either to the valves or the piston rings. If you don't have that, then it's not blowby.
Check your PCV system anyway. Sounds like it may not be working properly. How is your valve cover vented? Ask yourself why is it that the engine is pressurized. The venting system is designed to relieve the interior gases pressure.
Condensation on your oil cap may not be related to a head gasket coolant leak. On my 911 I could see small amounts of foam on the oil cap when the weather was cold and the car was driven short distances. Freaked out the first time but it is very common for those engines under those conditions.

[lancerevo]

Here is my setup. The pcv is deleted. I don't think is a bad setup or should I put the pcv back on?

[perucho]

Bad setup. It's pressurized. You need to be able to remove the gases trapped at the block and the valve cover. There's your problem.

[eurotiva]

Also never remove an aluminum head without shaving it before putting it back on.

[iceracerdude]

Here is my setup. The pcv is deleted. I don't think is a bad setup or should I put the pcv back on?

Your cc setup is bad, congradulations though, you've designed a system (we'll call it NPCV) that has pressurized both the crankcase and vc at the same time while creating an excellent evironment for sludge buildup...just like in those funny commercials! You're those guys!
You need to put the catch-can inline between the pcv valve and the intake plenum, with a very small fresh air inlet breather next to the intake tube at the minimum. The engineers like to take that source of "fresh air" from just after the maf or vaf because it's already been accounted for by the computer.
PCV actually stands for Positive Crankcase Ventilation by the way.
Are you running a turbo set-up? If no, why the catch-can at all?

Also, once I put a head back on, I heat cycle the engine a few times (think around 200 + or- miles of easy grocery runs) then I re-torque the head bolts to 60. You will find some have in fact backed off a little.

[Festiva Time]

Clarification on Blow-By: A health engine will generate a small amount of Blow-By pressure in the valve [Cam] cover. This is fed back into the air intake by both the PCV valve and the short hose from the valve cover to the Air cleaner snorkel (on Carb) or the large plastic intake pipe [to the Throttle Body.]. This small amount will force oil pass poorly sealed valve cover gasket. Large volume of Blow-by comes from the rings letting combustion pressures into the crankcase. Piston rings need to be installed correctly and do not use synethic oil, they won't allow the rings to seat. You may simply need to drive it more, especially at freeway speed, to break the rings in.

[Festiva Time]

You may also need to re-torque the head bolts. It's standard operation. Recheck the intake manifold bolts, too. If your head gasket was the problem, the engine would run rough or not at all.