Cranckcase Breather

[Riles]

I have a couple of questions. The first one is: how do valve cover breathers help the cranckcase? I thought the valves were all above the crankcase... how are they linked?

Secondly, is a valve cover breather enough to adequately breathe the crankcase, if I were to plug the hole between the tb and the crankcase?

Lastly, is an overpressurized crankcase the problem when people blow their main seals when they turbo/supercharge?

Thanks!

[imported_admin]

Breathers do not work on the 3.8. Vaporized oil will just pour out like a chimney.

Crankcase overpressurization is a consequence of piston blowby... which is what everyone said my engine was experiencing back when I ran 12 pounds on the stock internals for about 4 months. Turned out everyone was wrong (but back then I believed them).

I wouldn't worry about a breather or crank pressure at all, no matter what the boost. There are other things that would break first.

[black98V6]

<blockquote>quote:</font><hr>Originally posted by Stefan:
Breathers do not work on the 3.8. Vaporized oil will just pour out like a chimney.

Crankcase overpressurization is a consequence of piston blowby... which is what everyone said my engine was experiencing back when I ran 12 pounds on the stock internals for about 4 months. Turned out everyone was wrong (but back then I believed them).

I wouldn't worry about a breather or crank pressure at all, no matter what the boost. There are other things that would break first.<hr></blockquote>


yours was an exhaust issue wasn't it?? something about a hidden restriction at the cat or something like that??

[imported_admin]

Yep, even though I supposedly had a full 3" exhaust there was a section of pipe where the Y-pipe met the cat where it was exactly 2" in diameter. (You couldn't tell from just looking at the outside of the pipes so I never noticed until I gutted my cat over a year later.) Talk about a bottleneck! The backpressure there must have been off the charts, it's no wonder I kept shooting my dipstick no matter what I did to the engine to relieve the pressure. And I paid the people $1400 for that exhaust setup. [img]graemlins/thumbsdown.gif[/img] Classic case of a "performance" shop bending a customer over...

[Perry V]

I've got a breather where my oil cap is..... actually i originally had the entire breather on there, but there would be oil dripping out..... so what i did was..... i sanded down the edges of the oil cap, and drilled a small hole ( a lil' bit bigger than a pencil) in the cap.... and i put the breather on top of the cap......so it vents out a lil' pressure, but not as much as before.....and there's no oil dripping out anymore......plus it makes my engine bay look nicer :D

u think the the drop in pressure might hinder my performance gains at all, i know it is safer to have the breather on, but performance wise do u think i would be losing any power? I'm planning to consistantly hit 7-8psi when i get my blower back from powerdyne... i've got some antislip tape to put on the pulley that should work for a while...i hope.

thanx

[imported_admin]

<blockquote>quote:</font><hr>Originally posted by Perry V:
u think the the drop in pressure might hinder my performance gains at all, i know it is safer to have the breather on, but performance wise do u think i would be losing any power?<hr></blockquote>

How would it hurt your performance? Boost is only inside the cylinders, and as long as your oil pressure is around the middle mark (what, 60 psi?) everything will be lubricated fine.

But how's your oil level? Are you sure there isn't a little bit of vaporized oil coming out, just enough so you don't see it? I've seen some setups with condensors that recirculate the oil--quite complicated. Does yours gradually lose oil or is it steady? Rigging something like yours might be worth looking into, couldn't hurt as long as no oil escapes. [img]smile.gif[/img]

[Perry V]

I've had mine on like that for about a year now with no problems..... even last year before i stored my car away, me and my friend used to race home after university everyday down this long stretch that we have out here ( he's got an '87 GTA) .... anyways we gave our cars a pretty good beating everyday for a solid 30 mins on the way home for about a month and a bit.....and i remember he had some oil loss problems from all the hard driving, and i went and checked mine just to be safe, and was at perfect levels.....i was also running royal purple 5W30 at the time.....

but like i said, it looks cool in the engine bay
;)

[SLOWBRAEATER]

wait, doesnt zzp sell valve cover breathers that will work for our cars?

[imported_admin]

<blockquote>quote:</font><hr>Originally posted by SLOWBRAEATER:
wait, doesnt zzp sell valve cover breathers that will work for our cars?<hr></blockquote>

Define "will work". Will leak?

[Speed]

I'm not sure on the V6s but on the LT1, your poweradder can pressurize the block through the PCV system. On mine, there is a hose that runs from the side of the throttle body to the passenger side valve cover. Also that little check valve isn't incredible at holding boost pressure at bay.

[nocutt]

<blockquote>quote:</font><hr>Originally posted by Speed:
I'm not sure on the V6s but on the LT1, your poweradder can pressurize the block through the PCV system. On mine, there is a hose that runs from the side of the throttle body to the passenger side valve cover. Also that little check valve isn't incredible at holding boost pressure at bay.<hr></blockquote>

The 3800S2 are located in the TB...you take the tb out on the reverse side, drill it, thread it and plug it...then put valve cover breathers @ specified locations on the valve covers or better yet...run a hose at least 1" in diamter to the oil pan and vent...(I think that is the easiest) ;)

[Tiago]

on our 3.8 car it took the boost just fine and we never had any problem with dip stick shooting out or crankcase pressure that we noticed. IT runs the stock exaust manifolds too.

[nocutt]

<blockquote>quote:</font><hr>Originally posted by Tiago:
on our 3.8 car it took the boost just fine and we never had any problem with dip stick shooting out or crankcase pressure that we noticed. IT runs the stock exaust manifolds too.<hr></blockquote>

Then something ain't right somewhere...without blocking the PCV system from psi, you HAVE to put pressure in the crankcase...seriously!

[Tiago]

I did block tthe PVC system behind the throttle body, but that is all.

[nocutt]

<blockquote>quote:</font><hr>Originally posted by Tiago:
I did block tthe PVC system behind the throttle body, but that is all.<hr></blockquote>

The crankcase has to breath...