Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

What Is an Oil Catch Can, and Why Doesn't Every Car Have One?

Deuce

Super Stock
Joined
Feb 5, 2012
Messages
2,468
Reaction score
926
Points
113
Location
Meremere Dragway (as often as possible)
Members Ride
'94 VR SS V8
Next time you have the bonnet up and the engine running remove the engine oil filler cap and listen to the revs rise.
But what does this rev change mean? Increased revs is released pressure and easier on engine therefore needs bigger breathers?? Drop in revs means vacuum and pcv is working great??

I've seen engines do this before. But I'm pretty sure my 355 does not care if the filler cap is on or off. Revs just sit the same irrespective of cap on/off.
 

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,471
Reaction score
3,599
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
^^ but it doesn’t hurt it.
Maybe not in the short term but long term?

Like I said before, plenty of evidence on this forum that long term it does cause issues. Maybe more modern engine designs have better PCV systems but certainly not the older generation which includes ecotec/L67, Holden 304 as well as the LS1 engines which are renowned for filling the intake with oil. I've worked on a few engines in my time and I don't much like all the gunk that can accumulate on the intake system. EFI is the saving grace for the PCV system is it effectively washes the intake valve but anything carburated or TBI like my early V8 certainly does not like the oil on the valves.


But what does this rev change mean? Increased revs is released pressure and easier on engine therefore needs bigger breathers?? Drop in revs means vacuum and pcv is working great??

I've seen engines do this before. But I'm pretty sure my 355 does not care if the filler cap is on or off. Revs just sit the same irrespective of cap on/off.
Engine filler cap off effectively creates a vacuum leak (via the PCV system). Yours been MAP tuned it's not quiet so bad but with MAF based systems all of a sudden you are allowing a fair bit of un-metered air into the system.
 

Pollushon

Boost gives me a bar....
Joined
Nov 9, 2012
Messages
2,098
Reaction score
147
Points
63
Location
Canberra
Members Ride
VY SS
My combustion chambers after 220k. The carbon buildup was giving me extra compression :)

Whilst the motor ran fine, dumping boost on to this would have probably resulted in tears. Nothing will stop carbon, it's the nature of the beast but oil getting into the chamber exacerbates the issue. Besides the PCV I had some dead valve seals. End result was exhaust valves that wouldn't seal.

All in all not too awful for the kms. I gave the valve on the left a grind just to confirm my theory it could not be saved. EV8 stainless are a better choice for boost anyway.

pic25062017125152097~01~01.jpg


pic25062017125156170.jpg


pic24072017231038511.jpg
 

Pollushon

Boost gives me a bar....
Joined
Nov 9, 2012
Messages
2,098
Reaction score
147
Points
63
Location
Canberra
Members Ride
VY SS
@Pollushon that looks disgusting, have you thought about using alcohol (in the car)? I mean eFlex and decent synthetic like GL-5 oil doesn't do that.
Hahaha, funny you should mention that, yes I absolutely will be using alcohol in the form of methanol as part of the water injection kit. I'd convert to straight E85 if I could but Canberra has two bowsers and she's my daily. Apparently after the tune on Thursday my combustion chambers will stay shiny and clean forever more :)

She cleaned up okay
pic02072017145730702.jpg
 

VS_Pete

Donating Member
Joined
Dec 23, 2007
Messages
4,644
Reaction score
11,773
Points
113
Location
Brisbane
Members Ride
VE II SV6 MY12 SPORTWAGON
@Pollushon that looks disgusting, have you thought about using alcohol (in the car)? I mean eFlex and decent synthetic like GL-5 oil doesn't do that. Same effect with eight (or nine) alky injectors re cooling and knock.
Did you mean Penrite ENVIRO+ GF-5 5W-30?
I`m going to change to the above.
 

07GTS

Well-Known Member
Joined
Sep 8, 2013
Messages
2,224
Reaction score
673
Points
113
Location
Australia
Members Ride
VEGTS BLOWN E85
i had a issue with a couple valve stem seals going in mine (got pushed up) only found out by removing a spark plug one time and it having oil around it, put a camera into the cylinder and it was blackish where all others from E85 were clean, that also explained the slight difference in 02's bank to bank
 

Mike Litherous

Active Member
Joined
Jan 18, 2016
Messages
276
Reaction score
128
Points
43
Location
Melbourne
Members Ride
VE ssv
Golly gosh.
That looks like more carbon build up than between the legs of the Eurobed old chick.
 
Top