View Full Version : 16V Engine Breathing Problems
Hi
A question to all you 16V owners out there (and may be useful to ask others at club gti if anyone knows who to ask)
Have any of you noticed small amounts of oil around the oil filler cap on the cam cover and put it down to a knackered oil cap ? - especially noticable after thrashing it.
I suspect this may be due to cam cover pressurisation - many other cars (K-series, Vauxhall 16V, most V8's, metro's etc etc) have cam cover breathers but the VW 16V does not. When thrashed, there is enough pressure buildup in the cam cover to blow oil past the the cap seal (on my engine its here, even with a new cap, on others the pressure relief could be anywhere around the cam cover seal leading to oil leaks).
As an experiment, I found that a Nova oil cap nearly fits the 16V engine (dont do it on the road though as eventually it leaks) and modified the cap with some tubes to make a breather cap. Then ran the engine in the garage. Even at idle, there is considerable air pressure pulsing from the tube so this must be very significant at 7K rpm !
Are now in process of fitting a breather system to the cam cover which will T into the crankcase breather. This is made less easy as it appears the cam cover is made out of cheese !
Carn't think why VW never did this ??? Anyone ever seem similar devices on VW 16V race / rally cars ?
Cheers
Rob
ibizacupra
08-04-2002, 13:41
Hey Rob.
Mine, as you know does the same thing.
I did see a magazine (old one) where there was a 16v turbo motor with a breather fitted to the rocker cover. Strangely though, its was mounted on the chain drive end... where most of the oil slops about. I would'nt put my breather there personally, but the opposite side.
regards
Bill
mine used to leak like a seive rob,changed the cap and now its much better,but i had probs with my cam cover too, it too leaked and later found out at avemefist that it was loose:eek:
Originally posted by ibizacupra
Hey Rob.
Mine, as you know does the same thing.
I did see a magazine (old one) where there was a 16v turbo motor with a breather fitted to the rocker cover. Strangely though, its was mounted on the chain drive end... where most of the oil slops about. I would'nt put my breather there personally, but the opposite side.
regards
Bill
Hi Bill
Have drilled a hole at timing belt end of rocker cover between the last middle web and the end of the cover - just enough space, maybe 15mm max. When drilling hole found out that not enough material thickness and quality to tap. Thus, went to local welders to have 7/16 UNF ali welding flange welded on over hole only to be told metal was crap and couldnot be welded - would just breakthrough with arc. Thus, have had welding flange welded to some 6mm ali plate, to increase area to approx 40 x 40mm and are going to use high temp epoxy (max 600C, 300C constant, bond strength 4000psi) to glue it onto the cover. Are in process now.
Still nothing from wilwood.
Cheers
Rob
Originally posted by RobT
Hi Bill
Have drilled a hole at timing belt end of rocker cover between the last middle web and the end of the cover - just enough space, maybe 15mm max. When drilling hole found out that not enough material thickness and quality to tap. Thus, went to local welders to have 7/16 UNF ali welding flange welded on over hole only to be told metal was crap and couldnot be welded - would just breakthrough with arc. Thus, have had welding flange welded to some 6mm ali plate, to increase area to approx 40 x 40mm and are going to use high temp epoxy (max 600C, 300C constant, bond strength 4000psi) to glue it onto the cover. Are in process now.
Still nothing from wilwood.
Cheers
Rob
Well the breather is fitted and there is a small amount of milky / brownish liquid coming out cf what comes out of the crankcase breather. Will see how it goes and if it stops the oil cap leaks.
Cheers
Rob
cordobabrendy
15-04-2002, 16:55
milky brown??? water & oil mix ??? might be a bit of damp getting in rob.
Originally posted by cordobabrendy
milky brown??? water & oil mix ??? might be a bit of damp getting in rob.
Could be a bit of damp - especially since the car is not used daily - this is usual, but its also from products of combustion - burning makes water which mixes with some hot oil vapour = milky brown. There's not much of it really but I've seen similar things many times on race car engines - highly tuned and not used frequently.
And before anyone says it, no the head gasket hasn't gone.
Cheers
Rob
Would you Christmas Eve it? I wonder if my cam cover problem is related.
A while ago, noticed a misfire and had a look at HT lead KVs. Instead of being maxing out at say 14-15 KVs on idle, it was more like 25-30! I reckon it's been like that for some time so I count myself lucky it hasn't wiped out the ECU!
During its service last week, noticed number 4 had a leak around the cam cover seal, just seeping very slightly. Clearing it up, plugs in, fire up, misfire gone, but only to return once oil presence returned. It's having a new gasket and seal kit fitted as I type this (and cam belt + multi-rib belt to be safe).
Is there a design fault or should they generate shite loads of oil pressure up there?
Originally posted by blaklite
Would you Christmas Eve it? I wonder if my cam cover problem is related.
A while ago, noticed a misfire and had a look at HT lead KVs. Instead of being maxing out at say 14-15 KVs on idle, it was more like 25-30! I reckon it's been like that for some time so I count myself lucky it hasn't wiped out the ECU!
During its service last week, noticed number 4 had a leak around the cam cover seal, just seeping very slightly. Clearing it up, plugs in, fire up, misfire gone, but only to return once oil presence returned. It's having a new gasket and seal kit fitted as I type this (and cam belt + multi-rib belt to be safe).
Is there a design fault or should they generate shite loads of oil pressure up there?
last time I fitted the cam cover I was very careful to torque it down even and get all surfaces clean etc - thus, any pressure buildup relieved itself through the cap - the weakpoint, 'blowoff' on my engine. If you have a slightly dodgy seal on the cam cover itself, perhaps this is why it leaked there. My engine used to be 180bhp and was ok, no leaks. Put throttle bodies on it, 216bhp and leaks (Bill B's also with TB's also leaks). I suspect there is enough of a seal for X amount of pressure on say a 180bhp engine providing the seal is in good order and fitted correctly (std is 140-150bhp remember). Above X pressure with more power and leaks. Whats the power on your engine ?
Cheers
Rob
The engine is standard. I'm not going to tinker with it much because it's lots of money for very little benefit. Better off getting another turbo charged engine for modifying, and then it's not much money for shed loads of horsepower! That said, I'm pondering over having a the head done, then a chip, and then NoS!
A friend of mine runs a workshop called Complete Car Care, Ivatt Way in Peterborough. He has just compiled a kit which will add 25-40 BHP througout the rev range on full throttle only. It's switchable NoS so you don't have to run it all the time, only when you want to fry the arse off someone and light the tyres up! For about 700UKP (don't quote me on that!), it sounds quite reasonable.