Babalouie's 911 - start on p7

[Babalouie]

what sort of gains would you expect to see from said Ruf chip?

Most chips say +15hp or so, which I kinda find hard to believe :D Ruf don't make any power claims, but the most popular aftermarket chip (going by forum chat anyway) seems to be this guy: http://www.911chips.com/c2chips.html

[irsa76]

Ruf and Kremer, if they still do roadcar conversions, have been around for so long I'd be inclined to go for something from them over most other mobs.

[Babalouie]

And it's just plain fun to say "Kremer ecu" :D

[clutch-monkey]

Ruf and Kremer, if they still do roadcar conversions, have been around for so long I'd be inclined to go for something from them over most other mobs.

steve wong's 911 chips has been around forever too, my car had an earlier one of their chips in it when i bought it (didn't find out til this year). was wary of just plugging in a chip but chanced it given how many people use them

[Uncle]

And it's just plain fun to say "Kremer ecu" :D

[Shifty]

Kramer can see your powerchip.

[Babalouie]

At the beginning of January, I had Autohaus Hamilton sort out the oil leak from the power steering drive, which was getting really annoying. The leaked oil would coat the right-side heat exchanger, and when I stopped at a traffic light, a cloud of white smoke would waft past Thankfully Hamiltons sorted it out as part the major service, and two months later, the power steering drive housing is still squeaky clean.


However,m lately I've noticed an intermittent, and somewhat smaller waft of white smoke when I stop the car. It doesn't do it all the time, and isn't very repeatable. So up goes the car on stands for a look see.


First tell-tale is some oil residue on the heat exchanger intake pipe.


On a closer look, it seems as if the chain covers are leaking, and there is a conspicuous drip of oil on that conical round cover. I figure the smoke is from the oil droplets flying off that conical cover under braking, and dripping onto the heat exchanger, where it gets burnt and turns to smoke (a couple of droplets of oil can produce quite a surprising amount of smoke!)


When it comes to oil leaks, I find it quite confusing sometimes to separate cause from effect. My initial thoughts were that the chain covers were leaking, and that the oil was dripping down and collecting on that conical thing because it was the lowest point.

But replacing the chain cover seals is no small job, as it requires the bumper, exhaust, engine mount plate, a/c bracket and crank pulley to come off! So I'm not too keen on doing all that. But after a bit of searching on the Rennlist forums, I figured that the oil leak wasn't actually the chain covers at all. But first, the heat exchanger intake pipe has to come off, which it does easily, just 2 bolts to remove and a few hose clamps to loosen.


Once it's off, we can access that conical cover (which I've cleaned up first in this pic)


Undo the two nuts, and the conical cover comes off to reveal this. It's actuallt the cover plate for the chain tensioner.


The thing that looks like a coilover shock, is an oil fed chain tensioner, and the way it works, is that oil is fed into one of the holes in the cover plate, and it goes into that hole in the shock, which them extends its (spring assisted) piston, which pushes on a skid resting against the chain to keep it nice and taut. The excess oil just bypasses the tensioner and returns to the oiling system via that other hole.

So what really happens, is that oil is fed at great pressure into the conical cover, and the thing that prevents oil from gushing out everywhere, is this special gasket. You can't really tell in the pic, but the new gasket has three nice, soft and thick green o-rings bonded to it. And the new green o-rings stand proud of the metal gasket, whereas the old gasket's rubber o-rings have gone hard and are squashed permanently flat.


So...I figure that maybe, just maybe...the real culprit to the oil leak is actually the rubber seals on the old gasket being perished. The chain covers really just have to contain a smal amount of splashed oil, whereas the tensioner cover plate has to contain oil at great pressure (so that's much more likely to be a significant leak point).

Putting it back together is quite straightforward, although I have to say that it took quite a lot of effort to push the tensioner cover in place, against the tensioner spring, and it took quite a few goes before I got it pressed into position enough to get the nuts started on their threads. So if you are attempting this, make sure there's plenty of room for you to work, because you're going to have to muscle that thing back into place. But that aside...it was a pretty quick job, maybe half an hour or so. Once it's all buttoned up, start the engine...and if oil is not gushing out everywhere, then it's probably done


Now at this point, you're probably thinking that there must be another tensioner at the other side of the engine, and you'd be right. However it's location isn't symmetrical, and it's actually on the topside of the motor, inside the engine bay. So I figure that, by rights that one shouldn't have been exposed to the same heat from the exhaust, and hence the gasket won't be as far gone. But I do have a second new gasket, and I'll do the replacement in the next few days.

Fingers crossed this stops the wisps of smoke once and for all!

[Boxer]

Nice,

did you know what to expect before removing the conical cover ? (dialogue suggests not, but I'd be VERY surprised if you hadn't researched the shit outta it :D)

Thought of the cover projectiling off into your nose once the nuts get to the end of the thread for the uninitiated

[Babalouie]

Well, that was sort of my thought process over the past week or so. I started thinking it was the chain cover, but bought a gasket kit with everything anyway (incl the tensioner cover gaskets), and when I started to search forum threads on how to do the install, the penny dropped.

[Babalouie]

Well, a week after changing that gasket on the chain tensioner cap, and it's still dry. Also I notice that the chain covers are still dry too, so what looked like a weeping chain cover before, might actually have been leaked oil from the tensioner cap nearby...


However, I am still noticing some wisps of smoke when the car is stationary, and it always seems to be from the right side. So I keep poking around and...hmm...I can't believe I haven't noticed this before...


But the oil pipe going into the oil filter housing looks like it's leaking. I mean, it's not wet with oil by any means, but all that black dust sticking to it must mean that there's *something* going on there.


And the secondary muffler looks like it's had some oil leaked on it (and quite a lot, too!), judging by that stain at the seam. Needless to say, that hose sits right above this spot on the muffler.


So, the plan currently is to clean the offending pipe (which goes from the oil tank to the oil filter housing, so it's the feed pipe for the engine), and I'll keep an eye on it over the next few days. Hopefully any leaks will be easier to spot now that it's cleaned.


From searching the Rennlist forum, it seems that there are two possibilities: one is that the pipe itself is toast, and needs to be replaced...and the easier alternative, which is that the pipe is fine, but a sealing crush washer (at the join where the pipe bolts to the oil filter housing) is corroded and leaking.

...fingers crossed it's the latter! But going by that dark colour on the first few inches of hose...I think what's actually happening is that the braided hose has gone bad where it's crimped into its fitting, so a bad hose is probably the cause here.

[denmaster]

bad hose for sure. speeeeeddfloowwwww

[spiller]

DIY diagnostic master! i hate little oil leaks but its funny how they always appear to be major things at first when in the end, they are seemingly minor but finicky issues.

[Babalouie]

After driving to work today, this is the verdict!

Rather helpfully...there are some vertical drips marks on the secondary muffler...


The part where the flexible hose is swaged to the fitting seems dry...


But the spot where the union itself is bolted together...looks wet!


I think we have a winner, folks and if you trace the vertical oil drip on the muffler, it leads to the union, rather than the hose.

There's an alloy crush washer in the union between the hose and the filter housing, so I'll have a go at replacing it, and we'll see how we go.

[Babalouie]

Question, fellas.

I found a pic of a dismantled oil filter housing (where that leaky pipe bolts to) and it looks like there isn't a crush washer at that leak point after all, but rather it's a tapered fitting. It doesn't look like the industrial kind of compression fitting I'm used to tho (where you flare the end of the pipe).


There's a crush washer between the hose adapter and the housing, but I reckon that's not the leak point in my case.

So the question is...can I just loosen and retighten that hose fitting, or is the taper surface rooted/corroded once it starts to leak?

[spiller]

Surely the corrosion wouldn't cause a tapered fitting to leak as it would just be between the threads (i.e. surface corosion)?Probably a bitch to undo though!