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I was informed that I'd need an actual oil catch can, rather than just little pod filters on my rocker and crank breathers to compete in a hill climb next March, so i went out and bought one; a nice stainless Saas one from Autobarn. The can came with no instructions, but the guy talked me through fitting it.

I was a little surprised that the can didn't come with any kind of breather, just a bolt in the top and bottom, but then since I had never ejected any oil through my breathers at high revs how much pressure could build up in there anyway. I rigged it up and went for a test drive.

Wow... what a stupid f****** idea.

I knew in my gut it was wrong, and sure enough 20mins later I had lost oil pressure. Turns out I had fired my dipstick out of it's hole along with about a liter of oil. No breathers meant I had created a pressurized system in the crank case and probably also the rocker. I went to the servo and refilled the oil, corked the dipstick holder and removed the bolt from the top of the catch can to let vapors escape to atmosphere (Ill add a filter soon).

Unfortunately, driving home the engine changed tone. Nothing horrific, but definitely noticeable. I pulled over and there is definitely an off note - a light rattle that wasn't there previously.

What horror could I have visited on my engine by creating a sealed system (blown a rocker arm off, forced oil up past the rings to the head etc)? What should I do to find the rattle? I don't even know where to start :P

Anyway... I'm off to drink a bottle of vodka in the bath.

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I don't have anything to add about your engine. Regarding the oil catch can; consider that having a clogged up or dirty air filter on top of the can may have the same effect as having it blocked up the way that you did. You may (may not - its up to you) condsider venting the catch can back to your air intake behind the air filter.

Yeah... I'm pretty dirty on the Autobrain guy. You'd think there'd be a warning on the can, too.

I think the confusion stemmed from the can not really being an oil in-oil out arrangement. Both crank and rocker breathers are trying to expel vapors. They aren't going to form a circuit and drain back into the block, I guess. Both taps are at the top of the can.

Cheers for the venting tip Ben... that might work out.

I'm really worried about the engine internals. A boo-boo in the head won't ruin my summer, but if I've managed to blow something up in the block it's going to sting.

The only thing stopping me building up another is cost. I'd really like to do a 3.1L with forgies and kameri gear throughout, but the cost.... eek!

Also I've got a fresh L28. It's just that I seem bent on sending it to an early grave is all. Still, when you build your own engine using hand tools and a book you're bound to get some-to-most things wrong the first time round.

Got my fingers crossed that I may have forced oil through the rings and splashed some on the plugs or something minor like that. Not really keen for a major rebuild this year.

well....if it is a big end bearing the noise will get louder with revs. so have a good listen at idle then quick rev. if the knock is still there but it gets louder/the note changes, it may well be dead. I take it you've still got oil pressure?

The open top on the can is probably safe for now, like you said it should have a filter.

What breathers are on the stock system and what do you have hooked up atm?

Shit mate, I hope the motors alright.

Sounds like that catch can is a legal one that gets one side plumbed up to the rocker breather and the other back to the inlet behind the filter like mentioned earlier. Go back to Autobarn and headbutt old mate that sold it to you.

As for your engine woes, it sounds like your to soft on it, show it no mercy it's a Datto they love to be abused. Put a set of stokers on it and then burn'em off and repeat as necessary.

Doctors orders

Thanks for the sage advice guys.

Oil pressure is still there and still good.

Will try the idle-rev-listen trick, although if it's a big end I'd rather not know.

Will also listen with the timing gun attached to see if my noise is at crank speed or half crank speed (read cam related probs).

That makes so much sense that the can is supposed to be from rocker to air filter! All well and good other than I need a second can for the crank breather.

I struggle to remember the stock arrangement. The rocker is plumbed to the air filter and the crank is... can't remember!

Anyway, I'm off to throw a stick on Autobarn's roof.

You shouldn't need a second can for the crank breather - just use a t-piece going into the catch can.

Right! There's a plumbing supply place round the corner that can probably help me out with that.

Just fit a filter to the breather you created. And put some steel wool on the can - it gives the oil in the vapours something to condense onto.

Funnily enough I have a filter or two spare now. The steel wool sounds like a cracking idea too.

Oh well... moment of truth tomorrow morning. I've been hiding from the car all week.

i would like to drunkenly appreciate the amount of shit you have gone through with your car bro.

when you buy a C210, you gotta expect murphy's law around any corner lol. i love it. C210's keep you on your toes :D

too maggot to type

/rant

Wow... I really did foul my plugs with oil (2-6). Gave them a clean and the car sounds back-to-normal. I haven't done a compression test yet, but the car isn't blowing any blue smoke, so hopefully I didn't disrupt the rings too much.

That oil sitting between the pistons and head is just going to burn off... right?

Fingers crossed I've gotten off very lightly this time!

That's great news Drew, I was starting to think I should send the postage fee for those seat covers as you might need it to fund the repairs. As for the oil, yeah it'll all burn off, I put loads into my bores while it was in storage, nearly gassed myself on fire up. I've got a new cam going in on Monday, it's a 72 grind will be interesting to see the outcome.

Thanks all for the support and suggestions. I did a big test run and things have held together really well... what a huge relief not to need to budget time or money on a rebuild just yet.

I will plumb and filterize my catch can correctly this week. (I guessed the wool was to go in the can rather than just balancing it on top.)

72 degrees! Mine's only 70... Let me know how that works out Ricky. I'd love to put some cash towards performance mods in 2010 rather than blowing it on repairs all the time.

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