Positive Crank Pressure?
Turbo Mini Forums

So I installed my Sc12 Supercharger a little over a month ago. Was making about 6psi for a happy 500 miles or so. Booked it in for a dyno tune session and blew the head gasket on the way home... or so I thought. I was climbing a hill on the highway for about 10 seconds under boost and suddenly I lost power, and I had heavy white smoke come out of the tappet cover breather.... the smoke eventually dissipated, but the car felt off. I did a compression test when I got home and it showed #4=70 #3=90 #2=140 #1=135

So I pulled the head, and did not see what I was hoping for, blown between 3 and 4. I did not loose any coolant, overall car ran close to normal temps. It looked more as if the head had lifted. Anyway, fast forward to last week, fitted a new copper head gasket, ARP studs, torqued it down, then warmed up, retorqued and took it for a test run before rallye next day.

Everything was running fantastic, best it ever had. 30 minutes into run climbing a hill doing about 65mph... lost power, white smoke out the tappet cover breather... real heavy smoke. Sounded like it was running on 3 cylinders. Now CLUTCH is slipping, I only assume to possibly oil making it's way past the seal? I don't understand why I am getting so much crank pressure. Half my engine bay is covered in oil now, and left a huge oil spot under the car.

Engine is 1098 (STOCK), was in good health before charger, probably not so much anymore. I figured 2 breathers (1 on rocker cover, and 1 modded on the rear tappet cover), would have been sufficient. These are dropped into a vented catch can. Filter on catch can is soaked in oil, it actually puddled on the filter.

Anyway, at this point I am about to fit a stock carb back on the engine in hopes I can still cruise this summer/fall. I am building the garage and not gonna have time to fuss with it to much. I have a feeling clutch will probably not "burn" the oil off. As long as I wasn't laying into boost it would hold and not slip...

Thoughts?

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if you have s sudden increase in blowby you can pretty safely speculate you have cracked a ringland or 3 or burnt a piston up. sorry bud.

oddly, when I used to work on tuned motors day in day out, people would always say a motor was "running the best it ever has" right before it went pop. I speculate that the lean mixture or overly advanced ignition makes the engine a little more perky.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

My thought is that you've knackered your ringlands. Going NA now will still end up with oil oozing everywhere.

My other thought is that if the pistons are the circlip type then the circlips may have failed. Although this causes obvious damage to the bores.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

Arnt the 1098 pistons pretty weak too?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Honestly, I had never encountered this problem before. I was expecting a blown headgasket, or hoping for that. The gasket was wet around the outside edge of block. Checked head for warping, it was fine. Number 4 bore looked to have had a little bit of wear on 1 side, but not much else to report. The tune I thought was fine, no detonation, no pinging, plugs looked perfect, temps were 195 consistently. Anyway, that's where I am at right now. I'm not gonna have space to pull the engine and work on it next few months, that's why I was trying to get it ready before summer/fall season and just take it easy. Might just have to drive the Trabant around this summer.

Unfortunately you cannot assume pistons are ok by looking at them whilst still in the bores.

All symptoms you describe sound like broken pistons.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

You mention a couple of things, the engine was stock, what cr where you running?

Also you need to get the engine tuned straight away not putting 500 miles on the clock without having the fuel and timing setup.

I only mention this so you don't end up with the same result.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I agree with getting an engine setup immediately. Bed the cam in, recovered straight to rollers, engine hasn't had a problem other than a certain rolling road making a hash of the fuelling later on when we wanted to up the boost pressure, and then when that was sorted the clutch couldn't take the torque after 8psi. It's even had a breif period of 14psi and climbing because of a faulty(cheap chibese copy) bleed valve and no signs of any det etc.

blow by like that can only come from a burnt piston or broken rings imo

because you say no coolant lost and that there was no visible sings of cylinder to cylinder blow by say to me head gasket is unlikely.. so imo its rings or piston damage you have suffered

might be wrong and im no expert mind !!

im assuming you have good crank case breathers