Will it Explode?
 

Concern:
I put a known bad engine in a Boxster to see how well it would run. It runs great so far, but there's oil getting into the coolant. I want to drive the car in a Rallycross next week. I expect that a few two minute long runs at 5-6K rpm will probably kill off what's left of the block/cylinders/rods or whatever else is wearing out.

Other than destroying a failing engine what's the risk?

http://986forum.com/forums/uploads02...1677202754.jpg

Too much info:
This is Woody's old car. The engine seized in 2021 during a race. I was going to scrap the engine, but found that it was no longer seized and has good compression. I decided to see what the engine has left before I put another engine in.

I don't want to waste a race day by having it fail on the first run, but I don't have time to put another engine in before the event. Running hard with no care for the longevity of the engine will be fun. Having an engine compartment fire will not be fun and may upset my fellow rallycrossers.

Bolt in cage with easy egress out the door. 5 point harness and removable steering. Fire extinguisher in reach. Nomex coveralls and jacket. No 'fire system'.

Experience and advice welcome.

I have no special knowledge and no experience with your situation... but I don't see how this would be any different for an "normal" engine blow-up, if it should happen. Oil doesn't burn that easily and why would it be more dangerous when mixed with coolant?
But as someone, somewhere said:
"I am not an attorney, mechanic, or member of the clergy. Following any advice given in my posts is done at your own peril."

I don`t think engine fire is a high risk here, I would keep a fire extinguisher at hand just in case though. If hot oil/coolant starts bursting out from the engine you might be in danger, so I would put the engine cover back on if possible. I assume you already removed the cats. So what else could go wrong? Hook up a good onboard camera, I`d love to hear what it sounds like when it dies. :D

Go for it and have a good time.
It will be like your 18 again.

What we tell our DEers in the safety mtg would apply here:

If you have enough early warning, get off "the line" before dumping a bunch of oil on it. Your fellow competitors will find it much more enjoyable. You might want to also let your competitors know your situation so they don't follow too close and get involved in the aftermath.

I know nothing about rally cross, but this DE rule might also apply there: if someone has a fluid situation on the track, the track charges our club for the speedydry, which we pass on to the driver. It's been a while, but I think we were charged $20 / bag when this occurred 4 yrs ago. So don't be surprised if you're handed a bill for your entertainment.

Thanks for the comments.

In response to Terry, it's far from a DE, but some of your points translate well.
It's on a dirt course marked by cones, much like an autocross. Getting off the line and having a bag of oil absorbent material are great ideas.
There's not much worry of a competitor following close, but it made me realize I should have a recovery vehicle queued up to pull me off the course promptly to keep from disrupting the flow.

It's happening March 5th. I'll record some video and post it with some follow-up after the event.

First start of the engine after reinstalling:

<iframe width="560" height="315" src="https://www.youtube.com/embed/69j6wnN38fI" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>

Wheels, tires, and top going on when the warm weather comes back on Monday.

Nothing catastrophic. I made 11 runs and had competitive times. On the last two runs it stalled out just after I crossed the finish line and let off the gas. It had to sit about 15 minutes before it would crank and start. It drove onto the trailer at the end of the day, but had started popping and misfiring. I'm going to drain the fluids and pull the sump for a look, but I think it's done now.

It was Awesome!

http://986forum.com/forums/uploads02/3_5c1678077020.jpg

http://986forum.com/forums/uploads02/3_5b1678077047.jpg

Well, these are good cars. ;)

Does that big rear spoiler do anything on a dirt track?

I don't have data, but I do think it helps. The car that consistently posts the best times has ridiculous spoilers (and a great driver too):
https://live.staticflickr.com/65535/...0949940f_b.jpg
He tried various configurations and that works best. With speeds generally 35 to 60 mph, it appears that more extreme spoilers improve tire grip.
When Woody had this car he said that the biggest problem was getting the power to the ground. I may experiment with increasing the angle of attack more after I get a better feel for the car.

The Frog started right up to drive it off the trailer this morning. The 'popping' sound was more pronounced than yesterday - more of a rattle now. When I pulled the engine cover off and listened it was quite clear; the rod bearings are gone.
<iframe width="465" height="827" src="https://www.youtube.com/embed/m5dnwBF2Ka0" title="Porsche Boxster, Bad Engine Sound" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>

For a moment I thought of holding it at 5,000 rpm 'till it explodes, but that would make quite a mess to clean up. I'm really glad that I made it through the whole day Sunday without incident because this engine is ready to send pieces through the case any moment now.

Filter and cup:
https://live.staticflickr.com/65535/...aa712fc5_b.jpg

https://live.staticflickr.com/65535/...d9ee3e2c_b.jpg

I would have guessed that those were air-brakes, not spoilers. Especially in the front.

Don't know about 986 engines, but M97s have weak rod bolts. Under protracted runs near redline, they stretch which allows the rod bearings to slip, resulting in a spun bearing or two. Prior to my bore scoring rebuild, I always shifted at 6K rpm rather than running up to 7200 redline. Wonder if that's what's going on with your engine?

Out of about 20 986s I've bought (many as salvage) two of the '01s had rods that were in pieces. One looked like a bolt failure and the other was hard to tell from the pieces, but the bearings were mostly bad.

Woody actually built a 'stealth' front spoiler into this car hidden under the bumper:
http://986forum.com/forums/uploads02...1596060168.jpg

For most of the Rallycross cars, pushing a pile of air around in front of the car is not as much of a problem as keeping the keeping the tires in contact with solid ground. More HP just means you are throwing more dirt unless you are firmly planted.

As with most motorsport "Slow is smooth and smooth is fast." I'm still working on that:

<iframe width="985" height="739" src="https://www.youtube.com/embed/67tCf_b-9n0" title="March 5 '23 RallyX GoPro" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>

That looks like an absolute blast!!

Are there any regulations concerning the wheels and tyres? I think with different tyres the Box should have much more grip on dirt.

The engine sounds really bad now. Hope it's not gone too far, so parts or the whole engine can be rescued. It's getting harder and harder to find good engines and good engine parts.

Right now I'm running snow tires on 17" 'sport edition cup 4', 7.5" & 9" wheels.
http://986forum.com/forums/uploads02...1678386067.jpg

By summer the dirt on the course is like concrete and I'm planning to run on Nitto NT01 road tires - as recommended by more experienced drivers.

The nationally competitive guys I've talked to buy rally specialty tires imported from Europe.

For me, ferrous metal loose in the oil is 'gone too far'. Yes, it can be rebuilt, but I'd rather buy a used engine or another salvage car to pull an engine from. Reading Tom Stone's posts got me thinking of engines used for racing as a consumable item like brake pads. There are still plenty of 2.7L engines around here.

yo who did those calipers in green? Is that some of that anodizing like spraypaint? I like it

I hate to tell you, but I think that's actually overspray from when Woody painted the body green. http://986forum.com/forums/622608-post87.html It just looks like a nice a special coating from that angle.

I think we need more overspray. :D :cheers:

Love the video. How do you make the track looking so steady while the dash is moving? With a gimbal you mounted the camera on? Or offline editing?