I think I've melted stuff!!

Stainless Steve

Registered
I was racing at Silverstone at the weekend, it has very long straights so I was holding the car flat out for probably 8 to 10 seconds at a time.
I had it on the dyno a couple of race hours earlier, I have an MBE 9A4 standalone ECU with 3 bar MAP sensor. The tuner set it up the AFR at about 12.5, I thought this was a little lean but he assured me with the timing pulled out and the intercooler giving me 35 degrees C or 95 fahrenheit it would be good. We checked the compensation maps to be sure I could run any boost level right up to 25psi, I only run 12psi so even if I spiked, I'm way within anything my turbo could possiblyprovide (TD05 16G). After my last meeting I put new plugs in and the old ones were all a good consistant colour, I gapped the new ones to 23thou.
Saturday we were racing in cold conditions around 38degrees and I was running 97 RON petrol, my limiter is set to 10,800rpm.
I have'nt stripped the motor yet but I lost power and initially I thought the exhaust had broken because the note changed. The engine had felt a bit courser at the top end, if that makes sense, perhaps that was detonation? It's hard to tell with tha car having the engine up front and the high speed I was doing. The engine ground to a halt and once it cooled it was siezed. I took the plugs out and they all looked very pale/white like it was running really lean. I've studied my camera footage and I can see my AFR guage and it does'nt change from around 12.5 so nothing changed there.
Did the tuners lead me down a path of destruction or do I need to be checking other things?
I'll get the motor stripped in the next couple of evenings.
Sorry if my thoughts and ideas are incorrect, but I'm here to listen and learn and hopefully save myself some money!
Yours in depression
Steve.
 
It does sound a bit lean, and if it started detonating bad. You likely beat the bearings out the bottom, possibly starting to seize the crank. You may have just got some ring lands if you lucky. Pull oil pan and check for gold first... pull pickup and check it also..
 
Had a thought, I was lifting off slightly towards the end of the straight to stop it bouncing off the limiter, perhaps this did more damage than good as it could have leaned it out.
 
if you backed off cause you was on limiter and detonating look for gold on right side of pan near #3 rod...
 
Number 3 is shot, just looking up the bottom, the cap is black and the sump is covered in gold. My catch tank is full of oil and the dry sump tank is lower than normal, I'm not sure if the rings have blown by and pressured the crankcases, causing oil starvation.
What with the abnormally long straights at Silverstone maybe this is more the problem than the detonation idea.
Bet I can't buy just one Carrillo rod either I suppose.???
I'll carry on stripping the motor, no doubt the number 3 piston has whacked the valves.
 
Had a thought, I was lifting off slightly towards the end of the straight to stop it bouncing off the limiter, perhaps this did more damage than good as it could have leaned it out.

You will have a tough time making a turbo engine live if you are on the limiter,

Richard
 
You're probably right Richard, I'm already geared as tall as I can go with the diff, I could go larger diameter rear wheels. But I'm also going to have to figure a way of letting the cases breath better too, as this seems to be a big part of the problem.
I don't normally race at circuits with very long straights so the problem hasn't arrisen before. It looks like I've only got about 5 litres of oil left out of 7 that I normally run in the dry sump system.
 
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