Wiped center main bearing
Turbo Mini Forums

Sorry Colin,
My last post sounded snotty didnt mean it to I posted it on the I phone and its a hurrer to type on so tryed to keep it short:(

What I was trying to say was if the bearing metrial was damaged buy fuel contamination then the only way of removing the contamination would be to replace the bearings.

All thought I think you are right this bearing failure is not because of contamination it still cant be ruled out, as the bearings are the same from the start.

how are you so sure these bearings failed because of oil starvation ?

On 1st Jun, 2009 Sprocket said:
not sure wherew you are coming from

I built the engine up in october, had fueling problems in novemeber getting it running, using cheap shitty oil, replaced the oil with running in oil, replaced the oil with Millers CTV, all before the dyno shoot out at the begining of feb. engine stripped and rebuilt with cheap shitty oil run up to temp and then again the oil was changed to Millers CTV.

Im not sure how re using perfectly servicable bearings will cause oil starvation after only 300 miles when the exact same bearings were in use for 1200 miles without issue



Center main bearing housing out of round by -2 thou and number 3 bearing out of round by +1 thou at the mating faces. Block is now waiting to be line bored, and honed, Again,

Hi Colin,
Can I ask your planed rpm band, and what is your center main clearance (plastigauge)?
It's very important, to let the crank flex and so to increase his center main play.

If the only thing that's changed from the point of the rebuild is the O ring not being fitted, its got to be this causing cavitations in the oil, that's caused the problem. The O ring is in there to stop the oil leaking out and air getting drawn in, so makes sense really.

Glad to see your getting it sorted Colin.

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1/4mile in 13.2sec @ 111 terminal on 15psi

Not that sure, it can and right, make sens,
but that long shot on the dyno did push to much stress on the crank.

3 thou clearance on the mains and big ends, 5 thou clearance on the thrusts, 16 thou side clearance on the big ends and 3 thou clearance on the pistons. The crank is cross drilled both mains and big ends, is bladed wedged hardened and balanced as fine as the machine would allow. Millers CTV oil and oil temps no higher than 110c coolant temps no higher than 90c

The max RPM shown on the logs was 7500rpm

im sure the O ring and oil pressure pulsation are the contributing factor.

I have been reading the AE Bearing Failure Analysis bulletin, and it says oil starvation. it also mentions another possability, and that is lugging, high load low rpm, and if you watch the vid, he over loads the engine untill the car nearly jumps out the rollers and the engine nearly stalls, now if that is not high load low rpm, what is?

fact is, the pick up pipe o ring was not installed, and the only dick head responsable for that is me

7500 isn't that high , you're cerntainly right about the o ring.
we did use a std crank up to 8500 pick rpm at track , and we had the same picture as your, center main goosed,piston dust lightly kissed by valves after having increased is play to 0.3 mm it did survived the whole year.
future will tell.

I get the trophy this year for being the prize dickhead*happy*
NOt!
In hurry I forgotten to put the 18mm needle bearing on the layshaft!
NOISY!
then had to do it again in a hurry, forgotten to torque the three bolts on the layshaft double bearing:complete engine shot!

quell domage fab !!!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

just a lesson, wanted to make it in an evening, it took a week, and a bag of money!
When you haven't enough time to do it right, do it later, however it'll take you more and more time. We're growing with time

The crank does back your line of thought. When I took what was left of the bearings out of mine there was no damage or pick-up at all on the crank> So all possibilities considered lesson learned I would say :(

Own the day

Edited by Sprocket on 2nd Jun, 2009.

Forgot to fit the gasket between the transfer case and block once. And once was all it took thats one never getting repeated.

Own the day

I forgot to fit the baulk ring on 4th gear gear when I built my first SC box. Always thought it was a bit notchy into 4th. didnt realise til I stripped it 4 years later why.

Paul

I seriously doubt it!

ah, I have done the exact same thing on one of my friends box for his 4 hour racecar. It seriously did not look good after a season of 4 hour races!

All this came about initialy because the baffle plate fouled the crank, i then forgot to loctite the fixing screws, so the engine was on and off the box a few times. So really i should blame you Paul

Paul, is it not Dave?

Crank crack tested ok and is straight, so regrind it is on the mains to -0.020"

This engine surely does not like me!!

Got the block and crank back. cleaned and assembled the crank into the block, all bearing clearancies between 2.5 and 3 thou. spins nice and free with bottom thrusts in, fit the top thrusts as well and it nips up, take one top thrust out and it spins free. Conclusion, the cap has been machined on the piss and they thrust faces have not been cleaned up. Eased the top thrusts, crank now spins free. Im not overly concerned, as the bottom thrusts are standard new and un touched, the top of the cap leans to the front of the engine away from the clutch thrust. The top thrust on the thrust side will bed in that little bit.

That done with, but now when the oil pump is nipped up and the jack shaft is turned the pump tightens up, slacken the bolts, and its ok, nip the bolts up and the pump is tight. I had to open out the bolt holes on the pump, as they were a little tight, that sorted that, mustr have been out of alignment. Note to anyone, this was a Turbo 'Powerflow' pump from Minisport.

That done with, I continue. Bolt the head on, torquing down the head nuts progressively to 45lbft, and this happens



the threads are not stretched, you can wind a nut onto the stud, and the broken bit.

When I first built the engine, I could only find 9 genuine studs, 8 of those came from two 998s and the other from a box of bits, all genuine Austin Rover. I bought a full set of new studs on Ebay, but they were slightly different, more thread on the coarse end and less on the fine end, and, a little shorter. I was not overy happy with them, so I used the genuine ones and one of these new one to make up the ten. First time I bolted the head on, this stud took some more turn to get to the torque setting. Second time I bolted the head on, same stud, different location, again took more turn, but still torqued. This time again taking more turn, then pop, off came the top of the stud with the nut.

I'm getting pissd with this. But, im not going to rush it, if i miss Avon, so be it.

Edited by Sprocket on 7th Jun, 2009.

bloody hell, hope you get to the bottom of it all!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

you'll get there. Not far of...

All I have to Say is ARP Colin fit and forget

There was a post on one of the "other" forums recently about head stud failures...
Sorry, can't remeber which one or the post, but pretty much the same.... current "new" ones are crap it would seem.

Schrödinger's cat - so which one am I ???

Edited by Sprocket on 7th Jun, 2009.