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High Rpm= Spun Bearing?

gtr jet

By gtr jet,
in Engines & Forced Induction

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gtr jet Veteran

gtr jet

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A few months back i spun some bearings in the bottom of my RB26, the thing is it happened in the driveway when i started it and went to move it.

However a couple of days ealier i came on boost in the wet and the engine spun to around 9000rpm, just curious as to whether this may have been the cause of the bearings letting go a couple of days later.

The engines is balanced and tuned if that makes any difference.

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https://www.sau.com.au/forums/topic/334194-high-rpm-spun-bearing/
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GTScotT Grand Master

GTScotT

Posted
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Its more so a wear and tear thing than it is a single event mate. I dont think a single over rev of 9k would take out the bearings in one hit.

You are more than likely looking at prolonged user error here. How do you treat the engine? One spirited morning without the motor on opperating temp (and I mean more than the water temp gauge) will do more damage than one 9000rpm rev when its running.

gtr jet Veteran

gtr jet

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The engine was brand new, It had done less than 1000km and had only been tuned at racepace 3 or 4 weeks beforehand so that was the only spirited driving it had seen.

The nose was pointed up when it started. The high revs were done 2 or 3 days before the bearing span and it had been driven normaly between then and always warmed up.

STATUS Grand Master

STATUS

Posted
Posted

Im sure the best bet is to take it back to where it was built and tuned and let them have a look, you will only get assumption and guess's as to the issue via the net. The company that did your work has an excellent reputation and im sure they would like to find the issue as much as you, things can happen that are out of anyone's hands regardless of where and when it was done especially if a pump let go.

gtr jet Veteran

gtr jet

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Well the engine was built at home so what ever is wrong with it is most likely going to be my fault. Racepace has done nothing wrong, after the tune, when the car was running it was beautiful.

I was in the passenger seat and was watching the tacho as it came on boost in 3rd in the wet and it was around 9000rpm.

The oil pump was a brand new n1 unit so i hope that didnt fail.

It has a power fc and im not sure if it even has a rev limit. With the standard engine and ecu it would go a lil past 8000rpm but would sound like absolute shit and go nowhere but that was only tried once.

Rolls Grand Master

Rolls

Posted
Posted

Standard tachos can be wrong by up to 1000rpm when you are flicking the revs up and down in the lower gears due to the momentum of the needle. I really doubt a reputable tuning shop wouldn't have set a rev limit, can you hook it up to a PC and check?

I don't know much about power FCs but do they hold stats like highest rpm ever seen etc? Could be handy with diagnosing.

I'd be getting a decent oil pressure guage and checking that before driving it anymore though.

gtr jet Veteran

gtr jet

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Well your right, it could have spun to 10,000 for all i know and im not sure if there was a limit so id have to ask racepace. The engine is going to be stripped and rebuilt again so hopefully by then i can get some proper gauges and get it checked.

Not sure as to whether things like that can be checked with a power fc.

boostn0199 Grand Master

boostn0199

Posted
Posted
Well your right, it could have spun to 10,000 for all i know and im not sure if there was a limit so id have to ask racepace. The engine is going to be stripped and rebuilt again so hopefully by then i can get some proper gauges and get it checked.

Not sure as to whether things like that can be checked with a power fc.

You can check the max revs it hit during a session but once you turn off the car the vaules are reset so yeah if you didnt check when it happened then that vaule is gone now.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Well the engine was built at home so what ever is wrong with it is most likely going to be my fault. Racepace has done nothing wrong, after the tune, when the car was running it was beautiful.

I was in the passenger seat and was watching the tacho as it came on boost in 3rd in the wet and it was around 9000rpm.

The oil pump was a brand new n1 unit so i hope that didnt fail.

It has a power fc and im not sure if it even has a rev limit. With the standard engine and ecu it would go a lil past 8000rpm but would sound like absolute shit and go nowhere but that was only tried once.

The N1 pump would be the least of your worries mate to be dreadfully honest. Cheapest part to replace really considering you have to take the motor out...

I'd be more worried about the crank as it could be time for a new one .

... and hopefully give it to a reuptable builder...

Passenger seat, looking across, could have been more than 9k rpm :wacko:

gtr jet Veteran

gtr jet

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Yer I know the oil pump is one of the cheapest parts, i just hope its not another part ill have to replace, just like the crank because that was a new R33 item aswell.

I would give it to a builder but i dont really have the thousands it costs in labour to get done. I know its a risk to do it myself but im going to give it one last try.

Id just really like to know what the cause was so i could fix it for this time around.

I guess time will tell.

gtr jet Veteran

gtr jet

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Also i got quoted close to 10,000 from racepace to do the whole lot which i think included a new block as mines already been bored 40 thou.

That was engine in and out, pretty much a whole new bottom end and a retune.

N1GTR Grand Master

N1GTR

Posted
Posted

That's a decent price when you add up all the costs involved.

Racepace have a strong following on here, for good reason.

Add up all the costs of buying parts, machining, assembly, motor R and R, run in, tune etc and you'll probably see (like a lot of others) that a decent build can cost 8/10k without too much sweat.

There seems to be a lot of newcomers to these forums who believe a rebuild costs a few thousand, probably due to the cost of the rebuild kits out there. Then they find out the hard (expensive) way that they were wrong.

IMO, do it right the first time, then there's no second time. Works out cheaper than two budget builds not to mention FAR easier to just tow it to Chris, wait, pay then drive home once it's all done.

Goodluck with whatever you end up doing :wacko:

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