Crankshaft Whip

[SECURITY]

My motor is back at the engine builder due to some apparent whip in the crank. Its an RB30 that got the full treatment. strengthened rods + arp bolts, forgies etc. He also stated that he had to send the crank/block off to get checked out as it was supplied by me.

When i got the motor back from the builder it had a bearing/lifter noise from 2500-3000rpm on acceleration, we couldnt work out what it was. I asked the builder and he said that it was probably the VCT solenoid as it was blocked off and said to send the car back if it got worse. I have exact details and dates as I write EVERYTHING in my contract diary (also because these things are recognised in court - im a builder, covering my ass is my job).

I didnt drive the car hard, only small squirts on the highway to do some data logging to tidy up the tune. The motor then suddenly let go while giving it a squirt on the highway. afr's were between 11.5-12 (i have a very accurate PLX wideband+gauge which i annoyingly always keep my eyes on). It sounds like the 2500-3000rpm noise i had but all the way through the rev range.

The engine builder now has told me that there is whip in the crank which is caused by over-revving, mind you the rev limit is set to 7300rpm and was reached around 8-10 times during the 8 months ive had it on the road, i have also only travelled around 8,000km's since the build with 5 oil changes in total which includes the 3 run-in oil changes. The apparent parts that were damaged were the main bearings only, starting from the thrust bearing outward.

I've was warned about this engine builder AFTER i had dropped the car off to be rebuilt and work had commenced which is making me wonder if he is trying to shift blame over a dodgy build.

Can anyone give me some ideas on how whip develops?

I plan to get the engine off to an engineer after his assessment then contact the proper authorities. Can someone recommend an engineer in Sydney who will thoroughly inspect the parts and give a report?

If its my fault for whatever reason I have absolutely no problem in getting it fixed at my expense but I would like this to be confirmed by an independent engineer so I have proof if it has to go through fair trading/ACCC/court etc as I know i did nothing a regular person would do with a new motor. I just dont like getting dicked.

Cheers,

Joe

[Guilt-Toy]

can you get pics of the engine bearings?

Take a look at this site... (this took me ages to find)

http://www.bobistheoilguy.com/bearingwear/...earanalysis.htm

I will try find a engineer for you to do a write up on your engine.

[SECURITY]

good info there. thanks for helping out mate.

[WARLORD]

only 7300rpm i hit 8000rpm every day at least 10 times,

[SECURITY]

which is why i think it sounds weird that i'd get crank whip from that.

[dano4127]

I reckon it died from not driving it hard enough mate!!!

From what you have described you have done everything right and if it cant handle 1 trip to the limiter per month since start up something is fishy

[Public Enemy]

G'day mate,

i feel your pain, hope it all works out for ya.

I don't know enough about RB's to give advice so i'll just ask a few questions to maybe help out the more knowledgable people on this forum.

Does the RB30 run a big end bearing cradle like the RB26 does?

I assume you had no oil pressure problems but what sort of pump are you running?

Was the grade of oil suitable for the bearing clearences you were running? The engine builder should recommend the weight of oil suitable for your bearing clearences.

With the way you have described your driving habbits it sounds to me more like a lubrication problem than anything else.

What sort of power you running? 30psi from a T51R for example may offer some explanation, but 10psi on a stock turbo wouldn't.

Assuming this is a rear wheel drive skyline i find it unbelievable that you would have been able to hook it up well enough on the street to bend or flex the crank.

Good luck with it.

[STATUS]

which is why i think it sounds weird that i'd get crank whip from that.

i reckon it was bent Before it let go and it was not picked up prior., i have 3 rb cranks here (2x 26 , 1x 25) all with 4-6' bends in them..... and require a trip to crankshaft rebuilders IF i was to use them, which im not when a new one is only 1100.

what exactly let go? windowed block or just noisey?

Edited December 1, 2008 by URAS

[SECURITY]

all i know is what he told me let go - which is the main bearings only starting from the thrust bearing outwards which indicates whip. apparently nothing else went, even the big end bearings were fine.

also, my lifters were making LOTS of noise when it let go which is probably due to the main bearings.

[Blitz]

i reckon it was bent Before it let go and it was not picked up prior.

Took the words right out of my mouth Trent, this is exactly what I was thinking.

[SECURITY]

ok well this is looking like its going my way so far.

so the noise i had from 2300-3000rpm could have been my main bearing rattling?

[shanef]

Another possibility is that the cradle may have been bent aswell.

[SECURITY]

Just got off the phone with the engine builder.

He says that it was a mixture of detonation and over-revving which i know is complete bullshit.

does anyone know of an engineer i can send out to go inspect the parts?

[STATUS]

Another possibility is that the cradle may have been bent aswell.

It pays to get the lot line bored for peace of mind too, i usually line bore the whole lot and grind the crank to get my clearances spot on, so far not one issue with any of them (touch wood). It makes the bill longer and bigger though

[shanef]

It pays to get the lot line bored for peace of mind too, i usually line bore the whole lot and grind the crank to get my clearances spot on, so far not one issue with any of them (touch wood). It makes the bill longer and bigger though

Not really necessary if you are meticulous with the measuring and trust the machine shop, also that ~500 can be spent on other things, like a proper oil pump setup

[STATUS]

Not really necessary if you are meticulous with the measuring and trust the machine shop, also that ~500 can be spent on other things, like a proper oil pump setup

n)Definatley not necessary, but i run everything fairly tight, and being more than meticulous means (quite often) getting the lot line bored to achieve my prefferred clearances. Much like Piston to bore, i prefer yo run way under the spec sheets recomendation... if its a customers engine i like everything spot on.

[r33_racer]

oh Trent, you are right with all of that!

We have had bent girdles before! Line boring FTW!

It is now IMO that linishing in a race engine or any high hp engine to achieve any clearance is a complete wank! Any workshop that does it that way should be shot! Needs to be line bored, crank ground so everything is spot on.....none of this linish and have three different measurements across the face of one big/main journal.

There are many dodgy workshops out there who do that because its easier and cheaper!

Another lesson learnt....you cant trust machine shops....mic everything up yourself!

Edited December 1, 2008 by r33_racer

[Angus Smart]

Hey Joe,

you live around Bankstown dont you?? I do know a very decent rb30 engine builder you can take it to if you like in the Area..

if you would like his details let me know... unless it was him already which i doubt...?

Cheers

Andrew

[SECURITY]

Hey mate, hes not in Bankstown, I'll send you a PM shortly.

More news guys. Apparently the cause of the failure was detonation and lean mixtures. does this sound right?

i still cant find an engineer to go check it out. Trent, can you refer me to someone in Sydney with the knowledge to at least give me a well thought out diagnosis if not an engineer's report?

[SECURITY]

finally got an engineer who will do modified engines. i will finally find out next Wednesday!