My 26/30 Is Rooted

[rockabilly]

hi guys, alot of you on here have seen my thread ref my 26/30 build. car has run faultless for 12k and 2.5 years, decided to go link g4 this year so bought one and had a base map loaded to get my car ready for the mapping, when i started it up at home it was rich 8.1, got the laptop on straight away and after about 10 mins got it down correct, i had never used the g4 sofware before hence the delay in turning the fuelling down, anyway onto the trailer it went for the 300 mile round trip on the dynopacks. changed oil and filter before i went also, car runs cp,s spool rods, acl duraglides,n1 oil /water pumps, trust sump,6 boost many, gt4094r at 2bar boost, 1000cc inj,twin pumps etc.ran on the dyno for about 2 hours on low boost upto 1.4 bar and 8k limit. switched of had a brew then restated car, after a few seconds the engine started to tap, switched it of and removed plugs. no5 piston tapping head game over,stripped it down at home and no5 big end spun, all the rest mains and big ends are fine, apart from scoring which will be shell contamination, had crank checked, well bent 10 thou on no6 main.

questions.

did the overfuelling help do this

n1 oil pump issue at 8k

clearances on bearings when i built it where 2 thou mains/big ends 4thou endfloat,

enfloat is still 4thou after 12k

have bought a tomei pump now and 1000bhp ati damper.

rotating assembly was balanced but using original rb26 front pulley, this has slight cracking on the rubber now, could this have been an harmonic issue..

see pic below guys, feel free to comment, good or bad..lol

also some skirt scuffing and side wall bore markings, was bored at 3.5 thou clearance?.

[rockabilly]

couple more pics

mains in cradle

[Marko R1]

I'm sorry to hear that shane, I've been watching your build on the uk site and it is a weapon.

Of u spun a big end bearing maybe it is oil pressure related? U did a good thing binning that n1 pump.

What ecu were u running previous to the g4? If it happened when u did the ecu switch the cause sounds quite obvious, the base tune on the g4?

[rockabilly]

hi marko, was on apexi d-jetro b4, the car has never been driven on the road with the new g4. just had a rough base map loaded so i could run the car upto temp and check for oil leaks and water leaks.

[Marko R1]

Shaun, what did your tuner say? Surely he had an idea of the cause...I mean, u have driven it for 2.5yrs without any issues then when u changed the ecu the problem arises?

How did the oil pump look? I remember u saying 6mths ago that u had high oil pressure which is what u want

[rockabilly]

oil pump is good mate, took it apart no scoring or anything. tuner thinks the over fuelling washed the shells prior to the dyno session?. they all look very shiny like they have been chromed, i was using acl duraglides too not race..the only real difference i can see is that very rarely did i hold it at 8k, but it was at 8k for quite a few runs, not holding but peaking there,not sure if the constant 8k revs could have done this to it?.

[Marko R1]

Well my engine is rev limited to 9000rpm and other built engines such as rips racing can go to beyond 10krpm.

U really need the opinion of an expert, have u placed this thread on gtr.co.uk? I bet if rob at rips looked at it, he will work it out

Rob has helped me in the past and his theories have proved correct.

Once u put your thread on the uk, pls send me the link as I am highly interested in this.

Fuel washing out oil sounds possible as 8:1 is extremely rich BUT I'm not an engine builder, its also good that you bought an aftermarket balancer as I heard that rb30s are more susceptible to vibration at high revs

[rockabilly]

hyperlinked from here marko

http://www.gtr.co.uk/forum/134696-well-my-...tml#post1273721

[R31Nismoid]

U did a good thing binning that n1 pump.

Can you stop being a mindless sheep?

There is nothing wrong with N1 pumps when used within reason.

The N1 pump has nothing to do with the failure here at all. So it being a "good thing" to bin it is just silly and unfounded commentary.

[rockabilly]

Can you stop being a mindless sheep?

There is nothing wrong with N1 pumps when used within reason.

The N1 pump has nothing to do with the failure here at all. So it being a "good thing" to bin it is just silly and unfounded commentary.

good piont mate, i have sold the n1 on, not because its failed but because i will be revving higher when i rebuild it and just dont want to risk it.. i have run 2 x n1,s now on motors i have built no issues, my rev limit is 10k, high yes but i believe the issue with the n1 is rev limit related. so if you never hit the limiter your n1 should last. the pump has done many track days and been to 8350 rpm no issues. i am just taking a leap and trying the tomei, i have a friend running a gt42 on a 26/30 that revs over 9k and will been in the 900,s horsepower wise. so this has just swayed me to the tomei. bernie

[aerofocker]

well the big end bearing can realy only contact the crank surface when the protective oil film has broken down,this can be caused by lack of oil pressure supply to the bearing in question, extreme detonation or abbrasive particles in the oil, i believe 8krpm is well high enough but each to their own, crank specific harmonic dampers become very important on straight sixes at high rpm,the bent crank clearly indicated a problem! i would be very interested to see the cause of the failure,best of luck

[GTRNUR]

Damage to the main bearing journels could be colatteral damage, as a result of debris in the oil system after the rod bearing let go.

Do you know what your oil pressure was at 8000 rpm? The old school rule says 10psi per 1000 rpm but I'd be leaning to 15psi/1000 rpm with an engine that makes the power like yours does.

Were your rod bearing previously factor or clevite? Im wondering if it might have been a little detonation too, slowly hammering the rod bearings till they gave way. Changing to an ACL rod bearing may help the engine tolerate the punishment a little more next time.

[Swiper the Fox]

Can you stop being a mindless sheep?

There is nothing wrong with N1 pumps when used within reason.

The N1 pump has nothing to do with the failure here at all. So it being a "good thing" to bin it is just silly and unfounded commentary.

If you had lost an engine at 900klm you would feel the same way as Marko. The engine in question was a low revving item that was never put under stress...N1 went bang.

GTRNUR...correct...the mains are all shiny from eating rod bearing material.

Edited April 4, 2010 by Swiper the Fox

[aerofocker]

i often wonder if the gallery bores are sufficent to suply that kind of flow at such high rpm,the pressure indication means sweet toss all if the film is still getting broken down due to rpm film thinning and the oil port on the crank being unable to supply the required flow?

[Duncan]

have you still got the oil? get it checked for fuel that will tell you very quickly if that was the problem.

i think its more likely there was another problem that showed itself with the sustained high revs - maybe a slight bend in the crank from the start? was it tunnel bored or checked for straightness on first assembly? or more likely just pinging up high smashing the rod bearing (it is #6 after all)

[drf76]

not sure if it may have anything to do with your problem but in regards to the SPOOL rods, i was shocked to find out that all the rods where uneven heights (centre to centre).

When my engine builder dummy assembled the block he found that all the pistons where at different heights. he had to remachine the big ends so all good now. I thought maybe i got a bad batch of rods but my brother had EXACTLY the same problem. The material used is great but the build quality from experience is not.

I wonder how many ppl have just bolted these rods in without checking piston heights??? Just my 2 cent, like i said not sure if it has anything to do with your issue but worth checking if you havent already.

[drf76]

...

Edited April 5, 2010 by drf76

[drf76]

...

Edited April 5, 2010 by drf76

[James_03]

I reckon that crank might have been out right from the start. Then over time the shells have all eaten contaminents resulting in this.

My 2c.

Feel for you mate, my rb30dett is sitting in pieces too atm.

[rockabilly]

cheers guys for replying. to answer a few questions

i spoke to brad @ spool and these are the very first rods he had made. we just weighed them and fitted them not presuming they were different lengths, but then again its done over 15 trackdays and 12k so would have shown a problem sooner ?.

bearings were acl duraglide

oil pressure was 100 psi at 8k

oil was silkolene pro r 15/50w

old oil stank of petrol and had about a litre too much in, bear in mind i run twin pumps and 1000cc sards. wont take long at 8.0.1 afr to do that.was changed after afr set and prior to dyno run,car was never driven with the contaminated oil in the motor

crank was checked for true when i had it polished and collar fitted also.