In an attempt to quantify the major causes of failure in the engines we so much love in our cars I want forum mambers to take a few minutes out to report the failures they have had/witnessed and the circumstances. I suggest the following format to help reveal as much as possible. Pictures are not necessary but can be emailed to me if available. In particular I am interested in RB26 failures but all are necessary to establish the elements of concern. PM your friends to get broadest involvement in this survey on behalf of the forum members.

Engine/Car:

Type of failure:

Factors influencing the failure:

State of tune of the engine:

Suspension and tyres:

Oil used and service interval:

General comments:

Register on the forums for fewer ads.

OK here's my first one:

Engine/Car: RB25DET GTS25t

Type of failure: Ring lands and turbo compressor oil seal.

Factors influencing the failure: Hot day, suspect load of fuel, hard run in the country, loss of traction over a hill close to redline in third.

State of tune of the engine: As delivered from Japan, generally unknown but had been rebuilt once before as pistons were 0.5mm oversize. Standard computer and timing. 13psi boost. Standard intecooler and 3" cat back exhaust.

Suspension and tyres: RSR springs, 235/255-40-ZR17 tyres.

Oil used and service interval: Shell Helix synthetic (blue)

General comments: Too many things at once to pin the problem. Shell had some problems with fuel quality, the compressor oil seal failed, detonation occurred near redline cresting a small hill and wheelspin occurred. Resulted in huge white/blue oil smoke cloud behind the car. Same result if I tried to accelerate into boost. After a 1 hour cooldown the problem disappeared until 2000km later when severe blowby indicated ringland problems. Turbo was replaced within days of the incident to overcome the oil injestion problem.

Here's my second:

Engine/Car: RB25DET GTS25t

Type of failure: Big end bearings. Pulled down to discover 2 pistons faintly cracked.

Factors influencing the failure: Hot day (38deg) and had been conducting some testing on water sprays into intake and intercooler. The previous engine rebuild had the wrong pistons fitted at 0.5mm OS and was getting excessive blowby. I believe the bearings may have been reused as the car had only travelled 20000km since rebuild. At the last service I saw sparkles in the oil residue indicating bearing deterioration.

State of tune of the engine: Rigoli modded turbo, 11psi boost, cat back 3"

Suspension and tyres: RSR Springs, ZR tyres as above.

Oil used and service interval: Havoline synthetic changed every 5000km with a filter change.

General comments: during the road testing I had experienced detonation (2 aubible pings) when accelerating very close behind a porsche turbo in third on an extremely hot day. I also discovered the engine oil had blown around 300ml out into the catch can and drained this off and replaced it. Several days later on the very hot day I was driving normally in traffic and heard the rattling off the side of a passing van. When I arrived home to park in the garage it was becoming very audible. On pull down the #3 big eng had spun. All bearings were very worn and I discovered the pistons had been installed too small hence the blowby. I won't trust an engine builder again and now do it myself.

Come on. Post and be honest. If it was the nut behind the wheel let me know that too. This should be important enough to have done several pages by now.

Just cause you asked so nicely Geoff ,

R33 GTS25t 4 door Auto

RB25det :Bang:

Blown ringlands on No.1 punched small hole in skirt , & dropped the sparkplug in No. 5 (which ended up in the exhaust wheel of my turbo)

Caused by detonation! most likely due to excessively advanced timing

intake , exhaust, fmic , safc = 280rwhp

275/40/17 rear on 9 1/2" rims , 245/40/17 front , on 8 1/2" rims

Using Havoline Synerngy 10w50 fully synthetic

much more detail at

http://www.skylinesaustralia.com/forums/sh...65&page=1&pp=25

1) RB25DET - 5 busted ringlands

Root cause - Fuel pump hose clamp not done up tight enough, fuel leaked back into the tank instead of going to the rail & injectors, leaned out - then bang (or pop more like)

Running 14 PSI on a hi flow turbo at the time. (about 240 rwkw)

2) RB25DET - Spun Bearing

Probable root cause - hot day, bad oil, bad tune, slipping clutch (maybe) - the Jury is still out on this one......

Running bigger turbo (21 PSI) and about 300 rwkw at the time -

Engine/Car: R32 GTR RB26DETT

Type of failure: 2 pistons and 1 turbo blown

Factors influencing the failure: Faulty AFM

State of tune of the engine: Stock

Suspension and tyres: Stock with R33 GTR rims

Oil used and service interval: Mobil 1. Every 5000kms or every track day.

General comments: Faulty AFM casued motor to lean out and busted pistons 2 and 3. Fragments from pistons went down and smashed turbo. Engine popped at about 70,000km. I didn't get to check the bearing but before then the car hadn't been on the track yet. I'm assuming the car was hardly ever driven in anger as the rotors were thin but no cracks on the drilled holes. Also when it popped it left huge marks on the cylinder walls so a new block was needed.

Engine/Car : R32 GTSt RB20DET

Type of failure : 2 snapped exhaust valves, piston mashed, head mashed.

Factors influencing the failure : Overtightened idler bearing bolt.

State of tune to engine : approx 150 rwkw

Suspension and tyres : std.

Oil used and service interval : Penrite, at 100 000 kms major service by prevvious owner 3000 kms before i bought car.

General comments : 9000 kms after 100k service done just driving home from work, car went bang. A roadside mechanic (who happened to just be parked 30 metres away) heard it let go from that distance. Engine took a couple of seconds to wind down (travelling at 40kms at the time) by time i had come to a complete stop, piston had snapped 2 exhaust vavles, and repeatedly hit the debris into head. 1 dead head, and piston

No indication that failure was about to happen. Changing down from 4th to third when it let go. Those indentations in the pistons are the valve reliefs (std). The bolt just clean snapped off level with the block. Upon removing the timing covers, there was a rubber type dust inside and the idler bearing had a discolouration (like it was heated up). I dont know exactly what was replace at the 100,000 km service, ut the previous owner said it was the full service. I bought the car at 103,000 kms....at 109,000 kms it let go....6000 kms later

New motor is rb31det

Thanks guys.

B-Man, how old was the engine and what was it treated like for the spun bearing? The fuel pump is also an often overlooked issue so food for thought for us all.

Silver-Arrowz, did you take a look at the other components such as bearings when the engine was stripped? If so what was the mileage and how had the engine been treated up until then?

Bl4cK32, another often overlooked problem. Obviously all the pistons were replaced as I see indentations in the other pistons, or are they standard on a RB20 (it's been a while)? Were there any indicators such as humming noises from the bearing at idle and when cold or was it the bolt that just clean snapped off? Was there any sign of pre-cracking of the bolt (an old dirty/rusty part of the crack and a clean area)? Also new bearings in the rebuild? How did the old ones look at 106,000km?

Just edit your posts if you have the info.

Joke or no joke mate, i take serious offence to comments like that. How would you like it if your motor died after driving it 6000kms? Sure i chose to go for a performance motor, but it was the only way i was going to be happy knowing nothing would stuff up again.

Think about what you write mate, cos shit may come back on you one day...

Guys, I appreciate that comment is going to come in, but if it isn't relevant then try to restrain yourself. It may insult some people who are doing us all a huge favour by sharing their grief, and an engine failure is pretty nasty stuff when you have to be without the car for a while and are exposed to huge expense. I appreciate what may have been considered a free bump but I have had the thread stickied while I am in data gathering phase.

Just to clarify, I am gathering as much data as possible so I can establish the causes of the most common failures, when they occur and under what driving/servicing conditions. I will also detail the effected failure elements and when they are likely to fail as well (say after a seizure, what the effect on clutch and gearbox may be). This kind of effort is not inexpensive, having carried it out numerous times before and had to pay for it, so usually it averages $30K-$60K (I'm doing it for love of Skylines). I need good data so please treat the thread and the contributors with some dignity, and feel free to remove any unecessary posts.

I am extremely grateful to those who have shared already.

Engine/Car: RB26DETT/BCNR33

Type of failure: front cylinder (#1) bottom end bearing and rod overheated

Factors influencing the failure: Oil condition and level, new sticky tyres

State of tune of the engine: boost restrictor removed and untuned PowerFC

Suspension and tyres: Stock non-V-Spec, A032R

Oil used and service interval: Ummmm yeah

General comments: Rushed to track after getting tyres and clutch replaced, oil old and not overfilled

Not very old - 1000 kms after the rebuild (the first failure) - the motor was run in normally - not constant revs, loaded up, etc - Took it out to eastern creek for a crack at the 1/4 - lots of power , hot day , slipping clutch and still had run in oil in it (I didn't know about that bit) - and the rest is hisory.

Spun bearing, damaged the crank, and conrod so these needed to be replaced. Pistons and rings were fine - so not such a big job - just a new crank, bearings and conrod .