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im loving this thread, it has mapping and det, and fatigue battling it out all over.
Its interesting to note that det causes damage like whats been shown in the pics but surely the piston crown would show this det too?
And also good to know that a fatigued piston can fall apart after many many miles of abuse .
When they get old they do fall apart just never seen one falling apart lol, but they do and this is teaching me and im certain some other people some good lessons on det and fatigue thanks for the input .... keep it coming .
 

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If its not det what has caused it then? a piston just does not just fall apart because its old and worn out, my piston went the same and that was down to high cylinder pressures and that was doing 600 there are lots of RB engines running 550 all day long.
 

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Discussion Starter #25
How do i no wats coursed it, but ill tell you its not dett. Ide also like to no anycar thats done 35000 miles at 550bhp on stock internals that's still running well.

Number 6 thats gone.



No 2




And heres the lucky part, If ide have kept running it, i would have spun a shell on 6 anyway.

 

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the pictures say a thousand words

Ok so my observation not a qualified one but something id like to share to see if im correct or wrong .

piston crowns show alot of black and oily black maybe from taking them apart means that map was very very rich so on the safe side.

No 6 bearing looks like its picked up in a tapered form id that crank was whipping slightly proven by the one edge of the shell looking coppery and the other end looking ok, however some food for thought, no 6 is the leanest cylinder and is also the furtherest away from the oil pump meaning a lower form of oil pressure, so lean + slightly lower oil pressure can also cause problems on a bearing spinning shell etc.
What oil pump are you running if you dont mind me asking and what oil pressure were you seeing ?
 

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Yes was rich but was all okay. Part throttle was a little jumpy in the tables but not to bad.
There was no dett wats so ever. The map was still rich. the map was so retarded it was crazy.
This car has never suffered dett ever!
I wouldn't presume anything, piston tops black and wet is not how they should be, you quote rich and retarded as if that means "safe" and it simply is not.

If No6 big end looks worse than the others that may also indicate something different going on that cylinder.

Being rich is not good and having retarded ignition timing is also not good as it generates alot of unwanted heat that can lead to piston, valve and turbo failier.

Ide also like to no anycar thats done 35000 miles at 550bhp on stock internals that's still running well.
a piston just does not just fall apart because its old and worn out, my piston went the same and that was down to high cylinder pressures and that was doing 600 there are lots of RB engines running 550 all day long.
I agree, we also run stock internals at far more than 550-600hp and have seen 40,000-50,000 miles from them without issue.

My advise would be don't presume anything, get your injectors checked and flowed and do your initial startup on a dyno where everything can be monitored, don't presume rich and retarded is a safe tune, why not tell whoever tunes it you want CORRECT afr's and ignition timing?
 

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Discussion Starter #28 (Edited)
Well here goes, Car was last mapped by mark at abby, wen the -7s were newly fitted. Approx early 2010.

I bought the car in april 2011, then we checked the map, was incredible rich and retarded on the ignition side. On the dyno the car was running out of puff at 6600rpm. Felt flat but was running 480bhp.

At this moment i realised also the car was slightly using oil, wen free reved was smoking a little on over run.

So in July 2011 wen advanced the ignition on the cam, (dett cans and lamba all wired up) and monitored the fuelling on the dyno, backed the feul reg of a little and got the feuling to a better level through the map. Could not go into ecu as its HKS f con pro no licence.
It was like driving another car the difference was undeliverable 540bhp at 8000rpm. 1000 miles later wen the little rattle occurred.


So thats the story.

Car as standard oil pump, ran 1.32 bar of boost dropping to 1.2 at top end. and all oil pressures were fine before removal,

Oil temp 75c
Rpm 1400 3 bar
Rpm 3200 5 bar

Ive never wanted retarded ignition, if i was mapping a car and wanted to go safe and bring the bhp down etc, ide use many other methods, like lower boost for starters.

But i was told it was mapped like this for safety. also told that to much advance on ignition is wat killls these rb26s.

Thanks for all the input and advice its well appreciated, im not brilliant at writing out wat i want to say, but im gratefull for the responses in helping me solve or building my new engine. Thanks.
 

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Should be no issue with top speed runs of 1000m or a mile if the tune is right.
 

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Discussion Starter #31
So wats ur thoughts rob? Have u ever seen a piston go like this? Need a recomendation on rods also.

Wats ur spec jimbo out of intrest?
 
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Ignition advance

Am I missing something here but you say you have advanced the ignition but you cant access the F Con. I take it then that you advanced the base setting at the CAS which would have put an advance figure right across the map.
In my opinion that is probably the cause of your piston problem. A few degrees at 5-8000rpm probably found you some more power top end but in turn this would have given you increased piston skirt loadings around the max torque rpm range which coupled with high end skirt clearances due to the wear situation undoubtedly wouldnt have helped.
Sorry but I think you cant compare the RB26/28 with the RB30 because the con rods are much longer which leads to considerably lower cylinder wall loadings.That is why when HKS made possibley the ultimate RB engine block they made it high deck thus virtually cutting cylinder wall loadings by 25 percent.
Sorry but this is a case of buying a s/hand car with a decent tune taking it to a tuner with little or no experience of the RB or the software to tune it properly!
Oh and taking too much notice of the forum specialists. lol

Good luck with the build.

Tony
 

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My Point Tony you can't map a car with the CAS sensor if your man is so good at mapping then why did he do this?
is this how he does the time attack cars? How much experience has your mate with RB engines.
 

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Discussion Starter #35
8pot do i really need to answer that.

Have i compared the rb engines?

Any more power would have increased skirt loadings.

i dont no the life this engine has had, and neither do you. so pinpointing the course is mission impossible.

Anyways its in the making of getting rebuilt, anything rob recommends to check that i will do.
 

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ok ive read through what the posts have said still no response on the oil pump you were using .

Secondly i agree with Rob as i know for a fact RB's can see 550 Bhp easily all day long but there is one very important factor ..... ITS ALL ABOUT A GOOD TUNE

If you run 550 bhp and have a krap tune the engine will not last .

You can run a 450 bhp motor all day long but again if the tune is out the engine wont last.

Can i ask what are the other bearings looking like ? on the Conrods ? Big ends ?

Some one mentioned piston skirt to wall clearance ?? what it the correct piston skirt to wall clearance on a stock rb engine as i have some small size 1 pistons and i have a grade 2 block ?? will the cause problems with the pistons being 0.010mm too small for the bore ?

I think we might be chasing the wrong avenue.. but the right avenue .
Seems as though the car was suffering from blow by and oil usage and the remap pushed it too far ?
Am i right ?
So may be the problem was there from before as Rob mentioned pig Rich and retarted timing can cause bore wash and increased cylinder temps too.
 

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Discussion Starter #37
Sorry wen i say stock internal i mean stock oil pump also.

But i dont no how its been tuned all its life, well i do abbey Motorsport.

I dnt no if was suffering blow by, i doubt as leakage test was good, and now turbos are off, we have found that one is pushing oil in exhaust side.

Engineer amazed how good the block looks, and the other bearing are all good. bores havent suffered much wear.
 
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