Questions About Mantaining And Driving A Forged Motor

[Rolls]

I have just taken delivery with this http://www.skylinesaustralia.com/forums/Eo...ts-t285533.html

The RB25 has Arias forged pistons, Arp head studs and new bearings etc, gcg highflow and is roughly 2200kms old now. Now when cold it has a very slight chatter which I've been led to believe is completely normal for forged pistons, as this is due to the increased clearance between the cylinder wall and the piston.

Now the first few minutes if I accidentally get it on boost (1-2psi not much) it will blow a very small amount of blue oil smoke, as the pistons have not yet warmed up and theres still a gap I assume this is relatively normal? It currently has 15-50w mineral oil in it but I am planning on putting some fully synthetic 5w-40 in it soon. It only blows the smoke once, after this and once it is warm it runs beautifully and doesn't chatter or blow smoke. This should be nothing to worry about providing I warm the motor up before boosting it yes? The idle is also slightly rough, not as if it is missing just more like it has a cam (which I'm quite sure it doesn't).

Now with mantaining a forged motor, what are some things I should do to make sure I look after it. Does it require longer to warm up than a standard motor? and is synthetic 5w-40 quality oil (mobil, elf, motul etc) acceptable to use in it providing I change it every 5000kms. The car is a daily driven car and will see occasional track action and I just want to know if there is anything I should be doing differently than I would with a standard motor.

Oh also it currently has a run in tune with a rev limit of 6k and is running about 12psi making ~220kw as it now has 2200kms on the clock would it be safe to take it in for a full power tune with 18psi and a 7.5k rev limit? It has all the appropriate fueling to handle the gcg highflow turbo

Cheers everybody.

Edited September 28, 2009 by Rolls

[NYTSKY]

Do you know how the previous owner ran the engine in?

Shouldnt be blowing smoke at all if the rings have bed in. All of the rebuilt engines ive seen have never blown smoke.

Could have a very small oil leak in the turbo and oil that you see is it burning off.

But if its noisey when cold it the clearances might be a little too much. Nothing serious unless it breathes under load/RPM.

Did the previous owner build the motor? Does he have engine specs/measurements?

[Rolls]

Was built by sabbadin automotive in Victoria, they did all the work. The previous owner drove it very sedately for around 1600kms from what he told me, he seemed like a very honest bloke so I have no reason to doubt him. One the drive home vic-> sa we did about 700kms and we varied the driving a lot, cruising at 4k, a few 4th gear runs to 6k and varied the load around town.

It really is hardly any smoke at all and will only blow it once maybe twice, after that it is fine. If you start it warm it doesn't blow anything either. It definitely doesn't breathe under load when driving and is very smooth/quiet once warm as well so that was my conclusion, that the clearances were slightly too large.

I might ring up sabbadin tomorrow and request all the specs of the rebuilt just for my own knowledge.

[JonnoHR31]

The previous owner drove it very sedately for around 1600kms from what he told me

need to find out if it was run in properly. from what i've read driving sedately isnt the right way to run an engine in

[Rolls]

need to find out if it was run in properly. from what i've read driving sedately isnt the right way to run an engine in

I guess it wasn't run in optimally then, I've been giving it a fair bit of hell, varying loads etc since I've got it so is this the best way to do it?

[r33_racer]

Need to drive it hard and put it under plenty of load straight away. Easy driving wont help bed the rings in.

[R31Nismoid]

The RB25 has Arias forged pistons, Arp head studs and new bearings etc, gcg highflow and is roughly 2200kms old now. Now when cold it has a very slight chatter which I've been led to believe is completely normal for forged pistons, as this is due to the increased clearance between the cylinder wall and the piston.

A nice tight built forged motor should not have chatter in today's day and age, none of my built motors have EVER made a noise.

However it is normal for some forged motors to use a tiny bit of oil in between servicing, and by a little i don't mean 500ml's, maybe 100 or so (if you measure how much you put in/take out etc).

For it to be blowing a bit of smoke etc when cold points to one of two things in my book.

1. Not the tightest motor ever built

2. Rings not bed correctly

Now, given you are hearing noise on cold startup, it is likely to be #1.

However this does not mean #2 is ruled out

Need to drive it hard and put it under plenty of load straight away. Easy driving wont help bed the rings in.

Yep

And doing it 2,200km's later isn't going to fix the problem either.

Bed/seating the rings etc is critical and needs to be done in the first 20mins of engine starting for the first time.

Now with mantaining a forged motor, what are some things I should do to make sure I look after it. Does it require longer to warm up than a standard motor? and is synthetic 5w-40 quality oil (mobil, elf, motul etc) acceptable to use in it providing I change it every 5000kms. The car is a daily driven car and will see occasional track action and I just want to know if there is anything I should be doing differently than I would with a standard motor.

Oh also it currently has a run in tune with a rev limit of 6k and is running about 12psi making ~220kw as it now has 2200kms on the clock would it be safe to take it in for a full power tune with 18psi and a 7.5k rev limit? It has all the appropriate fueling to handle the gcg highflow turbo

Cheers everybody.

Simply start it up, ensure you have oil pressure and drive it lightly/easily for the first 10mins. No boost etc.

Do not go by when the water temp gauge is reading hot. You have motor/gearbox/diff oil etc etc to get warm as well

That is what i do, and so far it has not failed me.

Especially considering it sounds like it was a loose build, limit getting onto boost at all in the first 10mins.

As for what oil etc - totally depends on what the builder recommends to be honest.

My motors have all been under strict instruction of Castrol Edge 10/60, change every 5,000kms.

And yes - wind up the boost, get some power running into it. It should have had a full tune in the first 500km's IMO. But every builder has 'their ways'.

Some are older than others, ie older motors did require a bit more of a run in, tolerances were not as tight, things not as good in terms of quality... however things change over the years

Hope that helps.

Are you Vic?

[Rolls]

A nice tight built forged motor should not have chatter in today's day and age, none of my built motors have EVER made a noise.

Are you Vic?

Cheers nismoid, when I say chatter I mean very very minimal chatter, if you weren't trying to listen for it you wouldn't hear it and as soon as it is warm it sounds like a stock motor. Motor is amazingly responsive and torquey so even if it isn't the tighest motor ever its f**king amazing compared to my 20 year old rb20det I had

As far as the full tune I believe it has had a proper tune, just only at 12psi and a bit richer, when the seller (builder told him this) said full tune he meant bump it up to 18psi and sure it is running well at this. What is roughly the maximum psi the GcG highflow should be running on a rb25, I'm assuming they don't release a compressor map for this turbo? When I get it tuned for whatever the maximum flow this turbo can handle, what sort of rev limit should I be getting set, 7k? 7.5k? I will ask the tuner but be interesting to know what you guys think, the gears are way too short with the 6k rev limit at the moment and it seems to really start pulling at 6 so I'd think it would make good power all the way to 7.5k

With warming up my procedure is to start the motor, wait 30 seconds for oil pressure to come up and circulating then drive off very slowly, revs around 2.5k with absolutely minimal load for about 5 minutes.

Sounds like all is good, I will do a service on it tomorrow with some good quality fully synthetic oil, probably elf or motul depending on what is available.

There is a small leak coming from the front of the engine as well, maybe 6-8 drops over night can be seen the next morning, I've had a looked at it seems to be coming from the front of the sump. What seals could these be, cam seal, is there a front main seal ?? or anything else that could leak? Going to pull the CAS and timing cover off this weekend and figure out what seal it is, then replace it hopefully.

Oh and no I am in SA, I did buy the car from VIC however.

Edited September 28, 2009 by Rolls

[Rolls]

Since giving the motor hell on the drive back and the last few days it barely blows any smoke at all, few wiffs at startup if you accidentally boost it.

Should I dump the mineral oil now and put this Mobil 1 0w-40 fully synthetic oil I got for free off my mate? Or should I leave the run in oil in a bit longer? It is going in for full power tune on 18psi on Wednesday the 7th.

Edited September 30, 2009 by Rolls

[discopotato03]

Personally I think it's difficult to put a Km number on when to dump the first lot of oil , I reckon 1000 Km is a little high if you've run it in properly .

Putting around like grandma simply doesn't work because without some engine load you don't get high enough combustion pressure behind the compression rings to push them out against the cylinder walls while they have that rough honed finish .

Really having a turbo engine means you can achieve higher cylinder pressures so its easier to bed the rings in with a bit of boost .

I can't for the life of me work out why people think ahh ya can't run it on boost and must drive to Perth and back on 2% throttle and it's essential to have a tail wind . I just finished running in my dinosaur Subaru EA82T engine and it doesn't blow any smoke ever or use any oil - at all .

It was actually a less than perfect situation because the builder put Elf semi synthetic 10W50 oil in it and I didn't realise this for a couple of days .

Myself and a mechanic friend spent time loading this thing up (WOT and the full 6 lb farts worth of std boost) between 2500 and 4500 revs and I did my best to drive it up the longest steepest hills I could find at WOT .

At 800 k's I changed the oil to Mobil 1 Racing 4T 15W50 which is bike oil and it runs fine .

People absolutely have to understand that newly honed cylinder walls have rough peaks and they are intended to "wear" or bed the compression rings in . If you putt the thing around and waste those sharp peaks the rings may never bed in and seal properly . The only way to rectify that sitiation is re hone the bores and start again .

As for the oil I think a lot of the warm up urban myths come from using yester years honey like dino oils ie 20W50 . A good synthetic pours cold like water by comparison so its got to get around the engine faster at start up and lubricate properly to begin with . I'm not suggesting that people flog cold engines but if you had to I think a good synthetic would be kinder to the engine .

Your calls , cheers A .

[FATGTS-R]

Well said. Whenever we purchase a new truck isuzu tells us to load the back to maximum weight and flog the shit out of it. Can sit on full boost for a minute straight pulling up big inclines. They never use any oil. We also have another truck of same model year we got as an ex demo and it needs 500ml a week easily as it was pansied around as a demo.

Also seen a mates 500rwkw+ motor run in on the dyno for maybe 20 minutes maximum. Drain oil, refill with good stuff and full power tune.

If rings are not bed by over 2000km then its basically too late.

[Rolls]

Been flogging it since I got it and it barely blows a wiff now.The oil level on the dipstip hasn't moved either back 1000kms ago when it was blowing a bit of smoke.

Edited October 1, 2009 by Rolls

[Rolls]

Just got off the phone from the engine builder (rob sabbadin from sabbadin automotive) and he said the clearances are 3thou so there should be zero smoke even when cold. I've since looked in the catch can (basically empty) and pulled the intake piping off and it is full of oil, now theres no possible sources of oil apart from the turbo, the other possibility is leaking valve stem seals but the owner spent $900 on getting the head reconditioned.

He talked to me a lot about the motor and was very adamant that it was built with tight tollerances and was certainly not a sloppy build. He however suggested that the motor still needs to be run on mineral oil to make sure that it runs in properly, even after 2200kms which I am a bit dubious about, said the mobil 0w-40 oil I have will be too thin and that I should use a 15w-40 fully synth.

However I'm thinking it is most likely that a seal in the brand new gcg turbo that is leaking? Any idea which one and how hard it would be to fix?

The turbo is only 2200kms old so I'm sure it is under warranty, I just don't fancy removing it and sending it interstate.

Edited October 7, 2009 by Rolls

[R31Nismoid]

Mineral 2200km's into a build doesn't make sense to me to be honest.

None of my motors have had mineral in them for longer than the dyno runs - if at all (i vaguely remember someone telling me it was full synth from the first turn)

but he is the builder - do what he says

[Simon-S14]

Mineral 2200km's into a build doesn't make sense to me to be honest.

None of my motors have had mineral in them for longer than the dyno runs - if at all (i vaguely remember someone telling me it was full synth from the first turn)

but he is the builder - do what he says

they only say these things to cover their own arse... not because its the right thing to do or not.

in the few motors ive rebuilt and had rebuilt, ive loaded them up from the word go, run mineral oil for the first 1000 kms and then straight to synthetic oil.

its not a complex process, yet some people/builders believe that a motor is still running in some 2000 km later... no its not.

[NickR33]

(i vaguely remember someone telling me it was full synth from the first turn)

Benno told me its synth from the first turn... when I picked mine up, I waited til oil got up to temp and then gave it a hammering (as per instructions)

one of my old 25 builds (not from Ben) I babied for ages and it was never right... had piston slap when cold and never got any better... only lasted 25K before I destroyed it

[Rolls]

The phone was crackling at the end and he said it was a high soap engine and that will wash the bores so to use mineral. I assume he meant the oil (fully synth) was high soap content? I am going to do as he says and leave the mineral oil in there until it gets dyno tuned anyway.

So yeah re the turbo smoke issue what do you guys think? I will be sending GCG an email tonight and see what they have to say.

Edited October 7, 2009 by Rolls

[Simon-S14]

well it does sound very much like a turbo

[timsr33]

i had a turbo rebuilt by *** about two years ago and started leaking after about 500 kms ide be looking at the turbo

[Rolls]

i had a turbo rebuilt by *** about two years ago and started leaking after about 500 kms ide be looking at the turbo

Did they cover it under warranty? and if so how long was the turn around from taking it off to putting it back on?