R33 Rb30 Conversion

[VIPERGTSR01]

Thanks for the for number and info.

I thought I will look into a RB30 bottom end as I will have to rebuilt mine anyway but after reading that great guide you guys made It looks alittle more complex especially with the RB25DET head (welding head and running seperate oil feed etc).

[Cubes]

Yer its not hard though. Nothing a cylinder head pro couldn't sort out.

I had my head built at Chris Miltons Engineering. 83448070.

Brenton is the bloke to speak to.

[Fitzpatrick Speed Works]

In regards to an earlier post by Cubes about the dude on the calias forum....

Today i put both the standard (rb30) and a rb26 harmonic balancer(dampener) in the lathe to do some mild machining work on them and its no wonder these engines have harmonic problems. The dampener is that far from running true its not funny. I thought this might be a stuffed one or something so i grabbed two other rb25 ones and cheked and its the same.. Now if you run them in the lathe looking side on at them like this [] it runs true but look at it from the front ( ) and the outside circle is not runing true to the inside circle ie. the crank hole.... This is a big problem and its due to how they are manufactured with the rubber sandwiched between two planes, the outer circles can be squashed down uneven...

Multiply this by 7000+RPM and i can see why the balancers tend to wander around on the end of the shaft, and the logicbehind using the heaver rb25,26 dampeners is that they probably do it less due to the weight. Now i trued mine up and it wasnt that hard and had to re balance it, as you will notice on the standard item there are a heap of holes cut out to try and balance them, which tells me they arent made that great from the factory.

If i hadnt invested so much time setting up the gilmer belt setup on my existing dampener i would definately of tried to modify a fluid filled chev unit to suit the rb30, especially for anything over 600hp.

Hope this adds some info for those interested in trying to sort out harmonic dampeners.

[RB30-POWER]

Very Very Interesting...

I've never ever looked at them front on when they are spinning at speed, for obvious reasons (how hard is it to see behind the radiator), however i may go spin one up in a lathe to see how bad they actually are.

Are the two parts vulcanised together by the rubber or is the rubber some sort of dampening material or both?

I suppose they are a mass produced part afterall.

And under standard power it wouldn't be too much of a concern,

However a critical piece in the puzzle when searching for more reliable HP at higher RPM especially.

[Cubes]

I do have to admit. My RB20DET harmonic balancer was very out of balance from factory.

I can't say I've noticed it being out of true.

With the belts etc all on and tensioned up correctly mine sits perfectly still. No wobbles either way.

Its not to say it isn't though.

How is it possible to make true?, what part is actually out of wack?

[Alf]

Now reading about the harmonic issues.

How much will a 26 balancer set me back?

[Fitzpatrick Speed Works]

to true it up i just slightly machined the outer circumfrances, on an rb26 or 25 pully there is a fair bit of metal there that you can get running true to the centre hole... Having done that i still needed to balance it as i didnt square up the ribs where the belts run to run true with the center hole (crank hole). So if you look at your balancer from the back you will see its made in a few parts.... The center where the crank runs through is one cast piece and treat this as your center... There is another piece around this which is about the same size as you front pully then there is another piece that goes around it, these all have rubber sandwiched between them to dampen harmonics...I simply true up the very outside one, which is probably the furthest one out anyway, and its the only one you really get to....

The problem is you would never notice not running true one on the vehicle for a few reasons... you can never really look at it straight on, and with all the belts in place it hides a good view of the balancer. 700Hp would have noticed it on the engine dyno cause you can look at the engine quite carefully, thats why he mentions it....

I admit you cant totally make it true but you can improve on what is there!!!

[Fitzpatrick Speed Works]

alf last time i went to get a balancer for a rb26 when i chipped one i seem to remember them being around 300-400 brand new from nissan....

[Cubes]

Interestering.. So its not really the metal that is out, its the rubber that is throwing the outer ring out of true. Machining up the metal simply compensates.

That being said once loaded up with belt tension from the a/c, waterpump etc would this pull it in? Being rubber I would assume so?

[Sydneykid]

I really couldn't give a rats about the out of round, a harmonic balancer is supposed to run out of round, after all that's how it dampens the harmonics. That's why the rubber is there, to allow for it. Obviously a dynamic balance is a good idea when the harmonic balancer is coupled with a balanced engine.

[Cubes]

I've been doing a little bit of reading up on harmonic balancers.

The outer ring being ever so slightly untrue makes SFA difference to the reliability of an engine. Providing its all balanced as SK stated it will not create an issue when spinning.

What will reduce the reliability of an engine is removing noticable amounts of weight from that outer ring.

The weight in the outer ring in conjunction with the highly compressed rubber helps absorb the shock pulses.

That being said the reading I've done also stated that a bad harmonic balancer WILL cause oil pump crank engangement failures.

Is there any difference to the R32 and R33 harmonic balancers?

More importantly, is there any difference to the R33 Series 1 and R33 Series 2 harmonic balancers?

EDIT: Lightening the totally assembly will reduce the intensity of the shock.

*cough* Wiseco are the lightest pistons *cough* lol.

[Fitzpatrick Speed Works]

I took about 22 grams of metal out so Im not concerned about that part. I ran the balancer up on a lathe at 6000RPM and you should see the thing its absolute crap, just spending 20 mins trueing it up a bit just makes me feel better, and having it balanced indipendant to the motor is worth its while.

My main point is the standard unit is pretty damn rubbish, and i can see how it could cause possible problems especially the rb30 one (hence why we don't use them) having known what I know now I would have definately invested the time in modifying a chev or ford fluid dampener to suit!!! I thought i would mention my experience and for the time invested read: not much, it makes sense to spend some effort on your stock unit!!! Cheers

[Alf]

Lightening the totally assembly will reduce the intensity of the shock.

*cough* Wiseco are the lightest pistons *cough* lol.

How light is each one? but wouldn't a heavier balancer be better?

[Cubes]

There's a little link floating around on the specs of different pistons.

The Wiseco's also tend to have the thickest ring land and are one of the few Slipper type pistons.

I wouldn't imagine heavier would be better, it has to be engineered to suit the application.

These Fluid types.. Are they heavier? or is it the fluid is much more efficient at absorbing the shock.

I would be inclined not to use the RB30 balancer anyway. Its not really designed for performance or high rpm.

There's a HKS balancer available for around $1500 if any one is interestered. lol

I have never heard of the RB30's having issues with the twin cam balancers so maybe it was just a sohc balancer thing?

RIPS for one has never had any trouble, he's played quite a bit. NOS included.

[Fitzpatrick Speed Works]

I swear the HKS fluid dampener is a modified or supplied ATI dampener it looks exactly the same... Fluidampr would make me a dampener in a standar siz ie. ever 1/2 inch from 6-9 inch with the crank land at the size to suit for $1000... THese dapmeners are tested and designed with exacting measurements and manufactured to handle up to 14000RPM, and yes the fluid is there as it is a far better shock absorber!!!

[Cubes]

This little link doesn't really go in to much detail but helps explain what is going on with the harmonic balancer.

http://www.secoperformance.com/Tech_Corner_April.htm

Considering the RB25/20/26 Harmonic balancers are designed for highish 7000rpm use is an upgrade needed?

I would probably still think so if the motor is making double or triple the power the balancer was origionally designed around. The shocks would be much greater.

I'm keen to see how Fatz RB30DET goes/lasts as it hangs around drifting with its 7200rpm rev limit.

BUT are the harmonic balancers designed around a certian shock the crank it is designed for? In other words for a long stroke motor do you need a harmonic balancer that is designed a little more heavy duty than a short stroke motor that revs to the same rpm.

HKS definitely = ATI dampers..

http://www.atiperformanceproducts.com/prod...mpers/index.htm

[Cubes]

Well well..

http://www.atiperformanceproducts.com/prod...s/damnissan.htm

They make them for the rb26.. US free trade agreement.

[RB30-POWER]

The balancer i used on my twin camer was off the R31 Skyline RB30, it's different to the VL RB30 balancer and different to the 25 one as well as well. But obviously it suits the R31 accessories/pumps so thats what i used.

The R31 unit looks better then the VL unit, but they are probally all as crap as one another, lol.

[Cubes]

The ATI ones from the US don't look too expensive. around $450-$500 AUD.

[Fitzpatrick Speed Works]

SOunds alot better than HKS at around the $1500 mark.. Sh1t I think i might get me one of those they are going to be a hell of alot better than anything mass produced I will have to reassess my finances but i think it a good option after all I hope to make around 500rwkw with mine I need all the reassurances i can get when I give it a work out!!!hahaha Thanks Joel for that link!!!