R33 Rb30 Conversion

[shanef]

cheers for the extended response daniel

As a note the sump holes are at 10.8mm drill them to 12mm there is plenty enough meat there,with this done I am sure there will be wiggle room so they will all line up.

Is this 'slop' detremental to the holding ability of the bolts? Another way i can see it working, is bolt the plate to the sump, and drill out the holes in the plate through into the sump to take an M12 bolt. This way there won't be any 'slop' in the hole in the sump side. Although this may only work if the holes in the plate are currently M10.

I'm at work and home is a 45min train ride away, so cant confirm if this will work until i get home tonite.

[Fitzpatrick Speed Works]

yes this may work shane however if you go to m12 at least 3 of the bolts in the diff side will have ot be sacrificed as there is not enough meat on block to go all the way to a m12 bolt!!! the clamping pressure will be maintained as long a 40% of a bolt heads surface, and thats not meaning the hole bolt heads surface just the clamping area, is in contact with a the clamping surface... while the sump is heavy there is far beyond adequate bolting points the main reason for so many bolts is not to make it stronger but to prevent the sump leaking, its to pull the surface down evenly and prevent air or in this case liquid gaps. In theory and in accordance with Australian design standards you could easily hold that sump to the bottom of that motor with 4 bolts correctly positioned and pressured, you wouldnt, but there is adequate bolts there, the slop as you call it you may create will have no detramental effects on the strength or effectiveness of the sump bolting to the plate.

Cheers

Edited October 13, 2006 by Fitzpatrick Speed Works

[shanef]

yes this may work shane however if you go to m12 at least 3 of the bolts in the diff side will have ot be sacrificed as there is not enough meat on block to go all the way to a m12 bolt!!! the clamping pressure will be maintained as long a 40% of a bolt heads surface, and thats not meaning the hole bolt heads surface just the clamping area, is in contact with a the clamping surface... while the sump is heavy there is far beyond adequate bolting points the main reason for so many bolts is not to make it stronger but to prevent the sump leaking, its to pull the surface down evenly and prevent air or in this case liquid gaps. In theory and in accordance with Australian design standards you could easily hold that sump to the bottom of that motor with 4 bolts correctly positioned and pressured, you wouldnt, but there is adequate bolts there, the slop as you call it you may create will have no detramental effects on the strength or effectiveness of the sump bolting to the plate.

Cheers

The bolts on the diff side are fine, so they dont need to be changed to M12. I was referring to the 2 studs in the sump on the non-diff side. I've attached a pic and i've put a few details on. The measurements aren't 100% accurate, but are close, so i don't think there will be any problems changing the 2 M10 holes to M12 ones, will there?

Oh, and before i forget again, in ur instruction book u say the tapped holes in the plate and the bolts u supply have a thread pitch of 1.50, but they actually are 1.25 thread pitch, just thought i'd let you know

[Fitzpatrick Speed Works]

Yeah mate change those to m12 that would actually be a really good idea might even change that on the design

[paxter]

thats nuts

[Scooby]

Guys;

A number of posts on the very good GTROC UK RB30 thread refer to RB ignition scatter at >4500 rpm due to the CAS set up.

The last few pages describe a problem whereby there is significant ignition scatter due to cam belt flex affecting the CAS, and in particular the crank flex affecting the crank pulley and in turn the cam bet and CAS even more at high RPM + load.

A Datalog example to illustrate the problem is provided.

Theory seems to be that this can be alleviated by use of a crank trigger or ring gear trigger which makes sense, but the existence of the problem in the first place interests me. The thread is here;

http://www.gtr.co.uk/forum/upload/52458-rb...ight=r32+combat

I'm not viewing their findings either way as I haven't heard of it before, but there appears to be some evidence to support their argument.

Can anyone shed some light on this?

Cheers

[StockyMcStock]

i got my heap of cr@p running! it's a bit of an animal now. sounds crazy too.

pictures:

[Adriano]

Thats awesome, hope i can see it in the flesh one day, cant wait to see the results

[Bl4cK32]

i like pics.... nice

to quote someone else -"where's the damn vids "

that'll stop cubes asking....

[Drift_Mulisha]

Hey guys, about to start on an RB30 build & have got most of it sussed from reading this thread except when using the standard RB30E bottom end compression seems to be around 8.2:1 & was wondering if theres an easy way to bump this up a little? most people seem to be using an RB26 head gasket so would i be able to use an aftermarket metal gasket from tomei, hks or similar thats is slightly thinner to lift compression? does anyone know the thickness of a standard RB26 head gasket? ideally aiming for compression ratio between 8.5:1 - 9.0:1

Cheers in advance...

[Cubes]

No can do.. Grab your self a set of aftermarket pistons that suit the comp ratio you are after.

Either that or be happy with a few more $$ in your pocket and an 8.2:1 comp ratio.

----------

McStocky... Very nice indeed. Does it drive?

[Drift_Mulisha]

No can do.. Grab your self a set of aftermarket pistons that suit the comp ratio you are after.

Either that or be happy with a few more $$ in your pocket and an 8.2:1 comp ratio.

----------

Damn! is there any particular reason for this? i know there is varying thicknesses of aftermarket headgaskets.. is there a mechanical reason why this wont work? no budget for aftermarket pistons unfortunately this was my last hope.

[rob82]

Guys;

A number of posts on the very good GTROC UK RB30 thread refer to RB ignition scatter at >4500 rpm due to the CAS set up.

The last few pages describe a problem whereby there is significant ignition scatter due to cam belt flex affecting the CAS, and in particular the crank flex affecting the crank pulley and in turn the cam bet and CAS even more at high RPM + load.

A Datalog example to illustrate the problem is provided.

Theory seems to be that this can be alleviated by use of a crank trigger or ring gear trigger which makes sense, but the existence of the problem in the first place interests me. The thread is here;

http://www.gtr.co.uk/forum/upload/52458-rb...ight=r32+combat

I'm not viewing their findings either way as I haven't heard of it before, but there appears to be some evidence to support their argument.

Can anyone shed some light on this?

Cheers

I have seen lots of vibration/resonance with cam belts on various rb motors especially on rb30/26/25 with the additional cam belt length. We have even changed from using the standard CAS to a dedicated crank signal with the sync still on the cams with one motec system. I honestly felt there was no problem though with the timing control using both methods. I have however seen large timing variance (10-15deg) within the actual CAS spline/half moon key and I reckon this is what they are describing.

[Cubes]

Damn! is there any particular reason for this? i know there is varying thicknesses of aftermarket headgaskets.. is there a mechanical reason why this wont work? no budget for aftermarket pistons unfortunately this was my last hope.

Try to find an aftermarket headgasket thats thinner than 0.040".

Then there's the issue of high rpm and the pistons kissing the head.

You might get away with a 0.010" thinner headgasket but its not going to raise the compression a great deal.

[Drift_Mulisha]

Try to find an aftermarket headgasket thats thinner than 0.040".

Then there's the issue of high rpm and the pistons kissing the head.

You might get away with a 0.010" thinner headgasket but its not going to raise the compression a great deal.

Cheers cubes from memory a 1.2mm metal head gasket gives no change in compression on an RB26 so hopefully goin to a 1.00mm headgasket will bump it slightly, havent seen any thinner than that yet for obvious reasons .

Does anyone know the formula for working out what the compression ratio will be with a standard 30e block & r32 RB25DE head with a 1.0mm metal head gasket??

Also is there any factory valve springs that interchange with R32 RB25DE that can withstand 300rwkw? have seen stock springs float badly at 260rwkw. would RB20DET Springs be an upgrade? or RB26 etc.

Cheers.

[Scooby]

I have seen lots of vibration/resonance with cam belts on various rb motors especially on rb30/26/25 with the additional cam belt length. We have even changed from using the standard CAS to a dedicated crank signal with the sync still on the cams with one motec system. I honestly felt there was no problem though with the timing control using both methods. I have however seen large timing variance (10-15deg) within the actual CAS spline/half moon key and I reckon this is what they are describing.

They seem quite convinced it's to do with belt flex, but what you say re timing variance and the CAS spline is interesting and could well be the problem, as you suggest. Did you pursue a solution to eleiminate this?

[Cubes]

The RB20DET valve springs are no upgrade, they are what you have now. Just the RB25de valves are larger so they need thougher valve springs.

1.2mm headgasket will lower compression.. 1mm headgasket is standard 0.040". To work out the comp ratio correctly you need to make measurements, i.e rip the motor apart.

[rob82]

They seem quite convinced it's to do with belt flex, but what you say re timing variance and the CAS spline is interesting and could well be the problem, as you suggest. Did you pursue a solution to eleiminate this?

Replace camshaft and CAS - good as new. I wish I had of taken a picture of it as I diagnosed a car the other day, it just looks like the spline wears along the side where it engages onto the cam as for reasons I'm not sure as the car didn't have that many k's on it if you can believe an import odometer reading.

The rb's have been around for ages and there has been alot of rb30/26's as well cant really see me not noticing a 10deg timing variance on a full throttle ramp let alone all the other tuners out there or anyone with a bit of an idea.

[StockyMcStock]

i got my heap of junk dynoed for a bit today, just a quick check to make sure it was OK. fixed the AFR's back to 12:1 and didn't play with timing much at all. total of 1.5 hours on the dyno, 225rwkw at 9psi. graph and stuff can be seen here --> http://www.skylinesaustralia.com/forums/in...howtopic=104332

[Sydneykid]

Guys;

A number of posts on the very good GTROC UK RB30 thread refer to RB ignition scatter at >4500 rpm due to the CAS set up.

The last few pages describe a problem whereby there is significant ignition scatter due to cam belt flex affecting the CAS, and in particular the crank flex affecting the crank pulley and in turn the cam bet and CAS even more at high RPM + load.

A Datalog example to illustrate the problem is provided.

Theory seems to be that this can be alleviated by use of a crank trigger or ring gear trigger which makes sense, but the existence of the problem in the first place interests me. The thread is here;

http://www.gtr.co.uk/forum/upload/52458-rb...ight=r32+combat

I'm not viewing their findings either way as I haven't heard of it before, but there appears to be some evidence to support their argument.

Can anyone shed some light on this?

Cheers

There are in fact a number of problems that cause this sort of crap (suggested solutions in brackets);

1. Loose cambelt (re-tension the cambelt)

2. Poor relocation of the cambelt tensioner (mount them properly when you build the engine).

3. Worn camshaft/CAS interface (replace the worn components)

4. Poor choice of ECU, some ECU’s only use one of the trigger signals and therefore have no cross reference for “noise” elimination (if possible use the standard triggers with an ECU that has that capability).

5. Some ECU’s require the replacement of the standard trigger wheels, because they can’t interpret the standard CAS signals (select a more appropriate ECU in the first place.) (If you MUST use a high end ECU, then include the cost of separate crank and camshaft triggers).

6. Poor quality rewiring, insufficient “noise” insulation/suppression, low quality patch harnesses, ill fitting piggy back plugs, faulty wiring etc etc (use a plug and play ECU, like a Power FC or get a professional to do the engine wiring harness if using a high end ECU).

This is not all exclusive to RB30’s, I have seen all but #2 on other RB’s.

cheers