R33 Rb30 Conversion

[RBtwin]

Has anyone had harmonic problems in the timing belt? I have an issue at about 2000rpm where the timing belt vibrates fairly badly. It goes away after that and has some smaller harmonic periods further up. Just wondering if anyone has had the same problem?

RB30/25

Tensioner up top in the block

Gates timing belt

P.s. I don't know how to search this thread to find specifically where info is and I can't read 155 pages- I may die

[Cubes]

I'll check mine out today.

[RBtwin]

You would know if it does. It makes a fairly cranky noise like a bearing is cactus or its valve bouncing. It only lasts for 50rpm or so.

[[200]]

How do you think a HKS T04Z with a 1.0 a/r would go with one of these motors?

[MonstaS4]

Has anyone had harmonic problems in the timing belt? I have an issue at about 2000rpm where the timing belt vibrates fairly badly. It goes away after that and has some smaller harmonic periods further up. Just wondering if anyone has had the same problem?

RB30/25

Tensioner up top in the block

Gates timing belt

P.s. I don't know how to search this thread to find specifically where info is and I can't read 155 pages- I may die

<{POST_SNAPBACK}>

Are you using the powergrip belt? The tooth profile does not match the cam gear and could cause the harmonics issue.

[Cubes]

RBtwin, mines perfectly fine, no strange noises no strange wobbles or vibrations.

I used the Dayco belt.

I have also made mention of the apparent different tooth profile with the Powergrip belt in the guide.

Edited December 12, 2005 by Cubes

[RBtwin]

Thanks for checking guys I have a dayco on its way to me now.

On their web site they list two types of belts- a polychlorosomething and a HSN. Any idea which one you have or even what the difference is?

[RBtwin]

Okay the Dayco one went on. The harmonic has moved but its still there. Its not as bad- there is no noise, but it really sh1ts me. There is one at about 1500rpm and one at about 2600rpm. The belt goes through the harmonic because down the long side it gets a wave to it that has an amplitude of about 5mm each way at a guess.

Can anyone verify a harmonic? You need someone to look at the belt while you rev the motor up slowly. Mine only lasts for 50rpm or less. You can see it between the cam gears but easier to see down the drive side of the belt.

I am using a VL balancer- nothing flash and I have tried two different ones. The tensioner and idler have bearings in VGC. If this isn''t the problem the next port of call is to test rig the cam/spring combo. I don't want to do that! lol

[Cubes]

The loose side of the belt on mine at certian rpm's does look like it goes a little blury. I guess this is what you are calling harmonics?

I wouldn't say it wobbles 5mm though, looks like maybe half a mm but really quick so it looks like its not moving just slightly blury.

The drive side (right side looking at the motor from the engine bay) is always nice and tight with no bluryness.

With regards to the tensioners. I bought one genuine nissan one and then a genuine holden. They are basically the same apart from holden skimping out and running only 1 bearing instead of 2 that nissan do.

The holden one is ever so slightly cheaper.

Nissan use two bearings side by side within the shell that the belt runs on.

Holden use one bearing located in the center of the shell.

I didn't bother with using an idler as Nissan wanted $280 for one. lol What a joke. The tensioners the rb's use are locking tensioners so if anything they should be more expensive than the idler due to a slightly more complex design.

If that make sense. :S

Edited December 13, 2005 by Cubes

[StockyMcStock]

try running a bit more tension in it, might ease the flap out.

[RBtwin]

Belt tension is not the problem. I will put a strobe on the balancer tonight and I believe I will find it oscillates a few degrees for and aft. Will let you know. I will also try and film the belt and post it up.

[SirRacer]

Ive found some good information having talked to the man at ACL in Auckland, NZ (distributor) re forged pistons. This guy knew absolutely everything which was a huge help.

ACL and Ross Forged Pistons are owned by the same company .

Ross make the pistons for ACL that fit into the rb30. They are however sold as ACL pistons but have the quality of a ross piston.

These pistons are a custom piston made to suit the rb25 head as the standard rb30et pistons would have a very low 7 compression ratio.

They run about an 8.5.1 compression ratio and come in either 0.5mm oversized or 1mm oversized

Also they sell race bearings for the engine.

Part Numbers

6mkry9608 1mm oversized forged piston

race bearings

H Series bearing

6b2390 H Standard size Big Ends

7m2394H Standard size Mains

Hope that helps clear up some myths

Edited December 20, 2005 by SirRacer

[sky30]

Also they sell race bearings for the engine.

Part Numbers

6mkry9608 1mm oversized forged piston

race bearings

H Series bearing

6b2390 H Standard size Big Ends

7m2394H Standard size Big Engs

Hope that helps clear up some myths

<{POST_SNAPBACK}>

Are theese bearing numbers both big end like you have said, or is one a number for the mains(crank)?? If not what is the main bearings part number?

[platinum]

picked up mine tonight, excuse the rent-a-trailer

[sky30]

Platinum- what specs is turbo on your motor?

[conan7772]

I am planning on using forged pistons just trying to decide which ones to use. I thought thr rb30 harmonic from a R31 skyline run all ribbed belts it was the VL that had the single belt. Im more concerned with which one is more up to the task ie is one better than the other or I guess I just have to fork out for an ATI dampener.

<{POST_SNAPBACK}>

I ended up getting CP forged pistons for $1250 / set 8.3:1 cr

Chrone forged rings for $270 / set.

The finish on the pistons is absolutely brilliant.

Also using REV rods @ $1550 / set.

Couldn't get oil squirters in though.

What lift are the HKS 264 cams, and how were they in the RB20

Edited December 16, 2005 by conan7772

[MonstaS4]

Ive  found some good information having talked to the man at ACL in Auckland, NZ (distributor) re forged pistons. This guy knew absolutely everything which was a huge help.

ACL and Ross Forged Pistons are owned by the same company .

Ross make the pistons for ACL that fit into the rb30. They are however sold as ACL pistons but have the quality of a ross piston.

These pistons are a custom piston made to suit the rb25 head as the standard rb30et pistons would have a very low 7 compression ratio.

They run about an 8.5.1 compression ratio and come in either 0.5mm oversized or 1mm oversized

Also they sell race bearings for the engine.

Part Numbers

6mkry9608 1mm oversized forged piston

race bearings

H Series bearing

6b2390 H Standard size Big Ends

7m2394H Standard size Big Engs

Hope that helps clear up some myths

<{POST_SNAPBACK}>

Further to the above, Mahle own ACL. They are the sole manufacturers of pistons/rings in Australia. They also supply Holden, Ford, Mitsubishi and Toyota with their OEM gear. I done some work for them a couple of months ago. Pretty impressive factory.

[platinum]

Platinum- what specs is  turbo  on your motor?

<{POST_SNAPBACK}>

heh, its just a stock r33 turbo, will be using it to run things in for the moment and when I can afford it I'll be getting a nice gt42 + 6boost manilfold!

[conan7772]

heh, its just a stock r33 turbo, will be using it to run things in for the moment and when I can afford it I'll be getting a nice gt42 + 6boost manilfold!

<{POST_SNAPBACK}>

You could fit a high flow cartridge into that for about $1900.

Keep the stock manifold and plumb in a BOV. Cheaper than a whole new turbo kit, new manifold, new induction pipes plus labour.

My R33 had it done before I bought it, managed 247 rwkw @ 12psi, actually held 15 quite well.

The best configuration was to set it at 18psi for 3 secs then back to 15psi through the scrambler function on the boost controller.

The sound of the induction is awesome, with a low flutter on decelleration.

The compressor inlet was bored to take a 56 mm compressor wheel (inducer), a 500 hp ball bearing core fitted, hot side took a steel wheel with more trim, spools up very quick , could break traction easily.

Should get the RB30 fitted hopefully next week, I'll be leaving this turbo on for now, will post performance specs later.

Edited March 7, 2006 by conan7772

[R32GTST]

I ended up getting CP forged pistons for $1250 / set 8.3:1 cr

Chrone forged rings for $270 / set.

The finish on the pistons is absolutely brilliant.

Also using REV rods @ $1550 / set.

Couldn't get oil squirters in though.

What lift are the HKS 264 cams, and how were they in the RB20

<{POST_SNAPBACK}>

The cams have 9.0mm lift direct fits probably a bit of overkill for the rb20 but when everything comes on together is a good hit, should be nice in the RB30.

Where did you get your CP pistons from?