R33 Rb30 Conversion

[Bl4cK32]

I updated my piston list from P221

WISECO

Skyline RB30 w/ DOHC RB25det cylinder head

1.260" compresion height, 66.5cc head chamber, Dish top -11.3cc, 7.0:1 compression ratio, 21mm pin, 1mm gasket thickness, 1mm deck clearance.

K577M865 86.5mm

K577M87 87.00mm

U might wanna ask cubes about this as he and i are running the m87 rb25 pistons and have around the 9:1 comp ratio

Edited March 7, 2007 by Bl4cK32

[Spoolup]

To do the job right you need to do the following:

• rebush the small end to suit 21mm or 22mm pins – whatever you are using

• clearance ( machine ) the big end of the rod and small end side clearances so they fit on the big end journal of the crank and in the piston – as they are wider in std form

• you need to have the big end bearing machined in the rod at the same time otherwise it sticks out past the rod and wont fit on the journal

• machine the big end of the rod so it fits down the bore – as they are wider than the bore in std form and wont go down the bore

• then resize the big end tunnel after all that machining – as it distorts the big end tunnel clearances

• grind the crank approx 7 thou ( from memory ) to suit the rods with 40 thou oversize chev bearings

Its not a cheap exercise to get it done correctly

please shed some info as far as bearings and or mods required for the rods?

[@irborne]

I updated my piston list from P221

Added a new p/n for a flat top piston from Arias and added compression ratios for the Arias pistons. Two are quite high for a turbo engine!

Suit RB30/26

p/n= AP332103

flat top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 8.4-8.6

VHR32: Are these parts number off Arias catalog or is it a custom job part number?? I was looking over Arias current catalog and these numbers are not on the list.?!?

[Alf]

Suit RB30/26

p/n= AP332104

10.6cc dome top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 9.2-9.4

I have these, they also suit 25 as listed by Rocket industries.

[VHR32]

VHR32: Are these parts number off Arias catalog or is it a custom job part number?? I was looking over Arias current catalog and these numbers are not on the list.?!?

They are Rocket industries part numbers, they get them made from Arias and stock them here in Australia.

I have these, they also suit 25 as listed by Rocket industries.

All pistons suit 25 and 26 head, 26 has slightly lower compression due to the larger chamber.

What c/r did yours turn out to be?

What sort of boost do you run?

Has much timing been put into it?

[Spoolup]

Gary - what fuel filter is available that wont restrict the new fuel lines that Im about to install ? As most seem to be smaller than the 9 mm fuel hose ?

Cheers

From memory, Dash 6 fittings, they bolt straigh to the pump and 9 mm ID hose.

Under the car using the standard fuel rail clamps.

I use the standard feed pipework as the return and remove the standard return pipework.

On the R32GTST, I used the HICAS pipework, it was there, in the right place and plenty big enough.

cheers

[Guilt-Toy]

Hey

Can you work out the ACL one please? i got ACL pistons on in mine and when i do a compression test it sits at 120 in each cyl. the numbers on the top are

RA9608x 0.50 RIB 0.10 SE

Id like to know how low it is - i dont know if these are VL turbo ones or not - they do sit right up to the top of the block though. here is some pics

I updated my piston list from P221

Added a new p/n for a flat top piston from Arias and added compression ratios for the Arias pistons. Two are quite high for a turbo engine!

CP

All compression ratios are based on zero deck height, 1.2mm head gasket (7.13cc), RB25 @ 62.5cc, RB26 @ 64.5cc. They assure me they have done alot of work to make sure the facts are correct.

p/n= CP-RB30/26-.20

Flat top with no valve pockets

8.2:1 COMPRESSION RATIO with RB25 head and bit less with RB26 head

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize but can be custom ordered in any size.

p/n= CP-RB30/26-.20-9.0

6.0cc dome top,

9.0:1 COMPRESSION RATIO with RB25 head and bit less with RB26 head

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize but can be custom ordered in any size.

*Care must be taken when using on RB26 with more than 11.5mm valve lift*

ARIAS

Suit RB30/26

p/n= AP332103

flat top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 8.4-8.6

Suit RB30/26

p/n= AP332104

10.6cc dome top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 9.2-9.4

Suit RB30/25

p/n= AP332105

13cc dome top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 9.5-9.8

WISECO

Skyline RB30 w/ DOHC RB25det cylinder head

1.260" compresion height, 66.5cc head chamber, Dish top -11.3cc, 7.0:1 compression ratio, 21mm pin, 1mm gasket thickness, 1mm deck clearance.

K577M865 86.5mm

K577M87 87.00mm

ACL

6MKRY9608 (VL turbo)

87mm, -4.5cc dished top, 1.261" compression height, 21mm pin,

Standard RB30ET pistons are 7.8:1, with RB25 head it is 7.1:1

These are bumped up to 8.5:1 so with the RB25 head it may give about 7.5:1??

Using http://www.csgnetwork.com/compcalc.html I came up with 8.5 for VLT (spot on) and 7.6 with twin cam head with 64cc chamber.

I entered: 2, 87, 85, 87, 1.2, 64cc, -4.5cc = 7.6:1

BUT these have a lower compression height than the CP/Arias and im sure it stuffs up my calculations but its late and im too tired to look at it any more...

[Spoolup]

they are the VL turbo pistons.

Same as Im using, but with the NEO head.

You must be running reasonable low comp, high 7's maybe 8.0:1

[Guilt-Toy]

sweet.

i wanted low compression so i can put some big boost into it.. should be able to see 30psi on pump fuel im hoping...

i could shave the head a mm or 2 though couldnt i ?

[Spoolup]

yeah - you'd have to cc everything and then work out how much to take off the head to get the comp your after.

Higher comp gives better off boost respose, better fuel economy and if your tuner is good ( I know your tuning it - so no offense implied ) you should be able to make good power on lower boost.

Mine has no detonation at 18psi on 100 Shel V power, and Im hoping to run 22 plus psi.

[2BNVS]

after talking with steve from QRI he told me that for mainly street with occassional drag the p/n= CP-RB30/26-.20-9.0 would be the best ones to go for as with the rb26 head comp would drop down slightly which is where id want to go... ill just be using total seal gapless rings, as we've used them many times on other cars and prefer them

ben...

[Guilt-Toy]

come to think of it - my head has been shaved twice and the block has been shaved twice (to get good surface)

so it should be around the early 8's im thinking

[Spoolup]

yeah probably , could me more - hard to figure out once its assembled though

come to think of it - my head has been shaved twice and the block has been shaved twice (to get good surface)

so it should be around the early 8's im thinking

[Alf]

They are Rocket industries part numbers, they get them made from Arias and stock them here in Australia.

All pistons suit 25 and 26 head, 26 has slightly lower compression due to the larger chamber.

What c/r did yours turn out to be?

What sort of boost do you run?

Has much timing been put into it?

The motor is 95% complete.

Rocket/ARIAS are pretty much spot on when they say the AP332104 set makes 9.2 - 9.4:1 with a stock head, I calculated, it to be 9.3:1 based on 63cc bowls.

My R33 25 head has been resurfaced at least twice so when cc'ing the bowls they came to 58CC's, with a (1.3MM) stock head gasket the CR for my motor came to 10:1 comp.

I'm aiming for 9:1 so I'm looking for a MLS headgasket almost double standard.

The thickest I've found so far is this:- CMC4323-074 Cometic - Multi Layer Steel Head Gasket

Rb30det 3.0l 87mm Bore .074"(1.88mm) Thick. Which would make 9.5:1 comp.

At the moment the other option is to have one custom made.

Edited March 8, 2007 by Alf

[VHR32]

Woah! That would be responsive and great off boost!

[Cubes]

Mines an interesting setup. :S

I run the Wiseco RB25 pistons with a supposive 14cc dome and 1.240" pin height. 0.051" Cometic Headgasket 62cc combustion chamber.

The rods have been resized etc. Unsure how this will affect how the piston sits in the bore.

The engine builder said he was decking the block 0.040" due to the rb25's lower pin height. (1.240 vs 1.280)

If the block has been decked 0.040" which would result in an expected 0deck height then that would achieve a comp ratio of 10:1. :S

But I'm sure thats not the case as all cylinders only have ~154psi and have done so since day one.

If the deck height is 0.040" that drops the comp ratio down to ~9:1. But still 154psi for 9:1? Sounds a little low. BUT the stock rb25de n/a cams will be bleeding a little of that compression off as they do run a little more overlap compared to stock turbo cams.

Either way my tuner believes the comp is down around 8.5:1 ish according to the amount of ignition he runs vs boost level and power.

So who knows lol. :S

It does return excellent fuel economy though. Local short trips etc i'm getting mid 10's to low 11 litres per 100km's.

It does feel a hell of a lot more responsive than a mates GTS4 rb30det BUT that is running a much larger turbo, 250kg odd heavier car + my head has had quite a bit of porting/polishing and valve deshrouding done all of which helps.

[kastin]

i didn't think cylinder pressure had anything to do with static compression ratio? ie u can have a 170psi cylinder at 7:1 or 170psi cylinder at 10:5

Or am i wrong?

[Cubes]

Kastin,

You are correct, as I said in my post cam shaft specs (overlap etc) influence the guage reading/dynamic compression.

So given 2 cars with identical static comp ratio's and identical cam shaft specs both 'should' read near identical on the same guage.

[Craved]

anyone know a cheap place in Sydney to get some ARP rod bolts for the std rb30e rods?

[Alf]

I'm interested to know what radiator, fan, mods to reduce heak soak etc... you guys use for your 9:1 +15Psi motors and how well is the heat controlled in traffic and when giving it some stick.

I'm paranoid as it is with the stock rb20 in peak hour traffic.

This is what I've got planned for mine:

Ceramic coated and dry lubed ARIAS pistons :- done.

Ceramic coated valves :-done.

EF twin 12" thermos :-done

19 row oil cooler with thermo fan :-done.

Alloy double pass radiator :-coming soon.

Breather tank : coming soon

Mod inlet manifold for 3 extra coolant lines. :- coming soon

http://www.skylinesaustralia.com/forums/up...9_514_47789.jpg

http://www.skylinesaustralia.com/forums/up...9_514_50972.jpg

Edited March 11, 2007 by Alf