R33 Rb30 Conversion

[JVDSKYRINE]

I am currently using one on my rb25/30 setup.

I had to do 2 modifications to make it all fit nicely.

1/ Move the Power Steering pulley about 5mm forward on the shaft. My mechanic also welded the shaft to the pulley to add strength. The pulley had to be moved forward as the GTR belts are thicker (4 ribbed) than the GTST belts (3 ribbed). Thus the ATI pulley has the p/steering belt a little more forward than the gtst. I am still using the GTST belts; haven't had an issue.

2/ Lathed up a spacer/hub for the engine fan. A 10mm spacer was made for the fan to move it further away from the ATI pulley, as without the spacer there was only a 0.5-1.0mm clearance between the fan blades and the front of the pulley.

10mm was a fraction too big as it clipped the shroud when loaded at 5000rpm, i just simply trimmed the shroud to clear the fan, but i think a 5mm spacer would have no issues.

Note: Mod 2/ would not be necessary if you are going to use Thermo Fans to replace the clutch fan. My mechanic has a thing that he doesn't like using thermo fans on Skylines as he has found the cars to overheat in the past. His build his rules; that way he's the only one i could blame if something goes wrong

thanks alot for the help!!! appreciate it! but yeah I am in canada so taking weather into things i think i will be fine using electric fans

[GTRgeoff]

I love mechanics Al. They are so afraid of trying anything new. 7 lap sessions of Lakeside in the GTR, which only has 320rwkw with the twin ducted setup never saw over 92 deg on a nice 29deg day. With a 50mm core that would drop right to the 85deg sweet spot.

[CeJay]

Great thread, I've read through 160 pages and learnt a few things and thought I'd post here and asks some questions, as I don't really want to read the next 160 pages just to find out lol.

Basically the comment was made that if you have a gts4 or gtr it is best to either get a gtr head to do the conversion? or get a 26 instead?(in the case of a gts4? I currently have a 25 in the car) As mounting the rb30 in the bay without a greddy or plazmaman (sp) IM was a PITA? Is this still the case?

[GTRgeoff]

Chris, I think it was more along the lines of making life easier for 32GTSts/GTS4s so the bonnet doesn't need to be reworked. The inlet and manifold on a 20 and 25 engine sit above the head, so they then contact the bonnet, or even the strut brace. In these cases it is better to go with a side inlet system instead of an overhead inlet.

My preference was for the GTR manifold and throttles in the race car so the 26 head was the perfect solution.

BTW I've costed the 26/30 out several times and not including the turbos and Y pipe I keep getting the figure of $6500 cost doing the labour myself and including outsourcing the machining (naturally as no-one has all the machining tools in there backyard). That includes the Spool rod/CP piston package from Spoolup (Brad). Add extra for a harmonic balancer, turbos, special exhaust manifolds and dumps, Y pipe (and yes, the GTS25t exhaust will bolt straight up to twins; very convenient) and any other cool stuff you really desperately need. The trick is to get the head and inlet system at a decent price. If you can get a complete head with all bits bolted to it then half the grief is gone.

Then again there is absolutely nothing wrong (IMO) with going 25/30 for a sensational budget build.

[Al]

I love mechanics Al. They are so afraid of trying anything new. 7 lap sessions of Lakeside in the GTR, which only has 320rwkw with the twin ducted setup never saw over 92 deg on a nice 29deg day. With a 50mm core that would drop right to the 85deg sweet spot.

Am................ who said he never tried

............... he doesn't like using thermo fans on Skylines as he has found the cars to overheat in the past.

Now i do realize that is a very debatable topic, but i chose to go with what he felt was best.

[RB120WHY]

Some pics of mine for your enjoyment

[GTRgeoff]

S'alright Al, just winding you up mate. I know how protective you are of your favourite mechanics

Nice looking engine Steve. Which balancer is that on the front?

[RB120WHY]

S'alright Al, just winding you up mate. I know how protective you are of your favourite mechanics

Nice looking engine Steve. Which balancer is that on the front?

It's an Atomic brand. Exceeds Andra requirements which is all i am concerned about. It will be in the car by the end of the week. Damn full time work

[bluegts]

This has been covered - you can not just bolt the RB25DET R33 VCT head straight on without modifying the water gallery and blocking off the oil feed hole - going with no VCT

What needs modifying on the water gallery? And you didn't mention anything about an oil feed to VCT to lube up the cam. I've heard/read too many sides on this. What are you risking by not running oil to it? Why do the 25de non-vct heads not require an oil feed for it? Where do they get their oil?

Cheers, Jack

[shanef]

What needs modifying on the water gallery? And you didn't mention anything about an oil feed to VCT to lube up the cam. I've heard/read too many sides on this. What are you risking by not running oil to it? Why do the 25de non-vct heads not require an oil feed for it? Where do they get their oil?

Cheers, Jack

http://www.skylinesaustralia.com/forums/se....html&f=184

[Cubes]

or even better read the rb30 guide then look at the head and nut something out.

if you can't give the head to your machinist and tell him what needs to be done.

[bluegts]

Yeah heaps helpful. I've been looking into and reading about this for months, if I knew the answers I wouldn't have bothered asking...

Where exactly in the rb30 guide does it state how/why to modify the water gallery, or why the rb25de head doesnt require an oil feed? Or if it does, how it is done?

I apologise if I have missed something obvious, but I am only aware of the mods required to the VCT on the det head.

[Cubes]

Page 1.

The R32 RB25DE head bolts straight up to the RB30E bottom end. All water/oil galleys line up.

N/A valve springs have less tension which may cause issues when running big boost.

Cams and springs are interchangeable with RB20DET items. Valve springs identical, cams are slightly different.

The R33 RB25DE/T has variable cam timing (VCT/NVCS); this requires welding of the heads VCT oil feed.

The head still requires oil to its VCT, you will have to tap in to the oil galley and run an oil feed to it. The most common

used feed is T’ing into the oil pressure sender feed.

Compare the pictures below to gain an understanding of how the head needs to be modified.

Nothing states exactly thats you to yourself to look at the headgasket look at your head + the pics in the guide and think ok.. this needs to be done.

[r33_racer]

I disappeared for a few months, come back and people are still asking the same questions about the same things....dang i was hoping there would be new topics and problems people have come across by now

same ole same ole.... someone needs to do something really different and interesting!

[bluegts]

lol lol lol

I have complete understanding of the oil side of things. Someone refered to modifying the 'water' gallery. Or is blocking the vct oil feed and running an external line what they refered to as 'modding the water gallery'

If it is then I've obviously had a mis-understanding of what was said, if not then I'm still very lost with the 'water' gallery thing

Thanks, Jack

[Cubes]

Just block the vct oil feed off in the head via the face then drill/tap a new feed for it.

U can tell what to do by simply looking at the pics.

[shanef]

I disappeared for a few months, come back and people are still asking the same questions about the same things....dang i was hoping there would be new topics and problems people have come across by now

same ole same ole.... someone needs to do something really different and interesting!

so u missed my girdles and brads stroker cranks then...

[Craved]

i remember reading somewhere about what bluegts is asking - someone welded steel onto the Block arounda water gallery then had it decked - apparantly there was only a small amount of overlap between the water gallery and the edge of the block..

[Alf]

1st Q: Does anyone know what percentage a MLS head gasket should compress?

2nd Q: What gains are there from hi flowing a GT35R ?

Edited April 15, 2008 by Alf

[bluegts]

bah!!!! Nobody gets what I'm trying to ask. Oh well. It is not vct related.