R33 Rb30 Conversion

[Cubes]

it is in the lower hose to position it well below the radiator water line. To add some reverse engineering to understand the poroblem look at the vl commodore where the fill up point was lower than the highest point in the cooling system they always cracked head cause the bubbles in the cooling system would gather in the back of the head and crack them. PLus the way water criculats in the rb engine it is the last outlet so it is the stappoer that allows the water to heat up in the engine first!!

I'm a little sceptical about the RB30E's in the VL's cracking heads due to the radiator being lower.

I was under the impression the biggest problem with cracking heads was the plate in the radiator that seperates the top and bottom tank (tanks are located on the left and right of the fins) rusts, water passes the fins causing the car to overheat spit water out the overflow eventually run dry, suck in air create a hot spot THEN crack the head.

If you notice the Nissan RB's have a different radiator setup with a top tank and a bottom tank with fins inbetween. None of this horizontal water flow as per the VL.

[Alf]

Water flows in the lower hose from the radiator to the block and out of the top hose back into the radiator.

Ever felt the radiator hoses while the car is running, bottom one is cool and the top is hot.

Cheer's for the reply, it's what I thought but wasn't 100% sure.

Iv'e never started my 33 I bought it with a blown motor.

[RB30-POWER]

Iv'e never started my 33 I bought it with a blown motor.

Bet you can't wait to start that bad boy

[Alf]

Bet you can't wait to start that bad boy

That's an understatment, ooooh yeah.

[Cubes]

I remember the feeling quite well.

[Alf]

At what point do the girdle bolts become a concern?

I've been looking into a girdle stud kit and a RB26 head stud kit, and yes I'm aware that the head and block will need drilling for the thicker head studs.

[Cubes]

It would be worth while looking at the girdle if you were to constantly see high 7000rpm rev's.

Anything to help tighten up the bottom end will help remove/move those nasty harmonics some where else.

[Sydneykid]

At what point do the girdle bolts become a concern?

I've been looking into a girdle stud kit and a RB26 head stud kit, and yes I'm aware that the head and block will need drilling for the thicker head studs.

The ARP main bearing stud kit screws straight in, no mods required. If you are using an RB26 head then you have to drill and tap the RB30 block for the larger RB26 head bolts. So drilling and tapping for the even larger ARP head studs is no extra work. But be aware that you can't simply use a hand drill and tap, the studs have to be perfectly parrallel to each other and at 90 degrees to the block surface, otherwise the head will not slip over the studs.

Hope that helps:cheers:

[Alf]

If you are using an RB26 head then you have to drill and tap the RB30 block for the larger RB26 head bolts

Does the 25 head need drilling when using the 26 head studs?

ARP don't sell a head stud kit for the 25.

PS: Thanks for the fast and helpful replies

[Fitzpatrick Speed Works]

Im unsure but the rb26 head studs are 12mm x 1.5mm thread pitch. you can check this against the rb25 if they are the same no drilling of the head required!!!

[Nismo_Boy]

I'm not sure if this has been covered before in this thread, but reading 85+ pages’ doesn’t seem that fun just for one question, so here goes;

As far as I know, I'm told you can only use the rb25/rb26 head for this conversion - But after doing a quick search, some one stated that some one had used the rb20 head, is this true? If so, how much more work is needed to make it fit?

I ask as I have a good N/a rb20 head doing nothing, and the rb26dett I was buying has since been sold to some one else.

Thanks, Josh.

[Cubes]

The RB20det head is like trying to blow through a straw.

The RB25/26 head is like blowing through 2 straws.

You will pick up some average power with the rb20det head on the 3ltr however peak power rpm will be severely limited UNLESS you fit huge cams etc.

The RB20det really has ports that are too small and valves that are way too small for the 3ltr to ever really make any decent power easily.

[Nismo_Boy]

Thanks for your reply Cubes,

Seeing as I already have the head though, would it still be worth while sending it off for some major machine work ect?

Just seems like a waste of a good motor as no one really wants N/a things.

[Skyrine-Dave]

i wouldnt bother with the rb20 head at all.. It my be a good engine you have, but the amount of money you'll end up spending on it really wouldnt justfiy the end result.

You would need to spend a fair bit to get teh head flowing similar to an RB25 head.

I think its GiJor33? that is selling an rb25 head for $600... it jsut needs assembly... its been checked and everything. Really i wouldnt bother with the rb20 head., but thats just me.

[GTR-Ben]

Does the 25 head need drilling when using the 26 head studs?

ARP don't sell a head stud kit for the 25.

PS: Thanks for the fast and helpful replies

I had my block drilled to match the 26 head. Some people just use the smaller bolts.. I don't like the idea of that..

[dnb]

im going to take my 3l block back and get it tapped for studs.

so you just use a rb26 kit?

what about the bottom end? i will get studs for there aswell.

are the bolts the same size on the 26 for the bottom?

[Fitzpatrick Speed Works]

you dont need to use studs on everything people. I bought new rb26 head bolts from nissan for $140, and i have the advantage i dont need the camshafts out to fit and do up my head. For the mains and the crank girdle again i bout new bolts off nissan for $48. A bolt is the same strength as a stud. It would be different if you had to run a stud so you can run a bigger bolt size but 12mm an 10mm for the crank is very sturdy!!!!

The rb26 main cap bolts are 62mm long and rb30 is a little shorter i think with three of them a different length all together so just buy rb30 stuff for there.

[GTR32]

Guys;

i'd like to know what you think of an idea but please put your flamethrowers away. i want to do an rb 30 conversion on my R32 GTR. it's a daily driver, doesn't see the track and i don't drop the clutch at revs from the lights. but i do flatten it from there up to the speed limit if possible and i like torque for roll ons and corner exits.

i know the merits of rebuilding an engine with forgies etc but i think it's just too much for what i need.

i've read the threads here (ok most of them) and it seems a stock the rb30 is pretty bullet proof (see the very first thread from joel) and can stand 300-330 rwkw and 450 ftlbs reliably all day.

this is the bit where you put the flamethrowers down...

i called GEM engines and they quoted $1600 changeover for a short engine that could be built to my requirements if necessary ie balanced etc. so if i get a block drilled for the cam tensioner, the head bolt holes enlarged to suit an rb26 head, make sure the cr is right and keep revs to 7500 what can go wrong?

it seems to me that i'd be getting something close to a production line standard engine and i save myself the hassle of a rebuild.

over to you

[the phantom]

Dont forget the block adaptor plate for the 4WD sump, and the associated block mods...

[Scooby]

Dont forget the block adaptor plate for the 4WD sump, and the associated block mods...

Thanks Phantom, I left that out, I was was planning on going down the route of getting a RIPS one from NZ.

Regards