RD28->RB28 conversion, Offsetground crank

[Duncan]

I believe 3.4 strokers requires the rb30 block height, and may also require clearancing in the block too.

[flying fridge]

The big Problem to solve here are the different oil and water channels in the rd28 block to get matched to a rb25/rb26 head, i guess for the other crank related stuff there is a solution. 
How to get the oil and water channels matched? 

[GTSBoy]

24 minutes ago, flying fridge said:

How to get the oil and water channels matched?

Well, if it has been successfully done already, then knowing that much is half the battle won.

If it has been done but some of the coolant passages (or worse even, some of the oil passages) are just left completely blocked off, then I would consider the whole exercise a walkaway - if you want to beat on the engine. For a project where you were just desperately trying to keep a historic vehicle alive, then maybe I would tolerate bodgy shit. But not for a perfmormance project.

The trick will be to buy headgaskets for both engines, stack them up and see what falls out. If you have to move some openings a little, perhaps with a little welding to close up one side of some of them.....then maybe OK. If you have to try to drill tiny bleeders to allow for steam to escape (gasp!) or for at least minimum flow of coolant in an area (see bodgy shit referred to above), then maybe not so OK.

What is teh history of people using this block with a twincam head on it? Done at all? You're the first?

[flying fridge]

I guess we would be the first guys to drive a rd28 on the street, some guys are driving them for racing but without any water gallery’s but with grout etc. 

can someone with more experience please explain the different galleries in the Rb Block (left side in the picture) to me? I’m not sure on all of them if they are oil or water galleries.

[WMDC35]

22 hours ago, GTSBoy said:

Well, if it has been successfully done already, then knowing that much is half the battle won.

If it has been done but some of the coolant passages (or worse even, some of the oil passages) are just left completely blocked off, then I would consider the whole exercise a walkaway - if you want to beat on the engine. For a project where you were just desperately trying to keep a historic vehicle alive, then maybe I would tolerate bodgy shit. But not for a perfmormance project.

The trick will be to buy headgaskets for both engines, stack them up and see what falls out. If you have to move some openings a little, perhaps with a little welding to close up one side of some of them.....then maybe OK. If you have to try to drill tiny bleeders to allow for steam to escape (gasp!) or for at least minimum flow of coolant in an area (see bodgy shit referred to above), then maybe not so OK.

What is teh history of people using this block with a twincam head on it? Done at all? You're the first?

There was a couple of gtr's at the last gtr Cootamundra day running rd28 block 

[GTSBoy]

On 6/27/2023 at 10:25 PM, flying fridge said:

I guess we would be the first guys to drive a rd28 on the street, some guys are driving them for racing but without any water gallery’s but with grout etc. 

can someone with more experience please explain the different galleries in the Rb Block (left side in the picture) to me? I’m not sure on all of them if they are oil or water galleries.

Here's one image to help.

And here's my thoughts, which I hope are all correct.

[vladKraft]

Found a project of build rd28 block rb, but owner dont go on contact. This is translated spec:

-Based on rd28 block, RD28 crank with spline drive gears JUN oil pump, forged conrods from golf with machining.

-Tomei 88 pistons.

-Custom adapter plate for head, 2 external oil drains.

-Headgasket Cometic, 1.5мм. Oil sump from rb.

-Restrictors in head. Camshafts GREX 264, lift 9.15.

-Balanced all crank mechanism.

-Crank bearings ACL, Conrod bearings RD28 stock.

-Compression ratio (measured) 9.15. Engine capacity 3027CC.

Really want to know about his adapter plate. In fact there are a lot of rd blocks found used in drag race with concrete filled galleries.

Edited July 1, 2023 by vladKraft

[Isacnr7]

On 6/26/2023 at 11:39 PM, GTSBoy said:

Just buy billet crank?

Yeah i think u missed the budget part about this

[GTSBoy]

6 hours ago, Isacnr7 said:

Yeah i think u missed the budget part about this

The poor man pays twice.

[flying fridge]

Still the rd28 is the best option for internal strength even compared to the Rb30 block, that alone is enough for me to take the extra hassle that comes with it

[flying fridge]

8 hours ago, vladKraft said:

Found a project of build rd28 block rb, but owner dont go on contact. This is translated spec:

-Based on rd28 block, RD28 crank with spline drive gears JUN oil pump, forged conrods from golf with machining.

-Tomei 88 pistons.

-Custom adapter plate for head, 2 external oil drains.

-Headgasket Cometic, 1.5мм. Oil sump from rb.

-Restrictors in head. Camshafts GREX 264, lift 9.15.

-Balanced all crank mechanism.

-Crank bearings ACL, Conrod bearings RD28 stock.

-Compression ratio (measured) 9.15. Engine capacity 3027CC.

Really want to know about his adapter plate. In fact there are a lot of rd blocks found used in drag race with concrete filled galleries.

Very interesting, can you attach the link to this here please? He used golf rods?? 

[WMDC35]

2 hours ago, flying fridge said:

Still the rd28 is the best option for internal strength even compared to the Rb30 block, that alone is enough for me to take the extra hassle that comes with it

I haven't had much to do with them but if you bore it to suit rb pistons 86.5 etc then there's not much difference, if you can use an 85mm piston then would be thicker bore than a 30 

[joshuaho96]

4 hours ago, flying fridge said:

Still the rd28 is the best option for internal strength even compared to the Rb30 block, that alone is enough for me to take the extra hassle that comes with it

I’m pretty sure from what I recall of this if you bore to standard RB26 size the cylinder walls are no thicker than a normal RB. If you want a simple solution just get a PRP block whenever they release that. 

[vladKraft]

8 hours ago, flying fridge said:

Very interesting, can you attach the link to this here please? He used golf rods?? 

Its a problem I found him only offline through friends in laurel club, who participate in russian nismo club in another city, he selled car, dont want to say how it built, who buyed it and also behave like asshole. Tried to get drawings or photos of adapter plate and some more explanations, but no results. https://habarovsk.drom.ru/nissan/skyline_gt-r/36376520.html thats only link that i have

Edited July 2, 2023 by vladKraft

[flying fridge]

6 hours ago, WMDC35 said:

I haven't had much to do with them but if you bore it to suit rb pistons 86.5 etc then there's not much difference, if you can use an 85mm piston then would be thicker bore than a 30 

6 hours ago, WMDC35 said:

PRP did a block comparison few years ago: 

rd28 weighs about 10kg more than the same sized Rb30, there is more material/reinforcement in the block between the bore and the main caps, the external ribbing is thicker, internally inside the block is ribbing  below the bores, deck thickness is almost 13 mm compared to all rb‘s with 7-8mm. And it has oil squirters which Rb30 doesn’t.

The 85mm piston has few advantages:

-if you stay below the 86,5mm bore you get more wall thickness left obviously compared to any Rb block that you would have to hone to 86,5mm at least. 

- if you go to say 86,5 or 87mm bore you have more scope to do offset boring and you will end up with better wall thickness overall.

Edited July 2, 2023 by flying fridge

[flying fridge]

4 hours ago, joshuaho96 said:

I’m pretty sure from what I recall of this if you bore to standard RB26 size the cylinder walls are no thicker than a normal RB. If you want a simple solution just get a PRP block whenever they release that. 

I‘m excited to find out how many legs it will be and when it comes out 👍

[GTSBoy]

32 minutes ago, flying fridge said:

I‘m excited to find out how many legs it will be

If you have to ask, you probably don't have enough legs. Might need to go body snatching.

[flying fridge]

9 minutes ago, GTSBoy said:

If you have to ask, you probably don't have enough legs. Might need to go body snatching.

Unless PRP will change the internal built of their Rb30 it will be still weaker than the rd28, therefore not interested 

+ it will be like 4-5k minimum, even their refurbished used „prp prepped“ Rb30 is like starting at 2700€ up to 4500€.

but we will see 👍