Re-sleeving RB26 block

[Dror]

What are peoples thoughts on machining and re-sleeving a GTR block. Will it be as strong as original? Stronger? Or is it not recommended? I have heard different opinions on this and would like to see if anyone has done this before.

Cheers, Dror

[hungry6]

Unless your chasing massive HP then don't unless your cylinder wall are stuff.

Generally sleeving gives more strenght when quality sleeves are used and fitted by a competant machine shop"rare"

There are quite a few big hp rb26 running around with sleeve, but most of them aren't into discussing about what they've done.

Talk to a machine good shop and see their view.

[wrxhoon]

whats your reason to sleeve rb block ? just get the new pistons and machine the block to suit . is the block standard size now ? 86mm pistons ? if yes you can go to 86.5 or 87 mm

[Dror]

I don`t have a block at the moment. The one from my car has nice big holes in both sides. The problem is finding a block that is still at standard bore or a maximum of 0.5mm over. I am chasing around 700 flywheel hp from this engine so do not want a block that is over 86.5mm bore.

Cheers, Dror

[Sydneykid]

I am chasing around 700 flywheel hp from this engine so do not want a block that is over 86.5mm bore.

Cheers, Dror

We have several 900+ bhp engines with 87.5 mm bores.

[Dror]

Sydneykid,

Have you not had any problems at this power level with a block overbored that far? I had been warned that the cylinder walls would crack at this sort of power.

Cheers, Dror

[Sydneykid]

Sydneykid,

Have you not had any problems at this power level with a block overbored that far? I had been warned that the cylinder walls would crack at this sort of power.

Cheers, Dror

Only done 11 engines that bore size, no problems so far.

[N I B]

We have seen 87mm bore RB26s with cracks .we use std or .5mm over bore in very high powered RBs.We use new blocks when the budget allows at a cost of around 2k but remember that much of the machining is already done so some cost is recovered there.

500rwhp is the max we run 87-88mm at.The block flexes and cracks exturnaly on large bore motors and loose power due to bore flex.

[Merli]

I'm building my block for about 700hp (with nitrous) and I'm not game enough to overbore more than 20 thou.

Why un-necessarily weaken the block if you don't have to?

[N I B]

I think we do more RB engines than anyone in australia and believe your thinking is spoton.

I can take a few photos of the cracking if you want.

[PurpleR32]

Did i read somewhere Munro cracked his block with a 87.5 bore?

[NRB]

Photos would be good. I love these educational threads with pictures illustrating things... much like Troy's crashed car thread.

[hungry6]

Damn, if those are figures to go by, I'm glad i sleeved my block.

[Sydneykid]

We have seen 87mm bore RB26s with cracks .we use std or .5mm over bore in very high powered RBs.We use new blocks when the budget allows at a cost of around 2k but remember that much of the machining is already done so some cost is recovered there.  500rwhp is the max we run 87-88mm at.The block flexes and cracks exturnaly on large bore motors and loose power due to bore flex.

It is interesting how even very skilled people can have differing opinions and experiences. I have seen 86 mm (standard) bores with cracks as well, I don't believe that the bore size is the only reason. Temperature management, machining tolerances, metallurgy, boost pressure and parts used have as much to do with it as arbitrarily limiting bore sizes. Plus we never use "new" blocks, I much prefer an aged one. The more heat cycles they have seen, the higher chance there is that any manufacturing (and casting) stresses are long gone.

I like it when people have differing opinions, makes for an interesting discussion.

[TIMMMAYYY]

I think munro cracked his block on his street 33 chasing 500rwkw on the dyno. He should be able to confirm this.

[Cubes]

He was also running the OS 3ltr kit though wasn't he?

[SR910]

no

[Cubes]

Yer checked up he now uses the 3ltr as the drag car. No longer a streeter.

[GDZ1LA]

can a rb30 block be fully boared out (to like 94mm) and have a full new sleve put in to run 89-90mm pistons? it would seal the water jacket at the top and bottom of block,

what do the os gikin boys do when resleeving there n1 blocks with the rb30 kit? does it rmove the whole existing sleeve or just enought to press in?

when a rb engine is re-sleeved is it fully bores out or not?

i did the maths checking out spaing etc, i could use 92mm pistons if this works, and have new sleeves and sill have 2mm of bore around hole cyl (is 2mm enought) idd say 90mm a reliaty tho, 87x90=3320cc nice

[Sydneykid]

can a rb30 block be fully boared out (to like 94mm) and have a full new sleve put in to run 89-90mm pistons? it would seal the water jacket at the top and bottom of block,  

what do the os gikin boys do when resleeving there n1 blocks with the rb30 kit? does it rmove the whole existing sleeve or just enought to press in?

when a rb engine is re-sleeved is it fully bores out or not?

i did the maths checking out spaing etc, i could use 92mm pistons if this works, and have new sleeves and sill have 2mm of bore around hole cyl (is 2mm enought) idd say 90mm a reliaty tho, 87x90=3320cc nice

Adventurous, and I have no idea. RB30 blocks are cheap, all I can suggest is to try boring one cylinder and see how far you can go. It may also be worthwhile to check the cylinder head first. I don't think the water jacket will allow the combustion chamber to be much bigger than 88 mm. There would be no head gasket sealing surface.

From memory the OS Giken 3 Litre liners are around 5 mm thick at 86 mm bore, so that's ~96 mm OD.