# Block advice N1 or 05U ??



## DrGtr (Jul 18, 2009)

I have search on the forum and found plenty of ideas but not sure what is true and tested from people or tuners, i am going for a 2.8 stroker and i will be running high boost on 2860-5 so prob close to 1.7-1.9 bar with 87mm bore at the moment , i have seen in threads people who say that the 05U standard blocks are good to handle up to 900 hp and 2.2 bars others say that they twist so they have to cement the block( how can you do this??) and others that the 05U is no good cause of porosity. My block is the 05U which came with my ukr34 and has 90000 miles that means a lot of heat/cold cycles. 

And my question is should i use a new n1 block for the 87mm bore and 1.7-1.9 boost or keep my block??? , i know the common sense for most people will be the n1 but please answer if you really have some experience or seen a live example than talk theoretically.
Thanks in advance for any inputs.


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## xxfr (Apr 28, 2009)

Did you go ahead with this build? I am in the same boat of questions so your input would be helpful.


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## Sub Boy (Jan 28, 2008)

I think most people would agree that the 05 block is fine with the size turbos you are running....In fact fine with a heck of a lot more.

Personaly if your 05 block is OK, Then spend your money elsewhere like in the head, Better gains there.


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## WvdB (Aug 26, 2008)

Be sure you use a good 05U block without any cracks. However, if you're running 87mm pistons and relatively higher boost, it's wise to use an N1 block to play it on the safe side. A proper N1 block is far more reliable and is a lot more resistant to cracking since the sleeves are thicker. Cracking can occur immediately or after 10k miles. The early RB26 blocks are somewhat stronger than the later ones, but still suffer from cracking. You can fill up your block with hardblock (cement) but it doesn't solve this problem since hardblock is normally only below the BDC, so you'd still have the problem of cracking channels. Hardblock (cement) increases the strength of your block.

It's just your own opinion on how much "risk" you want to take. There are people with 05U's that are running thousands of miles just fine, and there are people which have had 2 or 3 rebuilds due to cracking.


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## mrjolly (Aug 1, 2009)

what makes the blocks crack? and where do they crack ?
is it just the increased heat? the extra stress on the bottom end ? excess compression pressures ?
anybody got pics of a cracked block?
i thought the rb26 was supposed to be one of the toughest engines out there. 
surely the cause could be engineered out with improved cooling and fault detection etc.
i ask this as its not a problem you tend to hear about with other modded engines running 3 times stock power, its usually rotating parts that fail .
indulge me someone:bowdown1:
neeeeeeeeeeed iiiiiiiiiiiiiiiiiiiiiiiiiinnnnnnnnnnnnnnpuuuuuuuut


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## xxfr (Apr 28, 2009)

mrjolly said:


> what makes the blocks crack? and where do they crack ?
> is it just the increased heat? the extra stress on the bottom end ? excess compression pressures ?
> anybody got pics of a cracked block?
> i thought the rb26 was supposed to be one of the toughest engines out there.
> ...


Please search and read more. There are heaps of topics that will help you out.


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## DrGtr (Jul 18, 2009)

xxfr said:


> Did you go ahead with this build? I am in the same boat of questions so your input would be helpful.


http://www.gtr.co.uk/forum/137171-lets-do-together-d-cyr34gtr-ultimate-responce-4.html

page 4 you will see after long time of thinking, if you are going to spent as much as i did for a project like this you shouldn't stay with the 05U just to be safe.if you are planing a smaller project then dont spent the extra. 
I will make a video with all the parts in couple of weeks to put it the forum in my page, now just missing 2 044 Bosh, and a nismo intercooler. i will continue in the summer due to i am not in Cyprus during the year.


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## Cris (Sep 17, 2007)

WvdB said:


> ...The early RB26 blocks are somewhat stronger than the later ones, ...


I've heard this said before do you know the source of it?


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## WvdB (Aug 26, 2008)

I don't know what the source of that on this forum is. But i'm saying this based on my own experience. The early RB26 castings are somewhat thicker and thus stronger.


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## dmcl1980 (Aug 26, 2006)

Why not resleeve the block with the likes of Darton sleeves or some others.


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## DrGtr (Jul 18, 2009)

It could be done but would it be the same as the factory made N1? i dont thing so.


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