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Cracking Rb26 Blocks

Roy

By Roy,
in Engines & Forced Induction

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Roy Grand Master

Roy

Posted
Posted

I have been hearing about RB26 blocks slitting/cracking lately. It has now happened to 4 RB26s i know of, with them typically producing 320-360rwkws.

Is it a common problem? Is there anything that can be done to prevent it?

...i should add the examples i know of do track work, so it may not be the case on everyday cars that dont get put under constant loads/stress...

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https://www.sau.com.au/forums/topic/153329-cracking-rb26-blocks/
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GTRgeoff Grand Master

GTRgeoff

Posted
Posted

You should add examples.

I only know of a couple and they were pushing some big numbers.

Now find me an RB26 head with all your contacts. I don't want to have to fork for a whole engine to separate. ;)

Leewah Veteran

Leewah

Posted
Posted

I've cracked 2 in my Skyline life time.

When we sent the 1st one to see if it could be repaired, we got a phone call within an hour saying there were 7 cracks on the deck alone. Not even worth doing an xray on it.

The second block had a hairline crack b/w 3 and 4 and the bores were no longer round :rolleyes:

Both these blocks were used to make more than 600awkw though :yes:

dontfeelcold Experienced

dontfeelcold

Posted
Posted

Is there a common cause for block cracking?

There is an article floating around (seen it on this forum), that covers the Gibson GTR over the period it ran in the Group A era. It mentioned something about block cracking being caused by harmonics and the fix was different engine mounts.

Chris_R33GTSt Proficient

Chris_R33GTSt

Posted
Posted
Is there a common cause for block cracking?

There is an article floating around (seen it on this forum), that covers the Gibson GTR over the period it ran in the Group A era. It mentioned something about block cracking being caused by harmonics and the fix was different engine mounts.

Very interesting indeed! I just tried a search and came up with nothing. Maybe I'm just shit at doing searches...

wrxhoon Grand Master

wrxhoon

Posted
Posted

I have seen several cracked RB26 blocks ( all on GTRS though). Around the oil feed mostly , all had over 300awkw, all with aftermarket turbos, some 86mm bore , some oversize. At first they seem to just loose coolant but eventualy the crack goes throught to the bore . All the cracked blocks I have seen are the standard 5u blocks ..

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