# RB26 (97) Block porous



## hornet (May 29, 2007)

Hi All,
Can anyone tell me if they have ever heard of any RB26 engine prone to leaking because the block became porous due to inferior casting?

I was told this by the engineer after having the car serviced locally by my skyline specialist, he told me that there was water/anti-freeze running down the side of the engine and on to the cross member underneath exhaust/turbo side.

Can anyone shed any light on this, is this true? can they be porous, I'm sure someone out there with the knowledge of RB26 engine can enlighten me as to the course or problem I could possibly have, one train of thought is it could be core plugs:flame:? any other possible suggestions:runaway:


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## weggy (Nov 14, 2007)

I was told about this that the later blocks are prone to being porous that is why lots of people use R32 blocks.


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## Piggaz (Sep 5, 2002)

As above. I have heard whispers that the Series 3 R33 blocks wernt the best.


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## paul cawson (Jul 3, 2003)

The block from my 92 R32 was porous, it also had a crack between the head stud hole and water jacket.

I still had a few track days out of it before it blew up, due to other issues


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## G40tee (Feb 25, 2008)

have heard this also


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## blue34 (Jul 28, 2005)

For "porous" read cracked block, cast iron isn't porous! check externally as far as possible with a torch and a mirror for obvious cracks. 

Is there any evidence of water in the oil or vice versa? if so be suspicious of the head gasket too and don't forget to have a very careful look at the core plugs and hoses if it's simply a coolant leak. 

Did you have plenty of anti-freeze in during the recent cold weather? Look for milky sludge in the oil and water are there obvious air bubbles in the expansion tank? Is the radiator over-pressurizing and lifting the radiator cap.

Let us know.


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## EtienneGignac (Mar 20, 2008)

I had oil in my coolant. Turns out the block was cracked. A couple of hairline cracks between the oil and water gallery. It was on a 90 R32.

Here found a pic:










Right after magnaflux. Can you see it ? It's on the lower right of the round hole. This was one of many cracks.


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## ctjordan (Jan 26, 2009)

EtienneGignac said:


> I had oil in my coolant. Turns out the block was cracked. A couple of hairline cracks between the oil and water gallery. It was on a 90 R32.
> 
> Here found a pic:
> 
> ...


Does this mean replacing the block? Is there anything that can be done?


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## Andy Hornsby (Mar 22, 2003)

Think John's on his forth block!!


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## paul cawson (Jul 3, 2003)

ctjordan said:


> Does this mean replacing the block? Is there anything that can be done?


Its common as are porous blocks, and depending on which power output you are aiming for does not really matter.


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## Bucky (Mar 21, 2003)

I had 3 cracks in my R32 block, these were between the head bolt holes and the water ways.

Also Porous blocks are common due to blocks being cast bad and air bubbles form in the cast when they are produced.
Anything cast has a chance of being porous.


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## max1 (Feb 24, 2002)

i have a porous block always drips jus below the turbo where the oil feed comes out ,i have also got numerous cracks loike the ones above and never had a problem ,i run over 900hp.
put in a can of block weld to water this usually stops the drip on mine .
the block i use was condemened by a couple of big uk tuners but i still run it after nearly four years .


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## Bucky (Mar 21, 2003)

max1 said:


> i have a porous block always drips jus below the turbo where the oil feed comes out ,i have also got numerous cracks loike the ones above and never had a problem ,i run over 900hp.
> put in a can of block weld to water this usually stops the drip on mine .
> the block i use was condemened by a couple of big uk tuners but i still run it after nearly four years .


The tuners will always say no to using a cracked block. Its not their money to get a new block.

It is piece of mind aswell though.


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## ctjordan (Jan 26, 2009)

max1 said:


> i have a porous block always drips jus below the turbo where the oil feed comes out ,i have also got numerous cracks loike the ones above and never had a problem ,i run over 900hp.
> put in a can of block weld to water this usually stops the drip on mine .
> the block i use was condemened by a couple of big uk tuners but i still run it after nearly four years .


Good to hear, I noticed two of these little hairline cracks yesterday after painting my block.


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## hornet (May 29, 2007)

Thanks Paul for your input, I'm wondering if its a case of over-tightening?
Well the leak now is something for me to sort come the spring..


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## lightspeed (Jul 11, 2002)

It's just fatigue cracks - repeated hot cold cycling, constant stress from head bolts and cyclic stress from cylinder pressure + block torsion and bending. Poilshing the edge of each waterway hole may help a little.

The N1 and GT blocks have a reduced size waterways in a couple of places on the deck where the distance to the adjacent head bolt is too close.


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## hornet (May 29, 2007)

Thanks Max,
At least your post was positive, I was going to try a ceramic radiator weld as a quick fix and play it by ear, If this does'nt work, where would I get Block weld? appreciate your help.
Alan.


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## Andy Hornsby (Mar 22, 2003)

Think you'd be better off in the long run getting a different block mate.


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## Bucky (Mar 21, 2003)

Buy a new N1 block, Newera supplied mine at a good price.

Then put your internals into that block with a new set of rings and shells and your engine will be fresh.


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