GRT RB 26 Engine Head Mods/Repair

[ukracer]

I have mentioned this in another thread but as that is now buried and we have actually solved the issue an alternative problem seems to have been highlighted.

Although everyman and his dog have an opinion on whats actually gone wrong. sadly no one can be sure until we first get a Bore camera inside and almost certainly have to take the head off.

If all goes badly we will need the engine out again because some are saying it will have wasked the bores as it was mapped without referencing the fuel pressure. But not a lot we can do as I am not slagging of a tunner/Company until the whole picture has come out.

Put simply if we get luky it might only cost a new head gasket and potential a secret mod.
WE have got a photo of what we believe the mod looks like externally but not internally.

The mod in the center we know all about as its a oil return but would not allow oil into the water.
Its the mod between the two sides of the head that we are trying to get info on.
If the head is cracked internally between the water jacket and oil ways we have been quoted 650 plus vat for a repair.
But as I think I have found another price rip off (will post that in the other thread.) I can see why they mention a GTR tax.
Next worst case is just replace head gasket
Next Worst case, but might be cheaper depending on state of bores, is engine out and hone the bores and new rings etc.
Worst case is damaged bores and pistons and its game over as there is no more capacity for a rebore.

Anyway main priority now is to identify the fix for the head if it looks like its leaking between the water jacket and oil ways

 

[Ruffian]

Dayton sleeves are always an option.
Expensive but good.

Will ask a mate about the rb26 engine mod as used to drift one.

 

[Brad93]

Get the head laser welded if it does need doing. Can recommend a firm if needed, not cheap but do some brilliant work.

 

[tom2207]

would a diesel ft in there instead ,, at what point do you shout stop .
I take it that a replacement blocks not to be had ? keep the good bits and start with a better block.

 

[ukracer]

Get the head laser welded if it does need doing. Can recommend a firm if needed, not cheap but do some brilliant work.

Cheers Brad.

 

[ukracer]

would a diesel ft in there instead ,, at what point do you shout stop .
I take it that a replacement blocks not to be had ? keep the good bits and start with a better block.

When it's fixed. Lol Diesel is not an option it's a 30k car with a full power engine.
Replacement block is about 4.5k but you can get a standard 26 engine for that when available.

 

[ukracer]

Dayton sleeves are always an option.
Expensive but good.

Will ask a mate about the rb26 engine mod as used to drift one.

Dayton or Darton ?

 

[tom2207]

When it's fixed. Lol Diesel is not an option it's a 30k car with a full power engine.
Replacement block is about 4.5k but you can get a standard 26 engine for that when available.

Good grief ,, I can see why your fixing it ,, thats a lot for a 4 pot block. is this the one with the turbo manifold issues too.

 

[qwakers]

rb26 is a 6 pot.

 

[tom2207]

rb26 is a 6 pot.

Ah skyline , sorry , I thought it was the camper van with the manifold prob.

 

[ukracer]

Good grief ,, I can see why your fixing it ,, thats a lot for a 4 pot block. is this the one with the turbo manifold issues too.

6 pot..which makes the additional pistons and rods , rings , valves etc add up. Lol

 

[ukracer]

Ah skyline , sorry , I thought it was the camper van with the manifold prob.

Lol I thought it was a bit weird suggesting a diesel.

 

[Munkul]

The mod pipe between the two sides of the head looks like a pressure balancing vent pipe, presumably in case oil airlocks in one side of the galleries (if that's even possible?). I dunno, not 100%, but I do know there were some weird and wonderful ideas out there to help with oil control on rb26's when drifting, which will have made their way across to fast road/track setups.

Anyways it's pointless speculating - get the head pulled, dye-pen it for cracks, and measure the bores for wear, first

 

[Ruffian]

Dayton or Darton ?

Darton, (damn autocorrect)

Usually get the guys at roland allsop engineering to do most of our subaru work, on the tuning side. Sleeves, rebores, balancing etc.

 

[ukracer]

The mod pipe between the two sides of the head looks like a pressure balancing vent pipe, presumably in case oil airlocks in one side of the galleries (if that's even possible?). I dunno, not 100%, but I do know there were some weird and wonderful ideas out there to help with oil control on rb26's when drifting, which will have made their way across to fast road/track setups.

Anyways it's pointless speculating - get the head pulled, dye-pen it for cracks, and measure the bores for wear, first

What's a dye-pen?

 

[Munkul]

dye penetrant inspection dye will seep back out of microscopic cracks and show up. It's not entirely foolproof, but it would be the first step I took, anyway.

 

[ukracer]

dye penetrant inspection dye will seep back out of microscopic cracks and show up. It's not entirely foolproof, but it would be the first step I took, anyway.

Not sure what that would show to be honest. We believe any crack will be internal between the water jacket and oil ways...

 

[Munkul]

Not sure what that would show to be honest. We believe any crack will be internal between the water jacket and oil ways...View attachment 257265

Oh, I see... I thought you meant the cylinder head face itself.

 

[hotponyshoes]

Not sure what that would show to be honest. We believe any crack will be internal between the water jacket and oil ways...View attachment 257265

Oh, I see... I thought you meant the cylinder head face itself.

Make an adaptor up so you can inject some of the dye into the oil ways.
Pressurise with an air line and have a look around the waterways with a uv torch.
Or just pressurise the oil lines and see if you can hear it coming out

 

[ukracer]

Make an adaptor up so you can inject some of the dye into the oil ways.
Pressurise with an air line and have a look around the waterways with a uv torch.
Or just pressurise the oil lines and see if you can hear it coming out

Thats very clever . I had not thought of that.

Problem we face is that we believe this crack only opens when heated so it probably wont show.

WE have now taken the engine back out and stripped it down to Block and will be taking the pistons out tonight.
One thing I do need to find out is the best way to clean everything in the engine bay as its all going to get a full clean before it all goes back in.

It was the ADHD led impulse to get it done quickly but without realising that the turbo lines, maybe oil lines etc could still have bits of metal in them.

Apart from this possibility that seems to have introduced some foreign bodies into the upper cylinerds and scored the bores slightly. It also seems we probably had a couple of other issues not least a fuel filter not up to the flow rates for fuel at higher powers that was not picked up by so called proffesional tuners. BUT also a potential crimped pipe on the fuel pump. Both of these have again been replaced.

This seems to have led to pressure in the crank case that threw oil out of the upper breathers (usually connected to a catch can.) and made it seems worse that it was.....HOWEVER it might have actually saved the engine long term and will result in a cleaner build and a cleaner car overall now my son has accepted you cant cut corners.