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Dry:

cy1 - 158psi,
cyl2 - 157psi
cyl3 - 157psi
cyl4 - 155psi
cyl5 - 149psi
cyl6 - 133psi

Wet:

cyl5 - 157psi
cyl6 - 138psi

Checked the turbo no signs of water or water marks there is some side to side movement and also end play. I do not have a dial gauge so cannot be certain of figures.

from those figures you have a valve issue on number 6, I wouldn't worry about 5 at all.

have the valves been inspected yet ? done a fuel in port check ?

I have just done the headgasket on my rb27 and its just made over 700 crank hp and the compression varies over all cylinder from 135 - 142 psi and it runs like a peach, but mine is forged with big cams.
 

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Discussion Starter · #62 ·
That is what I am doing, I am getting the whole engine built up over the next few months going forged internals changing all the major components on what is a std engine at the moment.
 

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Discussion Starter · #63 ·
BTW why is there not much detail about this head mod with exactly what is done and what part of the head cracks?
 

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Discussion Starter · #64 ·
Got my turbos back from having them tested no broken seals or any cracks there as well as all shaft play is in normal range.

Will have to check the water heat exchanger tomorrow. Head was pressure tested at 5 bar but people have said that will not show up the crack that is in the oil and water way.. I spoke to the engineering shop and they have said it is conclusive that if there was a crack that would allow oil in to the water way then that should have been picked up during the pressure test. I have two choices either get it x-rayed or got the gallery mod done but I am not happy to get it done with out confirmation that there is a crack.
 

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Discussion Starter · #66 ·
Yeah it is ok, I went thought it carefully layer by layer no signs of anything suspicious to be honest.
 

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Same as me so I ditched the oem cooler just link a pipe between each port and link the two water points together
 

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Discussion Starter · #71 ·
Also surely when my head was pressure tested at 5 bar that should have shown up a crack between the water and oil gallery?
 

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It should but as a few have stated it only opens when hot and I'm unsure if when pressure tested it is heated up or not ...

I had what I thought was a head gasket/oem oil cooler or cylinder head issue as I had milky residue under the oil cap but it turned out that due to the aftermarket oil cooler the oil temps weren't getting hot enough to evaporate any moisture in the oil hence the milk but I ditched the oil modene to eliminate it as it was a free to do job
 

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when i removed the stock water to oil exchanger, i capped off the 2 ports. i would think that connecting them together would result in less water running through the rest of the system...

like so: IMAG0311.jpg
 

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Why would it result in less water when the original system went into the cooler if anything your shortening the route
 

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Discussion Starter · #77 ·
It should but as a few have stated it only opens when hot and I'm unsure if when pressure tested it is heated up or not ...

I had what I thought was a head gasket/oem oil cooler or cylinder head issue as I had milky residue under the oil cap but it turned out that due to the aftermarket oil cooler the oil temps weren't getting hot enough to evaporate any moisture in the oil hence the milk but I ditched the oil modene to eliminate it as it was a free to do job
Interesting but did yours have a thermostat plate? Mine does.
 

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Discussion Starter · #78 ·
It should but as a few have stated it only opens when hot and I'm unsure if when pressure tested it is heated up or not ...
Surely when the head is heated up it expands so the crack would close up? They did mine in cold water.
 

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Surely when the head is heated up it expands so the crack would close up? They did mine in cold water.
nope, a crack will expand and open with heat.

when I build a final drive I put the bearings in 20w40 motor oil at 130 degrees and they fall on with ease, try putting them on cold and they can smash due to the impact needed with a club hammer (pressing isn't possible on some final drives I build) metal expands with heat different metals at different rates any fracture will open the hotter it gets.
 

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Discussion Starter · #80 ·
Right thanks for clearing that up so need to find someone who can pressure test with the head warmed up or in hot water. I am reluctant to do this head mod until a crack is found.
 
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