Jump to content
SAU Community

Recommended Posts

hi'yas

since start of December had my car in the shop doing a big head upgrade job, port etc with poncams, etc

the head was fitted and everything setup but was hell smokey while running

a pull down of the head reveals oil on top of piston no.6, other 5 are dry and fine

what can cause a failure in around the back area of the head?

oil pressure has been restricted at the head with x2 tomie oil gallery restrictors, then again at the turbo becuase pressure was too high there.

the turbo oil restrictor is now set and works well for the correct flow (journal bearing turbo)

however head has the issue with piston no.6 oil on surface area, ie leak from head in that specific area. was "wet" on top when others were dry

used 6mm new valve seals, new valve seats and guides but stock valves.

head was ported etc, by a rebuilder outsourced by the garage, with a Cometic head gasket (1.2mm x 87mm) & arp head stud kit, along with 8.8mm lift kit and poncams (tomei) with oil restrictors

Please - any thoughts on what may have failed?

Ive said to the tuner that it must be a head installation problem, car was fine beforehand; want to send the head back to the rebuilder to be redone properly - or at least redone over piston no.6 area.

whats the go here?? thoughts ??

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/
Share on other sites

Hmmm i've been thinking about this and the only thing i can think of is oil leaking through the head past the valve stem seal into the intake and then past the valves. So to me it looks like a valve stem seal not installed correctly?

Im sure some one on here a bit more experienced in head building could answer this question.

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4342301
Share on other sites

valve stem seals were seen to be all within tolerance. although Im pretty sure Neo stem seals were sent to me in my parts order.

the valve guides have been replaced and the original install work re-gone over, builder couldnt find a fault as all was within 'normal' scope.

being re-installed now, tuned tomorrow so we'll see how the story ends.

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4348677
Share on other sites

reinstalled and taken back off again

leaking oil still on top of piston #6

fk me

what could be wrong with it? told em to replace the seat, seal and guide, its been pressure tested and passed - perhaps a cracked head?

if a cracked head, how can that fkn happen, when the car was fine before the tune - no oil usage, no smoke etc.

how do heads crack? possible that the machinist dropped it??

any advice plz

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4353298
Share on other sites

sounds more like a head fark

ok doe's the inlet port show any signs of oil in it compared to the other inlet ports ?or do they all look the same .check the inlet yalve stem for straightness or and grooves along the stem that oil could pass thru .

check the valve guide for wear on one side of it or is showing that its wearing evenily.

it could be a crack from under the cams going into number 6 port i was hoping you would have had this sorted out by now bit hard to offer any more advice without seeing the head .

did they check the head for softness b4 starting the work ?

cheers mid life crisis

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4353361
Share on other sites

I'll chat to the tuner again (unless you wanna give shaun a call? to offer advice?), but its not in his hands either - outsourced to a machinist.

they should be replacing everything around #6 piston area of the head, and the pressure test came up ok anyway.

hasnt been xrayed because before it went in for some work it was 100% perfect and 200kw easy, no strain.

massive head fK because its out of my hands (here for advice to pass on - ) plus my fund$ are short!

im 200% positive the head was fine before it went in for upgrades. wonder what happened at the machinists? dropped the head and cracked it? faulty stem that hasnt been picked up twice now? (3rd time back at machinists, been bolted on twice and blew oil)

basically now just want the bloke doing the work (not the tuners, good peeps) to fix the fkup with all-new components / handywork around piston 6 area.

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4355477
Share on other sites

.

.

.

.

cracked head.

.

.

.

1

around the guide area the metal has deformed.

second head has been sent with mine to the machinist (who the tuner backs 100%) to swap it all over and redo again

just on of those things apparently.

close thread, unless ppl need advice on what not to do.

ie dont buy valve guides off the internet, let the shop doing the work supply them.

I'll learn from that.

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4355501
Share on other sites

So it was the valve guides afterall, thought so.

I should have my head back from them next week, fingers crossed mine turns out fine, the only thing i supplied was the valve springs.

Edited by PM-R33
Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4356123
Share on other sites

Not wrong type gary, just bad luck?

Im told they were frozen then tapped in, one has made a bulge of sorts when expanded, resulting in a micro crack. as far as Im aware

hasnt been xrayed but swapped and left with the tuner. no charge. was fully pressure tested and ok there, but spat oil. fixable / patchable I reckon.

end result was a new head being decked out for me, but just one of those things.

was a 7.5 week job but nothing but praise for the tuner (Boost Worx)

fantastic on the road. beautiful end result, very punchy, pulls hard, & isnt held up anywhere - on the road

cat converter is holding it back power wise, resulting in boost drop still.

will fix that up next tune midyear and be happy with it for a while :(

scan0001-3.jpg

Image007-1.jpg

http://www.skylinesaustralia.com/forums/Fi...Of-t252849.html

Link to comment
https://www.sau.com.au/forums/topic/250457-rb25-head-leak/#findComment-4372838
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Stock ECU (or more accurately stock tune) absolutely refuses to go over 10psi and behaves like you have seen. The Nistune is the same if it is the stock tune. If the Nistune chip has been tuned, the resulting tune could be literally anything for any combination of parts. The Nistune just makes the stock ECU Tunable.
    • So stock ECU does not like anything above 10 psi?  That Nistune one is just for "try" if it will be any different, I know it need to be tune for that. I know but YOU may know about these problem but i/we dont. They few little Skylines here let alone people who know anything about tham so that is why iam asking here  
    • So now we have a radiator with no attachments whatsoever. It lifts up with a particularly tight spot between the drivers side air box mount and the lower radiator outlet, but if you've got this far you will sort that too. This is the lower mounts with the rad out so you can see where the rubber bushes go, it is a straight shot upwards Done! Assembly is the reverse of disassembly, with blood less likely to be shed.
    • Right, onto the second last trick. The Air Con condenser is mounted to the front of the radiator and stays in the car when the radiator is removed. There are 2x 10mm headed self tappers holding the top of the condenser to the radiator, remove those The bottom of the condenser is attached to the radiator with clips. You need to lift the condenser out of those clips and clear (up, then forward). f**ked if  could work out how to do that last bit with the front bumper on. I hope you can, and you share the trick.  Bumper removal probably deserves its own thread one day once I've recovered the will to live, but basically you need to remove the wheels, front inner guard liners (clips and 10mm headed bolts), the self tapper between the guard and the bumper at the rearmost point of the bumper (same as an R32 that bit), any remaining clips at the top/front of the grill, an absolute bastard design with a plate that holds the top of the bumper above the headlight each side (only 1 bolt which is tricky to get to, but the plate catches 2 places on the bumper and must be removed....carefully!) and push clips between the bumper and guard under the headlight. If you've done all that you will be faced with wiring for the fog lights on both sides and in ADM Q50 RS at least, 4 nasty tight plugs on the driver's side for the ADAS stuff. So, the clips at the bottom look like this on drivers side (looking from the front) And on the passenger side (also from the front), you can see this one is already out Clearance on both of these are super tight; the condenser needs to move up but the upper rad support mount prevents that, and the radiator can't move down far because it is (rubber) mounted. Once you achieve the impossible and drop the condenser off those mounts so it does not stop the rad moving, you are good to go
    • OK, next the shroud needs to come off and there are a couple of tricks. Firstly, there is a loom from near the passenger side headlight to the fans, coolant temp sensor etc and there is no plug to undo.  In my case I was OK to leave the shroud on top of the engine so I just undid the passenger side fan plug and about 10 of the clips which gave enough free wire to put it aside. The fan plugs were super tight, the trick I used was a small falt screwdriver to push down on the release tab, then a larger flat screwdriver to lever the plug out of the fan unit....be careful with how much force you apply! If you need to remove the shroud altogether for some reason you will have to deal with all the plugs (tight) and clips (brittle)....good luck. I removed all of the clips and replaced them with cable ties that I will just cut next time. Also, in the Red Sport / 400R at least, the intake heat exchanger reservoir hose is bolted to the shroud in 2 places with 10mm headed bolts; so remove them (the hose stays in the car; no need to undo it at the t fittings down at the radiator lower mount. Once you've dealt with the HX hose and the wiring loom, there are 3x 10mm headed self tappers holding the top of the shroud to the radiator; remove those.   The shroud then lifts out of the bottom mounts where it sits on the radiator, up and onto the engine out of the way. Simples
×
×
  • Create New...