Rb30 25 neo cometic head gasket problem

[lcxu105]

Rb30 25 neo cometic head gasket problem

Ok everyone. 

Problem is a brand new engine 30 25 neo so all surfaces are machined flat fitted cometic rb30 head gasket and have a oil leak between the head and block rear passenger side. 

The gasket can only fit one way so thats not the problem.

Engine has 1mm oil restrictors fitted and vct mod. 

Just pulled the covers off and checked the torque settings at 110nm i know that it's 108.49nm for arp studs.

Just bumped it up to 118nm figured it couldn't hurt much.

Can anyone give me any insight as to why it might leak.

Thanks in advance.

 

[Weaselman]

Usually on the first steps of tightening the head you need to back the studs off and re do them. When using cometic gaskets I don't back them off because you've flattered the metal plates already and unloading them can cause them to leak. Now I'm not a qualified mechanic but it's how I do it and I've never had them leak.

[lcxu105]

Just used 3 equal steps to torque it down. rechecked them yesterday and they where all set at 110nm.

Reset the tension rench to 118nm and gave them all a bit more. will see how it goes.

[89CAL]

So are you saying you have loosened it all off and re-torqued it?

If it's already leaked and you've taken all the pressure off the gasket and torqued it back down, I would be putting the order in for a new head gasket now. Once oil gets inbetween the surfaces, its not likely to seal properly, And I agree with above, after the first time the gasket is crushed, I wouldn't use it again.

[KiwiRS4T]

I used a Tomei metal gasket. I have had reason to pull the head off twice and was able to re-use the gasket without drama so not expensive in the long run.

[AeroZR]

+1 for Tomei gasket. They are designed to be reusable

[jet_r31]

Yep, tomei are the best..

[lcxu105]

No just checked it was at 110nm and than gave it a bit more to 118nm

[AngryRB]

Is 118 even safe? wouldnt want a cracked head . 

[lcxu105]

Yes it will be fine. but i wouldn't give it anymore . 

I only run max of 24psi boost when its tuned.

[rx-line]

Threads need to be lubbed in order to keep the steel alloy of the stud from galling the aluminum, this will give an accurate torque, rather than a false torque if galling has occurred. A false torque could cause a leak for sure.

Also you might want to try torquing from the inside working your way from side to side to the outside of the head, we have had good luck with this.

As for a reason things change a fair bit when you clamp a head to a block, it's surprising how things move. If the above fails I would look at the head and block to see how well they have been surfaced.

Here's a thought as well, you might be experiencing above average crank case pressures due to you rings not being seated in with the new build. Make sure not to use synthetic oil when breaking it in, it delays the process by a lot. This may be exaggerating the leak.

Hopefully this may help you.

Edited November 18, 2016 by rx-line

[lcxu105]

Lube was used on threads to tension block was decked square  to tunnel and head was machined with reco and port work  i use hpr5 penrite. engine was run in on a dyno. 

I do think i have over filled the oil tho too.

 

Edited November 19, 2016 by lcxu105

[KiwiRS4T]

1 hour ago, lcxu105 said:

 i use hpr5 penrite. engine was run in on a dyno. 

Including initial fill? As RX-Line said mineral oil is better for running in - but probably too late to change now. Did you use Hylomar or similar to stick the gasket down? How much oil actually leaked? I wouldn't have expected overfiling to result in a leak from there.

[lcxu105]

No didn't use anything to stick the gasket down and the tuner said to use the oil the engine will use all the time. 

[lcxu105]

Leaks about 20mls everytime i take it for a drive and only from the  rear passenger side.