Jump to content
SAU Community

Rb30 25 neo cometic head gasket problem

lcxu105

By lcxu105,
in Engines & Forced Induction

 Share

Recommended Posts

lcxu105 Proficient

lcxu105

Posted
Posted
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 Collaborator

Weaselman

Posted
Posted

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.

89CAL Grand Master

89CAL

Posted
Posted

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.

rx-line Enthusiast

rx-line

Posted
Posted (edited)

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 by rx-line
lcxu105 Proficient

lcxu105

Posted
  • Author
Posted (edited)

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 by lcxu105
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
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.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • joshuaho96
      Front LSD Quaife , how streetable ?- QDF3L Owners

      By joshuaho96 · Posted

      Major thread necro but how bad of a job is it to DIY? Looking at it online it looks like if you reuse your ring and pinion as long as those are in good condition it should be fine to just pull the axles/front cover and replace the diff that way? Or should I be replacing everything and doing preload measurements/gear mesh testing like the factory service manual mentions for the rear diff?
    • Kinkstaah
      The FD RX7 is the best looking 90's JDM car

      By Kinkstaah · Posted

      in my list I had the R33 GTR as the best Skyline. Infact I had all GTR's (33>34=32), the NSX, the GTO, the 300ZX, the 180SX, the S15 better than the FD RX7. I had the MR2 and the A80 as 'just' better. I also think the DC5R Integra looks better but this is an 01 onwards car. I also think the FC>FD. It's almost like aesthetics are individual! The elements @GTSBoy likes about the FD and dislikes about the 180 are inverse in my eyes. I hate the rear end of the FD and it's weird tail lights that are bulbous and remind me of early hyundai excels. They are not striking, nor iconic, nor retro cool. The GTO has supercar proportions. I maintain these look much better in person (like the NSX) especially with nice wheels and suspension which is mandatory for all cars pretty much. Some (or all) of these you have to see in person to appreciate. You can't write a car off until you see one in the flesh IMO. Like most people we probably just like/dislike cars which represent certain eras of design or design styles in general. I also think the 60's Jag E type looks HORRIBLE, literally disgusting, and the 2000GT is nothing to write home about. FWIW I don't think the Dodge Viper Gen1's have aged very well either. You can probably see where I rate bubbly coupes like the FD. I know we're straying now but the C4 and C5 absolutely murder the Viper in the looks department as time goes on, for my eyes. Wouldn't surprise me if people who love the FD, also love the MX5, Dodge Viper, Jag E Type, etc etc.
    • GTSBoy
      The FD RX7 is the best looking 90's JDM car

      By GTSBoy · Posted

      I used to hate R31s, and any of the other Nissans that led up to it, and any of the Toyotas with similar styling, because of the boxiness. They were, and remain, childish, simplistic, and generally awful. I appreciate R31s a lot more now, but only the JDM 2 door. The ADM 4 door (and any other 4 door, even if they are unique compared to our local one) can eat a bowl of dicks. The Aussie R31 is also forever tarnished by their association with stereotypical bong clutching Aussie R31 owners of the 90s and early 2000s. I think the Nissans of the 70s (other than 120Y/180B/200B) are far superior looking to the 80s cars. The 240K era Skylines are boss. The same is broadly true of Toyotas. Hondas don't ever register in my thinking, from any era. Mitsus are all horrid shitboxen in any era, and so also don't register. Subarus are always awful, ditto. Daihatsus and Suzukis also don't generally register. They are all invisible. I think the SW20 MR2 looks fiddly. The 3000GT/GTO is like that but way worse. Too many silly plastic barnacles and fiddly gimmicks ruined what could have been a really nice base shape. Kinda-sorta looks like a big heavy ST165 Celica coupe (and I'm not sure if that's a good thing or a bad thing). I think the 180SX is dreadfully bland. It's not bad looking. But it has no excitement to it at all. It's just a liftback coupe thing with no interest in its lines, and bad graphical elements (ie wide expanses of taillight plastic on the rear garnish). The S13 Silvia is a little better - getting closer to R32 shapes. But still....bland. S14? Nope. Don't love it. S15...a little better. Probably a lot better, actually. Benefits from not being like a shrunk in the wash R34 (where the S13 was a shrunk in the wash R32 and the S14 looked like a Pulsar or something else from the stable on Nissan mid 90s horrors). The Z32 was hot as f**k when it came out but hasn't aged as well as the A80. Keep in mind that I think the R33 is the most disgusting looking thing - and out of all the previous cars mentioned is objectively closest to my precious R32. It's just....real bad, almost everywhere you look. And that is down to the majority of what was designed in the 90s being shit. All Nissans from that era look like shit. Most other brands ditto. In that context, the FD absolutely stands out as being by far the best looking car, for reasons already discussed. Going behind the aesthetics, the suspension alone makes it better than almost any other car.  
    • GTSBoy
      The FD RX7 is the best looking 90's JDM car

      By GTSBoy · Posted

      If they just called it the "Mazda Tiffany", it would have been spot on.
    • PLYNX
      The FD RX7 is the best looking 90's JDM car

      By PLYNX · Posted

      Yup but for me its the HR ! Cut my teeth on the old holden 6s in the day ! And here's me thinking in the day it was also the 300ZX and the Mitsubishi GT3000 ! All, as well had good lines, but always seemed to need finishing off, style wise.
×
×
  • Create New...