Jump to content
SAU Community

Recommended Posts

Hey Guys,

Old thread here:

http://www.sau.com.au/forums/topic/446963-head-stud-torque-pushing-coolant-600hp/#entry7367800

Basically my 26/30 is still lifting the head, and it's just driving me absolutely crazy.

Some background info:

26/30 engine with CP 9:1 pistons. Was originally running a standard nissan 26 HG, and rb25 ARP studs the non ARP 2000 type. Was running 98/Toluene and made about 500awhp. Went to get it dyno tuned again, and started to get pretty bad knock on the dyno which was attributed to the high comp, switched to E85 on the dyno, and ended up making 620awhp running very well. It did however start to lift the head on the very last pull. Despite this got it back, and it ran well for quite some time with no issues. Went to a track day a few months down the track, and after the day had ended noticed it was pushing coolant (a lot more), but still ran well despite this.

Fast forward and the issue became worse, to the point where it would start to break down at WOT which it had never done previously. Pull the head off and went a tomei 1.2mm HG with ARP 2000 head studs, ran fine again for a while and issue returned. Now the head had been faced previously, and upon installing the tomei HG I did not have the head faced, the face looked very good still, and had previously been running the old composite gasket, I just cleaned the face and removed any old gasket prior to installing. When this issue returned I put it down to not having the head faced, which was a oversight on my part.

So pulled the head off again, and took it in to be checked, had the clearances re-done whilst it was in, pressured tested as well and had it faced. Re-installed again using the old tomei HG using copper coat, cleaned all the coating off the tomei HG using gakset stripper prior to installation.

Re-torque head studs to 105ft/lb, used the ARP lube on head stud thread (both ends) and under the nuts themselves. Issue has returned again as of yesterday, it was bubbling up through the rad just on idle, will drive fine off boost but any boost and it breaks down pretty bad, so it's HG again.

I almost at my wits end.

Now it cold comps with a standard HG at around 200psi. So should I be using a greater clamp pressure then 105ft/lb? Should I re-drill the block for 26 studs instead? Could the block possibly be warped, and is it possible for this to occur?

ARP have a part number specifically for the 26 and 25/30 conversions now, does anyone know what the difference is between this and 25 studs?

Also someone recommended running dual washers, to stop them bottoming out on the studs, can anyone verify that they have also needed to do this? When I torqued the head, I went back to 0 again and none of the nuts had bottomed out, so I didn't end up doing that. Also I hadn't heard of anyone else having to do this out there.

Any thoughts, comments whatever, throw them at me.

Link to comment
https://www.sau.com.au/forums/topic/457787-rb2630-lifting-head-need-help/
Share on other sites

Have you pulled the plugs to check for water ingress?

Is the water level actually dropping?

Are you 100% positive that your RPM breakdown is a head gasket or are you jumping to that conclusion? (I seen heads get pulled off before where it wasn't the head gasket at all)

If all else fails and it is the head gasket, something will be warped or the deck finish on either surface is too rough.

Could also be in the tune, E85 is good at taking timing and boost however at those cyl pressures less knock will be more damaging as its at higher pressures.

The possibilities are endless. Anything from the block needing a skim too, all the way through to the head being soft from having been cooked at some time in the past. I think you may need to give up on trying to guess which bandaid to apply and dismantle it properly and give the bits to someone who has the right tools to answer those questions.

Yeh I thought it was spark so swapped out the plugs/ignitor/packs, made no difference. Then took it for a run yesterday, was breaking down under boost really bad. Let it cool down then took the cap off, started it without the cap and it was just bubbles everywhere.Yes water level was also dropping.

So the only solution is to pull it all down and remove the motor? Surely there is a way I can check things like a distorted block in the car with the head removed?

I run 2 washers on mine, never had issues, re-used old mls headgasket a few times not a problem. My studs are 8 years old and been used a few times aswell. Im only tensioning to 80ft lb

If u look the thread finishes just below one washer level, i think this could be your issue.

Edited by sky30
  • Like 1

I run 2 washers on mine, never had issues, re-used old mls headgasket a few times not a problem. My studs are 8 years old and been used a few times aswell. Im only tensioning to 80ft lb

If u look the thread finishes just below one washer level, i think this could be your issue.

OK cool thanks sky30. Why did you end up running dual washers?, did notice it was going to be close, or did you have some bottom out on you?

Cheers.

  • Like 1

Since you have gone to the trouble of lubing your studs at both ends you can be sure they have bottomed out in the block so an extra set of washers is so simple and cheap - definitely worth a try. But as you may have blown your H/G you will have to remove the head once more to check.

It's currently running 25psi and making 620awhp. I would love to just keep it at that, but with the head staying on, lel.

Maybe my issue has been the washers all along. Has anyone successfully re-drilled for 26 studs with the block still in the car? I read somewhere that the counter bore is done first, then drill out the main thread to 10.5 and tap. That's all fine, but doing it all square is my main concern.

It's currently running 25psi and making 620awhp. I would love to just keep it at that, but with the head staying on, lel.

Maybe my issue has been the washers all along. Has anyone successfully re-drilled for 26 studs with the block still in the car? I read somewhere that the counter bore is done first, then drill out the main thread to 10.5 and tap. That's all fine, but doing it all square is my main concern.

it would be possible.

Try and find someone with a mag drull (magnetically mounts and I'd set square).

Make sure you tape up everything except the holes to be drilled.

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

    • My thinking is that if the O2 sensor is shot then your entire above described experience is pure placebo.
    • Here is the mess that I made. That filler there was successful in filling dents in that area. But in the middle area. I can feel dents. And I've gone ocer it multiple times with filler. And the filler is no longer there because i accidently sanded it away. I've chased my tail on this job but this is something else lol. So I'm gonna attempt filler one more time and if it doesn't work I'll just high fill primer the door and see where the issues are because guidecoat is of no use atm.
    • Ok, so I think I sort of figured out where I went wrong. So I definitely overthinked it, and I over sanded, which is probably a large part of the problem. to fix it, I ended up tapping some spots that were likely to be high, made them low, filled them in, and I tackled small sections at a time, and it feels a lot better.    I think what confused me as well is you have the bare metal, and some spots darker and some are lighter, and when I run my finger across it, it' would feel like it's a low spot, but I think it's just a transition in different texture from metal to body filler.    When your finger's sliding on the body filler, and crosses over to the bare metal, going back and forth, it feels like it's a low spot. So I kept putting filler there and sanding, but I think it was just a transition in texture, nothing to do with the low or high spot. But the panel's feels a lot better, and I'm just going to end up priming it, and then I'll block it after with guide coat.   Ended up wasting just about all of my filler on this damn door lol  
    • -10 is plenty for running to an oil cooler. When you look at oil feeds, like power steering feeds, they're much smaller, and then just a larger hose size to move volume in less pressure. No need for -12. Even on the race cars, like Duncans, and endurance cars, most of them are all running -10 and everything works perfectly fine, temps are under control, and there's no restrictions.
    • Update: O2 sensor in my downpipe turned out to be faulty when I plugged in to the Haltech software. Was getting a "open circuit" warning. Tons of carbon buildup on it, probably from when I was running rich for a while before getting it corrected. Replaced with new unit and test drove again. The shuffle still happens, albeit far less now. I am not able to replicate it as reliably and it no longer happens at the same RPM levels as before. The only time I was able to hear it was in 5th going uphill and another time in 5th where there was no noticeable incline but applying more throttle first sped it up and then cleared it. Then once in 4th when I slightly lifted the throttle going over a bump but cleared right after. My understanding is that with the O2 sensor out, the ECU relies entirely on the MAP tune and isn't able to make its small adjustments based on the sensors reading. All in all, a big improvement, though not the silver bullet. Will try validating the actuators are set up correctly, and potentially setting up shop time to tune the boost controller on closed loop rather than the open loop it is set to now. Think if it's set up on closed loop to take the O2 reading, that should deal with these last bits. Will try to update again as I go. 
×
×
  • Create New...