Rb26/30 Lifting Head Need Help

[James_03]

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.

[GTRPSI]

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.

[GTSBoy]

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.

[Ben C34]

I could be wrong, but that cranking compression seems pretty high for 9:1 pistons.

[James_03]

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?

[AngryRB]

I have a 9.6:1 falcon that gets 200psi , put a straight edge over the top of the block in multiple directions and check with feeler guage for distortion?

Edited June 25, 2015 by AngryRB

[James_03]

I have a 9.6:1 falcon that gets 200psi , put a straight edge over the top of the block in multiple directions and check with feeler guage for distortion?

Yep that's what I'm thinking the next step is.

[GTRPSI]

And while your there with the head off get it pressure tested.

[sky30]

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 June 25, 2015 by sky30

[James_03]

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.

[scotty nm35]

Are there seriously no L19 or 625+ options? The spring tension of the standard ARP studs isn't much better than the stock bolts is it?

[jet_r31]

THe dual washer trick is common in the rb30 single cam turbo world.

For the reason sky30 explained

Cheers

Darren

[KiwiRS4T]

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.

[James_03]

OK should I re-drill and go 26 studs? Or should I just try the dual washers instead?

Thoughts?

[luke gtr]

For those running dual washers, are you using arp, or reusing genuine head bolt washers?

[sky30]

Just one std washer on bottom and the supplied arp on top.

How much boost/power u planing to run?

[James_03]

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.

[luke gtr]

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.

[Ben C34]

Lots more work than just putting on an extra washer though.

[r32-25t]

The 2 washer trick all the way, someone didn't fit 2 washer on my rb30 when the built it, it lifted the head the second we started it