Check bolts while my oil pan is off?

[zuhandenheit]

Hi All,

I've pulled the pan off my AAZ to make a new oil drain (it's in a vanagon at 50 degrees).

When I was first getting the motor together, I installed ARP main studs and new rod bolts. This was the first time I'd torqued anything so important, and I've always had a slightly uneasy feeling, especially because I foolishly used my new click torque wrench rather than my trusty old beam wrench. I didn't know that the latter is inherently more reliable.

I've run the motor for a few thousand miles.

Would it make sense for me to check the torque on the main bolts? Is there a way to do so without loosening and retorquing? The procedure involves a final turn beyond the torque value, but is there some torque value that's used for studs instead of the final turn, or that I could use to check the bolts?

Would it be dangerous for me to mess with the rod bolts at all, given that they are TTY? I had the thought of checking that everything is at least at some minimum value.

Is there anything else I could do while I've got the pan removed?

Thanks for any help!

[libbydiesel]

The mains torque spec should be what is provided by ARP, not what is in the Bentley.  If the ARP spec is for a torque plus degree, then you would need to loosen and start over in order to check it.  I would not recommend messing with the stock rod bolts beyond, as you stated, checking the minimum torque.

[zuhandenheit]

As always, thanks a lot. I was hoping you'd have a chance to write a reply.

The ARP spec for main studs is 60 ft/lb -- no additional turn. I went through the studs and they were all at, above, or very close to that. I probably won't touch the rod bolts.

I saw that Cascade had one remaining AAZ k03 and so I bought it, without really knowing if I need it.

I removed my existing turbo in the process of trying to diagnose a zero-boost condition. It was full of oil and looks very well-used, so I decided to use the new turbo. I had been draining oil to the block bung and always meant to make a drain to the pan, which I'm now finally doing.

But I am still not sure why I wasn't getting any boost. I had been running 10 psi, which dropped to 5. I was in the process of diagnosing this when I had to store the van for a year (I was in grad school in another state). When I came back, on the very first drive, I saw about 10 psi very briefly, and then it dropped to nothing, and the gauge was showing a vacuum (possibly this is inaccurate?)

The turbo wheels don't appear damaged and it seems to spin freely. I didn't see any significant boost leaks and I couldn't find an intake restriction. The wastegate seems to be okay.

Is it conceivable that the bearings are ruined in such a way that under pressure it's locking up?

I haven't heard any strange noises, though I could only briefly and intermittently hear the turbo.

This is off-topic, but I don't want to start a third thread!

[libbydiesel]

I have never seen or even heard of the turbo bearings seizing up to prevent the shaft from spinning.  Do you notice a dramatic loss of power?  If not, then double check the boost gauge.  If so, then make sure there isn't any intake tube that can collapse, make sure all tubing is free and clear, and make sure the air filter is clean and fresh.  Make sure the exhaust manifold and is all fastened properly to the head without leaks.  Make sure the turbo is mounted to the manifold solidly without leaks.  Double-check that the wastegate is closing properly.  Inspect all the intake connections from turbo to intake ports.  Remove any mouse nests...  :-P

[zuhandenheit]

I'll check for mouse nests.

I haven't run the new turbo yet, so I might try the old one again -- if for no other reason than curiosity.

There was a dramatic loss of power and a lot of black smoke.

I am having trouble with my boost leak tester so the test wasn't conclusive, but I was at least able to verify that there was no leak between the turbo and manifold. I'll go over the things you listed again. When I've had massive boost leaks before, I could hear the turbo very clearly -- which I could not. The wastegate appears to be closing fully and has a preload -- but i could try to find a way to pressure test it.