'98 V70 Practical ways to check warp in head/block?

[rwmm415]

Hi folks. I'm trying to rebuild the top end of my engine (98 V70 2.4L 20V NA 160K) after a head gasket failure and overheat situation. Once I managed to get the head off and inspect it, I realized I had a slightly warped head surface that was causing a coolant leak that brought about the engine failure. The shop took off 4/1000 inch of the aluminum to get it back to true.

Now as I research this problem here at MVS and other engine rebuild sites I'm learning that the effects of the heat damage can be pervasive (cracks, leaks, other warping in the head and block) and if I don't find and fix them all, slapping on a new gasket isn't going to solve the problem or give me a lasting fix.

So, here's what I've done so far. I've checked and resurfaced the head, taking off 4/1000 as mentioned above. I've pressure tested the head (it's OK) and checked the valves (2 bad exhaust valves now reground). I know that I need to check the deck (the top surface of the block) for warpage and look for cracks or scoring in the cylinder linings (OK). Also, I've the read that heat damage to the soft aluminum head may have warped the camshafts and their journals.

And that's where I'm stuck right now. I'm looking for advice on practical ways to measure the warp on the top of the block and some way to check the straightness of the camshafts and journals.

In theory, I know you can check the mating surface of the block that same way you would check the surface of the head -- with a straight edge and feeler gauge. But the cast iron cylinder linings stick up about 4/1000 from the surrounding aluminum. On my block all five of them protrude like this, so I'm assuming that engine was built that way. With the protruding linings and large gaps in the deck for the water jackets I can't find place(s) where I can lay the straight edge and get a useful reading with the feeler gauge. Any advice on how to do this would be great.

Also, I've read a couple of posting that say I need to be worried about heat damage to the camshafts. I have no idea what sort of a tool one needs to check the straightness of the shafts or their journals. Or, what the maximum out-of-straight tolerance would be. I can't see how one would lay a straight edge in the cam journal (or against the shaft) and get an accurate measurement with the feeler. Maybe I need a fancier tool. So, any advice on this would also be greatly appreciated.

As you can probably tell, I'm operating at the limits of my mechanical skill. Thanks for any tips or insights you can share.

[Ozark Lee]

You need a flat steel bar and it must be absolutely flat. You then lay the bar across the top of the block and use a feeler gauge to measure any variation in the top of the head. I do it corner to corner usually. I'm not sure what the service limits are off of the top of my head but typically the top of the block is not prone to deforming unless it got so hot that it cracks. If the cylinders look go and you have no cracks around the top of the cylinders then you can typically not sweat the warp test for the block itself and just bolt the resurfaced head back up.

...Lee