I pulled the heads on my 85 GL rebuild and the lower head bolts came out covered in a black sooty oily gunk. The upper 2 were clean as a whistle.  Ideas? Advice? Sympathy? 

that's about normal.  wire wheel them, parts cleaner, give them to a machine shop for their parts cleaner.  annoying.

How does gunk get into the bolt hole, other than a crack from the exhaust port?

That nasty black tar that smells horrible is engine oil that seeps in past the bolt head and bakes in there for a few decades. It's completely normal.

The heads bolts thread thru coolant and oil passages. the fluids capillary actoin up the threads. How foul the bolts are are conducive to the location of each one.

 other than a crack from the exhaust port?

it's definitely not that, looks like miles has it covered, it's normal.

One could use anaerobic on the threads to seal it out. This would be a good idea for intake manifold bolts since they rust.

 

So would be regular coolant and oil changes to prevent corrosion and varnitsh

Yeah, all the good advice here was repeated by the machine shop. There was some light pitting after running them across the wire wheel, but I feel pretty confident about reusing the ones with perfect threads. 

 

Would just about any metric thread chasers work to clean the case threads before reassembly?

Gravity.

 

If I were you, I'd use a degreaser (kerosene being the cheapest) and a brass brush.

 

Brass, as an extra assurance not to damage threads.

Edited October 27, 201312 yr by BoxerRebellion

Would just about any metric thread chasers work to clean the case threads before reassembly?

 

Nope.

 

M11 x1.25

 

Very hard size and pitch to find taps and die for.  Not impossible.......but very hard.

 

I gave up just used an old bolt and cut grooves long ways down the side to make a block chaser.

 

Got any spare bolts???

use-enco.com for M11-1.25 tap:

http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=891-4976&PMPXNO=3904809

If all fails, oil the bolt and run it in and out of the threads, wipe it off, and assemble.

KEEP 'EM STRAIGHT!!

 

I just finished a complete cleanup of the headbolts, oil and end-seal, replace the headgaskets and torque nicely. Only to find out I swapped the heads to the wrong side!

 

I am so P----ed!!

 

New head gaskets ordered. 1 week delay.

you can make it work. i had the luxury of working on one with reversed heads. It had a copper pipe across the top for the EGR.