cylinder head removed, looking for other issues

[vairter]

My 1975 E12 cylinder head cracked a few months ago and had to be removed.  While I'm working on getting a new head, I took a closer look at the intake/exhaust valves and piston tops to see if there are any other issues that I need to address while the engine is partially open.  Here are some pictures (Cylinder #1 is in the Upper Left).

 

INTAKE VALVES:

 

 

 

 

 

EXHAUST VALVES:

 

 

 

 

 

PISTON TOPS:

 

 

 

 

Here are the things that stick out to me:

 

(1) Intake valves: #1 and #4 valves have fluffy carbon deposits, which parallel the piston top pictures.  Unclear to me why 2 of the cylinders would be preferentially carboned up.

 

(2) Exhaust valves: #3 seems different from the others, with fluffy deposits.  This also seems to agree with the #3 piston-top picture, which seems to be wet.  I did pour oil down all 4 cyinders, through the spark plug holes, a few months ago when I discovered the possible coolant leak problem, to stabilize the situation for a few months while I didn't have time to deal with the problem.  Could #3 have been suffering from a valve seal deficiency?

 

(3) Piston-tops: #2 is lovely and clean, consistent with the coolant-leak steam cleaning it was getting.  Should I make any effort to remove the deposits on 1, 3, and 4 before I reattach the head?

 

If anyone sees any evidence of other problems that I should address before I re-assemble the engine, please let me know.  Please.

 

Terry

 

 

 

 

[Son of Marty]

I don't see anything that's way outa line #3 maybe burning a bit of oil but not bad, I'd lightly scrape the piston tops and run it?.

[vairter]

How does one "lightly scrape" the tops of the piston heads in a way that respects decades of German engine hygiene?  I don't want to make things worse...

 

 

[Son of Marty]

My method is too run the piston to be scraped down about a inch and coat the cyl wall with grease then run it back up to the top and then use a scotchbrite pad to clean the piston top then run the piston down to the bottom of the bore and wipe the grease off this will prevent the crap removed from fowling the rings, they don't need to be spotlessly clean but try to remove the outstanding deposits.

[Hans]

Make sure you somehow end up with a front cover that exactly matches the thickness of the head. 

Somewhere on here recently there was a comment about Scotchbrite disc contents that you might wish to review. The idea is to scrape carbon, not metal. 

Without wishing the dreaded scope creep upon you, how was the engine health before the head problem? How do the cyl walls look?

[tech71]

Why are you worried about the valve condition in a cracked head? Hopefully your replacement head assembly will have valves/seats/guides/height checked,surfaced,replaced as required.

Doesn't look too bad actually but a pic of your block with the head gasket removed would be more helpful.

[TobyB]

Looks like #2 was getting water into it...

 

What induction system?  unless it's throat- per- bore, I don't see anything worth a hiccough...

 

t

 

Edited January 6, 2020 by TobyB

[jimk]

Looks like the head bolt holes still have the oil in them.  Remove the oil or you may be shopping for a new block too after the headbolts split the block.

[TobyB]

Jim, I've tried to do this on an old, trashed E21 block, and all that happened was

that the oil oozed back up around the threads.  They're not THAT tight a fit.

If there was junk at the bottom of the hole, it simply stopped the bolt

short.  No clamping for you... but also, no block damage.  Unless the junk

messed up the end of the bolt, then it would gall the threads on the way back out.  I even

used a rattle gun...  I did eventually peel the threads out of the block, but by that time,

even the Honduhh crowd would have been wincing.

 

While I'd NEVER advocate NOT cleaning out the holes to the bottom

and then lightly oiling the threads of both the hole and the bolt,

I suspect that tale has grown out of vintage British motoring lore, where

the bolts fit really tight, and metallurgy wasn't a concern!

 

t

IF it's already broke, then let's break it some more!

[Hans]

Speaking of bolt holes, I would carefully check ALL the threads on a used head.

[TobyB]

Oh, boy, howdy, yes- and the cam journals, and that the rocker arm shafts go in, and so on and so on...

 

t

has had to helicoil heads AFTER he put them on...

[Son of Marty]

+1 on Toby's thread repair, it's a piece of cake on the bench where you can work on it with all the clearance you'll need to bring the tools straight on and you can see what your doing. Once did a heli-coil on the distributor drive cover with the engine installed, once being the operative word.

[vairter]

induction system: Weber 32/36