head melted near pre-chamber. What to do? - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• head melted near pre-chamber. What to do? by arifyn on 27 Apr, 2009 17:24
• First of all, this is my first post to these forums, and I have *already* learned so much from just poking around and using the search function, so I want to say thanks to all of you involved for contributing to such a great resource!
  
  Long story short, I bought an '82 diesel vanagon a few months ago. The engine is the stock 1.6 N/A, so it's about as slow as you might imagine, but the engine was rebuilt about 50k ago and was running very nicely.
  
  I say 'was' because on my latest trip the engine lost compression and coolant started spewing into the cylinders and out around the headgasket.
  The engine was running a bit hotter than normal so I'm at least partly to blame, but unless the van's temp gauge and idiot light aren't working right, it wasn't really into what I'd consider dangerous territory.
  
  I pulled the head off and the bolts weren't torqued down nearly as hard as  I expected - and I have a suspicion that they were re-used, since one of the 12-point heads was stripped in the direction of removal. The gasket wasn't even blown through, it just got loose enough to leak around the sides. I figure the head was, unfortunately, the path of least resistance when the coolant got hot..
  
  I don't have any experience working on these diesel engines but it isn't too hard to notice that something's wrong with the head on cylinder #2:
  
  
  
  Any idea what happened here? The hole with melted aluminum leads into the swirl chamber, but as far as I can tell not through the water jacket. There was just as much carbon on this part of the head as elsewhere, so I suppose it could have been that way for a while, but I'm assuming this is a BAD THING and I should probably not be re-using this head.
  
  I managed to get ahold of another 1.6d engine from a vanagon for almost nothing, and pulled the head off it, but aside from the fact that the engine was 'running' I know very little about it. It has a lot more carbon build-up and pretty large cracks between the valves (bordering on, if not over, 1mm/0.20in) - however, the valves do seem to seal ok.
  
  Here's a picture of the worst crack on that one:
  
  
  I don't particularly want to go all out and get a completely new/rebuilt head, since I can see myself replacing the engine with a 1.6td or 1.9 down the road, but I also want to do things *properly* and not be tearing it apart again in a few months.
  
  I'm wondering what you all would do if you were in this situation. Get the second head pressure tested and a valve job done? Rebuild one of them? Get a different head? Give up?
  
  Thanks in advance
  -A
• #1 by Smokey Eddy on 27 Apr, 2009 17:44
• if you actually plan on building a TD engine I'd get an aaz head build it your self port it and what not, then later on find a bottom end for it. OR get a turbo kit for the bottom end you have.
• #2 by subsonic on 27 Apr, 2009 19:17
• I think you pulling the head when you did might have saved it.  People might think I am crazy, but I bet you can get that cleaned up, check the seats, and you might still be able to run it.  It does not look like there is even a crack between the valves.  It may not be perfect, but if it will seal up it may be good to go until you make the jump to a full rebuild or a swap.  Anyone think I am crazy?
  
  X2 on the injector bladder buster.
• #3 by zukgod1 on 27 Apr, 2009 19:56
• That's from a bad injector for sure.
  
  I don't think I would be reusing that head unless you have the area welded up and machined flat. Looks like fuel has been leaking around the precup.
  
  The cracks are normal as you prob know but it looks like there is a chunk missing? Hard to tell from the pic.
  
  I bet you can find a good used head over trying to use that one.
  
  What ever you do DON'T GIVE UP!!!! It's not that big a deal even if you have to replace it with a good used one.
• #4 by zukgod1 on 27 Apr, 2009 19:57
• And Welcome to the forum
• #5 by arifyn on 27 Apr, 2009 21:36
• thanks!
  
  To Andrew A. Libbey:
  I don't see any valve impressions on the piston tops. To my untrained eye, the pistons and cylinders look just fine.
  
  The engine code is.. ME, so clearly not the original. I had never checked. From the engine code guide I found on thesamba, it looks like it belonged to a Golf, but was also a naturally aspirated 1.6. Still, maybe the head was originally a turbo head? Aside from the dimples, it has a different number (ends in 363M, the other one that's definitely original Vanagon is 363F, on a CS block) but I understand that those don't mean too much.
  
  Unfortunately I have no idea who rebuilt the engine, since it was done quite a while ago by the original owner (I am the third).
  
  Whatever I do, I will be sure and check that the injectors are working properly, thanks for the probable diagnosis!
  
  
  > Looks like fuel has been leaking around the precup.
  
  Almost certainly. If you pour solvent into the melted hole, it leaks into the precup, so I see no reason that diesel wouldn't have been doing the opposite. It's possible that it's not getting any worse, but with my overactive imagination I can imagine the hole getting bigger and eating into the water jacket or knocking the insert loose in the cylinder.
  
  That head looks to be in good shape otherwise - only tiny hairline cracks between two of the valves, everything seems to seal quite well - but I was thinking it might still be cheaper to find another head than to find a competent shop that could weld and fix the problem. By the way I am in Tucson, Arizona if anyone has experience or recommendations with local machine shops - maybe they are not quite as expensive as I suspect.
  
  The idea of building a head myself that could later be put on a turbo block is tempting, and might even be a lot of fun, but I have no experience building heads. It doesn't look too hard, but "doesn't look too hard" ranks up there with "hey guys, watch this!" in the book of famous last words...
• #6 by jtanguay on 27 Apr, 2009 21:50
• hate to say it, but when you can buy a bare head for around $300, thats probably the best option, unless theres a shop that can do the work for less.  me personally, i wouldn't spend anymore than that on such an old engine.  your valves look alright, and as long as they're not bent, can be transplanted to the new bare head, along with lifters and camshaft.  but be sure to inspect the lifters for the hairline fractures around the center.  that means it's probably a good time to change them  :wink:
  
  however when it comes to injectors and nozzles, its best to stick with the genuine bosch stuff.  skimping out in that department will most likely hurt, as the nozzles don't last as long anyways.
• #7 by subsonic on 28 Apr, 2009 06:15
• Yeah, Andrew gets all sweaty and flush over TD  :lol: Vanagons
• #8 by arifyn on 28 Apr, 2009 14:37
• The head has mechanical lifters.
  
  Andrew, I will definitely keep you in mind for a TD conversion. It will probably be a while before I do consider it, since my first step after the engine is working again is to seriously go over the van from front to back and make sure the cooling system/brakes/transmission are at least vaguely trustworthy before I even think about it.
  
  Regarding the Quantum you came to pick up - was that the "it was running great until the engine caught on fire" one I saw on craigslist, by any chance?
  
  Still considering what to do about the head. Maybe getting a new bare one and moving over the innards is the best course of action. I don't see anything wrong with my camshaft/lifters/valves...
• #9 by jtanguay on 28 Apr, 2009 15:24
• http://www.dieselvw.com/JKHead.htm
  
  says its not a turbodiesel head, but it should work fine even if turbo'd.  just don't go crazy with power and keep an egt gauge.
• #10 by Luckypabst on 28 Apr, 2009 17:40
• Holy Moses!
  
  You wanna sell that timing belt?
  
  Chris
• #11 by Luckypabst on 28 Apr, 2009 17:54
• OH! I have a good BOV in the shed. We can trade! You'll be up and running in no time...
• #12 by theman53 on 28 Apr, 2009 19:20
• Good luck with your head...
  
  
  Andrew, I wouldn't worry about it. As I would say in the 4x4 club "that will buff out, just run it"
• #13 by Vincent Waldon on 28 Apr, 2009 20:42
• The thing is, if you could get it to turn over it would probably run... and the timing belt might even hang on for a minute or two.  
  
  Not much electrical stuff on the engine to melt. :wink:
• #14 by arifyn on 01 May, 2009 09:08
• Well, I decided to just get a new bare 1.6 head and swap the parts from the old one over.  I still need to build or buy a working valve spring compressor to get the old valves out, but at least the camshaft and lifters look good.
  
  I was tempted by the AAZ head but I don't think it would have helped anything until I got a turbo and it would've been one more variable to worry about when troubleshooting.
  
  Of course now that I've got this whole thing apart, it seems silly not to do anything to the bottom half of the engine. I guess it depends how lucky I feel since I've never actually done this stuff before.
  
  Assuming it doesn't need any machining it looks like I could rebuild the bottom without even taking it out of the van. I'm not 100% sure the intermediate shaft will clear the bumper if I take it out but everything else seems pretty accessible. Anyone have experience with this?
  
  Thanks,
  A