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JX hairline crack on piston

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akw View Drop Down
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    Posted: 03 Apr 18 at 14:46
Hiya,

While I was close I pulled the cylinder head off my engine.  The head was badly cracked and is scrap so got a new one.  While cleaning the block/pistons I noticed what looks like a small crack on no2 piston:


Is this something that can be ignored or am I in for a bottom end rebuild now too?

The other pistons look fine and the block seems in good shape.  The honing marks still visible but I've not measured the bores properly yet.

Thanks!
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the ginger princess

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Post Options Post Options   Thanks (1) Thanks(1)   Quote mrhutch Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 18 at 08:45
you need to ascertain wether it is cracked or not chap - engineers blue?? 
if it is you need to replace
T3 1981 Westy Vanagon - thinks lubricant is a fuel
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 18 at 12:12
Thanks.  I'll clean it up a bit more and try doing a dye penetrant inspection to be sure.

Unfortunately I'm in a bit of a pickle here because I'm due a trip to Portugal at the beginning of May.  This realistically leaves me 3 weekends to put this engine back together (and I'm just a backyard 'mechanic').   I may have to slap the new head on, do the trip and pull the engine out afterwards to rebuild it properly.  A lot of extra work unfortunately.  I just hope it won't disintegrate on me.
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the ginger princess

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Post Options Post Options   Thanks (0) Thanks(0)   Quote mrhutch Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 18 at 12:24
I really wouldnt be heading to portugal with a cracked piston 

I have some JX pistons here (still in the lump) 
If you want I can remove and send you one?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 18 at 12:44
That would be amazing if you could.

I'm not sure what size piston it is though.  The markings on it are:

810
E
0701

Don't seem to correspond to any of the sizes in the manual as far as I can see. 

I can get the bore measured on Friday (waiting for tools to arrive) and get a correct size piston + rings from BW if necessary.

Other than the piston + rings, what else do I need to replace?  Can the old bearings be re-used? (given it's more or less a temporary measure).


Edited by akw - 04 Apr 18 at 12:46
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mrhutch Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 18 at 16:48
before you do fuck all else, verify you actually have a problem chap...


^^ should be possible to do en-situ 


T3 1981 Westy Vanagon - thinks lubricant is a fuel
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 18 at 17:42
Yeah, definitely.  Ordered the DPI kit this morning, should be here on Friday so will give that a go before touching anything else.

Looking at a zoomed pic it doesn't look great though:



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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 18 at 17:52
Just did the crack test and it doesn't look great:


After a bit more clean up, piston no1 has cracks too:

cracked piston no1

I think I'm going to pull the engine out of the van and take the block to my machine shop.  With a bit of luck they may be able to rebuild it for me on time. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mrhutch Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 18 at 18:38
wise move.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pete Westy Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 18 at 18:59
You could drop the sump and change the pistons with the engine in situ. You've done most of the work getting the head off. Almost certainly quicker than taking out and sending to your local machinist. You can check the bearing shells at the same time.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 08 Apr 18 at 22:17
Yeah, I have considered it, but decided to do it properly even if that means delaying trip a little  (hopefully not).  Once it's done it should be good for some years.

I don't know the history of that engine.  The PO put it in when the original got tired.  I have no idea how many miles it clocked.  It run alright after the usual tappets/timing treatment so I left it alone.

I dropped it out and stripped this weekend.  Was surprised how small the block looks without all the auxiliaries.  Here it is sitting in my conservatory:


No real issues getting it out so far which is unusual Big smile Getting the injection pump sprocket off without a puller was the hardest bit but managed to pop it off using the two chisel method.  All went smooth after that.  Used up all the biscuit tins in the house for parts...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 18 at 23:51
In the end I got a rebuilt block from AW Engineering as it was the fastest option and comes with a good rep.  Arrived today on a pallet, nice and black:


With a bit of luck it'll be running again this weekend
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Post Options Post Options   Thanks (0) Thanks(0)   Quote clift_d Quote  Post ReplyReply Direct Link To This Post Posted: 16 Apr 18 at 09:52
A good decision I think.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 18 Apr 18 at 00:51
Engine back in the van with new cylinder head and rebuilt injectors (GTD nozzles from BW, set to 155 bar)


Still few bits to go but I'm getting there.  So far on target time wise.  Spent a bit too much time dicking around cleaning and painting rusty bits and pieces...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dave friday Quote  Post ReplyReply Direct Link To This Post Posted: 18 Apr 18 at 10:23
Just so your prepared; you might have to drop the gearbox down a long way because the head( and other bits ) snag on the support bars...ask me how I know!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 18 Apr 18 at 13:29
I don't think I understand, drop the gearbox?

I have the engine supported from the bottom on a jack while one of the support bars is out, but yeah it is twisted a bit at the moment.  I'm hoping it'll be straight once I put the other support bar in.


Edited by akw - 18 Apr 18 at 13:58
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dave friday Quote  Post ReplyReply Direct Link To This Post Posted: 18 Apr 18 at 18:11
I meant drop the back of the gearbox,as you've got the engine your ok.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 25 Apr 18 at 00:18
Put it all back together this weekend.  All the little bits took the most time.



Went to get it started, pressed on the clutch and snap!  The release bearing has slipped of the forks... Must have cocked it up when mating the engine with the box.

Anyway, got it fired up after some hoofing and poofing and off it went.  Sounded like shit the first time, but I guess that's normal for fresh rebuild.  Rings not seated in yet, air in the fuel lines etc.  I must say I was shitting my pants while I was cranking it.

Warmed it up, nipped up the head bolts 1/4 turn.  Changed oil + filter.

Gearbox out, new release bearing in (had a spare knocking around luckily), gearbox back in, exhausted, sleep Ouch

Lots of little jobs next day before I fired it up again.  It started easier, lumpy when cold but sorted itself out a bit after a while.  Took it for a quick spin around the block.  Some oil leaking from the sump, nothing tragic.  Nipped up the sump bolts a notch and left it.

Today test drive #2.  Took it for an hour around county roads, some carriage way, varied conditions.  No more leaks!  The engine seems to have sorted itself out, smoother, quieter (for a jx).  Took it very easy but it definitely feels like it has more guts.  Removing the old cat converter must have helped too Big smile

As an added bonus my breaks now work properly after replacing the vacuum pump. Result!

It was a lot of work but overall pretty happy with it so far.  The Portugal trip is due in two weeks.  I'm aiming to clock 500miles before to run it in properly, do the final head bolts nip up and gain more confidence in it.  Fingers crossed and thanks for your help!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ob1 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Apr 18 at 14:48
Nice. Bet you were gutted to have to drop the box!

I expect you know better than I but I thought modern steel layered head gaskets do not need additional torquing?

I presume the engine recon gave you specific instructions otherwise?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote akw Quote  Post ReplyReply Direct Link To This Post Posted: 25 Apr 18 at 16:33
Yeah, dropping the tranny wasn't fun, but I did it before so it went pretty quick.  Mating it back with the engine is always a bit of a wiggle...

I'm following instructions that came with the Elring head gasket.  It's mostly fibre I think with metal rings around the bores:




Using new Elring set of bolts too.  I just hope they don't snap! Dead





Edited by akw - 25 Apr 18 at 16:35
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