Piston problem (this can't be good...)

[veeman]

I just acquired a caddy and thought I might check out the engine (1.6 CR code)  currently installed in it to see if it would be worth putting back on the road while putting together the TD for it...

The PO had blown a head gasket and pulled the head (I got the car like this).  When I rotated the engine and cleaned the pistons, I saw the piston in cyl number 1.



Yikes!  Looks like something went through that cylinder or perhaps the piston collided with the valves.  Funny thing is that the head looks fine and the damage looks "older".  It actually looks like the engine ran like that for a while.

Pistons 2 and 3 look fine, but #4 looks like this:



There's some minor damage and nicks on the piston, but not damage like number 1.

I'm assuming that piston number 1 is most likely junk, but not knowing about diesels and what's "normal", I'm not sure about no. 4.

I don't especially want to track down two pistons and re-ring the whole motor especially if I'm going to put the TD in, but it would be nice to run it around in NA form for a while.     Thoughts?

[Mark(The Miser)UK]

:shock: Crikey that piston face looks like an artist carved it out of clay. Slice the top off and set it in resin. :shock:
It looks like a prehistoric camel footprint


Couldn't help looking through your photo host site:

http://www.hostdub.com/g60racer:April_2005_010

 :twisted: Sorry I've not been very 'constructive' :twisted:

[chrissev]

pretty obvious what happened:  timing belt failure, valves hit piston, head was destroyed and replaced by PO but he didn't touch the block, car ran like that ever since.  My main worry would be regarding whether piston #1 has any cracks in it, and whether the connecting rod or bolts are damaged, rod slightly bent, etc (don't want to throw the rod through the side of the block).  Might want to replace rod and piston as a safety measure.  Piston #4 appears to have very light damage, probably just a small hit with Piston #1 taking the brunt of the impact.  Also looks like something was detonating in Cylinder #4 (little pinholes in the top of the piston).  No idea what that could have been.

The damage i think seems right as if Cyl #1 had been on the exhaust stroke when the belt failed (exhaust valve wide open, major damage), then cyl#3 would have been in compression (both valves closed, no damage) cyl#4 would have been on intake (probably intake was partially open, slight damage), and cyl #2 would just have come off its exhaust stroke (exhaust valve closed, no damage) and not yet gone into its intake stroke (intake valve mostly closed, no damage).  I think that would be right.

[veeman]

>> (Mark) Couldn't help looking through your photo host site:

Yep... there's some weird stuff on there from other users.  I just wanted a way to host / post pics online and as it turns out hostdub is VW/Audi friendly and run by enthusiasts.  Pretty reasonable (way less than buying my own webspace).

>>Might want to replace rod and piston as a safety measure

I thought that might be the  case.  With that much compression, is it safe just to replace one piston if it has new rings and the others don't?  

>>Piston #4 appears to have very light damage, probably just a small hit with Piston #1 taking the brunt of the impact

You're probably right... they're both "up" at the same time.  Amazing that the PO replaced the head and ran the car like that.  Pretty tough motor...either that or good luck.

[chrissev]

I thought that might be the  case.  With that much compression, is it safe just to replace one piston if it has new rings and the others don't?

I was going to say check the compression but that's hard to do with the head off, and you don't want to put the head on, check compression, then have to take it back off again.  That's a tough call.  If the rings are really bad on the other cylinders you want to replace them anyway (and glaze bust the cylinders a bit).  No real way of knowing how bad the rings are without checking the compression.  The engine might have some strange characteristics if one cylinder is running full compression and the others are weak.

[Mark(The Miser)UK]

I wonder how long it was running after the head damage? Maybe if it happened a long time ago (mileage wise) then the moon crater is just superficial  :shock: [Can you have a superficial meteor strike?] :shock:
  Call me crazy if you like; but I'm thinking of what others have said about introducing greater imbalances with single cylinder repairs not to mention the cost...

Can you talk to the PO or is he hiding under a stone somewhere with his fingers in his ears  :roll:

 :twisted: Taking the piston out would show if conrod was bent by sidewear on piston 90 degrees to pivot (perpendicular?) :idea:

[veeman]

>>I wonder how long it was running after the head damage? Maybe if it happened a long time ago (mileage wise) then the moon crater is just superficial

I had wondered the same thing.  If the damage had been done recently, causing the PO to pull the head, I'd expect the piston to look "newly gouged".  It doesn't at all.  It looks like it happened a while ago and that someone just put it back together.

>>introducing greater imbalances with single cylinder repairs not to mention the cost...

Seems like maybe the PO was driving it like that.  Can't imagine it had normal power or was healthy though.

>>Can you talk to the PO or is he hiding under a stone somewhere with his fingers in his ears

I'd say he doesn't know anything about it.  He parked it "as is" in a large garage when he lost the head gasket a few years ago

>>Taking the piston out would show if conrod was bent by sidewear on piston 90 degrees to pivot

Good point.  Maybe I'll tear it down if the engine comes out.  I guess I could drop the pan and get at the rod bolts from underneath, but at this point I'm trying to line up another complete engine...One that I know has a good head and components.

This_should_be a temp solution until I can get the time to do the TD motor for it.

[chrissev]

if you do take out the rod, don't reuse the bolts!

[fspGTD]

Veeman - that's sure looks like a messed up piston there, but if the ring seal is in tact, it might very well work, but I'd expect an uneveningly running motor that doesn't run very well.  I'd wager that's why the head was removed before you got it.  It does looks like those are the original pistons (bore: 76.48mm)  I have run the bottom end after piston valve interference before but the damage in the piston tops was just a small mark underneath where the valve heads were.  With that piston it looks like something got loose in the combustion chamber (like a valve head or fragment) and rattled around in there while getting pounded.  Thanks for sharing those pics and good luck with getting it running!

[veeman]

>>it might very well work, but I'd expect an uneveningly running motor that doesn't run very well

That's pretty much the conclusion I came to as well.  Luckily, a friend lined me up with a complete replacement engine last night (see the post on the green block paint).  It looks to be pretty clean and in good condition.  

No idea if it was running or not though.  My friend took it out to convert his truck to gas...  He never bothered to get it running.

I think I'll put it in "as is" and then go from there.  I don't have a compression tester at the moment, so I really can't tell if it's got a headgasket / ring / head problems either.  Either way, I'm assuming it'll be easier to evaluate once it's in the car and it runs / doesn't run.

Thanks for your help!

[jtanguay]

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=9889&item=4539552608&rd=1

look at the price on those!!! too bad they werent oversize pistons

[Mikeyworks]

just to reinforce what the others have said

...check the piston for cracks:


...check the rod for straightness



...replace the rod bolts, 'cause if you don't you could end up like this




Mikey (aka learned the hard way)

[fspGTD]

Wow Mikey, you are really coming off here like some accident prone kind of guy!  :lol:

PS - you left this beauty out of your photo saga...


:wink:

[Mikeyworks]

Wow Mikey, you are really coming off here like some accident prone kind of guy!  :lol:
:wink:

That's what I get when I buy crap dead engines and try to do forensic pathology on them!!!!

It may seem like I kill a lot of engine parts, but i do like to go around and find the dead engines in the area and figure out why they died.
That gives me the knowledge of what to avoid in the future.

Mikey

[fspGTD]

And thanks for sharing the pictures and stories with us - great info for the community to have.

I gave you the wink because I sure kill more than my fair share of parts as well!  :lol:  (Looking at a single cam lobe and bent valve sitting on my mantle as I write this... )