Never the same again?

madmelon · 14-03-2008, 06:10 PM

Well mums EL wagon has been due for some serious work for quite a while and the time finally arrived on Wednesday. Took it to our local dealer (always been serviced there, never had a problem) for head gasket, check out some tapping noises and replace a whole bunch of suspension stuff. All going well we get the usual, "we can't hear the tapping noise but we'll have a look while it's open." on Thursday, which I'm not too concerned about. They reportedly find no physical problems with the lifters.
Being in the car parts industry, I see the dealership guys every so often. Had a chat to one yesterday, saying mums car was in to which he replied "Yeh... head gasket or something wasn't it?.... Heard/saw a guy walking away from that car swearing his head off." That kinda took me back...got a bit worried but forgot about it as work was busy.
Come 8:00 thismorning, mum gets the dreaded phone call- the car ran for about a minute and then the timing chain snapped. I went off at hearing this..luckily I wasn't the one on the phone.
So we took a trip there thisarvo to pick up the rent-a-thrash, which I'm not allowed to drive

: and to check out the bits lying all over the floor.
Smashed up some of the timing case, ripped the key out of the keyway on the aux shaft but other than that doesn't appear to have any damage. All valves n pistons are ok, bearings all look brand new, no scuff marks anywhere. Bores may be a little glazed but for a 170,000km car, I'm pretty damn impressed.
Looks like the cam bearings may have been overtightened and so exerted excessive force on the chain. Only thing in sump was the broken link, but I'm still concerned that it'll never be the same again. It's never had a problem- totally reliable and notoriously quick (easily outrun manual EL xr6 and various Commodores to the speed limit). The bits are being sent to a former racing engineer and mechanic to be fully checked out but I still can't help but be worried.
Should I be?

TEaaron · 14-03-2008, 06:19 PM

Make them replace the motor, it's cheaper to buy a reco EL motor than it would to get that fixed.

madmelon · 14-03-2008, 07:00 PM

Quote:

Originally Posted by TEaaron

Make them replace the motor, it's cheaper to buy a reco EL motor than it would to get that fixed.

It's all on them- they're paying for the lot...and as I said- there was something about that car that made it good. I don't know what it was/is, but it always stood above the rest. If it was my choice, I'd prefer to have the same motor back. They mill the head when doing the gasket, so if anything it should be better due to the (admittedly minute) compression increase. Maybe I can convince them to put an XR6 camshaft into it to liven things up even more...

CADSKY · 14-03-2008, 06:35 PM

hmmm how long was it making tapping noises for? mine has been making tapping noises for about 10,000 k's now, it getting a service hopefully next week, maybe i should tell them to chec it? oh well im putten a V8 in it soon anyways

madmelon · 14-03-2008, 07:08 PM

It has been tapping on start up for a long long time. I just noticed it tapping whilst hot for the first time last week and just included it on the things to look at when gasket was done. Interesting thing is that it only did it once or twice that I noticed. Ford guys said the same thing- only for a few seconds on start up.
I did put the remains of a bottle (like 50-100mL) of that Nulon tappet quiet stuff in it, knowing service was coming up and it wouldn't be there for long. Maybe it did the job... if it's coming up for a service you could try it without having to worry about it being in there for long.

**ebxr8240** · 14-03-2008, 10:10 PM

I'd say one of the chain tensioners let go ??

arm79 · 17-03-2008, 12:34 PM

Quote:

Originally Posted by madmelon

Looks like the cam bearings may have been overtightened and so exerted excessive force on the chain.

How does someone overtighten cam bearings - I6's have none?

madmelon · 18-03-2008, 11:11 AM

Quote:

Originally Posted by arm79

How does someone overtighten cam bearings - I6's have none?

Yes, it does have cam bearings. How else would the camshaft rotate in the head? Have a look at the pictures in the "6 Treat" article on the Jim Mock website. Either way, it was a tensioner that did it in the end.

It has overheated once, not terribly as I realized in time and parked it.

A mate works at the dealership (as a sparky) and he was approached by the service manager who told him it's getting alot more work done than necessary, just to be sure. The block has been sent off to a race engineer/mechanic to be inspected, honed, etc. Anything wrong with it and it gets replaced. New rings, not sure if it's getting new pistons too. It'll get a proper clean up while it's there too, so won't be a problem with varnish.

As soon as it happened, they took the lot out, stripped the engine cleaned out the sump (only thing in there was the broken link) and got to work on getting it sorted. I don't know if the Aux. shaft still turns but it'll all be done properly.

To be honest, I'm kinda glad things have panned out the way they have, because the whole thing is getting a freshen up at worst and replaced at best (not like it needs it). As usual, we're all very satisfied with the way the dealership has handled things...and that's why our family always goes there.

arm79 · 25-03-2008, 04:21 PM

Quote:

Originally Posted by madmelon

Yes, it does have cam bearings. How else would the camshaft rotate in the head? Have a look at the pictures in the "6 Treat" article on the Jim Mock website. Either way, it was a tensioner that did it in the end.

Here I just thought the cam sat in the head on a hardened surface, there were no real bearings as such. Its a bearing surface, but not in the traditional sense, and clearances are not adjustable.

Sounds like they forgot to undo the tensioner when they started the car for the first time. I trust your chain noise is not related to the fact they didn't replace the guides as part of the rebuild.

AHMD6T · 26-03-2008, 02:42 PM

Quote:

Originally Posted by arm79

Sounds like they forgot to undo the tensioner when they started the car for the first time. I trust your chain noise is not related to the fact they didn't replace the guides as part of the rebuild.

Yeah I agree with the tensioner thing, that's what I was saying in my post. Normally it cooks the distributor shaft which is a machine fit in to the front of the block, so once it seize the block is fubar.

As for the chain noise, the head has been decked twice now hasn't it? Ever done a head gasket before this? It probably has been decked enough for the timing chain to lose some tension, which cause a rattly noise and hovering low revs - ie when the ISC kicks in to compensate for steering movements or air conditioner turning on, the revs rise and hover and this noise may occur.

Common problem on JMM head and gasket equipped vehicles.

ltd · 17-03-2008, 01:34 PM

Did it ever run hot? Has it ever overheated?
In the I6 if the engine gets too hot it will stretch a cylinder and give you piston slap. Check to see any scoring or if any of the cylinders looks slightly different.
Other than that it can only be lifters but hey, I've had an I6 that we just put a new head on make the most terrible lifter noise you ever heard for the first hour running, and then it went away when it finally freed itself. If your concerned do an oil flush when you get it back, as varnish and junk buildup can cause the lifters to become noisy. Also, get that broken piece of chain out of the sump.

AHMD6T · 17-03-2008, 01:57 PM

Sounds like the timing chain tension wasn't released when the gasket was done. Sometimes when you do this, for some reason the chain tightens up a LOT more when you put everything back together. Has happened to me on about 2 gasket changes out of maybe 10.

If its too tight you get a whine from the auxiliary shaft as it's being pressed hard against the block on it's right side, and heats up rapidly. It gets to a point where it gets so hot it just welds itself to the block.

When the happens the block is a throw away.

Quote:

Smashed up some of the timing case, ripped the key out of the keyway on the aux shaft

This is a dead giveaway of what I've just said. Does the shaft still turn? Have you pulled it out?

GK · 17-03-2008, 03:42 PM

Major bummer mate. At least they're paying for the lot. I'd get a different engine and keep the bits as well. There's a lot that went on the current unit. There's stuff on the current unit that may be of benefit later.

All the best with it.

GK

daniel_rossy · 17-03-2008, 10:56 PM

i think this is the month where all mechanics dont give a shh*t about anything and just do a half assed job. Well, some.

madmelon · 25-03-2008, 04:08 PM

Got the car back thisafternoon and as suspected it's not the same as it went in- it's BETTER, apart from one niggle.
It seems to go slightly harder, it's smoother, it's quieter and it's a damn sight better than the laser thrash-about. Only problem is that from just under to just over 1000rpm, there is a nasty rattle noise, like chain rubbing something. I don't know what it is, but when mum gets back from wherever she's going I'll ring em up and ask what's the go.
Next job- clean the oily handprints off everything- it's so filthy. The stuff on the manifold heat shield is starting to burn too so it stinks.

needaXYGT · 25-03-2008, 08:15 PM

yeh, it your that concerned that then a differnet motor good.

madmelon · 26-03-2008, 12:00 PM

went back thismorning, don't know anything yet. What i meant by cam bearings was the fact that it rotates in something. Whether it has inserts or a plated surface or not, it's still a bearing.
Tensioners were replaced- they were ripped apart when the chain let go.

madmelon · 27-03-2008, 07:07 PM

ok car is back, all is good- nice n quiet. loving it.