Hi, took my 2000 Scenic II RXE 2.0L Auto for a cambelt change. During
the repair they made a mistake. The garage told me they turned the
engine over by hand but when they started it there was a nasty noise.
This is a "critical' engine according to Renault, which means if the
timing is wrong all the valves are bent. They said they may have to
send the head away to a machine shop fo new valve guides

The garage has been good about it and lent us an auto courtesey car
and will be paying for the 'extra' work. What I am concerned about is
will they do a good repair, and will faults occur after months due to
a poor repair e.g. were the pistons, rings etc. damaged?

What would you do when you went to pick the car up (it's been 3.5
weeks since the nasty noise). I was thinking of a letter stating what
happened and a 1 year guarantee.

Thank you

On Mar 12, 4:32 pm, neil.farr... (AT) btinternet (DOT) com wrote:
If the pistons are alloy, which I suspect they would be, and if
they've hit anything enough to bend a valve then the piston tops will
likely have valve and debris imprints on them. I would suspect that
anything below the pistons would be OK. The head itself could also be
damaged I guess. Sounds like they want to install new valves and
guides (to the head) and if the shop does it properly this requires
grinding new valve seats. I guess you could argue that that reduces
the life of the seats but it wouldn't get you very far.

The head should be re-installed with new bolts etc but I'd be
seriously worried about letting a garage that can make that kind of
mistake do anything else on my car. I guess you've given your
approval for them to fix it. You should have asked for guarantees etc
back then. Ask them to throw in an oil change etc etc but again,
how'd you know they do it?

<neil.farrow1 (AT) btinternet (DOT) com> wrote

If it runs ok when/if you get it back then just get rid of it ASAP, let
someone else have the (possible) grief.

I have never, ever seen a rebuilt engine that has been done to the quality
of an original factory built engine, no matter what the make, no matter who
does it. It may run acceptably, but it is never the same, and modern
engines are much more critical than old. On most (all?) French engines the
cylinder liners are removable, problem is that they seal with a rubber ring
at the bottom of the liner, when removing the head it is ever so easy to
disturb that ring and internal leaks start to occur. The slightest
variation in combustion chamber size, valve seat width etc. etc. will all
make a difference. Most garages will not even have the right glue available
to reassemble it, they will probably use pattern gaskets and parts, etc.
etc.

Mrcheerful

IANAL

It might be worth checking in uk.legal as well, and I wonder if you pay
by credit card you get additional protection from them for ongoing
problems (consumer credit act section 75 makes the card issuer jointly
liable for purchases)

"adder1969" <adder1969 (AT) yahoo (DOT) co.uk> wrote

I've seen that done on one of these engines.

A lot of garages do cambelts without the proper tools (if you had to buy the
tools for every type of engine, you'd never make any profit, especially it
it's a one off job), but instead rely on the use of some tip-ex. Now that
works for most petrol engines, as all the pulleys are keyed to the relevant
shafts, so it's just a case of making sure you don't get the belt out by any
number of teeth, and the tip-ex is as good a method as any.
However, with this engine, the crankshaft isn't keyed, but the crank timing
belt pulley is.
So mechanic unbolts the crankshaft pulley, sees the keyway in the belt
pulley, assumes everything is locked nicely, and procedes to mark that with
tip-ex.
But unknown to the mechanic, during removal of the crank pulley, the timing
belt pulley has just spun around the crankshaft.
So once everything is rebuilt, they try to start it, and a couple
revolutions later, a nice set of bent valves.
Which is then followed by much headscratching wondering why it's just done
that, and the realising of why you really needed the special timing pin to
the align the crankshaft (similar idea to the ford 1.8 deisels).

The one I seen involved a mechanic (who realised the timing had moved and
wanted the proper timing pin), a supervisor (who wanting to meet deaslines
and not spend money got the mechanic to keep moving the timing back until
the engine would turn by hand, and then tried it on the starter), and a
foreman (who had to provide mediation between the two after it went tits
up).

The damage was limited to a set of exhaust valves, with no other visible
damage, and everything seemed fine afterwards.

On Mon, 12 Mar 2007 17:19:06 -0000, MrCheerful <nbkm57 (AT) hotmail (DOT) com> wrote:

Well my old Fiat engine worked much better after I rebuilt it & I can't
remember an A series that wasn't reassembled better than it came from the
factory.

In article <eYfJh.105369$1E3.37769 (AT) fe3 (DOT) news.blueyonder.co.uk>,
MrCheerful <nbkm57 (AT) hotmail (DOT) com> wrote:
Depends on the engine. Older ones use selective assembly for things like
pistons. Crank throws often weren't exactly 180 degrees to one another -
(four cylinder). Combustion chambers were simple castings and not matched
in volume. Etc, etc. A good machine shop would sort most of these when
reboring and regrinding. The balance could also be improved over the
factory standard. And a skilled mechanic or DIYer make at least as good a
job as the factory at re-assembly. Of course this probably isn't true
anymore with decent engines but I'll bet it still applies to some.

--
*Wrinkled was not one of the things I wanted to be when I grew up

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

In article <op.to3hk3mvyuobwl@lucy>,
Duncan Wood <newsto (AT) dmx512 (DOT) co.uk> wrote:
Yes. The last engine I did a full re-con on was a B-Series 1800, and that
ran like a sewing machine afterwards - far better than it ever had before.

--
*Can fat people go skinny-dipping?

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

"MrCheerful" <nbkm57 (AT) hotmail (DOT) com> wrote

<snip>

I hope you don't mind, but I'd like to vent a little spleen here. No, not
specifically at you, just about 0.004% spleen for everyone who wants to
fling a car with a problem onto someone else - that way, everyone who
deserves it gets some.

Let's say you have a Fnord Monvavoo which has an irritating rattle on
startup that lasts about 15 minutes and then goes away. You post on a
newsgroup and the advice coming back is that the 4th exhaust valve has
become un-noduled and a repair is £215+vat and fitting (a total of £415) is
needed. If this valve becomes totally nodule-less, it will promptly grow
teeth and gnaw a hole through the engine meaning a complete new engine is
required.
At this point, you decide you don't want to pay the £415 and would rather
flog the car and get a replacement. You put an ad in a newspaper and
someone rings saying they want to look at the car at 2pm. You take the car
for a run at 1:45 to get rid of the rattle. The punter buys the car and
drives off...

You go to a garage with the money and test-drive (subsequently buying)
another Fnord Monvavoo which you notice is already up to temperature(bah!
coincidence!). It's not long after you find the 4th exhaust valve has grown
teeth and eaten through the engine. Someone else has sold a dodgy car to a
garage, covering the evidence and they've sold it to you doing the same.
Wouldn't that piss you off?

It would be nice to find people who are willing to point out problems with
cars before they're sold - so far I've bought cars from decent people who
have said (sometimes with prompting) what is wrong with a car and it makes
me more liable to buy it knowing what I have to fix. There have been plenty
of cars I've looked at and then told the owner to go poke it because they
tried to cover up problems just to shift them and the expense onto some poor
sap The least anyone could do when selling a car because of a fault is let
the buyer know. If that scares you because of a potential non-seller, then
fix the fault or sell to someone who appreciates honesty. Don't be a bastard
and sell a lemon to someone who wants a peach.

--
Thingy.

<neil.farrow1 (AT) btinternet (DOT) com> wrote

I think that's quite fair of you to ask. I would. A main dealer did
something similar to my car and put it right the same day. Not a word said
until I went to get the keys and the manager explained there had been a
problem. I was quite annoyed but the car has been fine and that was three
years ago.