Technical Multijet rebuild

[DaveMcT]

Last year I bought an 09 Multijet from another forum member. It has 120,000 miles and a broken cam chain so I paid enough for the parts to cover the costs if it turned out to be a dead loss. It's actually a nice car so will be getting a full re-work including suspension and brakes as necessary.

The engine needs cam chain and rockers which are easily available. To make for easier access I plan to take the whole lump out of the car so I can work in the garage.
The job will be done with new cam chain and rocker kit, new oil pump and probably new sump pan. There is no air conditioning to complicate matters.

My Question -
At this age (13 years) and mileage (120K) should I be changing the cylinder head gasket? I ask because they can deteriorate on some engines so is the MJ one of them? usable

 

[koalar]

I never heard of one failing

take a look on the Corsa forums and see If they see them go

Although you could whip it off and check for damage before ordering any parts. Would incur extra cost if everything is okay, but would save money if valves are bent or pistons damaged or cylinder wear

most are straight forward rockers damage I believe

 

[irc]

Last year I bought an 09 Multijet from another forum member. It has 120,000 miles and a broken cam chain so I paid enough for the parts to cover the costs if it turned out to be a dead loss. It's actually a nice car so will be getting a full re-work including suspension and brakes as necessary.

The engine needs cam chain and rockers which are easily available. To make for easier access I plan to take the whole lump out of the car so I can work in the garage.
The job will be done with new cam chain and rocker kit, new oil pump and probably new sump pan. There is no air conditioning to complicate matters.

My Question -
At this age (13 years) and mileage (120K) should I be changing the cylinder head gasket? I ask because they can deteriorate on some engines so is the MJ one of them? usable

I would leave it alone UNLESS you suspect an existing problem. Most oil/water mixing problems I have come across are failures of the oil/water intercooler that is part of the filler/filter assembly. This is (apparently) often (mis) diagnosed as HG failure.

 

[irc]

When you get the chain cover off, check to see if the chain has been grinding the block... I have come across 2 recently which had grooves where the chain must have been grinding away at the block for ages before it finally snapped.
Both were relatively low mileage (under 100k). How the owners didn't hear the chain slapping around I have no idea. Scrapped both as they had iron filings everywhere.

Even with these two, I'm still not convinced that early chain failure isn't almost always the result of bad maintenance at some time in the engines life... the plunger that maintains chain tension requires the right grade of oil, and the slipper guides require relatively clean oil.
Fleets that use the correct oil and change it on time seem to be able to get 200k+ out of them and still sell them on in running order, without changing chains.
I fitted one as a stop-gap for a friend which came out of an ex-SSE van which got crashed at 180k miles. I didn't expect it to add 50k miles more without trouble, but it did. Unfortunately sill rot and heavy MOT failure have killed that Panda now. It was a bit too smoky and low compression to take out and use again, but it still ran just fine as it got driven to the scrapyard.

 

[DaveMcT]

Thanks for the tip on checking for metal filings.

The owner before me had looked after the car, did not hear any untoward noises before it failed and was not making any money from the sale, so hopefully it's all good. I have just pulled out the cam position sensor (magnetic). It's spotlessly clean so that's good sign. The sump has to come off as part of strip-down so it's easy enough to check for debris before spending money on parts.

I love the engine architecture with everything built in layers. It's just a great shame that Fiat did not use a twin row cam chain. Being 2x wider than deep, they are less prone to lateral slap and with 50% more side plates, each link carries less tension.

 

[DaveMcT]

I would leave it alone UNLESS you suspect an existing problem. Most oil/water mixing problems I have come across are failures of the oil/water intercooler that is part of the filler/filter assembly. This is (apparently) often (mis) diagnosed as HG failure.

Thanks. Looks like another item to consider replacing. I wonder why these coolers fail. Is there an easy way to check for problems?