Repair after timing belt failure....pic heavy.

Nissan doctor · 12-03-2012 11:45pm #1

I posted in another thread that I got a Chevy Nubira for €100 which had suffered a timing belt failure. A couple of people mentioned that they might like a thread on the repair so here it is.:)

First, some pics of the timing belt issue. Identical to another posters thread recently on their Nubira, the teeth on the belt failed due to being left well beyond its replacement interval. In this case, the guide pully also failed.

Failed guide pully:

Teeth stripped on the belt:

At the crank pully:

Broken pieces and stripped belt:

Onto the strip down, manifolds removed:

Rocker cover removed:

The head off and the impact marks from the pistons contacting the valves is pretty obvious:

And the view of the valves....all 16 flattened by the pistons:eek: The cars was seemingly doing 120kph when the belt failed.

Nissan doctor · 12-03-2012 11:53pm

Cylinder head ready for disassembly:

With the cams removed, the hydraulic tappets come out and get stored in fresh oil to prevent then running try and a noisy start up when refitted:

Compressing the valve springs to release the retainers/collets and remove the valves:

The valves needed to be driven out with a rubber mallet and punch as they were jammed into the valve guides:

And here is why:eek: All 16 were exactly the same:

With all the valves out, the stem seals are next:

Cylinder head stripped and everything stored in position for correct re-assembly. Waiting now on all the new parts and the head will be getting sent for new valve guides too:

Thats it for now....tune in next time:P

George Dalton · 13-03-2012 12:03am

Nice post, I would have put the thing out of its misery though, scrap metal is making good money these days

therewillbe · 13-03-2012 12:04am

You must be good at the Lego! Fair play to you. I wish I had your patience.You saved quite a few quid doing it yourself .Keep us up to speed.

tuxy · 13-03-2012 12:09am

Interesting post, thanks

Jimdagym · 13-03-2012 12:12am

Great work Doc. Thanks for that,

Can't believe how bent those valves are :eek:

MugMugs · 13-03-2012 11:55am

Good Job Doc!

trixyben · 13-03-2012 5:36pm

love to see these quality step by step photos like these, makes alot more sense to me seeing it done like this than just reading it from books or the net...

Doc you say you have to send the head away for new valves, can you not fit new ones yourself or do they have to be installed by certain machine?

Would really like to see this type of step by step guide for changing head gaskets, replacing clutches etc... As a keen amature dear I say mechanic

these are the best ways if find I learn an awful lot...

Anyhow fab job Doc

kona · 13-03-2012 5:49pm

trixyben wrote: »

Doc you say you have to send the head away for new valves, can you not fit new ones yourself or do they have to be installed by certain machine?

The Valve guides need to be pressed into the head. The head will also need to be reamed to the correct size to ensure a proper fit. So the use of a hydraulic press and a pillar drill with the reaming tool is needed. However, the valves, springs and collets are reinstalled with the spring compressor you can see in the pics above, when the shiney new guides are installed, the oile seals are like a top hat and sit ontop of the guides.

Mar4ix · 13-03-2012 6:12pm

will pistons goin to be replaced also ? well... i suppose.

in seventh picture where rocker cover off, is it just light or it is red ish on head walls ... indicating wrong oil in engine.

Nissan doctor · 13-03-2012 6:30pm

Mar4ix wrote: »

will pistons goin to be replaced also ? well... i suppose.

in seventh picture where rocker cover off, is it just light or it is red ish on head walls ... indicating wrong oil in engine.

There is no damage to the pistons, there rarely is unless the failure has happened at very high RPM or the valves have actually broken.

trixyben · 13-03-2012 9:01pm

kona wrote: »

The Valve guides need to be pressed into the head. The head will also need to be reamed to the correct size to ensure a proper fit. So the use of a hydraulic press and a pillar drill with the reaming tool is needed. However, the valves, springs and collets are reinstalled with the spring compressor you can see in the pics above, when the shiney new guides are installed, the oile seals are like a top hat and sit ontop of the guides.

who and where does that job out of interest?

jimmyw · 13-03-2012 9:56pm

Mr Foxman of this parish/forum is doing the same job on a Renault Megane he picked up for free.I have seen his youtube channel (and no he is not paying me;)), you can check it out, if he doesnt give out out to me:o for the mention.

If anyone is reluctant to have this job done, then this is the result and a warning for not changing your timing belt.

Nissan doctor · 13-03-2012 11:55pm

trixyben wrote: »

who and where does that job out of interest?

I'm using cylinder head services in Kilbarrack to fit the guides.

All 16 guides in this head where cracked due to the valves being forced sideways into them by the impact.

Row · 14-03-2012 10:52am

Nice one Doc...I see you keep your surgery impeccably clean....:cool:

Nissan doctor · 14-03-2012 10:55am

Row wrote: »

Nice one Doc...I see you keep your surgery impeccably clean....:cool:

Don't want any infections getting in:p

That's a room we have out the back which I emptied out and cleaned for engine assembly work. Could do with a lick of paint though:P

Row · 14-03-2012 2:11pm

Nissan doctor wrote: »

Don't want any infections getting in:p

That's a room we have out the back which I emptied out and cleaned for engine assembly work. Could do with a lick of paint though:P

Its good to have a room away from the dusty Environment of a shop
floor....:)
Last thing you want while doing this kind of work is some lad cutting off a section of an exhaust and covering the place with dust...:eek:

engrish? · 14-03-2012 3:05pm

This is fantastic! I was the poster with the timing belt gone in the Nubira.

It is my intention to deconstruct the engine during the summer and have a go at repairing it. I will be following this with a lot of interest!

Can you tell me how much the parts and repairs will set you back?

Thanks

shamwari · 14-03-2012 3:08pm

I know its a Chevy but it looks very similar to a GM 16V ecotec. Are the bits the same by any chance ?

Nissan doctor · 14-03-2012 4:10pm

engrish? wrote: »

This is fantastic! I was the poster with the timing belt gone in the Nubira.

It is my intention to deconstruct the engine during the summer and have a go at repairing it. I will be following this with a lot of interest!

Can you tell me how much the parts and repairs will set you back?

Thanks

I stuck a link to it on your thread....though it might be of interest to you alright.

Nissan doctor · 14-03-2012 4:11pm

shamwari wrote: »

I know its a Chevy but it looks very similar to a GM 16V ecotec. Are the bits the same by any chance ?

Its basically the same engine...Chevy part of GM too.

Nissan doctor · 14-03-2012 10:42pm

Few parts arrived..

TURRICAN · 15-03-2012 11:25am

Is this irish eric the car guy?:D

engrish? · 15-03-2012 12:39pm

Nissan doctor wrote: »

I stuck a link to it on your thread....though it might be of interest to you alright.

I am so excited about taking this on. This will be my summer project!

trixyben · 15-03-2012 1:25pm

Nissan doctor wrote: »

I'm using cylinder head services in Kilbarrack to fit the guides.

All 16 guides in this head where cracked due to the valves being forced sideways into them by the impact.

again just out of interest Doc how much roughly would ya be paying for the new guides to be put in?

Is it pretty much the same with most engines that have a snapped timing belt to be repaired in the way you have shown?

Nissan doctor · 15-03-2012 1:54pm

trixyben wrote: »

again just out of interest Doc how much roughly would ya be paying for the new guides to be put in?

Is it pretty much the same with most engines that have a snapped timing belt to be repaired in the way you have shown?

I'll post prices when I've the total job done to give people an idea.

Almost every belt failure is the same repair with varying degrees of damage. If the belt breaks on start up, as often happens, then the guides are often ok and all the valves may not be bent but if at very high speed or RPM then pieces of the guides or valves can break causing damage to pistons etc but this is rare in your average road car.

trixyben · 15-03-2012 3:25pm

Nissan doctor wrote: »

I'll post prices when I've the total job done to give people an idea.

Almost every belt failure is the same repair with varying degrees of damage. If the belt breaks on start up, as often happens, then the guides are often ok and all the valves may not be bent but if at very high speed or RPM then pieces of the guides or valves can break causing damage to pistons etc but this is rare in your average road car.

If say half of the valves or bent and guides cracked would you replace all anyway as you have it stripped down or just repair whats needed?

Im in the process of buying a cheap banger to start experimenting on, cant wait to start stripping it down and doing timing belts, clutches, engine rebuilts etc, only want to spend small money on one but hard to find as price of scrap so high!!!!

I actually went to look at a car yesterday evening it was a 1996 punto, no test or tax his long time, fairly rough was sitting up over a year with green algae all over it and rust patches, was advertised at €350 ono... Offered €200 and he wouldnt move a cent, said the car was going perfect and he was selling it cheap :eek: (I was thinking are we talking about the same car here :pac:

Nissan doctor · 15-03-2012 4:16pm

If there are any visible cracks in any valve guides I'd replace them all as there could be hairline cracks in others that you wouldn't see. As for the valves, it depends, my preferance would be to change them all as, depending on the engine, they are not expensive in the scheme of the whole job.

You'd normally do a leak down test on an engine with a failed timing belt and if you got readings of less then 20% leakdown on any cylinders then the valves are fine and you could leave them in place if you wanted.

15-03-2012 8:51pm

I don't like threads like this

The ZT is on the factory belts :pac:

Only joking ND, great thread, fair play for taking the time to take the pics and lash them up

Nissan doctor · 15-03-2012 9:27pm

RoverJames wrote: »

I don't like threads like this
The ZT is on the factory belts :pac:

Only joking ND, great thread, fair play for taking the time to take the pics and lash them up

You'd better takes notes so.:P

15-03-2012 9:39pm

Nissan doctor wrote: »

You'd better takes notes so.:P

I'd need more than notes to tackle a KV6 before it snapped a belt, not to mind after

Repair after timing belt failure....pic heavy.

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