Complete engine repair/rebuild - pic heavy

Nissan doctor

Another few pics to bore you all:P

A step by step(roughly) on a complete engine overhaul/rebuild.


This engine, a z14xep from a 2008 Opel astra, was suffering from very high oil consumption and was also loosing power at higher speeds(anything above 120km/h was a struggle). A leakdown test on all cylinders, showed 70% pressure loss on number 2 and 3 and a little under 50% on 1 and 4, after adding some oil to the each cylinder, the pressure loss dropped to just over 20% on all, so worn/damaged piston rings where proved by the above results to be the main problem.

However, it turned out, after an admission by the owner, the car had only been serviced properly twice in its 4 year and 115,000km life and had been let run low on oil numerous times...so it was decided that a complete inspection and overhaul(as well as a new appreciation for vehicle maintenance) was to be done.


So........

Engine out and most ancillaries removed:



Rocker cover removed, surprisingly, it doesn't look to bad around the cams:



Crank and water pump pullies off:



Engine flipped over to begin removing the sump bolts:



And the sump removed, things looking a but worse in here:



With the sump off the chain cover come off next:



And the chain, tensioner, guides and cams removed:

Nissan doctor

Next up the head is removed:



With the head removed, evidence of excess oil burning in the combustion chambers become obvious. Note the heavy build up on the piston crowns, cylinder 2 and 3 especially:



Engine upside down again, this time to remove the big end bearing caps to release the pistons and con rods:





Number 1 con rod and piston assembly removed:



With number 2 removed, the cause of the problem becomes visable, the oil scraper ring is completely seized into the ringland, and bad build up on the secondary compression ring and around the sides of the pistons:



Old rings removed:



All the heavy deposits cleaned from the piston, if left as they were, the amount of build up on the piston crowns would have lead to poor combustion, 'hot spots' amongst other issues:



And all 4 cleaned and ready for new rings:



The cylinder head is also getting a full clean and recondition to replace valve seals and re-seat the valves due, again, to heavy build up:



As on the piston crown, the valves showed a thick build up from the oil being burned, both on the combustion side of the valve, and, on the exhaust valves, the port side:





I won't go in to much more detail on the head rebuild as its all pretty much the same as what's in the repair after timing belt failure thread. http://www.boards.ie/vbulletin/showthread.php?p=77563130

Piston rings arriving tomorrow so ring gapping and fitting and cylinder/block preparation to come......if your really bored:P

Bobo78

Nice one, love seeing pictures like this
One question for you, when engine is suffering from burning oil issue would replacing the rings and valve stem seals solve the problem or would it require much more extensive work to block and head?

Jimdagym

Great work doc. I just adore these threads.

Nissan doctor

Bobo78 wrote: »

Nice one, love seeing pictures like this
One question for you, when engine is suffering from burning oil issue would replacing the rings and valve stem seals solve the problem or would it require much more extensive work to block and head?

It depends on the extent of any damage or wear but generally, ring and stem seal will cover the cause of the vast majority of oil burning issues.

Nissan doctor

LIGHTNING wrote: »

Great stuff! Since their is a lot of labour whats roughly the cost of the above work?

I think the final bill for this job is close to 2k but that includes a couple of other bits an bobs too like 2 tyres, brake pads etc.

Now if it were a Porsche.......:eek::P

trixyben

Can I ask just how exactly or how exactly the piston rings do there jobs? is the whole piston shaft submerged in oil all the time? then when piston coming down the rings prevent oil from getting into the combustion chamber? If thats the case they surely the walls of the chamber will have oil deposits and burnt oil will gather over time? What are the rings constructed from are they metal or rubber?

Also the pistons came up great after a clean Doc, how and what did ya use to clean them?

Nissan doctor

trixyben wrote: »

Can I ask just how exactly or how exactly the piston rings do there jobs? is the whole piston shaft submerged in oil all the time? then when piston coming down the rings prevent oil from getting into the combustion chamber? If thats the case they surely the walls of the chamber will have oil deposits and burnt oil will gather over time? What are the rings constructed from are they metal or rubber?

Also the pistons came up great after a clean Doc, how and what did ya use to clean them?

The con rod etc is not submerged in oil but the cylinder wall, under the pistons, gets sprayed with oil by the movement of the crank(some engines have nozzles which spray oil onto the underside of the pistons too) so the oil scraper ring(the bottom ring) removes this oil from the cylinder walls as the piston comes down the bore.

The top ring, or two rings in this case and as on most modern cars, are the compression rings, these seal the gap between the cylinder walls and the piston so as little compression as possible is lost as the piston is pushed upwards. The rings are metal and seal by being naturally slightly larger diameter then the bore, so when they are fitted into the grooves in the piston(ringlands)and then into the cylinder, they push out against the cylinder walls, creating the seal.


As for cleaning those pistons, the build up was so thick and hardened on that I had to use a bench grinder with a wire brush attachment to get it off with a final clean in a parts cleaning solvent to get them back to their original colour.

I love these threads and I don't even drive! I think I just like seeing things being taken apart and reassembled. I do it with electronics but not cars.

Nissan doctor

.......Part 2,



A final pic of the cylinder head with all valves cleaned,lapped and back in place:



Next step is prepping the block/cylinders with a hone. Honing firstly breaks any glaze that may have built up on the cylinder walls which can lead to the rings not sealing perfectly, secondly it adds cross hatching to the bore which is essentially sanding the cylinder walls(DON'T try it with sand paper though:eek:) which gives the rings a fresh surface to seal against. The hatchings are visible but are so fine that you can't actually feel them, the bore still feels smooth to the touch.

For this a specific cylinder honing tool is required along with a honing oil to lubricate the tool(paraffin does the same job) :



And all 4 done, after honing the block needs a good wash:



Next, the new rings need to be correctly gapped, this is done by fitting the rings into the cylinders and measuring the gap in the ring.

Fit the rings in and use the top of the piston to push the ring evenly into the cylinder:



Measuring the gap, you may think that having a gap in the rings is bad for sealing, but the rings expand when they get hot so need a specified gap to allow for this. Too small a gap and the rings can distort or even break and too large and you will loose compression. In the absence of a bore gauge, you can also use this method to check for any ovality or distortion in the cylinder by measuring the ring gap at different depths in the cylinder:



With this done for each ring on each piston, the rings can then be fitted to the pistons:

Nissan doctor

Next the pistons are fitted back onto the block, to do this properly with risking any damage you need a piston ring compressor, this holds the rings tight into the pistons so they can be lowered into the cylinders:



A gentle tap with a rubber mallet or similar to get the pistons in:



As a final check after fitting, check that the piston to cylinder gap is all within spec:



And all shiny pistons back in and a new head gasket on:

Nissan doctor

Back on with the cylinder head, torqued/angled to spec:



At this stage, on this engine, specific locking tools are fitted to keep the cams and crank locked in position before refitting the chain.

Cam locking plate:



Crank locking pin, from the outside and inside:





A new timing chain cover gasket goes on before the chain too:



With the chain and cover etc back on, another engine specific tool in used to position the cam sensor pick up correctly:



Finally, new sump gasket, sump, and rocker cover go back on to close up the engine at last:



And finally, ready to lift back to the place from whence it came:)

101sean

Nice thread, not something you see so often these days on modern engines.

Did my first engine rebuild last year, 3.5 Rover V8 in my 101, sooooo satisfying when it started first turn of the key and the oil light went out immediately

Nissan doctor

101sean wrote: »

Nice thread, not something you see so often these days on modern engines.

Did my first engine rebuild last year, 3.5 Rover V8 in my 101, sooooo satisfying when it started first turn of the key and the oil light went out immediately

Its very therapeutic work IMO, I have dozens of folders full of pics of various engine rebuilds over the last few years, mostly non standard performance Japanese stuff though.

Jimdagym

Nissan doctor wrote: »

Its very therapeutic work IMO, I have dozens of folders full of pics of various engine rebuilds over the last few years, mostly non standard performance Japanese stuff though.

Is most of your work services and the likes so when the interesting stuff like this comes in you jump on it doc?

Nissan doctor

Jimdagym wrote: »

Is most of your work services and the likes so when the interesting stuff like this comes in you jump on it doc?

Well I'd be the one who would do this stuff in my garage anyway but its definitely nice when this type of stuff comes in as the basic servicing etc can get a bit mundane sometimes.

johnner09

i just love these posts you put up Doc, well explained with good clear pics.... well done!

Tea drinker

Nic one with the thread ND. I have a friend who has a similar car, similarly abused or worse abused as it actually seized.... got a replacement engine fitted in past few weeks.
Surprising how many people "forget" to service or just check the oil in their cars.

shamwari

Great pics Doc! Just wondering if you've ever rebuilt a 2 litre diesel engine from a Mazda 5? If so, I'd be very keen to learn what you discovered !

Drummerboy08

Was the chain replaced while ye were at it, or did the old chain go back on?

Nissan doctor

Tea drinker wrote: »

Nic one with the thread ND. I have a friend who has a similar car, similarly abused or worse abused as it actually seized.... got a replacement engine fitted in past few weeks.
Surprising how many people "forget" to service or just check the oil in their cars.

You'd be shocked how many people think that the oil light is there to tell them that they need oil so never bother to check it:rolleyes:

shamwari wrote: »

Great pics Doc! Just wondering if you've ever rebuilt a 2 litre diesel engine from a Mazda 5? If so, I'd be very keen to learn what you discovered !

The last two Mazda 2.0 Diesels I stripped turned out to be beyond economical repair. The common problem, by far, on those is the oil pick up getting blocked and its usually the big ends that go first on them. If caught very early the crank could be ground and new suitably sized bearings fitted but on the last two the number 2(coincidence that they were both the same?)big end bearing was actually gone completely and the crank journal was destroyed as was the con rod and cap. A new crank alone from Mazda is around 2k from memory:eek:
On one of the engines, 2 of the rocker arms were also seized to the rocker shaft.

Drummerboy08 wrote: »

Was the chain replaced while ye were at it, or did the old chain go back on?

The chain and tensioner were the originals refitted, the chain was checked for any distortion and its length was still well within spec, the tensioner was stripped and cleaned and the spring was also measured and found to be all good too.

Voodoomelon

ND, do you reckon its worth while doing this job (pretty much a full strip down) on a perfectly functioning engine?

I always wondered if it would be worth while stripping my I6 down (12 years old with 101k miles), with new piston rings, freshly cross-hatched cylinders, machine scrubbed pistons, valves etc, along with new head gasket, valve cover gasket, oil seperator valve etc.

Would you see a noticeable improvement in refinement to justify the effort involved? (obviously on my own time)

Chuck Stone

So doing the refurb is more economical than just replacing the engine is it?

Nissan doctor

Voodoomelon wrote: »

ND, do you reckon its worth while doing this job (pretty much a full strip down) on a perfectly functioning engine?

I always wondered if it would be worth while stripping my I6 down (12 years old with 101k miles), with new piston rings, freshly cross-hatched cylinders, machine scrubbed pistons, valves etc, along with new head gasket, valve cover gasket, oil seperator valve etc.

Would you see a noticeable improvement in refinement to justify the effort involved? (obviously on my own time)

A leakdown test will give you a pretty instant answer as to there being any benefit to a recon. The fact that a car has x amount of miles doesn't always mean that it would benefit from it, a really well maintained and well driven engine can often be at its peak after a good few miles.

Chuck Stone wrote: »

So doing the refurb is more economical than just replacing the engine is it?

In the case of the engine in this Opel, you could certainly have got a second hand engine for less then these repairs, but it would be just that, second hand engine, with likely no proof of mileage or service history.

The price of the rebuild is less then a brand new engine, which is much closer to what you get when properly rebuilt.

Idbatterim

However, it turned out, after an admission by the owner, the car had only been serviced properly twice in its 4 year and 115,000km life and had been let run low on oil numerous times...

unbelievable!

Jane98

Nissan doctor wrote: »

Its very therapeutic work IMO, I have dozens of folders full of pics of various engine rebuilds over the last few years, mostly non standard performance Japanese stuff though.

Hey Nissan doctor,

Any experience rebuilding a Hyundai Sante Fe (current model) 2.2 litre diesel engine or any thought on what it might involve and cost?

Husband's car died 2 weeks ago. It had 110 k miles on it so not huge mileage by any standard. He was told by a Hyundai dealer that the damage was due to low oil, despite the fact no oil light came on. He is now faced with a bill in excess of €3500 to fix it. The turbo has to be replaced, along with the engine being bored and oversized pistons put into the engine in place of the originals.

Nissan doctor

Idbatterim wrote: »

unbelievable!

Sure it gets worse, she collected the car yesterday morning, I started by advising here to keep the engine below approx 3000-3500rpm for the first 1000kms or so and come back in about 2k for an oil change.

Her: What are rpm's?
Me: huh?, revs, on your rev gauge, its there with your speedometer
Her: sure I wouldn't know what they are, what speed is 3000rpm's?

:rolleyes:

Jane98 wrote: »

Hey Nissan doctor,

Any experience rebuilding a Hyundai Sante Fe (current model) 2.2 litre diesel engine or any thought on what it might involve and cost?

Husband's car died 2 weeks ago. It had 110 k miles on it so not huge mileage by any standard. He was told by a Hyundai dealer that the damage was due to low oil, despite the fact no oil light came on. He is now faced with a bill in excess of €3500 to fix it. The turbo has to be replaced, along with the engine being bored and oversized pistons put into the engine in place of the originals.

Tbh that price doesn't sound too bad if it does need new pistons and turbo etc

You could give IVI engines a call, the sell reconditioned engines and it may be a cheaper option for you.

trixyben

In most cases then Doc where oil is having to be topped up constantly, no leaks anywhere, coolant fine, is it more than likely to be getting through these piston rings and being burnt in the chamber?

A couple cars ive had in the past punto 1.1 sx, megane 1.4 rt, golf 1.4 all where oil guzzlers, none leaked oil at all and i couldnt figure out where the oil was going, until now!!!

Another one for ya Doc, nearly due an oil change on me mk1 focus tddi, and im thinking maybe this time taking off the sump cover and try giving there a good clean with compressed air if that is worthwhile doing?

Nissan doctor

trixyben wrote: »

In most cases then Doc where oil is having to be topped up constantly, no leaks anywhere, coolant fine, is it more than likely to be getting through these piston rings and being burnt in the chamber?

A couple cars ive had in the past punto 1.1 sx, megane 1.4 rt, golf 1.4 all where oil guzzlers, none leaked oil at all and i couldnt figure out where the oil was going, until now!!!

Another one for ya Doc, nearly due an oil change on me mk1 focus tddi, and im thinking maybe this time taking off the sump cover and try giving there a good clean with compressed air if that is worthwhile doing?

If there is no external leak, and the car has no Turbo, then the only two places that the oil can leak internally is past the rings or past the valve stem seals. A leak down test tells which as the stem seals don't effect cylinder pressure.

As for the Focus, it would be overkill in most cases to strip off the sump and clean inside unless you are having an oil pressure issue, think the car was never serviced properly previously or its an engine prone to sludge build up(which the focus isn't) but at the same time I couldn't do any harm. I wouldn't compressed air though, you'd wan't to use some kind of parts cleaning fluid. Brake cleaner is also good at removing oil/build up too.

Greyfoot

Excellent write-up, you certainly know your stuff. I always listened to your advice for others before but after this I`d be more willing to accept what you about to say without questioning your knowledge at the slightest! Not many mechanics willing and able to do this kind of work in Ireland!

Nissan doctor wrote: »

Its very therapeutic work IMO, I have dozens of folders full of pics of various engine rebuilds over the last few years, mostly non standard performance Japanese stuff though.

Now only if you`d had a folder labelled Mitsubishi Lancer 1.8 GSR...

Nissan doctor

Greyfoot wrote: »

Excellent write-up, you certainly know your stuff. I always listened to your advice for others before but after this I`d be more willing to accept what you about to say without questioning your knowledge at the slightest! Not many mechanics willing and able to do this kind of work in Ireland!



Now only if you`d had a folder labelled Mitsubishi Lancer 1.8 GSR...

I do....;)

Gary ITR

Nissan doctor wrote: »

Sure it gets worse, she collected the car yesterday morning, I started by advising here to keep the engine below approx 3000-3500rpm for the first 1000kms or so and come back in about 2k for an oil change.

Her: What are rpm's?
Me: huh?, revs, on your rev gauge, its there with your speedometer
Her: sure I wouldn't know what they are, what speed is 3000rpm's?

There's just no talking to some people. Reckon it'll ever see that oil change?

You'd nearly be as well running the car in for her, saves hassle in the long run

Nissan doctor

Gary ITR wrote: »

There's just no talking to some people. Reckon it'll ever see that oil change?

You'd nearly be as well running the car in for her, saves hassle in the long run

In an ideal world yes, but the truth is she hasn't got the slightest idea of the sort of work that was done. All she knows is that we made her car not need lots of oil any more.

Its a different ball game to working in the tuning/modifying game where most customers at least have some knowledge and interest in what's happening to their car.


Oh...and it hasn't been back for an oil change yet....:rolleyes:

Gary ITR

Nissan doctor wrote: »

Its a different ball game to working in the tuning/modifying game where most customers at least have some knowledge and interest in what's happening to their car.

You're joking right? I had a customer (modified/tuned car) who came in complaining about his temps going all over the place, so I opened the bonnet to find it without a drop of coolant, I topped it up and as I was waiting for the fan to come on he told me he'd removed the thermostat to help it cool better. I have hundreds more like that, a buddy of mine swears by the following statement 'people are stupid', I think he's right :pac:

JimmyCrackCorn

My brother lent me his car about a year ago, I had it for a week and had to replace the break disks battery and thermostat. (oil,filter,plugs as a bonus)

I asked him was the car ok after doing all this and his response was its not going into vtec. Then I showed him the receipts from the motor factors and Honda.


I froze my arse off on the M50 as the car wouldn't warm up in the snow and the car wouldn't start in the morning due to the weak battery. (i slipped and fell down the stairs of the apartment bringing out the new battery )

It was also cold fixing all that stuff on the driveway in the snow.


I'm sure Gary gets to see all degrees of special cases.

GALLA_4

How much something like this cost Paul?

Esel

GALLA_4 wrote: »

How much something like this cost Paul?

Answer is in post #7 of thid thread (which you made me read... )

Great thread, ND!

galwaytt

...excellent post ND, not something seen as often as used to, these days.........between used, p/ex and new engines, not many get rebuilt as in the past.

Couple of questions for you: regarding the ring end-gap. If too small, would you hone the ends with an oilstone or something ? And if too big.......... ?

haulagebasher

hi Nissan Doctor. That was a very interesting post. Just one question for you though - I noticed that your honing pattern in the bores looks to be horizontal as opposed to the more usual reccomendation that it be a cross hatch pattern with the stokes at around 20-30 degrees from the horizontal, made by moving the hone up and down the bore rapidly. The pattern also appears to be quite coarse too in the pics. Is what I see in the photos just an effect that the camera flash had making the cross hatch invisible and the pattern more coarse or is the hone pattern indeed horizontal? If horizontal, is this a requirement of this particular type of engine or could it result in problems with lubrication and accelerated ring/piston wear from a too coarse hone pattern. Just curious about it as practically every hone i've seen, all i've done have been cross hatch. (i'm big into diesel stationary engines which on modern oils can glaze up under light loads so honing is almost universal im my rebuilds.)

Nissan doctor

haulagebasher wrote: »

hi Nissan Doctor. That was a very interesting post. Just one question for you though - I noticed that your honing pattern in the bores looks to be horizontal as opposed to the more usual reccomendation that it be a cross hatch pattern with the stokes at around 20-30 degrees from the horizontal, made by moving the hone up and down the bore rapidly. The pattern also appears to be quite coarse too in the pics. Is what I see in the photos just an effect that the camera flash had making the cross hatch invisible and the pattern more coarse or is the hone pattern indeed horizontal? If horizontal, is this a requirement of this particular type of engine or could it result in problems with lubrication and accelerated ring/piston wear from a too coarse hone pattern. Just curious about it as practically every hone i've seen, all i've done have been cross hatch. (i'm big into diesel stationary engines which on modern oils can glaze up under light loads so honing is almost universal im my rebuilds.)

Its the flash of the camera making them appear as rough as they are. If you look at the pic with the pistons etc fitted and the head gasket on the block you can barely see the honing hatches. As they where, you couldn't feel them on the boor at all.

The recommended hatching for the rings that I fitted was in the region of 15 degrees which is defiantly at the lower end of what's normally recommended.. Doing it by hand and gauging it by eye can be awkward and ideally I'd prefer to use a flexi hone on engines like this due to not having to worry as much about customer with no mechanical knowledge bedding the engine in properly.