engine rebuild thoughts

Mar4ix

Hi folks.

Recently my punto mk1 1.2 8v had overheating , there was no signs of blown headgasket, also carbon test in coolant in one garage showed blown headgasket, in other garage didnt show. any way i didnt like how she is working, decided take off engine head.

3rd cylinders exhaust valve was black colour (suppose to be white), and guy in machine shop after examining head, said , there was slight coolant leak in cylinder .... but there were no smoke from exhaust, but some air pressure build up in cooling system.
engine head skimmed and test ... all fine.

Before i had bad feelings about sound, which goes off warm engine .. kind metal rubbing, or similar to worn alternator or timbelt bearing .... but it wasnt, as i replaced them all brand new.

So i decided split an engine.

theoretically i know how to do it, but never did really.... so puntos engine is good training ...

while taking off first cylinder.... i pushed down ... which was wrong...it stuck there and all rings expand.... i manage get two compressor rings squeeze ... third one - oil one... couldnt ... and i broke it.

So after chasing around for rings managed get one set (3 rings) for one piston - 25 euro.

when i compared rings, old rings was worn, new ring was around 1.5 mm wider.

After examining piston and half moon bearings, found them with loads of scratches.

this piston in pictures with new rings.










What yous think, is that ok condition? or they have to be replaced ? rings for other 3cylinders goin to cost extra 75 €, and those bearings (half moon ones) God knows how much goin to cost. I know, punto not goin worth these moneys. it already stands to me twice of its market value.


Thanks for advices.

George Dalton

Those bearings are ok. I would change the rings on the other cylinders if I were you though. Do you have a way of honing the cylinders? They will need to be honed to break the glaze on them to allow the new piston rings to bed in.

Nissan doctor

Mar4ix wrote: »

Hi folks.

Recently my punto mk1 1.2 8v had overheating , there was no signs of blown headgasket, also carbon test in coolant in one garage showed blown headgasket, in other garage didnt show. any way i didnt like how she is working, decided take off engine head.

3rd cylinders exhaust valve was black colour (suppose to be white), and guy in machine shop after examining head, said , there was slight coolant leak in cylinder .... but there were no smoke from exhaust, but some air pressure build up in cooling system.
engine head skimmed and test ... all fine.

Before i had bad feelings about sound, which goes off warm engine .. kind metal rubbing, or similar to worn alternator or timbelt bearing .... but it wasnt, as i replaced them all brand new.

So i decided split an engine.

theoretically i know how to do it, but never did really.... so puntos engine is good training ...

while taking off first cylinder.... i pushed down ... which was wrong...it stuck there and all rings expand.... i manage get two compressor rings squeeze ... third one - oil one... couldnt ... and i broke it.

So after chasing around for rings managed get one set (3 rings) for one piston - 25 euro.

when i compared rings, old rings was worn, new ring was around 1.5 mm wider.

After examining piston and half moon bearings, found them with loads of scratches.

this piston in pictures with new rings.










What yous think, is that ok condition? or they have to be replaced ? rings for other 3cylinders goin to cost extra 75 €, and those bearings (half moon ones) God knows how much goin to cost. I know, punto not goin worth these moneys. it already stands to me twice of its market value.


Thanks for advices.

The big end bearings(the ones you have pictured) are not expensive but you will need to ensure you have them matched to the crank.

If you remove the bearing shell it should have markings which normally say STD(standard, i.e, factory size) 0.025, 0.25, or 0.5 would be the normal options, relating to how oversized the bearings may be.

They would normally only be oversized if it had spun a bearing before and the crank journals where ground/polished.

Also, if the big end bearings are like that, then the main bearings are likely to be as well so you really should change those too, although the crank has to come out for that.

The score marks of the piston skirt that you have pictured look more likely to be related to small amounts of contaminants in the oil then a major issue. If you were suffering piston slap, excess clearance or a combustion issue then the scoring would be much worse and would run right to the bottom of the skirt. On the cylinder wall, can you feel any matching scoring(run your finger nail over it to feel) or is it just marked? If just marked, or with very very minor scoring, you could have the cylinder wall honed to give a smooth, hatched surface for the new rings to seal against.

You will really need a workshop manual for the engine to do a precise job as you need the factory clearances for the main/big end bearings to crank, piston to cylinder wall, piston ring gap etc etc. Even the new rings will likely need to be gapped to spec.

As George has said, you shouldn't change the rings on just one piston. Also, when fitting the rings, be aware that some rings have a top and bottom and the ring gaps should be staggered around the piston. You will also need a piston ring compressor to refit the piston into the cylinder without damage.


Hope that helps a bit...

TECHNICALTOM

Just to add to the good advice already offered, sometimes it much easier to just buy an engine from a good car breakers that offer some kind of realistic warranty,the reason I make this suggestion is because without insulting you or doubting your ability, engine reconditioning at home without some or all the correct equiptment is a gamble to say the least.As is buying an engine from a scrapy.but the scrapyard engine can often be seen/heard running before you part with your hard earned cash.
If you are really derermined to DIY. then price all the parts first ,full engine gasket set , engine oil +filter, cambelt kit, piston ring set,crankshaft bearing set,+buy or borrow a Haynes workshop manual, if you dont have a good torque wrench either hire or buy one ,you will find that many of the bolts used in those Fiat engines are Torque to Yield , so will need a replacement head bolt set at least. Whatever you do, best of luck to you.:)

Mar4ix

TECHNICALTOM wrote: »

Just to add to the good advice already offered, sometimes it much easier to just buy an engine from a good car breakers that offer some kind of realistic warranty,the reason I make this suggestion is because without insulting you or doubting your ability, engine reconditioning at home without some or all the correct equiptment is a gamble to say the least.As is buying an engine from a scrapy.but the scrapyard engine can often be seen/heard running before you part with your hard earned cash.
If you are really derermined to DIY. then price all the parts first ,full engine gasket set , engine oil +filter, cambelt kit, piston ring set,crankshaft bearing set,+buy or borrow a Haynes workshop manual, if you dont have a good torque wrench either hire or buy one ,you will find that many of the bolts used in those Fiat engines are Torque to Yield , so will need a replacement head bolt set at least. Whatever you do, best of luck to you.:)

Thanks for advice.
I had to change headgasket , as it was gone, and i do have a full set gaskets and bolts for such work.

I have split cylinder block, as there was some weird sound .... checked all bearings... people keep saying that they fine, i was doing compression test before i was taking engine head off, in average there was 15 bars pressure, and 16 bars with fully open throttle, i dont know is that good figure or no, but all cylinders was approximately same... except third, which was on half bar lower pressure... hence gasket gone at third cyl...

I do have tools and torque wrench ... actually two of them ... one for small mechanical torque wrench ... got it in halfords... from 8 nm to 45 nm... if i am not mistaken, and other torque wrench (with digital display) is for bigger figures, from 40 nm till 350 or so....

Tomorrow i am getting piston ring clamper... 15 euro from local motorshop.

I am not bad equipped for such works. Punto engine is light.

today bolted main crankshaft bearings .... 40 nm + 90 degrees

put oil pump , water pump and crankshaft oil seal (new one) from flywheel side.

Also split gearbox, changed main shaft bearing, also took off differential, bearings on them are gone... but i have new bearings, bought them half year ago... didnt had chance change them.

I am very curious what will be at the end of work.

et the end ... if it all wont work out , presume there is loads of puntos in scrapyards. I know, i even may put mk2 punto engine(cylinder block).

d o'c

I would visually inspect everything before assemlby to find the cause of the noise. If you don't find anything I would be checking the crank big end bearing clearances. Get some plastigauge to check the clearances compare with spec

I'd say possilbly you had oil issue and or heating issue looking at the piston skirt. The skirt is the widest part of the piston and would be the first area of the piston to touch the bore.
If the oil became diluted you would find that certain components would make metal to metal contact ( big ends), and give you noise.

I don't know if your aware but you do a clearance check with a dry bearing and journel, torque the caps to spec. When your happy , oil the bearing halves ( journel side only!!), torque the caps to spec..

Mar4ix

while i was driving that car, oil never been diluted with water ... changing headgasket, because there was small leak from burning chamber to coolant system , and pressure was rising in cooling system, and ... presume "air" bubble stuck there, causing overheating. Overheating wasnt major... most of times went up to 3/4 scale.... when temperature was so high, cold air start go from wents, so i guess there was air bubble.

where i can get those big end bearings ? cant go to shop, and take from shelf, need order, and wait for one or two days. found them in ebay... something around 30 euro for big end bearing set.

will call tomorrow to engine shop, where i use to skim engine heads, will ask them. big ends not look good, what you think, if ill put new standard size, would be ok ? or go for .25 ?

d o'c

i would change the big end bearings.

You go for std size unless the crank has been reground at some point.

when you plastiguage you're checking the gap between the crank journel and the bearing surface..
a pack will cost around a fiver.
this small clearance will be filled with oil at all times, to stop them touching, so it's critical to get it right.

bryaner

Nissan doctor wrote: »

The big end bearings(the ones you have pictured) are not expensive but you will need to ensure you have them matched to the crank.

If you remove the bearing shell it should have markings which normally say STD(standard, i.e, factory size) 0.025, 0.25, or 0.5 would be the normal options, relating to how undersized the bearings may be.

They would normally only be undersized if it had spun a bearing before and the crank journals where ground/polished.

Also, if the big end bearings are like that, then the main bearings are likely to be as well so you really should change those too, although the crank has to come out for that.

The score marks of the piston skirt that you have pictured look more likely to be related to small amounts of contaminants in the oil then a major issue. If you were suffering piston slap, excess clearance or a combustion issue then the scoring would be much worse and would run right to the bottom of the skirt. On the cylinder wall, can you feel any matching scoring(run your finger nail over it to feel) or is it just marked? If just marked, or with very very minor scoring, you could have the cylinder wall honed to give a smooth, hatched surface for the new rings to seal against.

You will really need a workshop manual for the engine to do a precise job as you need the factory clearances for the main/big end bearings to crank, piston to cylinder wall, piston ring gap etc etc. Even the new rings will likely need to be gapped to spec.

As George has said, you shouldn't change the rings on just one piston. Also, when fitting the rings, be aware that some rings have a top and bottom and the ring gaps should be staggered around the piston. You will also need a piston ring compressor to refit the piston into the cylinder without damage.


Hope that helps a bit...

Fyp..;)

Mar4ix

d o'c wrote: »

i would change the big end bearings.

You go for std size unless the crank has been reground at some point.

when you plastiguage you're checking the gap between the crank journel and the bearing surface..
a pack will cost around a fiver.
this small clearance will be filled with oil at all times, to stop them, so it's critical to get it right.

dohhh... never did it before. found some info how to do it, still stays for me unclear how to do this plastiquage . :cool:

Nissan doctor

bryaner wrote: »

Fyp..;)

If the crank is ground, its diameter is reduced, so the bearing shells have to be increased by matching increments to keep the required clearance...hence the bearings are oversized. No?

Mech1

"today bolted main crankshaft bearings .... 40 nm + 90 degrees"

I hope these where new bolts. You cant stretch (torque to angle) old bolts, these are a one time only bolt.

Mar4ix

Mech1 wrote: »

"today bolted main crankshaft bearings .... 40 nm + 90 degrees"

I hope these where new bolts. You cant stretch (torque to angle) old bolts, these are a one time only bolt.

Nope, these are old bolts, and according audotata, no need to be replaced.

Mar4ix

Nissan doctor wrote: »

Autodata also says they should be tightened to 20nm + 40 degrees

This about big end bearings, i did crancshaft main bearings.

ref . pic.

Nissan doctor

Ah, I didn't read right. I didn't think you had removed the main bearing caps.

Mar4ix

Nissan doctor wrote: »

Ah, I didn't read right. I didn't think you had removed the main bearing caps.

I did... over my own.. critical , non experienced inspection , main bearings looks fine... right , they are bit worn, but no major signs.... apart big ends looks bad, tomorrow, mean today , will order new ones, make sure ill drive that car for another good few years.

KGking

advise to get bearings off a main dealer,they have the spec of ur engine,make sure u get the right size bearing,engines from the factory have machining tool wear at different times i.e. a crank made at 1 would have a different spec to a crack made at 2 due to the hour of wear the cutting head so bearings and conrods componsate the change in wear by making them different sizes,i had a problem in work with a punto long story short,DIY job the dude put 3 right sized pistons in and 1 wrong size piston which was a spurious piston,the car was burning oil like nuts,point is make sure u have to right parts the car mite run ok but problems come into it down the road....P.S. 15 bar compression is great,why did u take the head off in the first place,the car could have been running bad for a number of reasons,also dont put spurious plugs into a fiat if u ar planning on replacing them,they cause too much back EMF on the coil packs,and puntos ar great engine to learn on.

Mar4ix

KGking wrote: »

advise to get bearings off a main dealer,they have the spec of ur engine,make sure u get the right size bearing,engines from the factory have machining tool wear at different times i.e. a crank made at 1 would have a different spec to a crack made at 2 due to the hour of wear the cutting head so bearings and conrods componsate the change in wear by making them different sizes,i had a problem in work with a punto long story short,DIY job the dude put 3 right sized pistons in and 1 wrong size piston which was a spurious piston,the car was burning oil like nuts,point is make sure u have to right parts the car mite run ok but problems come into it down the road....P.S. 15 bar compression is great,why did u take the head off in the first place,the car could have been running bad for a number of reasons,also dont put spurious plugs into a fiat if u ar planning on replacing them,they cause too much back EMF on the coil packs,and puntos ar great engine to learn on.

I wrote, that i was overheating, and when head was off, guy in engine shop pointed that at cyl 3 could see marks water leaking in burning chamber(also exhaust valve was black)... but very tiny ....(there was around 14.5 bars, in ff forum i was speaking about bit more- http://www.fiatforum.com/punto/289129-strange-overheating-problem.html
wont go for dealers.... o ring and couple gaskets was waiting for 3 days.

Plugs last time took which i got from motorfactors, but now, ill try get ones which are on autodata recomended.

KGking

autodata isent always right,and i ment go to MD for the likes of bearings and pistons

bryaner

Nissan doctor wrote: »

bryaner wrote: »

Fyp..;)

If the crank is ground, its diameter is reduced, so the bearing shells have to be increased by matching increments to keep the required clearance...hence the bearings are oversized. No?

Afraid not once the crank is ground down you order undersized bearings as the crank is undersized from std, same as boring a block you order oversized pistons as the bore is now oversized from std.

Mar4ix

ordered rest of piston rings. you guys convinced me get full set of new piston rings and new big end beqarings, ... old one is on average condition.... well i dont know... never had experiance with them, so new big end bearings goes in. will get them in monday lunch time, will fire up car tusday lunch time. (hopefully , toch wood, all will be fine.)

dgt

Talk to these lads, got us our bits within a day. Rings, shells, head skim and head set for £200. The car runs like a clock

dgt

Mech1 wrote: »

"today bolted main crankshaft bearings .... 40 nm + 90 degrees"

I hope these where new bolts. You cant stretch (torque to angle) old bolts, these are a one time only bolt.

They're not a stretch bolt and can be reused. Head bolts are stretch bolts like so

bryaner

KGking wrote: »

advise to get bearings off a main dealer,they have the spec of ur engine,make sure u get the right size bearing,engines from the factory have machining tool wear at different times i.e. a crank made at 1 would have a different spec to a crack made at 2 due to the hour of wear the cutting head so bearings and conrods componsate the change in wear by making them different sizes,i had a problem in work with a punto long story short,DIY job the dude put 3 right sized pistons in and 1 wrong size piston which was a spurious piston,the car was burning oil like nuts,point is make sure u have to right parts the car mite run ok but problems come into it down the road....P.S. 15 bar compression is great,why did u take the head off in the first place,the car could have been running bad for a number of reasons,also dont put spurious plugs into a fiat if u ar planning on replacing them,they cause too much back EMF on the coil packs,and puntos ar great engine to learn on.

Sorry but your well wrong there, always keep rods matched with their cylinders but there is no such thing as new bearings matching rods-cylinders..

d o'c

if the engine uses graded parts, then this is correct to some degree, but the dealer won't have that info. The grading stamps will be on the block, and the crank,. ie within each engine. IF this grading system is used.

bryaner

d o'c wrote: »

if the engine uses graded parts, then this is correct to some degree, but the dealer won't have that info. The grading stamps will be on the block, and the crank,. ie within each engine. IF this grading system is used.

So whats the story on KS bearings OE in most German makes as an example?

d o'c

Mar4ix wrote: »

ordered rest of piston rings. you guys convinced me get full set of new piston rings and new big end beqarings, ... old one is on average condition.... well i dont know... never had experiance with them, so new big end bearings goes in. will get them in monday lunch time, will fire up car tusday lunch time. (hopefully , toch wood, all will be fine.)

I think you're just going to chance the big end shell without checking clearances.. trust me well worth doing.

if your changing the rings get the bore lightly honed.

check the ring end gap with feeler gauge, you may need to file them.

Nissan doctor

bryaner wrote: »

Afraid not once the crank is ground down you order undersized bearings as the crank is undersized from std, same as boring a block you order oversized pistons as the bore is now oversized from std.

I can only assume that you are under the impression that the terms oversized and undersized when talking about bearing shells refares to inner diameter of the shells as opposed to their thickness.

bryaner

Nissan doctor wrote: »

I can only assume that you are under the impression that the terms oversized and undersized when talking about bearing shells refares to inner diameter of the shells as opposed to their thickness.

I'm just assuming that the people that I worked with in the engine reconditioning business (who were in it for 40 years and me 20) and the people that supplied the parts (Edmunds Walker, B+R Howard's, Vehicle Spares etc I could go on and on) and all the catalogue's and data were right in referring to bearings supplied for a ground down shaft of 0.25 0.50 0.75mm or 10 20 or 30 thou in older engines as undersized bearings..

Nissan doctor

bryaner wrote: »

I'm just assuming that the people that I worked with in the engine reconditioning business (who were in it for 40 years and me 20) and the people that supplied the parts (Edmunds Walker, B+R Howard's, Vehicle Spares etc I could go on and on) and all the catalogue's and data were right in referring to bearings supplied for a ground down shaft of 0.25 0.50 0.75mm or 10 20 or 30 thou in older engines as undersized bearings..

Hands up, my error:o The majority of times I've fitted bearings they had been supplied by the engineers after they ground the crank, I just checked the clearance after fitting.
I have two old dockets in my box for .25 'oversized' bearings..but having checked the cars I fitted them to they were both for engines that got new cranks and were line honed rather then ground cranks..hence the bearings being oversized.

bryaner

Nissan doctor wrote: »

Hands up, my error:o The majority of times I've fitted bearings they had been supplied by the engineers after they ground the crank, I just checked the clearance after fitting.
I have two old dockets in my box for .25 'oversized' bearings..but having checked the cars I fitted them to they were both for engines that got new cranks and were line honed rather then ground cranks..hence the bearings being oversized.

Aye I see where your coming from dude, they were called undersized oversized bearings when I was at it, smaller diameter on the inside for the grind and larger outside for the line hone-line bore..

Or should i say more meat on both sides:)

Mar4ix

grrr ... parts delayed. everything moving for one day longer. Badly would need car tomorrow, but unfortunately cant have well ... thats life. managed split gearbox, change main shaft bearing and two differential bearings, assembled. and welded a bit my exhaust, small hole at cat made sporty unhealthy sound, so sorted waiting tomorrow.

Mar4ix

question about trustbearings, which are attached to central crankshaft bearing, others dont have. look like here it kind half "o" shape attached to bearing, one felt off, other doesnt hold , it moving, i can see they are welded to bearing. Do they have to be welded toghether, or they may be loose, as they have own shape gap.. i dont know how to call that.

Nissan doctor

Mar4ix wrote: »

question about trustbearings, which are attached to central crankshaft bearing, others dont have. look like here it kind half "o" shape attached to bearing, one felt off, other doesnt hold , it moving, i can see they are welded to bearing. Do they have to be welded toghether, or they may be loose, as they have own shape gap.. i dont know how to call that.

It depends, on some engines, they are part of the center main bearing, on others they are sperate and sit into groves in the center casting.

I'm not sure off the top of my head which type a punto has.

Mar4ix

Nissan doctor wrote: »

It depends, on some engines, they are part of the center main bearing, on others they are sperate and sit into groves in the center casting.

I'm not sure off the top of my head which type a punto has.

yes, they have groves, they nicely sit in, and outside part of crankshaft Bracket, which holds the crankshaft with two screws, covers them, so cant go anywhere.

galwaydude18

Have you turned the engine over yet? Been following this thread with great interest.

Mar4ix

galwaydude18 wrote: »

Have you turned the engine over yet? Been following this thread with great interest.

today mate.

nearly everything is up. Biggest problem was get gearbox on, real pain in a$$, as I am doing alone on drive way at front of my house. .. well not first time, but still struggling.

before i put engine head, i put starter and alternator, was confused about wiring, so connected battery , and turn engine over for 2 sec. (i have some oil in engine) ... seems to be everything fine.

Engine head is on, was using new bolts. , torqued, camshaft on, head cover on, was using new seals, came together with headgasket.

I have left to stick timing belt, inlet manifold, exhaust manifold, exhaust, wire up everything fill oils to level, put driveshafts, and thats it.
Will put some pictures after i finished.

Nissan doctor

You turned the engine over on the starter before you fitted the timing belt?:eek:

Mar4ix

Nissan doctor wrote: »

You turned the engine over on the starter before you fitted the timing belt?:eek:

Well, i turned over, when NO head was on, so ......NO PANIC....., also punto engines are safe engine( 1.2.l., 8 valve), if ,while driving, snaps timingbelt, nothing will happen, just put new one , and no hassle.


At this point i turned over engine, it was like in pictur.

Mar4ix

So engine completed. i have left over some bits put around.
There is some pictures.

There iis engine just connected with one bush.






then engine with gearbox. really tired after i manage put that box correctly and right.




And here is with engine head and camshaft.






And finally got her running,

http://youtu.be/8D3HMYeP6lM

I couldnt get her worm properly, as i got call to work, and it was getting dark.

By all that work with engine, ive done some other small work around... maybe not small...

split gearbox, changed differential two bearings, main shaft bearing with oil seal.

welded a bit exhaust, was leaking beside cat., also welded cooling metal pipe, i discovered hole after work with sandpaper on it.

exhaust got new ruber bushes.. i dont know how to call them right.
new oils and filters all around.

still have to bolt on driveshafts.. they are fitted, but need to get bolt on, and some other small bits and boobs.