After Engine Overhauling

[Horse_rider]

AoA
I just want to know about some of my problems. i have overhauled my engine (just rings and gasket) but the problem is immediate smoke start after overhaul. and the problem was not solved. my mechanic said that the smoke and oil burning will last for next 1000 KM and then it will be solved itself. so do u think he is telling the truth or it is not right? what u say. he also told me that after 1000 KM the oil should be changed and the engine will be ok then, and will not consume oil and smoke anymore. also tell me that should I expect any smoke after rings and gasket change? or this is just the case with me? also someone told me that the engine should be break in with a mineral oil and one should not use any synthetic oil during the initial break in period because the synthetic stuff is much slippery than the mineral one, because i have refilled with synthetic after ring change therefore after the friend advice i have changed to mineral after 317KM driven so there is smoke in the tailpipe and the oil is still consuming. so do u think i should go for valve seal change also with piston and piston rings change or i should wait for 1000 KM drive? please guide me. Thank You.

[faadmemood]

Wsalaam! Brother Your Problem Is Wierd.. I Got The Rings And Seals etc Changed Last Year But My Car(City 04) Did'nt Give Such Problem Of Oil Consuming And Smoke.. We Had To Keep Low Speed And Also Were Advised To Change Oil After 1000KM's.. Which Car Do You Own And From Where You Got It Overhauled?!

[Horse_rider]

Wsalaam! Brother Your Problem Is Wierd.. I Got The Rings And Seals etc Changed Last Year But My Car(City 04) Did'nt Give Such Problem Of Oil Consuming And Smoke.. We Had To Keep Low Speed And Also Were Advised To Change Oil After 1000KM's.. Which Car Do You Own And From Where You Got It Overhauled?!

My car is Santro 2003 model and i overhauled from I-9 Islamabad, the mechanic and most of the international forums and shell aviation site says that every new engine rings required some time to seat will to the cylinder walls for perfect seal, also for proper wear and seal we should use mineral oils not synthetic as synthetic is more slippery causing the pistons to not wear and seal properly. so this initial period required some 500 KM- 1500 KMs to seat and seal well, so therefore in the initial stage when the rings are not wear enough the engine will consume oil and will smoke, i have read these words from a lot of forums, and also my mechanic says the same, so what you all expert think and experience something like this initial period are this period is just for the last century vehicles not for the new millennium.

[Horse_rider]

where is all experts roaming around? :-#

[aviatorx]

What's the name of the workshop? I, too had the rings of my hyundai excel replaced from I-9. The name of the workshop was Friends Autos and he ruined everything. He didn't install rings and the gasket correctly which resulted in another overhaul in less than 2 weeks. The guy charged me some 23,000 rs for nothing. My second overhaul was performed by a workshop in G-10 right next to baig autos. The mechanic's name is Khalil and the guy is really skilled in terms of fixing and overhauling carby engines. Don't know if he does efi engines but its well worth asking him. My second overhaul cost me 13,750 rs which included a new set of rings, head valve seals, and a couple of other items plus labour. It's also worth mentioning that since your engine is efi, its better to go for 10w 40 instead of 20W 50 viscosity mineral oil. Horse_rider is correct regarding use of synthetic oil after an overhaul. Always go for mineral based motor oil

[Horse_rider]

i have overhauled from noorani engineering opposite to VEBRA the name of mechanic is Ghulam Nabi,
@aviatorx

after engine overhaul from I-9 what did you experience about the smoke and oil consumption immediately, and when you last overhaul from G10 then what you experienced again? please share your experience in terms of smoke on first start and subsequent miles.

[Getafix]

I had the piston rings & valve seals replaced in my previous car. If the job had been done properly the car wouldn't still be giving out smoke or consuming oil.

If it's still giving out smoke then it means that the oil is still going past the rings into the exhaust, hence the white smoke. Did you personally witness the mechanic replacing the rings in your car?

[Horse_rider]

yes brother i was there at the time of replacement. he did change the rings purchased by me. what you say now about the valve seal replacement alone or i should change the piston rings and valve seals both next time? please guide me

[ahsanzs]

This is not called an overhaul. You just got the rings replaced - no more, no less. In an overhaul the entire engine is disassembled and each and every worn-out part is replaced, the cylinder lining is honed again and entire cylinder head is also properly machined, valve seats are re-made to perfection etc.

The semi-overhaul that you have got done usually fails (because cylinder lining is not smooth and also because valves are leaking oil). This is only done in case you have worn out your rings very quick e.g. in 60k km. It is assumed in this case that other parts e.g. oil pump etc. have much life remaining and the only purpose is to reduce oil consumption. Take note that in fitness test nobody cares about the condition of your engine (I mean compression etc.) but every fitness test is designed to check for emissions. So if there is lots of soot in your exhaust your car will not pass the fitness test. In places like here where fitness standards are not properly enforced, you would still like to reduce the oil consumption because it is very expensive. I once had a car which required 1 litre of oil per 300 km. I had a running of 3500km per month and needed three 4 litre bottles every month (that means Rs. 3600). So the rings were changed and the consumption came down to 1 litre per 6000km. This was a big (20 times) improvement. The remaining 1 litre consumption was due to leakage from valve jackets. I think this is your problem.

You will soon need a full rebuild (you should have gone for it in the first place). Nowadays are tough times and full rebuilds are not the norm, plus people are also running their cars less because fuel is so unaffordable, so if you run only 20k km this year you'll be able to complete 12 months on this engine. My advice: Go for a total rebuild but not now, only when you start losing so much compression you have acceleration like a hand-cart.

As for your mineral oil question, always break-in using a mineral oil. Then switch to synthetic after 10k km (which would be your third oil change after 1k and 5k). Even for cars which have synthetic recommended as standard you have to use special break-in oils which have less friction modifiers.

[Vaqas1]

Ahsanzs did u hear term over sized rings? what are your views about that?

I am hearing a lot of people on standard bore going for over size .25 rings so that helps too.

[sherwan_88]

Two things,

Either the valve are leaking or the cylinders are wider than the specs the rings are for, as there is blow by which goes in the sump, which in turn pressurizes the sump sending oil flying around to the top and out the valve cover and into the intake. If you've got blowby local term "Blow"..
You've got go pay the mechanic a visit, and one thing i know when a mechanic tells me when you drive it, it will get better, i know there is something fishy about it. The only reason he says that it will get better is that when the oil is burned it leaves quite a bit of residue which in turn sticks to the piston crown and fill up the gaps, which create compression. We apply this trick to diesels which start to blow to put in a few more months of life on the engine.

[kamilali]

Two things,

Either the valve are leaking or the cylinders are wider than the specs the rings are for, as there is blow by which goes in the sump, which in turn pressurizes the sump sending oil flying around to the top and out the valve cover and into the intake. If you've got blowby local term "Blow"..
You've got go pay the mechanic a visit, and one thing i know when a mechanic tells me when you drive it, it will get better, i know there is something fishy about it. The only reason he says that it will get better is that when the oil is burned it leaves quite a bit of residue which in turn sticks to the piston crown and fill up the gaps, which create compression. We apply this trick to diesels which start to blow to put in a few more months of life on the engine.

You are absolutely rite,
the same problem I was facing a year back in my charade, & finally I got an experts advice that You must rebuild your engine, well, this problem seems to be because of faulty piston as far my knowledge & lil experience is concerned.

[sherwan_88]

The proper way to just replacing the rings is, disassemble the engine, get new rings, then give the block, pistons with connecting rods and rings to the machinist, and ask him to re-bore and hone the cylinders to get the clearances right according to the rings. Proper compression and no leakage. I bet that the mechanic just removed the head, and just put in new rings without even having the clearances measured, he got his dough and you got your youself a smoker. Common practice. I bet the mechanic will say that what i said above is total "BS"...

I am more inclined towards the rings, as the compression would not be right.
If Horse_rider could provide more info on the symptoms a better diagnosis can be reached.

[Vaqas1]

you cant get it to work by replacing just one thing. rings and valves i feel you wont get it to work properly with just replacing one of these.

A example though its not engine but if you ever replaced leaking rear brake cylinder and didnt replace the other one within months the other one will leak as well bcoz the pressure is back to normal so the other one also gave up.

If ur mechanic is unable to fix it let me know i will give u no of my mechanic i am sure he will fix the prob. But remember it might cost u same or less to fix this.

[Farhansa]

get ur vaulve seals changed.

[afarooqi]

Bhai there could be oil in silencer, because before overhaul oil must have been leaking from valves. So until this oil burns out of silencer, you will see smoke.

But just to check, ur mechanic is not fooling you around, keep a constant check on engine oil Level.

you can check for if there is oil in silencer, for this you just physically examine silencer for oil remains.

[Horse_rider]

@sherwan
brother the mechanic just give the piston, new rings and cylinder to the machinist and the machinist measure and cut the rings and also adjust according to the head/cylinder (whichever it was) also now after ring and gasket changed the engine is when started at the morning it give a blue smoke for 3 seconds then the smoke finish, after the engine is idle for 3-4 minutes the smoke again appears but this time the smoke is white like water vapors and small drop of water as well and the smoke is less and hardly visible, if i try to smell the smoke then it will smell like burning oil and burn eyes, next when i accelerate the car the smoke is mostly visible and maximizes, next when i rev the car and accelerate hard the smoke is visible only on the side mirror because it is not a big smoke, then when i reach a stop signal and stop the car the smoke is also visible through side mirror.

@afarooqi

brother, the mechanic also told me the same that there is some oil in the silencer and when this oil will finished the smoke will finish. now after changing the rings i visited several time to that mechanic workshop and at every visit he told me that there is enough oil in the silencer so wait for some hundreds Kilo meters to let the oil finished, but brother i also consume some oil from the engine as well, as it is reducing on the dipstick also. another thing is important for the experts to know that when i run on petrol the engine oil coming out from tailpipe is more than when the car is on CNG, so what you say about the engine oil coming out of the tailpipe also?

[sherwan_88]

@sherwan
brother the mechanic just give the piston, new rings and cylinder to the machinist and the machinist measure and cut the rings and also adjust according to the head/cylinder (whichever it was) also now after ring and gasket changed the engine is when started at the morning it give a blue smoke for 3 seconds then the smoke finish, after the engine is idle for 3-4 minutes the smoke again appears but this time the smoke is white like water vapors and small drop of water as well and the smoke is less and hardly visible, if i try to smell the smoke then it will smell like burning oil and burn eyes, next when i accelerate the car the smoke is mostly visible and maximizes, next when i rev the car and accelerate hard the smoke is visible only on the side mirror because it is not a big smoke, then when i reach a stop signal and stop the car the smoke is also visible through side mirror

So at 3-4 minutes idle no smoke, after that white smoke, if it were the rings that were bad it would be the opposite, as the engine warms up the compression averages up, this rather points to a different issue. If the smoke appears after 3-4 minutes, it usually means when the engine oil expands/get thinner its going in to the cylinders through somewhere else, if it were the rings which are new and cylinder matched, the smoke should go away after warm up. In the oil pumps case, when the oil pump doesn't circulate the oil, pressure builds up in the sump because of the engine running as there is always some amount of blow by even when everything is new, when the pressure builds up it pushes the oil up, which goes into the intake manifold and into the cylinders.

Your issue leans towards either the valve seals, or your oil pump is loosing pressure. Does your oil light stay on for a while? do you have a starting problem?

[mazamwarraich]

HORSE_RIDER well mechanic is right but not in this case why oil level droping. smoke may be due to different reason but where oil goes. why level is reducing.

i sold out mehran 2003 when i purchased it i didn't check myself my mechanic only checked and i just asked him he told me ride is ok so i purchased. After few days i noticed my car is having smoke i asked the mechanic he said change the rings so i did one valve was also leaking. that was also fixed. we didn't put new piston or new bore. just put oversize rings cut by mechanic by himself not by machinest. i drove for two years safely no problem at all. i toured Gujranwala 4 time on same mehran.

After two years same problem and i did again same and car was ok but soon after i sold it out. so in my opinion their may be some problem in valves or in valves seals as well. u should have check for it also same time i guess ur mechanic is not good other wise he should have checked these things same time when he was putting new rings. so u can get check it .

[afarooqi]

if u r loosing oil, then there is some problem with overhaul. Most probably, the valves are the main culprit.

what i am suspecting is the overhaul is not upto mark.

one thing u can check, go to silencer wala, ask him to burn all the oil in dholkee, he will make a small cut and will make it burn for sometime. this will forcibly burn all the oil residing in dholkee, moreover, ask him to burn pipe as well. so ur silencer goes oil free. after that there will chance of smoke from silencer if the engine overhaul is sound.