M20 Engine Overhaul

[june_yap]

Does it happen only when the engine is cold or ALL the time?

If it is happening all the time, chances are the piston rings need to be replaced, and you should then do a complete overhaul.

Cheers

the asap come out when tekan minyak kau kau.... if no tekan, its ok...

 

[teejay]

the asap come out when tekan minyak kau kau.... if no tekan, its ok...

its the valve seals for sure, a top overhaul is due.

do you also notice if you tekan kaukau your engine oil level depletes faster?

 

[stormhunt3r]

i can't really differentiate the color of the smoke. mine had smoke when i start then engine and i think it's white/ grey color. Then when i adjust the rpm to go higher eg 700-750, the smoke went off.

I suspect that it's water condensation.

Teejay, since u mention engine oil depleting faster. When i was using castrol 15w40, my engine oil level drops pretty fast. Before it reaches 5000km service interval, it would drop to the middle. Then i need to top up. What could be wrong? I've changed to ZIC 10w40 engine oil now and had been monitoring the engine oil level and it seems to be ok for now. Would 10w40 be too thin for my 1985 m20 engine?

 

[teejay]

oil grades are used for different engine requirements. 15w40 maybe just about right for some but if your engine has not had any major overhaul, there could be a possibility the oil degrades faster- i.e. thicker, hence the reduction in volume. another possibility is the thicker oil remains in the top cylinder head due to its thickness and it getting thicker, but doesnt mean its gone to half

the thinner 10w40 is thinner, thus doesnt seem to deplete , i.e. not getting held up in any part of the engine- good and bad.....good is you know the level, bad is the engine doesnt getting lube at first start, higher wear and tear

there is also the properties of synthetic and mineral oil to consider, but that explanation will probably take me a book to write down.... faster if you type S Y N T H E T I C VS M I N E R A L O I L in google.com

 

[stormhunt3r]

teejay, thx for the info. I didn't know oil would remains at the top cylinder head. my car had been through a top overhaul only. The engine still sounds good, juz a little tappety.

i'll search through the web for that.

 

[teejay]

teejay, thx for the info. I didn't know oil would remains at the top cylinder head. my car had been through a top overhaul only. The engine still sounds good, juz a little tappety.

i'll search through the web for that.

you mentioned tappety? another possible oil loss is due to tappet adjustment that actually releases some oil into the combustion chamber, dont know to explain it further, perhaps Mechanical Engineer Sifu Mr Jules is able to expalin it in layman terms :top:

when you start the car in the mornings, thicker oil stays on the top cylinder head and is release , thats why first combustion you see smoke.
A simple test is to take a clean good morning towel wrap your exhaust start the car, then take the towel and soak it in a small pail of hot water.
take that water, then put it in the freezer, but if you have some chemical solutions , you are able to detect the amount of oil in the water.
After frozen if you can see droplets of oil, you would have some oil going into your combustion chamber for sure. Mind you there are some remnents of the oil in the towel,but you could further do an ash test, but this will require a full lab setup.
From there the volume of oil will be able to calculated how much oil is being consumed by the engine, compared with the theoretical value, the excess oil will indicate a leak in the combustion. Sounds alittle bit complicated ya!