Engine Knocking Sound

[faiyaz]

Just rebuilt and installed a toyota 2L 2.4D engine (the one with rockers) back into my LN65 hilux. I took it out because it overheated and the head gasket had a slight oil leak. Coupled with this the core plugs at the back pf the engine were corroded. Once i removed the cylinder head the pistons had alot of play. So I suspected the rings were worn. The engine has about 215,000km on it. Once the pistons were removed the bore had ridges so had to get the engine re sleeved and had to buy new pistons, rings and gudgeon pin bushes . The conrod and main bearings were still in good condition so i didn't see the need to get grind the crankshaft. However i did replaced them with new standard bearings.Got the head skimmed too and lapped the valves.Fitted new nozzles in the injectors. Basically overhauled the engine. Anyways installed the engine back and started it up initially it ran slightly ruff and louder than normal. Adjusted the valve clearances and it was much better. However i couldn't help but notice a knocking sound as you rev the engine up . Its also there when the vehicle is accelerating. Im aware there is a break in period for the engine, could it be due to things wearing in?It also smokes slightly during idle, is this due the rings and bore wearing in? Really don't want to tear apart the engine again . Any suggestions would be highly appreciated.

Attached are some pics of the rebuild process and the fitted engine.

[Bear]

Good afternoon Faiyaz
Everyone has their own opinions of what needs replacement when doing an engine. For an engine to run as it came out from the factory all internals need to be refurbished and the crank being polished, rotary parts should be rebalanced. Depending on the amount of wear on the crank the correct size bearings need to be used.
With all that being said, not sure if the motor was done up previously. You state that you installed standard bearings. An engineer should measure the crank to check the size of the bearing required. Seems to me that the standard bearings are undersized. The crank could have been ground previously. That is what may be causing the knocking sound, (to much of a play). Wearing in does not cause engine knock.
Generally smoke at idle is valve stem seals, when cold. Make sure you using the correct grade oil as well.

[faiyaz]

This is the first time the motor was opened. Im planning on removing the sump to check the wear on the bearings if any. Does the injection pump make any noise ? Should have gotten the crank checked by an engineer. I fitted new valve seals. Im hoping the smoke clears up once the rings and sleeves wear in. I used to use the ENGEN brand motor oil sae 40. After the rebuild I decided to start using Castrol Gtx 15w40 diesel oil. As its better quality.

[Bear]

Try to source a good Mechanics who has a Mechanics Stethoscope. The area of the sound can be traced or narrowed down to.

[faiyaz]

ok thanks ill try to do that!

[Baby Cruiser]

Hallo faijaz.
These days the after market spares leaves alot to be desired. I have found that pistons out of the same box have considerably diffrent heights when installed.
It would be wise to let someone with more experiance listen and try to isolate the sound.
Has the piston pretrution been checked. ( piston stand out)
On those engines you get 3 diffrent head gasket thicknesses.
The gasket has 3 notches on the side and Toyota spesify witch gasket ( number of notches ) thickness to use with a certain piston standout.
An old mechanic , I used to work with , tested it like follows. Start with 0.1 mm and then go to 0.2 mm and up.
He would take the tappet cover off , let the engine idle and then take a feeler guage and put it in the tappet area so he could hear witch valves are touching the pistons. ( Especially when you say it got better after adjusting the valves and that it got worse when revving. Does it get worse the higher you rev? If so it could be valves touching pistons. I think if you got to 0.4 mm or 0.5 and are unable to hear anithing at idle the valves are ok.
Luckily you can see the nothes from outside so you would be able to tell what thickness you have got without removing it.
If I get around to it I will try and get those specs for you.
But stil there can be alot of things making a sound.

[faiyaz]

Hey! sorry for the (very) late reply. I left for uni and have not been on this page ever since. Till date the engine is working day in day out without issues. Not sure about the sound. True after market parts can be poorly produced. This engine is the first gen 2L and uses a paper head gasket. the second gen uses the metal head gasket. As far as i know there are no notch head gaskets for this model all are standard thickness. According the Toyota parts website there is only a single part number for the head gasket. Usually when there's multiple sizes they elaborate and have different part numbers. Thanks for the info to check using the tappet adjustment. Will give it a go once I'm back home (in about 5 months) if things have not settled. The head gasket fitted did not have any notch marks too.