Mitsubishi 4G54 top overhaul

gunnerzz

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gunnerzz

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Jul 3, 2014
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This journey begin last Sat when i drop by at my parents house and saw my bro and dad is peeking donw the engine bay of the Pajero while discussing something. I decided to join and they said they want to do top overhaul of the engine and i noticed that the hood and the air cleaner assembly is already off so i guess they are serious about it. Since i had my tool set on standby in my BLM bonnet i brought it to the scene.I also happened to have a Haynes service manual for the car...what can go wrong right???

Anyway here is the car...its an LO47 Pajero powered by 4G54 engine. Previously it was using a different set of wheels ( Mangles 16 inch ) but was changed recently. BTW the Mangles is up for sale.


Sadly i did not take picture when the air cleaner, intake & exhaust,radiator fan assembly, valve cover,are still attached to the engine. I also skip the finding TDC part as i bet most of u guys are more expert than me. Only few picture after;
Intake off:

Exhaust off:


We leave the carb attached to the intake manifold to reduce labor and work time. After all none of us are mechanic and this is our first time doing major job. The carb is laden with vacuum hoses and we really dont want to mess with the setup.


Initially we thought the timing chain can be removed from the sprocket after we removed the bolt which holds the sprocket to the camshaft. The manual said that can be done but will require a special tool. So, the timing chain cover have to go too to access the tensioner...well actually there is a window to access the tensioner but since we have gone this far...why not. To do this, all the acc bolted to the engine are removed which are the power steering pump, water pump, alternator, compressor.



After we loosen the tensioner we loosen the bolt holding the head and it comes off easily. Luckily there is lots of space in the engine bay after the front part of the engine acc and radiator assembly is removed. I actually climb into the engine bay to lift the head off the block. It was quite heavy;

Lots of carbon build up. The concern is on cylinder no 4 as there are traces of engine oil.

More closed up pictures;



Here are the piston....Lots of carbon build up and again, no 4 had traces of oil;
FYI no 1 is closest to the timing chain.


Few shots of WD40 into all cylinder does not show that the rings are worn out as the fluid remained there.
Same test on the head also returned similar result. Nonetheless we will still grind the valve before reassembly apart from replacing all seals and gasket.

Rocker arm off;


It was late evening and after ordering the gasket set i set to do minor cleaning on the timing chain cover and here is the result;


Petrol works well in removing the varnish but i rinse it off with degreaser ( alkaline based ) as petrol will leave behind oily stain. I removed the old gasket and cleaned the surface so its easy for the person doing assembly to hold the park and work with the part.

Here is the aftermath of the disassembly;



I might not be around for assembly so i remind my bro to rake pictures. If i am able to join him which i strongly hope so then i will take picture myself. It was fun doing this as most of the time we are diving in blind as the diagram in the manual totally differ from what we are having in front of our eyes.

BTW, if anyone know where to source fiberglass hood for this Pajero do let me know. We want to shed some weight.
 

gunnerzz

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gunnerzz

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Few item needed input from experts;
1.should i use the valve seal which will comes together with the gasket set or source a better one for longer reliability?
2.should i replace the timing chain tensioner and its guide since its its accessible? so far no issue that we notices?
3.How to check the teppets condition?
 

gunnerzz

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gunnerzz

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IMG-20190305-WA0038.jpg
IMG_20190305_182248.jpg
IMG_20190305_182222.jpg

Update....Gasket arrived yesterday and when i drop by at the 'workshop' i discovered that the timing chain cover and the valve cover is cleaned.

My bro is working on grinding the valve.
So far so good. We will find a way to clean the intake without removing it from the engine bay if possible as other parts are just too cleaned.
 
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gunnerzz

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gunnerzz

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IMG-20190307-WA0019.jpg
Update;
Valves are grinded, carbon cleaned and sent to be resurface...All too shiny, belong in a display cabinet;

Cost RM30 to resurface.
 
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gunnerzz

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gunnerzz

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Your work better then sending to mechanic.......:driver:
Well the engineering shop must do as much as they can in a day...its income for them.
I really wonder why my bro send it to be resurface as i know its in good shape and only the gasket residue needs to be removed. He cant wait for engine start up maybe.
 

vr2turbo

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Well the engineering shop must do as much as they can in a day...its income for them.
I really wonder why my bro send it to be resurface as i know its in good shape and only the gasket residue needs to be removed. He cant wait for engine start up maybe.
Yah! if only top overhaul no need resurface, unless overheated.....lol
 

gunnerzz

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gunnerzz

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Gunnerz : how'd you remove the timing chain?
Initially we thought it can be removed after removing the sprocket but we discovered that wont work as the tensioner put more tension on the chain and we dont have the special tool to push the tensioner.

We remove the timing chain cover and press the tensioner, removed a metal thing and removed the chain from the sprocket. The chain tensioner is oil pressure driven and can be pressed using hands to release the tension. Chain is left on the engine.

To removed it completely off the engine block will require removal of the oil pump sprocket which is driven by a shorter chain. We dont do this.

Update....the head is on the block last Saturday and torqed down with 3 step as recommended by the manual 34>69>75 ft/lb. Head gasket is sprayed with copper spray.
Will update the picture tonight.
 

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Initially we thought it can be removed after removing the sprocket but we discovered that wont work as the tensioner put more tension on the chain and we dont have the special tool to push the tensioner.

We remove the timing chain cover and press the tensioner, removed a metal thing and removed the chain from the sprocket. The chain tensioner is oil pressure driven and can be pressed using hands to release the tension. Chain is left on the engine.

To removed it completely off the engine block will require removal of the oil pump sprocket which is driven by a shorter chain. We dont do this.

Update....the head is on the block last Saturday and torqed down with 3 step as recommended by the manual 34>69>75 ft/lb. Head gasket is sprayed with copper spray.
Will update the picture tonight.
Does the chain have a specific spot to sit in or it doesn't matter? Like timing belt needs the sprocket to line up with a certain marker etc etc. Never messed with chain before
 

gunnerzz

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gunnerzz

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Does the chain have a specific spot to sit in or it doesn't matter? Like timing belt needs the sprocket to line up with a certain marker etc etc. Never messed with chain before
Yup, there is a mark on the cam sprocket and the chain but since we do not removed it from the crank sprocket everything lined up perfectly when reinstall.

Words makes it sound so easy but in realy life it was hell trying to put the chain onto the sprocket and sprocket to the cam.

Just to be sure we turn the engine few times by turning the crank and so far so good.

I really wonder why the timing belt or chain must be alligned at the marker?
Then there is facin IN/OUT oso for belt.
 
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parakey

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Yup, there is a mark on the cam sprocket and the chain but since we do not removed it from the crank sprocket everything lined up perfectly when reinstall.
This part I have trouble understanding. Isnt there a mark on the head to align to the sprocket? Did you not mark a spot before removal? I see 2 camshafts but only one sprocket. How is the other shaft driven?
 

gunnerzz

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This part I have trouble understanding. Isnt there a mark on the head to align to the sprocket? Did you not mark a spot before removal? I see 2 camshafts but only one sprocket. How is the other shaft driven?
There is a small hole on the camshaft end which matches the cam sprocket notch.

Before we put the head back on we adjust the camshaft position first so that both valve on No1 is closed and piston no 1 in the block is at its highest position. Basically we just adjust those item so that no1 is at TDC (compression stroke).
We reinstall the sprocket after installing the head.

The 4G54 is a single cam engine.
I wish it was twincam...lesser fuel required to run it maybe?
 

punk

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View attachment 574041 Update;
Valves are grinded, carbon cleaned and sent to be resurface...All too shiny, belong in a display cabinet;

Cost RM30 to resurface.
Bro, i have campro head . sorry for off topic:biggrin:

Based on the manual, only can skim up to 0.2mm max.

Based on measurement using straight edge and thickness gauges, my head warped 0.08mm

How to determine/know the foreman/specialist didnt resurface more than 0.2mm.

How about ur case? How much the guy skim ur engine head?
 

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gunnerzz

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Bro, i have campro head . sorry for off topic:biggrin:

Based on the manual, only can skim up to 0.2mm max.

Based on measurement using straight edge and thickness gauges, my head warped 0.08mm

How to determine/know the foreman/specialist didnt resurface more than 0.2mm.

How about ur case? How much the guy skim ur engine head?
hahaha...i also dunno.
i guess they just resurface the thing judging from the cheapo cost.

Anyway, car has been running for 2 weeks now and teppet is adjusted again last weekend. Syiook, now properly feels like a 2.6 petrol.
 

punk

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hahaha...i also dunno.
i guess they just resurface the thing judging from the cheapo cost.

Anyway, car has been running for 2 weeks now and teppet is adjusted again last weekend. Syiook, now properly feels like a 2.6 petrol.
i see
 

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the good thing DIY.. everything can be inspected and cleaned properly prior to re-install
 

gunnerzz

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the good thing DIY.. everything can be inspected and cleaned properly prior to re-install
Agreed, last Sat drove the Pajero for 'slight' offroading while trying to find a piece of land which we failed.

Then upon reaching home go offroading again at a construction site. 4L is just amazing.
 

gunnerzz

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Those days they got by sound. If chain loose/elongated , will have noise
usually can feel performance drop, sluggish low end, noise, and usually around 200-300k timeframe
The noise is significant so i guess better change it. The engine also have a 'silent chain' which i think runs the oil pump.

My bro ask spare part shop and was quoted slightly below RM500 for the timing chain + guide and silent chain.
 

gunnerzz

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Update,
My bro changed the timing chain, silent chain and their sprocket. Tensioner also changed. There are groove on the chain guide and tensioner. Will post pic later.
I wonder why we did not detect this during the top overhaul.

Last saturday i went to see the car and notice he was working on it and i thought he was putting everything back together. I was surprised when he said he was removing everything back as the engine cant be started and backfire thru the exhaust despite cranking just fine.

He suspected the installation of the timing chain is done wrong but this does not make sense as all the pulley have marking. Thus, in goes the long screwdriver into cylinder one to find TDC just in case the marking is off. The marking on the crank pulley match the TDC for cylinder one thus we conclude that installation is correct.

Next is the distributor, we removed the cap to see the position and it was off by 180 degree. This makes the sparks being sent to the wrong cylinder and at the wrong time. We make the necessary adjustment and engine starts on second crank.

Why not first crank? because my bro forgot to remove the ratchet which is on the crank pulley bolt and it flies off hitting the water pump pulley producing noise as if the engine exploded when we crank the engine. 1 bolt at the pulley holder broke off.

Engine is super quiet....
How much does it cost?
Timing chain+silent chain+their pulley+tensioner is abt RM 380.
 
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brokenjars

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Update,
My bro changed the timing chain, silent chain and their sprocket. Tensioner also changed. There are groove on the chain guide and tensioner. Will post pic later.
I wonder why we did not detect this during the top overhaul.

Last saturday i went to see the car and notice he was working on it and i thought he was putting everything back together. I was surprised when he said he was removing everything back as the engine cant be started and backfire thru the exhaust despite cranking just fine.

He suspected the installation of the timing chain is done wrong but this does not make sense as all the pulley have marking. Thus, in goes the long screwdriver into cylinder one to find TDC just in case the marking is off. The marking on the crank pulley match the TDC for cylinder one thus we conclude that installation is correct.

Next is the distributor, we removed the cap to see the position and it was off by 180 degree. This makes the sparks being sent to the wrong cylinder and at the wrong time. We make the necessary adjustment and engine starts on second crank.

Why not first crank? because my bro forgot to remove the ratchet which is on the crank pulley bolt and it flies off hitting the water pump pulley producing noise as if the engine exploded when we crank the engine. 1 bolt at the pulley holder broke off.

Engine is super quiet....
How much does it cost?
Timing chain+silent chain+their pulley+tensioner is abt RM 380.
Very cheap. How much for labour?
 

gunnerzz

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gunnerzz

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This is the tensioner...notice the groove?
Thats how much it has worn out. The chain guide also have groove but not as deep as the tensioner.

I dont have the chance to compare the chain but my bro said the length is very much the same but the old chain have more freeplay laterally.
 

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