Welcome to the blog of a cameraman who works across Japan and Africa.
This blog introduces the maintenance diary of Land Cruiser 75, Trupy, which the manager has been riding in Kenya for many years.
This time, we will focus on adjusting the valve clearance of the 1HZ engine.
All are African style without using special tools.
For the time being, just for reference.
If you do the work, please do so at your own risk.
The manual book I bought at the same time as I bought the Land Cruiser, as always, I am working with reference to this book.
Land Cruiser Bible, now more shabby
table of contents
I decided to adjust the valve clearance
Start work
Measuring shim thickness
As a result of the measurement, it was out of the specified clearance range at 4 points.
Adjusted test results
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I decided to adjust the valve clearance
A long time ago, the engine sound of my car, Land Cruiser, became louder and rattled.
The roaring noise that occurs when driving with the engine brake applied, especially on downhill slopes.
It sounds like a truck, and I feel that it's not a healthy 1HZ sound.
Changing the oil will improve it a little, but the pitch will not change much.
There seems to be a little black smoke when accelerating, what is the cause?
And, is there a variation in valve clearance? I suspected that I decided to adjust the valve clearance.
For the 1HZ engine, the valve clearance can be adjusted by replacing the coin-shaped shim.
The work that was done once (8 years ago), this time I will take up the thing at that time.
The strongest engine that I personally think is selfish.
1HZ, in-line 6-cylinder, 4.2L, naturally aspirated diesel engine.
The strongest means that it is easy to run, strong and hard to break, rather than being strong.
It's a size with a margin of 4.2 liters, and it doesn't have a turbo, so it doesn't force the force, so it feels like it will last a long time.
It is no exaggeration to say that most of Kenya's safari cars carry this engine.
Even if you use poor quality fuel in a harsh environment, it will not be dented and will work reliably.
In-line 6-cylinder, well-balanced and good sound! (Personal impression)
As mentioned above, if you don't neglect to manage the engine and oil that can run in any environment, you can normally run 1 million kilometers.
In-line 6-cylinder SOHC 1HZ diesel engine, 1 camshaft, valves are arranged in order from the front, intake and exhaust, 12 places in total.
I often see stickers with valve clearance on the engine and cylinder head covers.
Valve clearance, intake side clearance 0.15 to 0.25 mm, exhaust side clearance 0.35 to 0.45 mm,
The clearance should be within this 0.10mm range.
The error range of the valve clearance gap is 0.10 mm.
Diesel engine, regardless of appearance, the contents are very delicate.
Start work
First, clean the area around the cylinder head to prevent dust from getting inside.
In addition to the rag, I carefully cleaned the blower for the camera and the brush for painting.
Just in case, I worked over and over again until I opened the cylinder head cover, removing the dust.
Remove the accelerator wire and intake duct, and finally remove the cylinder head cover.
The camshaft and shims for adjusting valve clearance were exposed.
Now you are ready to adjust the valve clearance.
Then, in order to measure the valve clearance, the crank position of the engine is moved to the specified place, TDC.
TDC means top, dead, and center. Is it top dead center in Japanese?
This TDC point is marked to match the TDC when the front timing belt cover is removed, and can be adjusted accurately.
Originally, I should have done so, but I didn't actually do so because I wanted to measure at the non-protruding part of the camshaft.
In the end, I had to measure the valve clearance many times during the measurement, go under the car, and turn the crankshaft repeatedly.
Even if I opened the timing belt cover later, I thought that the work would have been much easier if I adjusted it to the TDC.
Feeler gauge used to measure valve clearance
It is hard, heavy and almost impossible to turn the crankshaft of the engine in place by hand. I was able to do it, but still a lot of hard work
As always, I thought, "The power of the starter motor is amazing."
If you load this starter motor on a bicycle and connect it with gears, it will speed up considerably!
80 kg / hour is hard! ?? 100 km / hour or more may come out?
It seems to be quite dangerous.
This valve clearance inspection work, the manual at hand says that it should be done every 50,000 km.
To check the clearance, use the feeler gauge in the above photo (upper photo).
Valve clearance recording paper
The valve clearance was measured one by one, and the thickness of the shim and the thickness of the shim to be replaced were also recorded and summarized in a table.
The table was sandwiched between the Land Cruiser manuals and remained at hand. Looking at the date, it was already 8 years ago.
When I measured it, there was a big deviation in the clearance of the valve at the front and back.
In both cases, the clearance was widened by about 0.05 mm.
We also found two valves with reduced clearance.
The ones that were shrinking were the exhaust of the 6th, 11th, and 3rd cylinders in the above table, and the intake valve of the 6th cylinder.
After the measurement, we decided to replace the shims that did not fit in the specified clearance.
The shim needs to be removed for replacement.
There seems to be a special tool for removing this shim, but after trial and error, the method shown in the photo below has become the easiest method.
Use one large and small flat-blade screwdriver and one ring spanner.
Pass a huge minus driver through the hole of the 18-19mm ring spanner and slide it down to push down the valve.
Push the valve in nicely and use a small flat-blade screwdriver to remove the shim.
Even if I let go of my hand, I can fix the valve while pushing it down. I'm interested in this, which is a good way to do it.
It doesn't damage the parts, so it's a method that I can recommend to others.
With this feeling, I was able to remove the shim quite easily
With this method, even one person can easily remove the shim.
The picture was taken by her daughter.
Measuring shim thickness
The manual requires a microgauge, but it was done with a vernier caliper.
The measurement scale of Vernier caliper is up to 1/20 mm (0.05 mm), but this is a good point of analog, but it is about 1/5 (0.01 mm) can be measured visually.
It seems that there are 20 types of shims with thicknesses from 2.35mm to 3.30mm in 0.05mm increments.
That means that if you can read the scale of 0.05mm and vernier caliper, that is enough.
The upper shim was measured as 2.775mm
The upper shim was probably 2.80mm thick, but it was running and reduced by 0.025mm.
Vernier caliper can handle the measurement required to replace the shim, so I didn't buy a micro gauge and didn't have to spend extra money.
Shim, lower wear pattern (taken 8 years later)
No big scratches were found on the shim, and the camshaft was shiny.
On the underside of the shim, there is a pattern that you can see that it is spinning around while driving.
The upper side where the camshaft touched was evenly shiny on the entire surface.
The big scratches are those that have been stored for many years.
The engine oil used at that time may have been changed frequently every 2500 kg, which is a cheap 40 fixed grade.
Recently, I use multi-grade 15w-40 and replace it about every 3000km.
The replacement is based on the touch of oil, engine noise, and changes in performance.
If the frequency of oil changes and long-distance driving at high speeds are high, it will increase to about 5,000 kilometers.
When I'm running, I'm starting to feel the oil settling little by little from about 2500km.
The reason for changing from fixed grade to multi-grade engine oil is that the engine noise at high speeds has become quieter.
Since it is an old engine, it always uses mineral oil.
I will talk about engine oil soon.
Measurement result
As a result of the measurement, it was out of the specified clearance range at 4 points.
For shims whose clearance is within the specified range, remove the shims that are close to the specified range and measure the thickness.
As much as possible, the valve clearance was aligned with the center of the specified range.
The center value is
Intake valve, 0.20mm
Exhaust valve, 0.40mm
I exchanged the ones that could be exchanged for each, so in the end I only had to buy two more shims.
But I didn't have to buy it.
Photographs when adjusting valve clearance, shims arranged by thickness
I replaced it when I disassembled the engine before, and checked if there was anything I could use in the shim I had.
I went around the store with a caliper in one hand and got two shims of the required size.
Luckily, the old man at the store gave me two sims for free with the joy of saying, "The president who supported the election was elected!"
This work was done immediately after the Kenyan presidential election and the announcement of the results.
Attach each shim in place!
After installing all the shims, rotate the crank once and measure again.
It was confirmed that all valve clearances were within the specified range.
After that, reverse the removal work.
All parts have been replaced.
Adjusted test results
And start the engine!
The engine sound changed dramatically from the idle.
It feels clear with less voiced sound.
In the driving test, the black smoke seemed to be reduced, and the engine noise when braking the engine on the downhill was much quieter than before.
It is said that the sound of the engine will change so much with a change in valve clearance of only about 0.1 mm.
Only 4 out of 12 valves.
I felt once again that the sturdy diesel engine and the contents were very delicate.
After this work, I was able to hear the 1HZ engine sound and the sound "Valve clearance, isn't it crazy?"
Eight years have passed since I did this work, and now I feel that the sound of the 1HZ straight 6 engine has become muddy again.
I wonder if I should try adjusting the valve clearance again.
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Thank you for reading to the end.
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