1HZ compression figures

[petermac]

Anyone know if these are good compression figures for a 1HZ?

1st : 54kg/cm2
2nd : 54kg/cm2
3rd : 55kg/cm2
4th : 55kg/cm2
5th : 55kg/cm2
6th : 56kg/cm2

Thanks!

Peter

 

[petermac]

PSI conversion:

By my calculations - which could be wrong - these numbers convert to around 780 psi.

Thanks for any help!

Peter

 

[-uhuru-]

compression specs

Peter,

According to my Max Ellery vehicle repair manual for the 1HZ:

STD Compression:

37 kg-cm2

Minimum Compression:

27 kg-cm2

Yours seems to be way high ... did you follow the following considerations?

1- engine must be at operative temp.
2- battery must be at full charge
3- compression was checked by removing a glow plug
4- fuel was cut-off to the engine
5- accelerator fully depressed while craking w/o fuel

these must be followed to get an accurate reading .... if you didn't do one of these go back and recheck compression

let us know if you have done any mods to the engine or if the head has ever been machined? If so what # head gasket are you using?

good luck

tito

 

[Greg_B]

PSI conversion:

By my calculations - which could be wrong - these numbers convert to around 780 psi.

Thanks for any help!

Peter

You are using 14.22 as the conversion times factor? Typical readings that I have seen are 550-600psi with the HZ's.

hth's

gb

 

[petermac]

Well, it looks like the figures I've been given are way too high. The test was carried out in Japan - I'm buying the truck from Kohei, it's the 1991/2 HZJ73 91,000km listed on his website.

I wonder if there is a mistake somewhere.

If the compression numbers are accurate, what does this mean? What could cause such high compression figures in a 1HZ?

I'm waiting for clarification from Kohei. I'll post up with new info as soon as I know anything.

Thanks Tito and Greg!

Peter

 

[HZJ60 Guy]

All six of my cylinders tested above 600psi.

 

[crushers]

Well, it looks like the figures I've been given are way too high. The test was carried out in Japan - I'm buying the truck from Kohei, it's the 1991/2 HZJ73 91,000km listed on his website.

I wonder if there is a mistake somewhere.

If the compression numbers are accurate, what does this mean? What could cause such high compression figures in a 1HZ?

I'm waiting for clarification from Kohei. I'll post up with new info as soon as I know anything.

Thanks Tito and Greg!

Peter

maybe have the compression done independently and have the shop contact you direct...
just a suggestion...

 

[Tapage]

but 700 psi .. ! are a lots of compresion. I thought the compresion in my 2H are much more than a 1HZ and I never get those awesome numbers ..

 

[Dave]

Too funny, I had a long talk today with a guy from Kobe today and he was telling me about this guy on a Japanese BBS asking if the compression numbers he got were wrong, they were the exact same numbers.

They are way off. He either has a screwed gauge or he has no idea what he is doing. Those numbers are about 40% over the upper limit of what can be expected from a 1HZ.

 

[crushers]

could be he forgot to shut of the fuel?

you do get around eh Dave?

 

[-uhuru-]

could it be possible that this 1HZ has a turbo or blower?

 

[bigbrowndog]

I think they would need an eggcup full of ep80/90 in each cylinder to get those figures.LOL. Think they are having a lend of you. cheers gazza.

 

[crushers]

could it be possible that this 1HZ has a turbo or blower?

that would not change the compression test figures...

 

[crushers]

Anyone know if these are good compression figures for a 1HZ?

1st : 54kg/cm2
2nd : 54kg/cm2
3rd : 55kg/cm2
4th : 55kg/cm2
5th : 55kg/cm2
6th : 56kg/cm2

Thanks!

Peter

humm,
540, 540, 550,550,550,560 might make more sense. i wonder if they meant imperial...
just a wild guess...

 

[roscoFJ73]

humm,
540, 540, 550,550,550,560 might make more sense. i wonder if they meant imperial...
just a wild guess...

Good point ,the metric equivalent should have been in kilopascals anyway according to the FSM and Gregorys

 

[petermac]

Apparently they didn't shut off the gas to the engine. I'll have the compression tested again when the truck lands. I'm keeping my fingers crossed.

Thanks for all the input!

 

[petermac]

Too funny, I had a long talk today with a guy from Kobe today and he was telling me about this guy on a Japanese BBS asking if the compression numbers he got were wrong, they were the exact same numbers.

That should have been Kohei. He did some searching and spoke to a couple other mechanics in Japan who seem to think that with the gas not shut off, the figures are what you would expect. He promises the engine is good. If it isn't, he's going to pay for repairs - that's our agreement. We'll see what happens, either way.

I'm glad it's a 1HZ though...

Peter

 

[crushers]

with the fuel not shut off then there is no accurate readings that can be taken...
sorry.

 

[petermac]

with the fuel not shut off then there is no accurate readings that can be taken...
sorry.

Thanks Wayne, I've asked them to redo the compression test. Not sure what they we're thinking...


.

 

[crushers]

make sure it isn' the same compression tester, i did this to one of mine and it never read correct again. i ended up buying a snap on unit...