did a compression test this weekend

[Rich]

compression numbers give a good indication to the health of the engine (ring wise)

don't forget the valves play a big role in compression too

it's supposedly due to the reduced size of the combustion chambers in the 1jz head, opposed to the 2jz head

yes, i know that, but has anyone actualy measured this?

 

[tlo86]

yes, i know that, but has anyone actualy measured this?

:umno:

 

[Andre]

don't forget the valves play a big role in compression too


yes, i know that, but has anyone actualy measured this?

I did not measered this because i do not have a 2JZ head

To do this you wil need 2 stock head that has not be surfaced

BTW maybe your numbers are so hi because your head has been surfaced more then ones ????


BTW does camgears has influence on the compresion numbers ?

I wil do an compresion test to to see how healthy my engine is

And if the numbers are to low i wil raise the boost :icon_razz naah just kidding

Maybe i wil do an leakdown test

 

[Rich]

I did not measered this because i do not have a 2JZ head

To do this you wil need 2 stock head that has not be surfaced

BTW maybe your numbers are so hi because your head has been surfaced more then ones ????


BTW does camgears has influence on the compresion numbers ?

I wil do an compresion test to to see how healthy my engine is

And if the numbers are to low i wil raise the boost :icon_razz naah just kidding

Maybe i wil do an leakdown test

Yes, that's the best way to compare heads; use stock ones.

As far as i could tell this was the first time the head was surfaced; no signs of milling.

Camgears don't influence compression numbers, leaking valves or leaking rings will.
Hope your compression numbers turn out good as well.

 

[Andre]

Yes, that's the best way to compare heads; use stock ones.

As far as i could tell this was the first time the head was surfaced; no signs of milling.

Camgears don't influence compression numbers, leaking valves or leaking rings will.
Hope your compression numbers turn out good as well.

I thought iff your valves where open at the same time ( iff you are using adjustable cam gears) the numbers would be lower then when you set you camgears at zero

Somebody correct me if i wrong

 

[WeDgE]

I thought iff your valves where open at the same time ( iff you are using adjustable cam gears) the numbers would be lower then when you set you camgears at zero

Somebody correct me if i wrong

At TDC, none of the valves should be open for the compression stroke.

 

[viperkillertt]

Very nice!

 

[Rich]

I thought iff your valves where open at the same time ( iff you are using adjustable cam gears) the numbers would be lower then when you set you camgears at zero

Somebody correct me if i wrong

you're confusing the overlap during the intake/outlet stroke with the compression/combustion stroke; then valves are all shut like wedge says

Very nice!

thanks

 

[tissimo]

with more overlap the valves are open longer while the piston rises, force the air out through the valves, less air in the cyl = less pressure at TDC.

 

[Andre]

with more overlap the valves are open longer while the piston rises, force the air out through the valves, less air in the cyl = less pressure at TDC.

Thanks for the info

BTW i want to do an compresion test

But check my settings (cam gears)

Should i leave it like this ? are just set them at zero

 

[tissimo]

if thats how you run your car around town, do it. Dont stress over the finaly numbers too much (unless they're abnormally low for whatever reason) but more of they're all equal.

IIRC it looks like you advanced the exhaust cam quiet a bit and retarded the intake cam? i might be backwards though, but if you did that, you have decreased the overlap and you may have higher numbers then you would if you had them zeroed

 

[Rich]

if thats how you run your car around town, do it. Dont stress over the finaly numbers too much (unless they're abnormally low for whatever reason) but more of they're all equal.

IIRC it looks like you advanced the exhaust cam quiet a bit and retarded the intake cam? i might be backwards though, but if you did that, you have decreased the overlap and you may have higher numbers then you would if you had them zeroed

yep, that's correct

he got this engine this way from a mkiii straight from japan, it has been tuned over there and he didn't touch the cam gears