What should the compression in a 98 spec b18c be?


Loaf

Loaf

98 EK9
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Feb 12, 2008
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I'm testing the car today? What numbers am i looking for?
 
If I remember correctly the CR of a 98 spec R B18C engine should be 11.0:1
 
he want the compression in the cylinder not the compression ratio
 
cyek9 said:
If I remember correctly the CR of a 98 spec R B18C engine should be 11.0:1
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Yeah I know that, i need the compression guidelines.

On honda tech they say around 250psi but is american psi different to psi here?

And it's 11.1:1:nice:
 
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you want an even reading on all 4 ie within 10 psi or so of each other.all testers read differently no way youll get 250 but anything from 190 up to 230 has always been fine in my experience.a better haelth check is a leak down test.
 
shooter mcgavan said:
you want an even reading on all 4 ie within 10 psi or so of each other.all testers read differently no way youll get 250 but anything from 190 up to 230 has always been fine in my experience.a better haelth check is a leak down test.
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I'll have to go to a garage to do a leak down test though.

I only want to check it out of curiosity.
 
Depends on the gauge brand you're using to measure. Don't forget to open the throttle when measuring.. (push the gas pedal down lol)

In my old 98 spec teggy I had a reading of 225psi in all 4 cylinders.
 
Thread revival, apologies!

I just did a compression test on my B18C-R JDM.

Engine was warm, dry cylinders, all spark plugs out, let the starter turn the engine 5 times (enough to max out the needle rise on the tester) - one thing to note I completely forgot to open the throttle during the test on ALL cylinders.

Results are as follows:
Cylender 1 220 psi
Cylender 2 220 psi
Cylender 3 225 psi
Cylender 4 220 psi
 
just seen what all u guys were getting, got a jdm b18c-r cammed & itb, skimmed head.. new hg.

i only got 195 psi on all 4 cylinders :( but the engine was stone cold was trying to figure out a problem back then. the leakdown test was done well within tolerance too.
 
dk11290 said:
just seen what all u guys were getting, got a jdm b18c-r cammed & itb, skimmed head.. new hg.

i only got 195 psi on all 4 cylinders :( but the engine was stone cold was trying to figure out a problem back then. the leakdown test was done well within tolerance too.
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Did you have the throttle wide open when cranking the engine?
 
Vtec6000 said:
Did you have the throttle wide open when cranking the engine?
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Even then it wouldn't explain why he's getting a lot less, I didn't have my throttle open and achieved 220 psi, but it will help diagnose possible reasons why it may be lower I guess.

I know people say it depends on the gauge but I would imagine it cant be that different between brands?

And if the engine is warm or cold, I did mine lightly warm the fan didn't kick in as i didn't want to remove the spark plugs with the engine warm as I've herd people saying you shouldn't remove spark plugs in an aluminium engine as it makes it easier to strip the thread in the engine, I don't know if that's true but didn't want to throw caution to the wind.
 
^^^regarding the plugs, i always use anti-cease on the threads of the plugs going back on the head to help prevent damage to the threads on the head when removing them. in case you are not doing that already.

the gauge does vary from maker to maker...some sort of base line should be established prior to thinking anything is not right with the engine.
 
Yeah I use anti cease on the threads, it's just something I herd on the www's regarding warm aluminium stripping.

I herd its more important to have an equal range between cylinders than it is to have high numbers as it showed even wear and that there isn't one specific cylinder that has issues holding pressure?

But as always it's nice to think your engine is compressing close as possible to its original rating :)
 
your numbers look ok to me; range between all 4 cylinders.

metal expansion being different between plugs and head, makes sense to me. however ive not had an issue with this either way, being hot or cold.
 
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offspringy said:
Even then it wouldn't explain why he's getting a lot less, I didn't have my throttle open and achieved 220 psi, but it will help diagnose possible reasons why it may be lower I guess.

I know people say it depends on the gauge but I would imagine it cant be that different between brands?

And if the engine is warm or cold, I did mine lightly warm the fan didn't kick in as i didn't want to remove the spark plugs with the engine warm as I've herd people saying you shouldn't remove spark plugs in an aluminium engine as it makes it easier to strip the thread in the engine, I don't know if that's true but didn't want to throw caution to the wind.
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I've seen +20 on compression tester if you hold the throttle open whilst cranking(the correct way to do it)

Most recommend to compression test when engine is hot.

Also his cams may be contributing to the lower CR readings.
 
Vtec6000 said:
I've seen +20 on compression tester if you hold the throttle open whilst cranking(the correct way to do it)

Most recommend to compression test when engine is hot.

Also his cams may be contributing to the lower CR readings.
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Could it be that there is no adjustable cams with the cams being used?

Im completely out of my depth when it comes to Valve Overlap and Cam Gears etc
 
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