ok, did the test. cyl #4-150, 3#-135, #2-135, #1-140. are those numbers good enough to boost? are those numbers even good?

 

As you can tell, you're right at the 10% difference between the highest cylinder & the lowest. That's pretty borderline.
Any LS motor owners here able to tell us what the number should be ideally?
As far as boost........I can't answer that for ya. Hopefully we can get someone else to chime in w/ more knowledge.
I to have an LS motor in my civic that I just swapped in. I need to check mine as well before & put a different head on and boost.
This info is great for the both of us.
ANYONE???

 

Thats how i was taught to do compression test and it seemed to always work. However, i've never done it on a Honda engine.

 

i hear you, does anyone know where to get that info for the compression on a ls?

 

I knew I forgot to mention a step...[:@]


I was under the impression that the general rule of thumb was a 10psi or less difference between cylinders was optimal

 

Its a 10% diff b/c diff cars have diff compressions so the 10% will be standard across teh board.

 

what i do.

pull all spark plug wires and place them on the valve cover

pull all spark plugs

either find the fuel pump fuse and pull it or just leave it alone

screw tester into #1 cylinder

hold the gas pedal all the way down

crank car for about 5-8 seconds

look at gauge and write down number

repeat for other 3 cylinders.

good cylinders should be no more than 10% of a difference




if you have one cylinder lower than the others take a tablespoon of oil and dump it into the bad cylinder fmo the spark plug hole, crank the car and then look at the gauge, if it goes back up your rings are letting go, if it stays the same then you either have a warped head or valves not sealing.

hope this helps

 

^^^
Rock on!!! Awesome stuff that I forgot to mention. This works great for detecting bad rings.

So as you can see. He has exactly 10% difference. Still pretty safe to run boost or re-ring or worse???
Again....anybody know the area which LS motors should be at numbers wise having to do w/ compression??? What's high & what's low??? Looks like a few of us would like to know.