ok so heres the deal i did a compression check on my freshly built ls vtec today with all the plugs out pedal down and everything the numbers where
239 240 239 and still a mystery to me 220 psi on my number 4 i then heard that some people do it by taking out one spark plug at a time so i tried that and the numbers where 234 240 231 239 now this looks like some excilent numbers why the loss of pressure in cyl number 4 with all the plugs out???

btw the engine was hot both times

anyways this is my first build ever and ima little scared of things going wrong so should i just keep the close numbers and call it good??

 

What engine?

Those numbers look just fine to me.

 

gotta ls vtec 81.5 pr3 pistons flat valves buddy club spec 4 cams and buddy club head gasket

 

Seems like your just fine to me. I have no idea why the number would be different with all the plugs out.

Where you WOT and on a warm engine?

 

Numbers doesn't matter to me. As long as they are all within 10 points of eachother then you should be good. Just make sure the numbers are 180psi or up; recommended from Honda.

I'd take a closer look at Cyl# 4 why that it's a bit lower than the other three. Maybe rings aren't seated well?

 

Yea wot and warm engine all done the way it should be done

 

Well like that's the thing the compression levels where all good with plugs in infact number 4 was one of the highest like that idk y it would b different but it was

 

your supposed to take the plugs out because the gasket could be leaking into the other cylinders, so if you leave the plugs in the compression will look higher, all thats happening is its masking the problem of the cylinder leaking. i would suggest doing a leakdown test to verify whats going on there.

 

Who said anything about a bad head gasket idk what your talking about but that is totally irrelevant in this thread

 

you should actually pay attention to what you read, might make more sense.

 

ok i get what your saying but it would take much more psi to lift the head slightly and force a little more air into another cylinder. it just rele makes no sence when its bolted down to spec with a new head gasket and freshly re-surfaced deck and head close to impossible, not to mention thats how the engine operates with all 4 plugs, if anything having the plugs in simulates proper compression rather than having them off but if i seem to still not be getting it please feel free to clear things up for me...

 

ok i kinda see what your saying now doing one cylinder at a time without plugs might tell you if the head is not bolted down in that certain area is that kinda what ur saying?

 

alright update!! from 1-4 dry test results with all spark plugs out was 239,240,231,235 and wet without plugs was from 1-4 244,245,235,237 so i guess my comp test is pretty good idk y it was weird the very first time but now the numbers look fair

 

Yes, your fine.