I have recently been blowing alot of blueish smoke at high rpms (around 6-8.2k), I am planning on building up the cylinder head, replacing valve seals and wanted to see if I need to replace piston rings/bearings as well.

Did a leak down test today with the engine warm @ TDC and a compression test as well, here are they results...thoughts?

Motor:94 JDM B16a2

Compression
1- 238 psi
2 - 238 psi
3 - 238 psi
4 - 238 psi

Leak Down
1 - 25%
2 - 25%
3 - 25%
4 - 25%

 

thats alot of leakdown

 

You might want to do the leak down one time.

 

is 25% ok or is that enough to be rings? there was the faintest bit of air coming out the dip stick hole/ i used one that said a different brand but it is the exact same thing as this one
http://www.wescotools.com/p-1571-cyl...-products.aspx

 

25% is very high. If that result is correct then you will need new rings and a valve job.

 

Psh, 25% is nothing lol, my buddies last motor was pushing 80% haha.

I'm just kidding about that not being a lot, I would just do the bottem end as well, that way you wouldn't have to worry about it later on. I'm sure that with your head built you will be pushing your car even more and with that extra beating it will just be a matter of time before you need to get the rings etc. done.

 

x2

 

why you talkin' bout my motor son! haha

But yeah, 25% is a little high. Mine read 80% in cylinder 2 and i ended up getting a valve job and rebuilding the head while it was off. Have to replace my piston rings in the near future as well. But, do the leakdown one more time to make sure the readings were accurate. If they are then you'd need a vlave job or new rings as stated above.

 

Haha, naw man. I was actually talkin' about Ruben's Teg lol. He's at 80% in all 4 cylinders hahaha. It's koo, we got something in the works soon so whatever ;P

 

ok thanks for your help everyone. I WILL be upgrading the cylinder and I can get OEM parts at cost so I am just gonna order rings and plan on replacing them.

 

I find it hard to believe that all 4 are at 25%. I think your tester may be messed up or something.

 

yea, if you actually had 25% leakage I doubt you would have had compression numbers of 238.

 

Wait.... all 4 are 25% and 238 psi.... either that's one seriously balanced and evenly worn engine or something is screwey with your test equipment.

numbers that are close is normal, but identical is highly unlikely. (unless you're doing a "ehh it looks like this to me" type of read)

 

I thought the same thing but I also tested my bros car the same day and got varying numbers on his turbo LS with the exact same procedure and tester. His compression varied a bit also, so I was comparing the results to his results to confirm they were valid. I have done a few compression tests on this motor since i got it and its been dead even every time...this is the first leak down test i have performed on this motor.

 

I'm guessing the motor sat for a while before i got it so I am hoping good compression means I can install new rings without honing, call it a day.

 

if it sat for a while im willing to bet your valve seals have taken a $hit on the motor

 

I would honestly hone. It makes a difference.

 

it would be an unwise move to not get the block re-honed. you can find plenty of places that will be willing to do it under $150. take the right precautions otherwise you're wasting the time buying the rings.

 

not unless you want to rebuild it twice

 

OP,

Read below,

Good advice

Good advice

Good advice

Spend $150 at a machine shop to get the basic stuff squared away. When you have the proper clearances, with a proper assembly and tune, your motor will make power.

 

I heard if there are no vertical scratches then honing is not necessary on a honda block...might get jumped on for this.

 

Your compression seems too good for those leakdown numbers and I have never seen all 4 cylinders measure the same.

Use new equipment and go from there.

 

I didn't see anyone ask .. Where is the air blowing by during leak down ? Crank case ? , exhaust valves ? intake ? Radiator ?

 

If there are no scratches then a bore is not necessary. Honing the block gets rid of the glaze on the cylinder wall and the cross hatch pattern put on the cylinder walls by the honing process allows the rings to seat properly against the cylinder for a perfect seal. Theres more to it then just slapping on a set of rings and calling it a day.

The first one is a glazed cylinder, it happens to all engines its unavoidable. It's also the worst place to put a set of new rings.

The second one is how a freshly honed cylinder looks, notice the crosshatch pattern.

 

In this case either past the rings or valves.