im guessing someone out there must be able to help me with this.

long story short im having compression trouble with my fresh b20 vtec.

84mm
ycp itr spec pistons.
new bearings.
rings gapped right etc
piston to walls were fine.
stock b16a head
new gaskets etc and new everything (oil pump etc etc)

after 1000 miles of break in i went to comp test the engine. (snap on compression tester, very accurate and not cheap)
got these results (gauge only reads up to 250 psi):

4-250+
3-249
2-250+
1-225

cylinder 1 was worrying as it was so low. we put oil in the bore and did it again and got over 250+ psi.

so to find out if it was all going by the rings i got a gunson twin gauge leak down tester.

according to the instructions i should do the following.

set cylinder to TDC
install cylinder to gauge hose in the plug hole.
connect the gauge unit to a air supply (did this, set generator supply to 100 psi)
then it says to open the air valve on the leak down tester so the leakage gauge shows 0. it only does this at around 7-10 psi!
then to connect the gauge to cylinder hose together. i do this and it tells me i have 40% leak on both cylinder 4 and 3.

i looked on cspeeds site at their how to and it says this needs to be done at 100psi.
if i plug it all together, and open the valve the second gauge never moves, infact it stays well over showing a negitave leak down figure! (like -30% leak down!)

if i set the unit like who the instructions tell me, then increase the pressure as soon as it shows more than 15psi the leak down gauge reads again a negative figure.

i dont think that any way i do this is correct, their way or c speeds way! how can a cylinder that makes good compression have the same leak down as one that does not?

 

sorry here are the instruction for my tool and the tools itself!

http://www.gunson.co.uk/items/pdf/Pr...nstruction.pdf

http://www.gunson.co.uk/item.aspx?cat=666&item=3441