Compression Numbers and Leakdown test for 2008cc motor numbers please???

[00black1.8t]

Hey guys,
Just been running through a few tests on the build since Im approaching the 4000 mile mark. Can anyone confirm if these numbers are low for a built motor with 9:1 compression? Obviously I cant use OEM as a guide. I have two questions/ hunches. Car burns a decent amount of oil. Not enough to smoke tho....(pretty sure its a few leaking valve seals) I have a used head with no idea how many miles are on it. It has new seals but valve guides could be bad. I plan to build another one once I money up again. Oils fine and coolants great. So skip the head gasket.

Compression Test: (turned over 7 times)
#1 = 142psi
#2 = 142psi
#3 = 147psi
#4 = 150 psi
(note for future readers.. these numbers are with the throttle plate closed- must be open while testing) my bad...

Leakdown Test: (if i remember right after 1 min with 120psi)
#1 = 14%
#2 = 25%
#3 = 15%
#4 = 14%

Second question that I have is that my coil pack wire harness had the dreaded cracking last week so I replaced them with a OEM overlay harness. Everything's working fine but I am getting a miss fire at 20 psi. I could easily go 24 psi with never a miss fire after the build/tune. I changed the plugs from NGK-BKR6E-11 to NGK-BKE7E. Made a small difference but still does it. Always cylinder 2 and doesn't move with the coil pack. Thinking about just wiring the new harness right to the original harness. Just going back to what worked....

Last but not least... if you have anyone selling components to build a head or have a head that's built they wanna sell let me know please. :)

Relevant MODS
2.0l stroker - 058 Block
2000 converted to 2001 for Maestro 7 (MAF less)
JE Pistons 9:1
Scat Rods
ABA Crank
Stock AEB Head (slightly ported and gasket matched)
Walbro FP
Injector Dynamics 1000cc
GT3071r
Treadstone SS Manifold
Custom 3" exhaust - catless
Tial 38mm with (large blue and small red springs)
Tial BOV Q with -10.00 psi spring for "-16in/hg to -19in/hg vacuum pressure"
2.0 coil packs
NGK-BKR6E-11 (.44 gap) or NGK-BKR7E
Hallman Pro Kit Boost Controller

[walky_talky20]

For the misfire, I would take the plug gap down. If you are running .044 now, take it down to .032 and see if it improves. My guess is the compression has gone up since the initial build and that is the variable that changed. You now need more voltage to cross the gap, and you are at the limit.

[00black1.8t]

For the misfire, I would take the plug gap down. If you are running .044 now, take it down to .032 and see if it improves. My guess is the compression has gone up since the initial build and that is the variable that changed. You now need more voltage to cross the gap, and you are at the limit.

I ran the NGK-BKR6E-11 (Plug standard gap) for the last 4000 miles during tuning and driving. NGK-BKR7E are what I just put in to lessen the gap and see if that helped (gapped at .032).
I replaced the fuel filter tonight and Ill see tomorrow if that helps. Its been at least 40-60k since I have changed it. Ill report back tomorrow...

[Avant Nate]

Compression numbers are lower at altitude as well. By how much, I don't know.

[00black1.8t]

It was just brought to my attention... I didn't run the compression test with the throttle open. oops forgot that. That should explain the lower numbers.

[vrmm]

I've never done it with the throttle body open(never even heard of that) and got 180ish with stock pistons back in the day, but you could definitely give it a try. I have je pistons on 1.8l's same compression ratio. Swap out that 150 for a 135 and that all consistent with mine with maybe 1k less miles than you. I've never done a leak down so not sure how that would compare.

What's an overlay harness? You could try swapping plugs. And definitely lowering your gap to .028. Maybe even .026. 9 times out of 10 my misfires have been gap. It's been cylinder special for me before.

[00black1.8t]

They call it an overlay because you don't wanna split open the engine harness to pull the few wires out. So they suggest capping them off and install new wires directly from the ECU output. Old wires get unpinned from ECU as well. There's a technical bulletin for it from VW. I just don't understand why I should have to lower the gap so much from before since it ran just fine before. I give it a try tho.

http://www.uspmotorsports.com/Engine...placement.html

[vrmm]

Gotcha. I personally wouldn't imagine that harness to be a cause based on boost. It would have to be further down the line. So you recently started using the 2.0 coils with the new harness you just added then?

[happy2B5]

Compression numbers are lower at altitude as well. By how much, I don't know.

Altitude Factor
1000 .9711
2000 .9428
3000 .9151
4000 .8881
5000 .8617
6000 .8359
7000 .8106
8000 .7860

[00black1.8t]

I've used the 2.0 coils since I put the turbo in... 2-3 years ago. I bought a new set with new engine build 4000 miles ago.


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