Well, I did a leakdown/compression test on my Vitara/Eagle D16A6.

I was a little concerned...

My leakdown results are as follows:

Cyl. 1: 17%
Cyl. 2: 22%
Cyl. 3: 22%
Cyl. 4: 17%

Compression test results:

All cylinders around 125 psi.

This is a motor with .0035 PTW clearance and fairly large ring gaps. The tests were done with the coolant temp around 150*. Leakdown was heard through the oil fill cap and dipstick, indicating rings.

I think that since the numbers are fairly consistent the problem lies in the fact that the motor was built on the "loose" side. Do you think if the tests were done after a few boost pulls that the numbers would be better due to the pistons/rings being hotter?

 

I would suggest trying it a few more times, maybe starting with ~70psi if its a 100psi gauge. Gauges are always less accurate near the edges of their sensing range, sometimes 10x less accurate.

Also make sure there was clearance between the valves/lifters when this was done (to be absolutely sure), and try the oil trick. There's also the possibility a little bit of oil was in #1 and #4, leading to less leaking.

Lastly, sometimes motors take a while to break in. I would almost suspect the inner cylinders to break in faster for various reasons, but at least there may be a pattern with 1/4 & 2/3 being similar, respectably.

 

Yes, I used 100 psi.

As for break-in, the motor has ~10,000k. on it.

 

did you pull the wastegate to see if any was coming out the exhaust valves? That's usually where it leaks the most in my experience.

How does the motor run? If it's not pushing a lot of pressure out the breather when it's idleing, I wouldn't worry about it.

 

Motor runs strong, pulls hard under boost. At idle, you can hear a little air coming out the catch can, but nothing major.

I think the low compression numbers are due to the 7.9:1 compression pistons, and the high leakdown numbers are due to the large ring gaps.

 

I'm just wondering what the ptw clearance suzuki reccomends with those pistons

 

I don't know what Suzuki reccomends, but most Honda guys are running .0035-.004.