Compression results after 300 miles

[kalla]

Rebuilt my motor .020 over with Ross 8.5:1 pistons and Eagle rods. Put about 300 miles on and did a compression test this afternoon, the motor read 170 psi across the board. Can I expect the compression to continue to increase a little more as the motor gets more miles on it? After how many miles can you expect the rings to be as seated as they're gonna get?

 

[Bastard1g]

170 is pretty good man, do you expect more?

 

[TSIfreek]

The rings have already seated. Test on a hot engine to get the best results because of heat expansion (pistons).

 

[kalla]

Yep, tested after driving the car. Thanks for the info, it was the first motor I ever rebuilt, I was kind of wondering if I would get the ring file-fitting right but looks like I did fine.

 

[MitsuBoost]

the compression should rise as your pistons develop carbon build-up, probably after 2K miles or so

 

[2.4 turbo Hyped]

8.5:1 compression I woudlnt expect a Higher reading as that seems perfect for that ratio. I have 8.8:1 and read 180 on all four.

 

[Waredtalontsi]

I read 185 on all 4, thats on ross 8.5, and also with HKS 272's.

 

[anconover]

on 8:5:1 i would expect 180-185 on a perfectly sealed cylinder. But nothing wrong with 170.

 

[2.4 turbo Hyped]

on 8:5:1 i would expect 180-185 on a perfectly sealed cylinder. But nothing wrong with 170.

Modified cam timing can alter compression numbers.

 

[blackGSX2g]

Sounds fine...stock 2g standard compression on 8.5:1 compression is like 176 or 178 I think. It sounds ok to me.

 

[2GeNTSi]

i think got 165 last time i did one, all across.

 

[1fast97gsx]

It also depends on the headgasket and how much milling was done on the head and block. 170 should be pretty damn good though.

 

[NDgsx]

Remember to keep the throtle open for the most accurate results.