Rebuilt 028, compression still only 150?

[kd460]

OK, so I rebuilt this 028 about 8 months ago, (tecomec super piston and cylinder kit) been cutting with it since. Runs good, starts easy enough, gets the job done. Compression shortly after rebuild was 148 to 152 range.

Was cleaning the garage today and came accross my compression gauge (yes it is accurate and the correct type). For giggles, I checked the compression. It has not changed one bit. Should the compression have gone up once it was broken in? Is this a good number? Should I expect more? I read posts of guys saying "my 028 still has 160 compression" and I wonder what is wrong?

Looking into the cylinder thru the intake and exhaust shows a new looking cylinder and piston/rings. Nothing out of the ordinary. I run a 16 inch .325 chain. Every now and then when cutting some bigger wood, I have thought "this thing should have a little more oomph". But did not really dwell on it.

Now, after todays compression check, I am starting to wonder. KD

 

[Bowtie]

I look forward to the answers to your post. I have an 028 that I need to get going on, and hopefully I can at least learn something from this thread.:help:

 

[16:1mix]

Should I expect more? I read posts of guys saying "my 028 still has 160 compression" and I wonder what is wrong?

Ahhhhh....right away I wonder if the gauges that read 160 are accurate compared to yours. The ultimate test would be use the same gauge on all the saws in question to get an accurate comparison. Of course I realize this is not possible but it does illustrate the possibility of gauge error / testing methods.

If I were you I'd run it!!!!

 

[Lakeside53]

Nothering is wrong... just cut wood... Compression testers can vary all over the map. They should just have three zones - red - bad; yellow - "o.k"' green - great!

 

[buck futter]

There are many factors that affect the static compression reading you received including how long it sits. The older the saw typically the looser the squish band clearance was held because of fuel quality. There are little things you can do to get your rings to seat tighter, basically a little abrasion of the surfaces that rub together will make them seat tighter. Most stihl use two rings so you are likely to receive good enough compression to have a decent running saw for a LONG time! I think 150 is a good number for a stock saw, You will see a little higher compression on the newer stihl pro saws like 160-165 but that should be thought of as very good/ above average. The highest I have ever seen on a stock saw is my 5100 dolmar, she has a lot of miles but still has 170psi! You can run that saw down to 125-130 before you start running low on power and it will progressively get harder to start.

The truth is, if you think your compression should be a little higher, maybe you haven't run it enough.

 

[Erick]

Run it, 150 is fine.

 

[kd460]

Thanks to all, feel better now. Gonna run it till there really is a problem. KD