Stihl MS192T cylinder differences

I have 4 or 5 MS192T/TC saws that I'm rebuilding and noticed that on the earlier T models up to 2007 the cylinder is different and the compression is higher.

On the newer TC models with Ergo-start there is a groove in the cylinder wall extending just below the exhaust port. It reduces compression, and probably makes it easier to start, but why did Stihl do this? A 30cc saw is not tough to pull over. Everything else about the two cylinders looks the same, and they have different part numbers.

The older T pushes about 175psi, and the newer TC only comes up with about 140 psi.

 

That is referred to by Stihl as a "pre-exhaust groove", but I don't know the rationale behind it.

 

Yea if a 30cc is hard to pull over you might have trouble lifting all but twigs that you cut

 

Does the older t cylinder fit on the newer tc saws?

 

Yes.

 

I just finished rebuilding a couple of TC saws with the older T cylinder (OEM) and they have a very noticeable difference in compression. With the carb limiters removed, and the muffler outlet opened up, they really run well.

 

This is confirmed as a fact?

In error I have dimpled my 192tc cylinder wall attempting to repair a loose muffler and will need to replace it.

 

See post #5.

 

I have used a number of the 'T' cylinders #1137-020-1203 and they bolt in just fine. There is only one piston part number, so it works with either style cylinder if you are re-using an old piston. Dealer charges $99 for the P/C assembly... haven't found any aftermarket ones yet.

 

Thank you for the sound counsel. Before checking for a reply here I called and Mark at Stihl confirmed that the 192tc is compatible with the 192t cylinder just as you folks have confirmed.

Off to go get that done.