Originally Posted by
Jaz240
I was hoping to not have him losing his compression by running any hotter than that, he seems to just have that new engine pinch, and I think it best to just free it up a bit, and not have it sit so loose that he loses any power, but you seem to have more experience with the STS engine, so if it worked for you it may work for him also. I think it may be a little overboard to go past 250 degrees though
Its all good man, and either way will probably run it in fine. I had to put a gallon through my first one before it ran good so on all my others I "lapped" in the piston and sleeve with a compound then put it back together. I think everyone that's ever used one of these knows they had a few production runs where the pinch was entirely too tight. So I just use compound to shorten break in and save me from replacing the rod or the crank. Also, make sure you seal it up......most of these leak like crazy and it makes for a tuning nightmare.
Just as a side note, modding one of these is a waste of time in my opinion. They make decent power in stock form and if you go modding it the crank or rod will just break quicker. These aren't really made to mod in that they are just cheap power and not made to do more than they do in stock form. I've use a D5R (which is a .12) as well and I wouldn't touch it either. I've never used a .21 from STS so I can't speak to how they would be.