Tom Lay claimed to not change the timing on the ST G.51 (CL version). I don't know if he changed the head, but could check both, now that I think of it. He said he hardened and honed the liner and changed to a Bowman ring (as did Big Jim and probably everybody else), changed bearings if needed, and did the spraybar through the case revision. He also said the Chinese engines were just as good as Italian ones. I took that to mean the Chinese ones were ok....but maybe he meant that the Italian ones were also crappy?
The ex-Dirt G.51 (reworked R/C cylinder and stock head) I sent to Tom to get a CL cylinder and the full T&L rework didn't work out too well for me. Never had any sort of ring seal and still doesn't. Interestingly, and as expected, lowering the spraybar had no effect on tank height. Last I flew it was in Edmonton in 2010. I flew my officials with a 12.25 x 3.75 APC, and it sucked in the wind, later in the day. I decided right there, that a piped engine would be a good way to go.
Dirt said he (Dan) was changing over to a CL cylinder from the reworked R/C cylinder, because he thought he could get more "power" (torque) out of it. Logical, due to lower timing numbers. Bigger prop at lower revs. He also said that he'd previously used a lower compression head, but had changed back to stock. Later, Dan flew an Impact with his CL version G.51, and it seemed to work quite well. Tho, I can't speak to how stock the cylinder was, either.
Steve
Topic: ST51 (late model) ABC sets (Read 17140 times)