We've seen a lot of barrels over the years, with cracked exhaust bridges and/or front transfer ports. Like Rob, we've had them repaired, and some crack again, but the majority seem to be OK.
The niggling question is always, how long was it cracked before it was discovered?! Naturally, we would never re-use a barrel with a crack in one of our builds, but it does make you wonder if some of them have been running like it for thousands of miles already.
It's very important to allow the motor to warm up gradually. This is especially true for the MC16/18s (hexagonal barrels), which have much smaller water jackets around the barrels, and consequently heat up much quicker.
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Andy.
NSR-WORLD.COM
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