wera710
Well Known Member
Need help on reducing CHT on the Number 2 cylinder (Front Left). I?ve read everything I could find on CHT issues on VAF but quite often the replies seem to gravitate to #3 Cyl or conversations about LOP v ROP. I?d like some advice strictly on how to reduce CHT in climb or in cruise on #2 on a standard Van?s cowl and baffling on the RV-8. The engine is a carbureted O-360A1D. CS prop. Bendix shower of sparks type mags. EDM-700 for CHT and EGT readings on all four cylinders. Nothing special or modified. In climb at 25 Square I am seeing CHTs on #2 as high as 415 to 420 deg. This is both at max performance type climbs or in cruise climbs with low angle and higher speed. Even throttled back ? still over 400. Other three cylinders all within a reasonably cool range during climb. Valves look great by the way?but still, I want this sucker cooled down.
I?ve checked the baffling and there are no glaring issues. It?s tight where it needs to be and the front of the cylinder vanes are not blocked off, although as others have noted, the vanes are pretty shallow.
More annoying is that in cruise, ROP operations keep the temps up in the 395+ range on that cylinder, while others drop as low as 335. Basically I have two cylinders that average 375 and one that is always low, around 335, and then number 2, which just won?t come down below 390 unless I lean to LOP.
Operating at 42 deg LOP in cruise, I can easily get #2 down to 373 to 385. But as soon as I go ROP its right back up to 395 or above. I don?t want to get into the LOP v ROP in carbureted engines debate, I just want to get this cylinder under control and close to the rest, temp wise, at ALL settings.
Any ideas would be much appreciated. Thanks.
I?ve checked the baffling and there are no glaring issues. It?s tight where it needs to be and the front of the cylinder vanes are not blocked off, although as others have noted, the vanes are pretty shallow.
More annoying is that in cruise, ROP operations keep the temps up in the 395+ range on that cylinder, while others drop as low as 335. Basically I have two cylinders that average 375 and one that is always low, around 335, and then number 2, which just won?t come down below 390 unless I lean to LOP.
Operating at 42 deg LOP in cruise, I can easily get #2 down to 373 to 385. But as soon as I go ROP its right back up to 395 or above. I don?t want to get into the LOP v ROP in carbureted engines debate, I just want to get this cylinder under control and close to the rest, temp wise, at ALL settings.
Any ideas would be much appreciated. Thanks.