Gap behind #3
Just to chime in here a bit. While down at TEX 2006 a couple of people asked me about my SJ engine plenum and if my #3 cylinder was still the hottest. It is and always has been. My #1 is the coolest and the #3 the hottest. #2 and #4 have always been very close with each other. (I do have tape on the front of both #1/#2 cylinders.)
This past weekend, I pulled the plenum off and did two things. I put a washer between the cylinder and baffle on #3. (Baffle was right up against cylinder.) I also completely blocked off the 2" outlet for cabin heat. Don't need heat in the summer and I figured this was just wasted air blowing to nowhere when it could be cooling my cylinder.
After test flying my #2/3/4 cylinder temps were within 4 degrees of each other, right around 355. (Previously the #3 cylinder was runninng 380's) My #1 is still cooler at 335 but I could put a little more tape on it to bring it up inline with the rest.
When building, I was worried about the #4 cylinder since I have a 3" scat tube back there for the firewall mounted oil cooler. The majority of the 3" hole is behind the cylinder head with only a small amount showing above. I've never had problems with #4.
On a side note... I've never had problems with oil temperatures being to HIGH with my FW mounted oil cooler (with Van's install kit).. I've struggled to get the oil temp WARM enough. That firewall mounted oil cooler is working just fine! I'd read many didn't like Van's fw mounted oil cooler kit and oil temps would be 10-20 degree's warmer than a baffle mounted oil cooler. It's been in the 90's here in KS the last couple of weeks and I've had absolutely no problem at all with high oil temps, even on climb out.
Just my $.02.
Just to chime in here a bit. While down at TEX 2006 a couple of people asked me about my SJ engine plenum and if my #3 cylinder was still the hottest. It is and always has been. My #1 is the coolest and the #3 the hottest. #2 and #4 have always been very close with each other. (I do have tape on the front of both #1/#2 cylinders.)
This past weekend, I pulled the plenum off and did two things. I put a washer between the cylinder and baffle on #3. (Baffle was right up against cylinder.) I also completely blocked off the 2" outlet for cabin heat. Don't need heat in the summer and I figured this was just wasted air blowing to nowhere when it could be cooling my cylinder.
After test flying my #2/3/4 cylinder temps were within 4 degrees of each other, right around 355. (Previously the #3 cylinder was runninng 380's) My #1 is still cooler at 335 but I could put a little more tape on it to bring it up inline with the rest.
When building, I was worried about the #4 cylinder since I have a 3" scat tube back there for the firewall mounted oil cooler. The majority of the 3" hole is behind the cylinder head with only a small amount showing above. I've never had problems with #4.
On a side note... I've never had problems with oil temperatures being to HIGH with my FW mounted oil cooler (with Van's install kit).. I've struggled to get the oil temp WARM enough. That firewall mounted oil cooler is working just fine! I'd read many didn't like Van's fw mounted oil cooler kit and oil temps would be 10-20 degree's warmer than a baffle mounted oil cooler. It's been in the 90's here in KS the last couple of weeks and I've had absolutely no problem at all with high oil temps, even on climb out.
Just my $.02.