CHT temps, individual cylinder differences? |
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CHT temps, individual cylinder differences? |
falcor75 |
Apr 12 2018, 10:50 PM
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#1
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Senior Member Group: Members Posts: 1,578 Joined: 22-November 12 From: Sweden Member No.: 15,176 Region Association: Scandinavia |
For those of you that are running 4 CHT sensors under the plugs, what differences do you see between the cylinders?
Whats your typical temps for each cylinder with: A: Engine warmed up sitting at idle for a minute or two. B: Engine warmed up, cruising at 50-55 mph in fifth gear. |
falcor75 |
Apr 15 2018, 05:28 AM
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#2
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Senior Member Group: Members Posts: 1,578 Joined: 22-November 12 From: Sweden Member No.: 15,176 Region Association: Scandinavia |
Just spend the last 3 hours fiddling with the thottles.
Started with disconnecting the throttle cable and making sure the 1-2 (master) side was as closed as it would possibly go. Then I hooked up the throttle cable again and made sure there was no slack in the slave cable to the 3-4 side so both sides open simultaneously. I started the engine and let it warm up for about 10 minutes at different rpms. (the neighbours love me) Then I took out the air gauge and started measuring. To start with 1 drew the most air, followed by 3 and 4 and last 2. By first adjusting the slave cable slightly and then the idle air screws I got cylinder 1,3 and 4 to draw the same amount of air, just below the 6 mark on the scale. CHT temps at idle was then around 110C (320F) for #1 and 125C (257F) for # 3 and #4. Cylinder 1 Cylinder 2 The odd one out is still #2, when the others draw just below the 6 mark, #2 draws like 4,5-4,8, about a full scale marker lower and the temp is around 95 C or 205F. What could cause #2 to draw that much less air? air leak between head and manifold, airleak between manifold and throttle body are the only things I can come up with.... |
barefoot |
Apr 16 2018, 02:12 PM
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#3
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Senior Member Group: Members Posts: 1,264 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States |
Just spend the last 3 hours fiddling with the thottles. The odd one out is still #2, when the others draw just below the 6 mark, #2 draws like 4,5-4,8, about a full scale marker lower and the temp is around 95 C or 205F. What could cause #2 to draw that much less air? air leak between head and manifold, airleak between manifold and throttle body are the only things I can come up with.... I've just been playing with carb idle air flow issues with one carb. The exact opening at the butterfly's at idle was very difficult to get even on one carb. At idle, there is VERY little open area at each butterfly. The stock injection system avoids this by using a single butterfly for all 4 cylinders, so much larger open area at idle. use some very thin feeler gages to measure butterfly opening on adjacent cylinders. |
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