Number 1 cyl temp reduction CHT

So I recently purchased an rv6a and have been working on it to get it to where I want it.

I've felt cyl head temps were a little high so I added a washer on number 3 cyl baffle which has dropped the temp on number 3. Problem is I'm seeing higher than normal temps on number 1.
In the north east cooler air temps (60 degrees ) I've seen it as high as 410 (I typically keep it below 400) on initial climb out with all other cylinders being 390 or lower. This is at 100 mph climb out, I can drop the nose to 120 mph and I'll see a reduction or chop power but I feel like that's a bandaid.

Previously number 3 was my hottest cylinder. It's now typically the coolest.
I've got a ramp up over number 1 I'm wondering if I should reduce or remove that ramp?

I'm used to flying an archer I can put at 73 kts and climb out like a rocket without temp concerns so this shallow climb out concerns me. Especially with friends (who have been checked out but don't fly it as often) flying it.

Only new change was that I put new O rings in the primer. As a previous drag racer I always try to look to the last change made.

So is your primer connected to cyl #1 only? I had high EGT/CHT on cyl #1 due to a leaking primer line in the cockpit which sucked air into #1.

snopercod said:

So is your primer connected to cyl #1 only? I had high EGT/CHT on cyl #1 due to a leaking primer line in the cockpit which sucked air into #1.

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I don't know if it's only on one cyl. I'll have to check that out.

The reason I put new o rings in is a friend felt it was a little easy to move and opened it while running and it pulled itself closed , so we put new o rings in. The ball in the end and spring seemed to be working fine, His mooney doesn't have a primer.
I've mostly flown club airplanes that were maintained by others, so I'm not very familiar with primers.

Mechanically, I've worked on race cars of several types for years though.
I figured I might switch up to a solenoid and 3 position switch in the near future anyway to get the lines out of the cockpit So I didn't get in depth with the primer system.

primer solenoid?

Turbo69bird said:

I figured I might switch up to a solenoid and 3 position switch...

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Now that's a great idea, but is 6" of pressure from a boost pump enough? (My engine is carbureted)

My primer is connected to 3 cylinders. The next lowest today was 367 while no 1 was 410

Only on climb out though.
They drop below 380 in cruise, temp was 48 degrees oat.

I'll try to get better data with the go pro fixed on it tomorrow.

I don't know if the boost pump is enough for the other system it was recommended by a freind whose done it. I'll ask for more details

Does everyone else have a ramp in front of the number 1 cyl? Mine has approximately a 2 inch ramp riveted in place. I'm thinking about removing it to see if that's the issue.

The "washer trick" can create one problem as it solves another. The cause of the #3 (or 5) heat is the lack of air to about 6 particular fins on the head. The washer allows some air to those fins but also opens up a big gap all the way across the head. Make sure the gap is sealed tight everywhere but those particular fins or you will lose valuable delta p. This leak may be driving #1 hotter.

The more elegant solution is to build a dedicated bypass duct which is detailed in several threads. Search for "#3 cooling" or something along those lines. There is plenty to read.

Toobuilder said:

The "washer trick" can create one problem as it solves another. The cause of the #3 (or 5) heat is the lack of air to about 6 particular fins on the head. The washer allows some air to those fins but also opens up a big gap all the way across the head. Make sure the gap is sealed tight everywhere but those particular fins or you will lose valuable delta p. This leak may be driving #1 hotter.

The more elegant solution is to build a dedicated bypass duct which is detailed in several threads. Search for "#3 cooling" or something along those lines. There is plenty to read.

Click to expand...

Thanks I saw thecooling duct thread, just figured I'd try the washer first to see if it would work for me. Didn't realize it could cause the no1 to get hotter but thought it might be the issue since it was one of the last things changed..

I'm hoping to look into it a little further this week

Turbo69bird said:

Thanks I saw thecooling duct thread, just figured I'd try the washer first to see if it would work for me. Didn't realize it could cause the no1 to get hotter but thought it might be the issue since it was one of the last things changed..

I'm hoping to look into it a little further this week

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To lower the #1 temps, trying cutting down the front **** in small increments. It is designed as a larger than necessary starting point, not an engineered size. I cut mine off early in Phase I and lately just kept moving a piece of Aluminum tape until I got it where I wanted it. Mine is about 3/4" above the top of the angle piece. I also did the washer trick and never did the proper duct Michael refers to. However, I never get CHT's above 400 in any condition or ambient, so haven't made it a priority.

Larry

I've cut it down a bit and CHTs are within 20 degrees of the other cylinders on take off and with in 10 degrees of the other cylinders in cruise and even in slow flight 65mph. I haven't looked at the EGTs no good reason just was focused on CHTs

It's pretty cold here so the low CHTs aren't really indicative of much yesterday was 24 degrees on take off. The CHTs are in the 350s on other Cyl. High 360s low 370s on T/O for number 1