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Hot Cylinders 1 & 2

Aiki_Aviator

Aiki_Aviator

Well Known Member
Hi All,

wondering what people have found regarding hot cylinders.

Have people got hot 1 & 2 cylinders or not? Or did people find other cylinders hot.

If they found hot 1 & 2 cylinders, what did they do to correct?

Thanks in advance.
 
Did you remove the tabs I told you about?

What is your meaning of hot? Memory failing me but what Ignition do you have and what is the advance on spark timing.

What fuel flow on takeoff are you getting at WOT and what RPM?

What does your EMS data tell you?

There is a class you know about?.. ;)
 
Hot Cylinders 1&2

How much hotter than the other 4 is the question. Some variation is expected.
Before you make any structural changes make sure your fuel injectors are close to balanced. There should be no more than a 1 gph difference in fuel flow from when the first cylinder peaks while leaning to the last cylinder.
You can lower the temps on 1&2 by cutting down the height of the dams in front of them. My cylinders run: 3&4 coolest, 1&2 next, followed by 5&6. They stay within 20-30 degrees of each other.
 
Hot 1 & 2

Hi Dan,

Dams not changed as yet, wanted to get a full range of feedback first, however is at present the primary option for change.

Jets coming in mail this week, also hopefully fine wire plugs. So getting very close.

Dan, would love to get to that course, however, unfortunately it just too expensive for me to consider. Great idea though.

Look forward to other feedback also. :)
 
Hi Andrew

My front cylinders where both hot and I removed the front air dams which equalized the cylinder temps.

Cheers
 
Andrew, I think a search of the archives will show that no one leaves the air dams at full height. Folks seem to end up somewhere between 50% height and removing them completely. Mine are at about 50%.

My perspective is that good cooling is a matter of paying attention to a lot of little details.
 
Had to remove the dams

tried just cutting them down, finally removed them --- CHTs then evened out considerably.

R.
 
The other trick with the dams is to use screws instead of rivets. It makes experimentation easier.

My left side is removed and my right side is about 1/2".
 
I put 2 AN960 washers behind the angle where the bolt attaches the front baffle ramp and dam to the #1&2 cylinders. This made for a slight gap between this part of the baffle and these cylinders. This lowered my CHT's by a few degrees.
 
Looks like Dams are coming out :)

Thanks all for the feedback, and thanks DAN (i.e. David) late night the other night... doh!!!
 
I paid close attention to our CHT's on a flight yesterday. With no air dams, 5 of the 6 were within 15 degrees of eachother. Cyl 4 was cooler than the rest by another 15 degrees.
 
No dams

I never put the dams on, and recommend they come off on every airplane I've licensed, at least for the first flight where high temps are usually the norm. My CHT's are balanced across the board in cruise within 5-10 degrees and no dams.

Vic
 
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