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PNW Baffle Expert?

622BH

Well Known Member
In the Pacific Northwest, who is considered the baffle expert?

I've got one cylinder running colder than the rest and one that is slightly hotter. Though many would consider them acceptable, I want to see if I can get the temperatures more even across all.

To do that, I know I need to talk with someone much more experienced than the local builders.
 
Spread

Depending on flight regime, #1 is from 40 ~ 70 degrees cooler than 2, 3, & 4.
#s 2 & 4 are usually within 5 degrees of each other and #3 is the hottest, about 10 ~ 15 above 2 & 4.

Thinking I'll just jump on the issue by first manufacturing the "duct" around the #3 cylinder (I've gapped that area for flow - but seems not enough) and re-installing the dam in front of #1 then just incrementally cut it down until I get it "evened" out. I'm interested in talking to an "expert" to see if building a ramp in front of #1 to "lift" the airflow up over and to the rear might be feasible.

I know getting too tricky in that area could generate more problems than its worth.
 
You don't need an expert. You need about 4" of metallic aluminum duct tape stuck to the front of #1, and a few minutes in flight. ;)
 
Start with aluminum tape. Partially block off the front of cylinder #1's fins and go fly. Check the results, it may be all you need.

If cylinder #3 is still too warm, use a washer under the rear right baffle mounting screw to provide a pathway for airflow.

Neither of these are permanent mods. Once you get things dialed in, you can build a permanent dam for #1. A 'ramp' isn't required. I attached a dam with platenuts to make changes easy.

v
 
Washer Didn't Work

Naw, the washer didn't work - tried that a long time ago. Decided to "deform" the baffle aluminum around the fins; that's where I am now, with that #3 cylinder still a bit warmer than I would like.
I'll work on the ducting technique upon returning from a month+ travels over the pond.

#1 cylinder being quite a bit cooler than the other three is more pressing (in my mind) so will begin with that by trying the aluminum tape method and adjust that until I get it where I like it. (If I keep putzing with it, I'll get it within 5 degrees... yeah a bit anal I know...)

So, I've got some work / playing to do upon the return.

Thanks everyone.
 
I made those front air dams removable (plate nuts and 8-32 screws) and have trimmed them until my temperatures are balanced.

As Dan and Vern mentioned, I started with tape until I knew about what size I needed and then installed my air dams based on the size of the tape I had used. Even then, I still removed them to make some adjustments.

One advantage to the removable dams is that you can make a set for the winter and a set for the summer, if you need.

Take a look at where the baffles slide together, if there is a gap, fill it. Even a small air leak can make a huge difference in temperatures.
 
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Understood

Yes, I've pushed a lot of RTV around the baffles/cylinders/engine. I don't believe that's where my issue(s) lie.
#1 cylinder - When the engine was brand new, the temps were really hot, so I removed the dam. Now after 250+ hours, the cylinders are "stabilizing" and #1 is colder than the rest; so I believe I need to put some of that dam back. Its an issue of just how much to get that cylinder's temperature up in-line with #s 2 & 4.
#3 - I tried the washer trick but that didn't bring its temperature down sufficiently. So I deformed the baffle metal in that area. Now, its hotter than #s 2 & 4, as I've mentioned. My next plan-of-attack is to manufacture the duct as has been mentioned in other threads.

All that will take more time than I've got at this time, so it'll have to wait until I return from travels.
 
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