Anyone figure a good way to cool cylinder #3 ?

[pappas]

I know that we all have issues with #1 or #3 cylinders running hot, even after 100 hours. For me, #3 is the issue. I am able to keep it under control and under maximum temps, but it is always 50 - 60 degrees hotter than the others indicate.
Has anyone come up with a device, or technique, or an air diverter of some sort that is effective in directly cooling an individual problem cylinder?

Looking for all suggestions. Thanks!

[GraemeSmith]

I believe mine is running hotter because it's running leaner. The EGT on 3 is out ahead of the others and the CHT follows.

I did some extra porting around the No 3 inlet to try and get it more of a fuel charge into that one so it ran a little richer and so cooler.

Still playing with it - but my No3 is now only consistently 30 degrees ahead of the others.

--

I did try the Great Plains Inlet manifolds recommended elsewhere - but what I was sent by GP were junk that required significant rework and finishing and didn't do any good even after I did.

[pappas]

Interesting. My #1 is always the hottest EGT - but the coolest CHT. #3 cylinder is always hottest but EGT is 2nd coolest. Go figure!

[tx_swordguy]

Perhaps rivet a piece of aluminum angled down to hit between 3-5 that way you hopefully wont rob air from 5. I wrapped my exhaust pipes all the way to the cylinder and it helped my cooling by 20 plus degrees on my problem cyl. I know there is a trade off because it can hold moisture on the pipes once cool and can poss cause rusting from what ive been told but between that and what i said earlier it has helped my #5 temps and #3 although 5 was the prob cyl. You might swap cht sender with 1 or5 just to make sure its not a sender issue.

[mike.smith]

My EGTs are all about dead nuts even. #3 CHT runs hottest, but really nothing to ever worry about. On a hot day I might max out at 380 deg on #3 in a climb, but that goes down when I get into cruise. But in the winter my #2 and #4 run significantly cooler than 1 and 3, so in the winter I made deflectors that let some air get to 2 and 4, but send a more of it back to 1 and 3 (to try to get 2 and 4 to run hotter). So I have the reverse problem as Lou, but the same solution might help.

I don't have a photo, but it's just a flat piece of .025 screwed to the aluminum baffle ramp just inside the right inset. It makes the inlet ramp "longer" to throw air up over #4, to get back to #3. I experimented with different sizes. I started big, then cut back as I experimented. In the warm months I remove the ramps entirely since I don't have a cooling problem.

[mike.smith]

Lou, what are the max CHTs on 1 and 3? If they are hot but running in the green, then there really isn't an issue. If they are bumping up closer to 400 deg then that is a problem.

[pappas]

Mark,
I forgot to mention that this is an Aerovee Turbo, not a 3300. I did exactly as you suggested for my 3300 in my last Waiex and it worked well. Thanks.

Mike,

I spoke to Kerry about this during the first 50 hours, I'm at 105 hours now. He told me that 420 degrees for 5 minutes was within limits. I can get #3 to 420 during climb out and drop the nose to cool it before five minutes elapses, but I don't like it.

I prefer to cruise lean for less fuel burn. 135 to 138 mph looks like this; at cruise of 30 inches and 3000 rpm #'s 1, 2, and 4 CHT's are around 325 deg. 3 will be at 375-380 and I am burning 5.5 to 6.1 gph. If I can find a way to spot reduce #3, I can run leaner, burn less fuel, and have less stress on #3.
If I run this turbo much over 30 inches, the fuel burn can get to 7, 8, or higher gph pretty quickly.

[Area 51%]

You could run a "blast tube" to force outside air onto the #3 CHT probe to cool it, like others have done to bring their oil temperature down.

OR..........

Do you trust where your CHT probes are? I only have two located at the rear cylinders. I installed the probes under the spark plugs and was running high temperatures (400 plus) in climb during the first 25hrs as expected. No relief came at 30hrs, so I relocated a probe to the recommended spot about an inch away from the plug. Abbra-Kadabra....that probe has never topped 400deg no matter how hard I try. The other (still under the plug) sits on 420+ during a prolonged climb while the other is cooling it's heels at 375. Across the board, I get a 50deg difference between the two.

If the damn probes weren't $65 each, I'd relocate the other one.

[pappas]

Yeah. I have my probes screwed into the heads at the recommended locations already. I suppose that I could relocate #3 to an exterior antenna mount and get a lower reading..... concur ??

[Scott Todd]

That's funny Lou :)

For years I have read/heard where people move their CHT probe to get a lower reading and are then happy. I'm only an Aerospace Engineer so maybe I don't get that black magic. Someone may have to explain it to me.

But I have to admit, that's the first I have heard of directing cooling air to the actual probe to solve the problem ;)

And I do concur Lou. It would give you a lower reading :) :) :)

Edit: But you may have to be selective about which antenna to avoid EMI.