Summer temperatures and cooling

[Bryan Cotton]

In the final analysis what do you attribute your improvements to? Are the oem springs worth trying? Did you have to modify them? Curious can you replace the springs without draining the oil? I've had the oil drained each time I've pulled the springs and plungers.
Peter

Peter,
Hard to say for sure, but I suspect 75% springs and 25% airflow. For some reason I can't get my steady oil pressures below 60 psi. Someday when I have to overhaul it I'll investigate. So to compensate I stretched my original oil cooler bypass spring and that seemed to be the final thing that got me over the goal line. I think that for most installations those OEM springs should be good. Not sure why I had high oil pressures with the springs that came in my Aerovee kit. But if your pressures are good, then there is probably going to be no change.

It's an easy and cheap thing to try. You will lose a pint or so of oil, whatever is in the galleys above the plunger. And because of gravity that oil will go on your tools and hands. But overall it's not a bad job.

This morning I went out to fly a couple of loops and rolls. I climbed at 80kts straight to 6000', and topped out at 211F on the climb. Ambient was about 75F. For my acro flying I was in the low 200s and on the taxi back to the hangar my oil was 186. I feel like I won this one.

[BRS]

Bryan hope you don't mind me tagging this onto your thread. Just didn't seem worthy of a new one.

OK, Summer is gone but I've still been fine tuning my Sonex-A w/Revmaster. The new Rotec MKII is amazing (not for this thread though) the other pesky item has been warmer cylinders than desired. FINALLY figured it out. Yes, uneven fuel distribution was part of it - solved. Still they were not where they should have been. Making the change pictured below made a considerable difference.

For the original installation that top plate was really just a safety wire holder to keep the bottom (not shown) plate in place. But it it is clear that most of the cooling air would sneak around the side instead of going through the fins. I was unsure how much difference this would make. Now I know, it makes a lot of difference.

[Bryan Cotton]

Brock,
Good addition to the thread I think. Can you post a picture from a wider view? I think I know what I'm looking at, but not sure.

[BRS]

Here are some larger pictures...

So, here is the old Intercylinder Baffle on the top. Really it was installed to hold the safety wire for the baffle below the cylinders. It's fault is that the air is not forced through the cylinder fins.

I replaced the old with this newer version which does force the air through the fins. Not too that it is also wider (covers more fin). It is interesting that the AeroVee's / Lycoming doesn't wrap the cylinders yet Revmaster need it. The wrap is not shown in this pic.

Here is the template I used. I had cut a few of these and fitted them in place (just the paper) until it was right. Also note the old top baffle piece is on the lower right while the newer is in the upper right.

[pfhoeycfi]

I'm curious how others have addressed the flashing on the empi heads, between the fins etc. Also if anyone has a pic to post of what they've done in this regard that would be great. I'm also wondering what the factory does...I put the question to them as well. My number 3 is still hotter than the others. It's manageable but I'd like to bring the temp down.
Peter

[Bryan Cotton]

Anything I could get with a needle file, I went after. It was not a lot.

[Bryan Cotton]

Bryan hope you don't mind me tagging this onto your thread. Just didn't seem worthy of a new one.

OK, Summer is gone but I've still been fine tuning my Sonex-A w/Revmaster. The new Rotec MKII is amazing (not for this thread though) the other pesky item has been warmer cylinders than desired. FINALLY figured it out. Yes, uneven fuel distribution was part of it - solved. Still they were not where they should have been. Making the change pictured below made a considerable difference.

For the original installation that top plate was really just a safety wire holder to keep the bottom (not shown) plate in place. But it it is clear that most of the cooling air would sneak around the side instead of going through the fins. I was unsure how much difference this would make. Now I know, it makes a lot of difference.

I wonder why the AeroVee doesn't have this. The air that sneaks through the slot in the middle of the head won't have a chance to pick up much heat, and the intake ports are right there helping to cool things off anyway. But by turning the corner it will be blowing across the fins. I'm thinking of adding this baffle.

Edit: I just cleaned out the slot in one of my new heads.

[Bryan Cotton]

Brock, your pictures look like that plate is installed on the top. That seems odd to me - don't you want the air to go through to the bottom? Here is my current setup simulated by holding the super tin on the bottom of the head:

This is the head that has not had its center slot cleaned up yet. But once cleaned up, the air will come down through the center slot and just exit straight down. I'm thinking the original "top plate" you showed should go on the bottom, so the air coming down is deflected forward and aft to the cooling fins. Alternatively, you could set it up to just deflect air aft, since the back cylinders run hotter. The front gets plenty of cooling because the air blasts right on it from the inlets.

Any thoughts?

[Bryan Cotton]

Prototype inter cylinder baffle.

Here it's removed and you can see the sharpie mark I traced from the baffle.

[Bryan Cotton]

Here is one ready to install.

inter cylinder baffle safety wire.png (463.27 KiB) Viewed 501 times