High Oil Temps----Problem Solved - Page 2

Bruce · #11 06-14-2011, 05:39 PM

Front Gear Leg cover---Before

Look all the way to the front on this one and then the forward gear leg hole.

You can compare this to the other one I posted on the before for the
side view.

You can see that I cleaned up the whole area around the nose gear.
Note that you can see the filter housing in the nose of the cowl. You
can also see why I plugged the hole for the front nose gear fairing.

As of speed that Rocket was talking about I will have to see in
the future. I hope I did not lose too much speed. Still very aerodynamic
but will have to see on the cooling drag portion of it. I was a concern
but the temps were a bigger concern.

Bruce · #12 06-14-2011, 05:45 PM

Ok,

Here is the side view before and after.

And don't send me a note about having to sand
any of this. Test flown and parked after 200 miler.

After

Before

lostpilot28 · #13 06-14-2011, 08:59 PM

So Bruce, the louvers didn't help your temp situation at all? Or did they help a little bit, but not enough?

Bruce · #14 06-15-2011, 05:11 AM

Quote:

Originally Posted by lostpilot28

So Bruce, the louvers didn't help your temp situation at all? Or did they help a little bit, but not enough?

They helped keeping the temps to 230.

I will cover the louvers later and report back.

Bruce · #15 06-21-2011, 05:20 AM

Bump,

Looking for this thread and the one with
the louvers.

Bruce · #16 03-12-2016, 01:03 PM

Hopefully AIRGUY will see this thread.

airguy · #17 03-12-2016, 08:09 PM

Would be handy if the pics were still there though.

My latest status - changed the cooler to a 10-row and installed a rough diffuser, it dropped cruise temps to 210 but I still hit 235-240 in extended climbs. I'm spilling enough air off the left side of the plenum that now my 2 and 4 cylinders are running about 40F hotter than they were, so I'm obviously moving more air but now I've got widely spread CHT's. I pulled filter adapter and vernatherm, all measurements check out with a micrometer, I installed a new vernatherm this morning with no difference in temps.

My cowl is a Sam James long cowl, and was originally cut to meet the firewall everywhere but the exit tunnel. The exit tunnel actually extends back to the original length of the virgin cowl right now today, about 1" aft of the firewall. I'm going to trim this flush with the firewall and reseal the edge and test fly that, I know it will increase the exit airflow (and likely increase my drag too) but I've got to improve the cooling. I may end up angling that cut forward another inch later on, but first cut will be straight and flush with the firewall.

I'm also going to do some fiberglass surgery on my plenum to improve my intakes, they are not ideal right now and I know I'm generating some turbulence on the inlets, and I know that's not a good thing. Right now I have several "not good things" working against me and the trick is knowing (or guessing) which one is the biggest offender. I'm certainly not an expert on airflows in this type of environment, I'll admit I didn't have a **** clue walking in, but I'm learning fast.

Interestingly, I still think my #4 cylinder is not broken in - on a cold start this morning in the 50's that cylinder head temp reached 125 about the time the others were upper 80's, indicating quite a bit more friction, and this has been the case on each start over the last several hours. It's also definitely the hottest at high power, followed closely by #2. I have 12.5 hours on the engine now at this point.

Bruce · #18 03-13-2016, 09:11 AM

Greg,
Pics gone and can't get back.

Do you still have the front dams on 1 & 3?
I saw that on your web page.
Only make one change at a time , fly, evaluate.
Can use aluminum tape after removal to steady cht's.

Remove dams will lower your cht's.

airguy · #19 03-13-2016, 08:50 PM

Yes, the inlet dams are unchanged from the pics on my build site.

Next step is cutting the cowl exit even with the firewall and flying that, and I'm going to insulate my FWF fuel delivery line as well. It works fine with 100LL but running 91 premium auto fuel (with the higher vapor pressure) it absorbs too much heat during low power operatings (lower fuel flow, more time spent in the line picking up heat) and has a tendency to flash into vapor between the servo and the injectors where the pressure drops.

I'm going to do both of those things this week and fly again this coming weekend, then the next step is going to be a lengthy one - plenum inlet fiberglass surgery. It needs to be cleaned up anyway, even if it's not one of the major contributing causes (though I believe it is), it's going to change. I think cutting the exit opening wider is going to be my major contributor.

db1yg · #20 03-14-2016, 08:58 AM

Hi Greg,

Ref your fuel vapor issue--another way of reducing this is to increase the "head pressure" by going down in injector restrictor size. I believe the stock injector restrictors for the 180 hp Lyc (or clone) are 028. I went down to 024 and reduced about 80% of my issue (stumbling on low power approaches and stumbling when taxing in after a flight in hot conditions). Don Rivera of AFP did the calculations for me and said I could go all the way down to 023 and still have sufficient flow for up to (speaking from memory here) 185hp.

Cheers,

db