Tom,

 

I have a 360 straight valve with 10:1 pistons,fuel injected with a slightly bigger oil cooler then normal. I increased my inlet air to four inches and a stock RV baffling system sealed tight.My exit air is 3"x 17. If not careful (too lean) on hot days I can go over 400 on takeoff/climb out on a hot day. However if I level off/ reduce power/rpm  I can stop the CHTS from going over 400, Once  cooled down (stabilized) from the takeoff I can resume full power/climb and manage the temps just fine. I never run my engine over 400 chts.

 

 I recently ran a race in Pogosa Springs Co. it was 150 miles. I ran wide open and 2650rpms, I controlled the chts with fuel and never went over 390. The oil peaked at 210, I averaged 254 mph. I do not have ney nossils nor a Plenum just a tight stock RV baffling system. I expect lower CHTS once I build a nose gear door for the bottom cowl opening that has to be upsetting the exit air from the strut opening. I also see a plenum in the future as I clean-up cooling drag that might allow me to close down inlet and exit air. But for now My cooling is fine

 

Lycon warns not to go over 400 for break-in. Doing so puts you at great risk of glazing the cylinders and annealing the rings, which will cause blow-by, burning oil. Thus causing the cylinders to run hotter. This is what I would suspect is your results.

 

Splitting the case and installing Ney nossils is not the answer in my opion. If your baffling system is correctly done with 4" inlets and adequate exit air you should not have a problem, just control the heat on climb out,if you install ney nossils it may help but its the wrong band-aid at a high price.

 

It sounds to me that you will need to re-ring and hone the cylinders and try the break-in again. Fall is here and cooler outside temps will aid in the break-in just remember do not go over 400 on the break-in.

 

 

 

steve alderman   25SA   360

 

-----Original Message-----
From: N20087 <n20087@yahoo.com>
To: lml <lml@lancaironline.net>
Sent: Sun, Oct 7, 2012 10:34 am
Subject: [LML] Piston oil cooling jets

> Folks

This is addressed to the hard core engine experts on the forum.  I would love 
your feedback on this 

I am considering having my io360 crankcase modified so that I can install piston 
cooling jets which are standard in 200hp engines.  The reason being, I have had 
to take aircraft out of service twice, once at 80 hrs and now at 160 due to 
lousy break-in and high CHTs. I have done all the obvious stuff such as plenum, 
timing, plugs, flowed the fuel servo to the rich side, baffles etc.. I am 
running 9:1 eci cerminil cylinders and they will hit 430 on climb out.  They 
went to 450 twice in the initial break-in. They will run 370 in 75% cruise and 
340 lop

All this aside, the pistons at 80 hrs (both times) were coated in dark varnish 
under the crown and the top of the crowns were heavily carbonized from oil 
blowback

I am just getting tired of it and don't want to pul the engine apart again 
anytime soon after this downturn

So,,,I am wondering if anybody has any experience or data concerning the cooling 
benefits of the piston oil nozzles.  Ie is it 5 degrees or 20+

Also, I am debating whether to split the crankcase myself or take the closed 
case (jugs and every accessory removed) with con rods still attached to the 
local shop and have them split the case, do the machining and reassemble.  The 
shop is very very reputable but of course the cost will be higher if I get them 
to do the breakdown and reassembly 

As another cooling remediation measure I was thinking of opening up the cowl 
inlets to 4 inches but a little reluctant due to the increased drag and limited 
benefit.  I added an electric cowl flap by the way and achieved only a 2 degree 
CHT improvement in climb at 130 knots Go figure!

Again, any feedback on my plan here would appreciated 

Thanks in advance 

Tom 



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