I agree but also
I would also suggest looking at your fuel flow, in other words is your main jet large enough? The way to find out is to start leaning (after reducing power to less than 75%). At 3000' you should see at least a 150F rise in EGT before the first cylinder reaches peak EGT and starts to cool. At 8000' try again at WOT and note the EGT rise from full rich before the 1st cylinder peaks.
I believe the lean main jet size is 0.097". Larger main jets are available - or some suggest carefully drilling out one number drill size at a time. I have heard of people going to +0.007" (ie main jet = 0.104") with a significant (20 or 30F) reduction in climb CHTs.
At the same time I would check and check again that your plenum is doing what you think, are there any holes, and are all CHTs roughly equal - within 20 or 30F? Are your CHT probes calibrated?
I have louvres in my hangar and have not yet fitted them to my 6A (O-320 regular cowl). Every time I get close someone else pipes up and says don't install louvres, improve the baffling. I'm not sure that you lose very much installing louvres so they might be going in this winter!
Pete
Pete, you are right and good info but my RV-6 would pass the lean test while flying but failed miserably in the climb.!
I've found out the hard way the 0-360 A1A with the 10-3878 carb is too lean on takeoff for proper cooling. This was after glassing in the ramps and trimming the bottom of the cowling and sealing my baffels and cleaning cast flashing from my cylinder head cooling fins and setting timing and measuring inlet and outlet sizes, etc etc.
Van's should address this, but he doesn't for some reason.
The carb set up passes the lean rich test in flight and that is where Precision would stop blaming the induction setup and
start telling guys it is a airflow problem if you are overheating.
Look at
AVWeb.......Pelican Perch ........John Deakin
Where should I run my engine Part #1 #2 and #3,
print them out and read them.......very good info.
I cut and pasted a few critical paragraphs for you to get the idea of what he is teaching.
Part #1 link herehttp://www.avweb.com/news/pelican/182179-1.htmlIf you take nothing else from this column, pay attention to that statement. That fuel flow is vital for cooling, and that redline is a minimum, not a maximum. The vast majority of all these engines are set too lean by the manufacturer's recommendation! Almost all mechanics will resist this idea, and they seem to think that if the book specifies a fuel flow redline, then a little less than redline is somehow "better." If you cannot get your mechanic to set this up properly, find a mechanic who will. If your full-power fuel flow is a bit over redline, so much the better! You can always manually lean it back to redline if you wish, but you can't do much with a fuel flow that is less than redline. Even half a gallon per hour can make a large difference in CHTs right after takeoff, and during climb. Normal climb CHT in a well-baffled normally aspirated engine is around 330?F at full power and sea level, at any decent climb airspeed. CHT might be higher if you insist on low climb airspeeds. If you see higher CHTs on your engine monitor, your fuel flow is too low. A lot of these fuel flow indicators are not very accurate at all, and most are not even true fuel flow gauges at all. They're pressure gauges, marked in flow. We really like digital fuel flow systems that have been calibrated by actual tests for this reason. If your redline is 27.0 GPH, and you get only 26.5, have it set higher.
Part #2 link here:http://www.avweb.com/news/pelican/182176-1.html
I will also repeat from the previous column, YOU MUST BE GETTING FULL REDLINE FUEL FLOW at full takeoff power AT SEA LEVEL! In truth, the factory redlines are often a bit on the low side, and flows should be tweaked up just a bit. Even a half-gallon per hour makes a BIG difference in CHTs during climb.
In general, and speaking very roughly, if you see EGTs anywhere over about 1,300?F (lower will not hurt a thing and is probably ?better?) during a sea-level takeoff, or CHTs above about 360?F right after takeoff, YOUR FUEL FLOW IS TOO LOW. Having a good understanding of the proper relationship between the EGTs and the fuel flow at very rich mixture settings will always give you a good cross-check on whether or not you are getting adequate fuel flow -- even if your fuel flow needle breaks off and falls to the bottom of the instrument!
If your fuel flow is too low on takeoff, don't let your mechanic talk you out of setting it up a bit, and if necessary, find a mechanic who will do it. VERY few mechanics understand the importance of this. Far too many mechanics consider the fuel flow redline a maximum, and they consider a little bit less as "good," or "better for the engine," thinking they are being "conservative." After all, we all like to stay a little bit (or a lot) away from all sorts of redlines, right? That fuel flow redline is a MINIMUM, not a maximum. Treat it as such.
Part #3 link here:
http://www.avweb.com/news/pelican/182583-1.html
Again, read his articles to put everything in context.......
Good Luck.
