- Jan 13, 2011
- United States
It is the best 1 hour you can invest you your engine. On persistent climb I rarly breach 300f in cruise it settle around 240F +/- 15F I have climbed from 850fee to 6500 feet on a 95f OAT day and only my oil was reaching the limits.Personally, I would prefer to stack the deck in my favor where possible. It only takes a little elbow grease and time to open up the air passages around the exhaust ports, so why not?
I replied over on that thread and I should know better. There's a bunch of great folks over there and a few that live in a river in Egypt.I got a little push-back on the Sonex forum for this. "my AeroVee cools just fine after 500 hours, and I did nothing special".
While I respect experience, my aim is to eliminate as much risk as possible. I have heard enough horror stories over the last 35 years to confirm what my Sensei, Veeduber, told me: the heads must cool. And he gave me the tools to ensure they do. I miss the SoB...
I concur I learned much from Bob Hoover over 20 years and Pops is the closest thing we have to Bob on how to build out and care for a Aviation VW. I read everything he writes! Matching the airframe and the load to live within limits of a VW is the key many great single seater fly well on a 1834cc my higher stress 2276 does well on the Cygnet because it has allot of wing and fairly clean I get a solid 500-700ft/minute at 1230lbs. My cruise setting- is about 45hp and the heads are super cool I am blessed by a finely made baffle the original builder Zig Berzins made and use cool tins under the cylinders as the best weight trade off to be had. Many other 2 seaters put too much persistent stress on the VW requiring a much more rigerouse inspection and maintenance schedule and may be responsible for clouding perception of the VW aero engine. Used within it's limits, properly assembled from quality parts following established prop hub practices it is a known quantity that will reliable commit aviation.Pops is an excellent resource on here and has proven how to be a successful builder and flyer of VW powered aircraft. There are a number of threads on here about how to keep these things cool. Bottom line is that there is a limit to what one can expect from these engines. You can ask more than that but valve & head problems come with that.
And how is it running after 600 hours? 500 hours seems to be about the mean time valve problems start to crop up."my AeroVee cools just fine after 500 hours, and I did nothing special".
Probably a reasonable thing to do. VW had plenty of resources to test this. They put the head temp sender for their FI engines here:At one time it was recommend (by Great Plains IIRC) to use the head stud near the exhaust valve
The Veeduber we've been talking about had a set of (HVX) modifications that sought to put more oil near the exhaust valves. Only some of them can be done on a built engine though, and I'm not cracking my case just to do them.Could adding an oil jet over each exhaust valve stem help with removing heat on the hot side of the heads?
Some of the newer VW "Industrial engines" also have a CHT probe located in this position.