Applications: (US) Hummel Hummel Bird. The stud broke off flush with the case, and given that it was buried down in the cylinder fins, engine disassembly was required to fix it! . This head clearly has better air passages than anything else I've seen in the aftermarket world these days. As you can see, they were quite deformed, and there were even chunks of stainless sprinkled around the keeper area (captured by the keepers until now).
So what's even holding this thing in place? Applications: (UK) Taylor (John) Monoplane. KP4/02. O-63 - - {3.622 / 3.071 / 63.3} / {92 / 78 / 1037}. Please call to discuss. Besides that, the automotive Revmaster heads are very well made and about the same cost as the "other" brands, but the aircraft heads (with their special sparkplug machining) are about double the price of the automotive heads. The small-diameter part of the guide is only 2.125" long, so there's only 5/8" of surface area remaining for the guide to dissipate it's heat to the finned head. He told me to go look at the photos on the automotive website, since they were the same RM-049 heads for either application. KP4/00, 4/01, 4/02, 4/03, 4/05. I'd seen this before as a VW mechanic, and always junked them in response. Just for comparison, this is a Corvair head. All of this in a mere 50 hours of flying. This temperature difference was measured under the spark plug in both VW and Corvair engines, on all plugs, using the same thermocouples. And for the time being, my engine is single ignition anyway, and as long as I have a robust ignition system with dual power sources and independent switching, I think I have that covered. Here's the finished DRD 043 head, deflashed and cooling plate installed (hence the darkness in between the fins at the bottom of the photo). 4cyl; Great Plains 2180cc Direct Drive; 70hp@3400rpm, 76@3600 (TO); 1983-present; Wt = 168#. They can only be used in homebuilt aircraft that are certified in the "experimental category". I have found that Great Plains have done more research and development on the VW engine aero conversion than anyone else to make it the most reliable VW aero conversion engine available. So I called Joe Horvath at Revmaster and asked how his heads hold up with the large valves, and he said "they don't crack, not a problem...these are our own castings, and they are plenty thick enough to keep that from happening". The slot is for the factory installed bellows control rod that opens the Beetle's fan shroud flaps. My first clue that something was awry was how much filing I had to do on these stainless valves to get them to slide out the guide. Needless to say, the valve wobble in the guides was very excessive also, so no wonder the seats and valves were worn enough to yield low compressions...these valves were free to roam around as they pleased!
I NEVER had valve issues with either one of them. This development was carried out in conjunction with Liquid Cooled One, LLC and the firm is now offering liquid-cooled head kits for the 92mm bore Great Plains OL-133 and another version for a 94mm bore engine. By the way, be careful when putting CHT probes under the head nuts. O-102 - - {3.465 / 2.717 / 102.4} / {88 / 69 / 1679}. VW Type 1; Carbureted engine with single ignition; plans are for either a cut or complete crankcase, but kits are for a complete crankcase only. They have extended their development of VW engines by converting to drive from the rear of VW engines and also have worked since 1999 with Valley Engineering so that they now sell Valley cog-belt-driven Propeller Speed Reduction Units (PSRU). Return to Mark Langford's KR2S N56ML. New 2276cc turn key engine.
Octane requirements will vary with compression ratio as will horsepower output. Applications: None found. So what's even holding this thing in place? I NEVER had valve issues with either one of them. I immediately went to the source everybody swears by, Revmaster, and ordered a pair of their RM-049 heads from the automotive side, rather than from the aircraft side, because I'm skeptical of the second set of plug wires coming through the valve covers. What else could it be? The above weights are for engines that include the Diehl Accessory Case package, intake manifold, Slick ignition system and oil cooler. Applications: (Australia) Corby Starlet. O-127 - - {3.622 / 3.071 / 126.6} / {92 / 78 / 2074}.
It's as if the valves had been running very hot, lost their temper, and had deformed. I'm pretty sure these valves should be up to the task, as they are 21-4N stainless steel with chromed stems and hardened tips (made by HPC in Las Vegas).
When I bought it, N891JF's 2180cc engine logbook chronicled: After the engine spun a bearing just a few hours after I bought it, I rebuilt the 2180 on N891JF, and found a crack between all four pairs of valves. The guides were still in great shape, as these heads only had 120 hours on them. The initial Great Plains VW Type 1 conversions were direct front drive (off the pulley end of the engine).
KP4/00, 4/01, 4/02, 4/03, 4/05. KP4/00, 4/01, 4/02, 4/03, 4/05. After seeing that photo, I was not impressed that the passages are much better than what has become normal for VW head castings, although the castings are clearly not stock VW derived.
Octane requirements will vary with compression ratio as will horsepower output. Complete, plug and play ready to fit.
This is especially true of the big-valve heads, where the distance between the two valve seats is just a few mm. All of this in a mere 50 hours of flying. Same bore as O-63, O-112, O-127. The condition of the valves was not stellar either...after only 50 hours in the engine in brand new heads! (US) Evans VP-1 Volksplane; Flaglor Sky Scooter; Monnett Sonerai I; Parker (Calvin) Teenie Two; Pazmany PL-4A; T.E.A.M. Applications: (US) Great Plains Easy Eagle; Monnett Sonerai I, II. O-144 - - {4.055 / 2.795 / 144.4} / {103 / 71 / 2366}. I don't skimp on exhaust valves, but the next step up is titanium! After I removed the guides, I could see that they were deliberately counterbored by a special stepped cutter, apparently in an effort to minimize the effect of the angled port. Applications: None found. The information here has been obtained from the references below and the Great Plains Website. . How about a gap around the valve guides between the boss material. My first clue that something was awry was how much filing I had to do on these stainless valves to get them to slide out the guide. While I had him on the phone, I asked if he'd ever seen a cracked valve guide. (US) Avid Flyer; Fisher Youngster V; Monnett Sonerai I, II L, II LS, II LT, II LTS; Preceptor Ultra Pup; Rand Robinson KR-1, KR-2, KR-2S; SkyStar KitFox Classic 3, IV; Slipstream Industries Dragonfly; Sonex Ltd. Sonex. OK, so it's time for new heads...AGAIN! 4cyl; Great Plains 2300cc; 76hp@3400rpm, 80@3600 (TO); 1983-present; Wt = N/A. Besides that, the automotive Revmaster heads are very well made and about the same cost as the "other" brands, but the aircraft heads (with their special sparkplug machining) are about double the price of the automotive heads. Given the overall quality of these castings, I'm going to ASSume that they wouldn't install crappy seats in an otherwise decent looking head, so I ordered a pair, especially after seeing a photo that DRD provided. Above is a MOFOCO 040 head.
50-80 hp . I'd never seen this before either, and immediately wondered how the guide was supposed to get support from the head, and more importantly, how was it supposed to dissipate heat with nothing but an air gap between the guide and the aluminum??