J

John Courte

Well Known Member
Got a line on an O-360-A1F6, which is the 180hp A1A but with the counterweighted crank. This specific combo isn't addressed in the Hartzell chart of tested combinations, but I actually have two questions: One, is this engine, with its front-mount governor, suitable for the RV-7, and two, will it swing that prop safely? This is further complicated by the fact that there's no carb on this engine, so I'd put an Ellison TBI or Precision Silverhawk system on it. The core alone is worth the asking price, so if it's at all viable, I'm going to do it. Anyone know of any obvious non-starters with this engine/prop combination?

cheers,
-John
 
A1F6

Find an A&P or Tech Counselor and ask them to look up the TCDS or Type Certificate Data Sheet for both the engine and prop and see if they are able to be used together. You may be able to do this on-line. Before you opt for the Ellison or the Silverhawk, check with Don Rivera at Airflow Performance dot Com. He advertises on this site. No connection, just a satisfied customer.
 
ACtually, I messed up. It's a F1A6, not an A1F6. Does that one have a rear-facing intake like the C1x series, and is it even compatible with our planes?

Argh. So many things to find out. Thanks for the reminder on the crank AD, I totally forgot about that one.
 
I have a similar combination. I have the C case with the front governor and counterweight crank. The counterweight crank gets rid of all the RPM restrictions and the front governor sure makes for a lot less clutter in the back of the engine. I put an M sump with forward facing AFP FI. This is a very smooth combination and fits in the 7 just great. Don
 
It should work but I do believe that you need a different sump. The sump on the F1A6 is not compatible with the RV's. Everything else about it is fine. I would love to have a counterweighted crank, as it eliminates most rpm restrictions that are placed on non counterweighted versions wich most of us are flying. If you plan on flying aerobatics however, I probably would not recomend this engine as fast throttle changes can cause damage to counterweighted engines. Good Luck.
 
Thanks for all the info.. I did look up the TCDS on my prop, and although the 7496 BF blade wasn't listed, my hub was, and sure enough, there are no rpm restrictions for the F1A6 engine. So I bought it. It had 951 hours when it was pulled from a C172 RG, ran well, had good compression (77-78 on all 4) and was, as far as I know, stored properly afterwards. With a FI system and a new sump/tube setup, assuming the inspection doesn't find any showstoppers, I might be able to get this whole thing done for not much more than the core value of the motor, $12,700. If it needs a full-on rebuild, then I've just graduated to the price of a 180hp lyclone. Based on information from the seller, it doesn't have the crankshaft AD either, which is a plus.

Rapidly approaching the stage where all the parts in my barn will make a flying airplane if they're assembled correctly.
 
Jarvis, when you say "aerobatics," would you say no aerobatics whatsoever, or would aileron rolls, loops, spins, and immelmanns be OK? The mission is primarily cross-country cruising and local hops, but I'd like to be able to do a few maneuvers that are well inside the performance envelope of the design. I did read somewhere that the counterweighted engines are more sensitive to overspeed conditions, but I haven't actually found a good source for info on my particular combo, other than sifting through the TCDS's. And VAF, of course.

I'm now leaning towards the AFP or Silverhawk FI system, although the Ellison is still an option.

Again, I really appreciate all the info, as I seem to be revealing new layers of ignorance with each thing learned and each step taken.
 
John, Smooth gentleman aerobatics with no abrupt power changes are fine with a counterweight crank. Go with the AFP fuel injection. Very high quality and great service. Don
 
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