Liney RV-2 first run
- Thread starter Sshire
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Help Support Home Model Engine Machinist Forum:
I always ask these questions, since I have the drawings, and may try building this engine:
Any trouble working off the drawings?
Did you build the engine as designed, or did you make some changes? If yes, what changes did you make?
Just asking. Beautiful engine, great video. Congrat's.
Frank
Any trouble working off the drawings?
Did you build the engine as designed, or did you make some changes? If yes, what changes did you make?
Just asking. Beautiful engine, great video. Congrat's.
Frank
Very cool! Congrats!
Sshire
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Thanks, guys. Much appreciated.
The build (unlike most of my others) followed the plans. For the most part the plans are fine with no errors, but I did find some things that could have been better. The crankcase, IIRC, has some holes drilled with a #50 drill, but no mention of tapping. Since anytime I see a #50 hole, it's the tap drill size for a 2-56 thread. I emailed Doug at Liney and he confirmed this.
There was also no indication about fixing the pipes, which connect the heads to the manifolds. Solder? Press fit? Loctite? Again, an email to Doug confirmed that they are silver soldered at both the head and manifold ends.
Finally, no hints at all about a starting position of the rotary valve in relation to TDC for optimum timing. So, that was kind of a guess based on looking at the valve outside of the engine. I scribed a witness mark at the end of the valve to indicate one of the intake flats and used this to position it relative to TDC of the appropriate cylinders.
The actual first run didn't run. After much re-measuring, checking parts against plans and some single malt scotch, I found that one end of the valve block was 2 thou larger than the valve diameter. This, of course, caused air to leak back around the valve and resulted in air to prevent the exhaust stroke from happening. It appeared that the end of the valve block hole was bell-mouthed just enough to screw things up. Not sure how that happened since ,with brass, I use a drill a few sizes under the reamer that will follow it. Could have been a crappy drill bit. In any case, I remade the valve, and the engine ran perfectly.
One last tip that I got from a friend at MEM who built the RV2. The bearings are a FINGER PRESS into the holes in the crankcase. Don't use too small a hole and a bearing press. These Boca Bearings are beautifully and precisely made but will not function properly with a fit that is outside of their design tolerance.
Hope this helps
The build (unlike most of my others) followed the plans. For the most part the plans are fine with no errors, but I did find some things that could have been better. The crankcase, IIRC, has some holes drilled with a #50 drill, but no mention of tapping. Since anytime I see a #50 hole, it's the tap drill size for a 2-56 thread. I emailed Doug at Liney and he confirmed this.
There was also no indication about fixing the pipes, which connect the heads to the manifolds. Solder? Press fit? Loctite? Again, an email to Doug confirmed that they are silver soldered at both the head and manifold ends.
Finally, no hints at all about a starting position of the rotary valve in relation to TDC for optimum timing. So, that was kind of a guess based on looking at the valve outside of the engine. I scribed a witness mark at the end of the valve to indicate one of the intake flats and used this to position it relative to TDC of the appropriate cylinders.
The actual first run didn't run. After much re-measuring, checking parts against plans and some single malt scotch, I found that one end of the valve block was 2 thou larger than the valve diameter. This, of course, caused air to leak back around the valve and resulted in air to prevent the exhaust stroke from happening. It appeared that the end of the valve block hole was bell-mouthed just enough to screw things up. Not sure how that happened since ,with brass, I use a drill a few sizes under the reamer that will follow it. Could have been a crappy drill bit. In any case, I remade the valve, and the engine ran perfectly.
One last tip that I got from a friend at MEM who built the RV2. The bearings are a FINGER PRESS into the holes in the crankcase. Don't use too small a hole and a bearing press. These Boca Bearings are beautifully and precisely made but will not function properly with a fit that is outside of their design tolerance.
Hope this helps
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Looks and runs great Stan.
Heard by the grapevine that you are planning Elmer's cross twin as a next project. I built one some time ago and it is one of the most asked to see run engines in my collection. You will enjoy it.
Gail in NM
Heard by the grapevine that you are planning Elmer's cross twin as a next project. I built one some time ago and it is one of the most asked to see run engines in my collection. You will enjoy it.
Gail in NM
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