Hey Crist!  It looks just like mine!

On my SV 11 I used a Rev Up surplus 12-5 with the tips shaped and phillips entry.  On my USA-1 I used a Eather 12-4 3/4 cut to about 11 3/4, three blade.

Gonna start running my other new one soon.

BTW: I used Sig 25% all castor in mine as Tom suggested.  Never got it to run quite the same when I tried the Sig 1/2 and 1/2 oil. ()

AWESOME ENGINE!

Bill <><

What are the advantages of moving the NVA down into the crank case? I have one of these I want to send to Mr. Lay for rework but I'd prefer to not have the case drilled.

cheers,
Ken

Another way, needle installed in existing hole.

""""BTW: I used Sig 25% all castor in mine as Tom suggested.  Never got it to run quite the same when I tried the Sig 1/2 and 1/2 oil. ()"""

Hi Bill
The G51 is a steel sleeve ringed motor  it needs as I have stated many times 23 to 24 % oil content, they run very well on 1/2 synth 1/2 castor, but SIG Champion is  only 20 % total oil, I have built hundreds of these motors and can tell you that if you add 4% more oil to your Champion it will run very well for a long time, and  will keep the engine cleaner and will not  stick the ring from the castor build up.

If you want to boost the Champion up to about 24% total oil you will need to add  5.12 ounces of castor  to the gallon

Randy

Hi Crist

Not really true. it only matters where the fuel goes out in the air  not  where the needle is, In a true venturie instead of a restrictor, the fuel enters the atmosphere lower than where the needle is, so there is almost  zero differance as far as  where the tank is located. but you do loose the advantages of the true venturie and also you will have the disadvantage of having another hole drilled in the case , and you will have to make sure you completly seal the open holes that you leave when you drill the case.

Regards
Randy

Randy,
I answered the question in regards to a standard C/L motor from the Factory.  As you can see from the picture that the NVA is a further distance from the motor mounts.  Now compare the one Tom delivers.  As you can see the NVA is less distance from the motor mount.  We are not talking about true venturis and where the fuel enters the air stream.  In my examples, the fuel basically enters the air stream where the needle is (less the diameter of the spray bar which in this case are the same).  I still stand by my comment.  Using these two pictures as a basis.  With all due respect, please explain why I'm wrong using these pictures.

Randy,
I thought that's what you meant.  You had me going there for awhile.

All the best,

I flew my ex-Dirt G.51 with a stock type venturi with the spraybar mounted above the case, and then later with the T&L venturi setup, with the NV mounted in the case on centerline of the venturi bore. DID NOT have to adjust tank height at all, FYI. If you read the writings of both Rabe and Fancher, they both experimented with changing the spraybar height with NO CHANGE required in tank height.

When I added a sump to the bottom of my SV-11's 6 oz metal tank (holds 7 oz now), NO CHANGE in tank height was required. The engine "sees" only the outboard end of the uniflow tube, from what I've read. NO, I don't understand it either.  I'm hoping Howard will 'splain.
  Steve

PS: Why does auto-correct keep trying to change "venturi" to "venture"? Isn't "venturi" in the dictionary? Is this part of a plot to dumb-down America?

 

 I will add my two cents to the ST/51 problems. I bought two CL versions from Tower Years ago. Ran them with stock NV mounted in the tall tube added above the case. They were erratic at best and then the rings broke in both. They sat for years and last year when I had Frank make me some Double Star parts I ordered rings for them. Still erratic so on one I moved the needle down to the draw bar hole and made a sprinkler venturi for it. On the other one I drilled the case. Both now ran well, no longer erratic and now much more powerful. I put one in my 70oz Bearcat and it flew it easily.
 I believe most of the early problems came from the oddball venturi. One thing I found  my motors like a short venturi,one half inch works well with a .292 hole for the drilled case. It seems to me that a long venturi makes the motor RPM sensitive.
 Just my thought on what worked for me. I am looking forward to the Brian ABC P/L.    I am getting pretty old so I hope he doesn't take to long
EddyR