Re: Olympic .15 Disc Valve Engine?

Jason_WI Wed Jan 30, 2019 1:07 am

Forgot to post a pic of the disc valve engine cleaned up. Not sure what can be done with the tool marks on the head. I have a MECOA .15 head adapter ordered as well as the NVA. I can turn the fins off on that to match the turned down cylinder.

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getback Wed Jan 30, 2019 8:02 am

Jason you going to try and run it with the crank pin the way it is ?

GallopingGhostler Wed Jan 30, 2019 9:26 am

Jason_WI wrote:Forgot to post a pic of the disc valve engine cleaned up. Not sure what can be done with the tool marks on the head. I have a MECOA .15 head adapter ordered as well as the NVA. I can turn the fins off on that to match the turned down cylinder.

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Simplest solution would be to straighten fins, then gently file off the burrs both top and bottom of the tool nicks with a fine file. It won't completely remove the damage but it will clean it up to a point more acceptable.

I've done that to a few engines and it is amazing how much better they looked after a little burr removal clean up.

Jason_WI Mon Feb 04, 2019 7:37 pm

The K&B racing needle came in. It fit perfectly in the threads. Do I need to add shims to have the NVA halves moved out to open up the venturi? With them turned in it blocks airflow which will probably affect performance. There is also a small threaded hole in the top of the venturi body. Was this used as a flood off control? I can block it off with a short screw. I don’t think is was an air bleed since this is a fully open venturi.

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**Cribbs74** Tue Feb 05, 2019 11:12 am

I would space it out better. Not sure what the little hole is for. Run it open and run it blocked off and see if one is better than another. Honestly though any increase in airflow that little hole provides can just be compensated with the needle.

Jason_WI Wed Feb 06, 2019 10:42 pm

I picked up a small spool of POM filament. This is basically Delrin which is what the Cox carb bodies were made of. I don’t hold much hope as this stuff likes to warp. I’ll give it a try over the weekend.

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**Cribbs74** Wed Feb 06, 2019 11:49 pm

Fingers crossed. Hope it wasn’t too expensive.

GallopingGhostler Wed Feb 06, 2019 11:50 pm

NVA is two piece similar to some of the A.C. Gilbert NVA's. For those, the 1 piece was preferred over the two piece as being easier to adjust and more reliable feed. Given the design of the NVA, could it be that this was intended for a bladder pressure setup?

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