Rotor Beveling engine builder discussions
 

Sorry for cross posting this but I think I had it in the wrong section before.

Looking to chat with other builders about experience and thoughts on rotor beveling.

I have been playing with this and sacrificing port timing changes and using the rotors to adjust the advance and or closing times to some degree.

The porting itself tends to be more time consuming and more costly doing this. But the results seem to be far more drastic then just adjusting the porting on the iron. I feel like I have been getting a more aggressive sounding and more responsive overlap by milling the rotors. Throttle response also seems good.

Does anyone have some input or experience perhaps learned information on this particular method.

I have been testing several styles over the past 8 months or so. I posted pics of the latest variance I am running right now. I have tried more of the RX8 and differing angles and so far this one is by far the most promonet I have assembled. They are not CNC'ed yet I have been doing them by hand. I have not figured out how far I can go yet but I also have not dug into a bad rotor to find out, also afraid of making the side seal support to thin.

https://www.rx7club.com/attachment.p...3&d=1237952134
https://www.rx7club.com/attachment.p...2&d=1237952134

congrats for making something new... of course it isn't new... Carlos has been doing them for a while and probably he isn't the first.

i spent some time recently considering the bevel deal and was about to take a set to my local CNC guy but the thing that stopped me was compression.

it seems to me that the total additional volume from the bevels will work against compression. sort of another set of combustion chambers.

what do you think?

howard

Approximately how much weight do you think you removed from each rotor?
I am I correct in assuming you had the counter weights rebalanced to compensate?

I don't think going to thin on the front could affect the side seal, seeing as the back is where the most support is.

Looks good so far!

it does lower compression, but by how much, and does it matter @20psi?

it could upset combustion too, but you'd prolly have to go nuts with it

800grams or so per rotor and yes they were rebalanced. Not really sure on compression possible minute amount but theres no compression numbers to go by one build to another can yield entirely different results.. I have just been documenting performance and effects compared to adjusting on the port itself that why I have this thread to speak with other builders who also have experience doing this. The usage is slim most builders stay away from uncharted territory and I like living a little bit different.

Do you mind sharing what you have found so far? Wish I could help but I stick with templates.

I will at some point. I would like to wait till other builders who are doing this can state some of there knowledge and start a discussion. I would rather not be wrong and give out ill information when all aspects could simply be discussed out before hand.

IT would be really great to start moving my beveling into CNC phase and be able to give people a sound product I believe in. Bringing this out of RND stage is something I am looking forward to.

One thing to be aware of, basically straight from the mouth of my 4th year mechanical engineering student buddy.

"Corners and edges in metal in combustion chambers and similar will always tend to be hot spots. It is because of the ratio is surface area to metal sinking out the heat."

This is probably something you don't want inside the combustion chamber, and is probably is the reason why there are very shallow angles on the area where the bathtub meets the rotor face.

if those bevels do lower compression too much, you could just offset that loss by starting with a set of S5 N/A rotors wich have a smaller dish and higher compression to start with.

Shhhhhhhhh

that's a secret? lol

There is a great there here from a few years ago. I wish it had pictures, but you can read what Carlos Lopez of CLR states. IMO, his rotors *look* very impressive with the CNC work. I find this information that he provides to be very intriguing as well. Take a read:
https://www.rx7club.com/showthread.p...ighlight=rotor

-Chris