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Engine basics => Engine set up tips => Topic started by: Rob Killick on July 24, 2008, 03:48:42 PM
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Hi ,
I'm wondering if converting my Fox .35's to an ABC piston and liner will allow me to change the type of fuel mix , from a high castor content to an option of a synth/castor blend ?
I ask this , due to the fact that I live in an area where there I have difficulty finding a fuel that suits the iron P/L combo (the best I can do is PowerMaster 5%to 10% nitro and 18% lube) . According to the can label the fuel contains more synth lube than castor , but the label doesn't specify the separate %'s of lube . I know I can supplement castor content .
Any comments would be greatly appreciated y1
Thanks in advance ,
Rob K.
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Simply put, yes. The conversion WILL tolerate some blend more so thasn the straight steel iron set up. Keep in mind though that the Fox Stunt 35 is still woefully short on cooling fins and depends on the castor to carry out a lot of the heat. Synthetics do not do as good of job of carrying out heat as castor does. I would try to stay around the 25% to 29% total oil with as much of it castor as is possible and reasonable.
fox Mfg has discontinued making the ABC set-up for their Stunt 35 and have gone to the Ceramic type set-up. The ceramic (in my opinion) is even more tolerant of oil blends than avan the ABCs.
At the last contact that I had with the Fox factory, they were waiting for another shipment of Stunt 35 Ceramic P & L assemblies.
With the 18% lube, you can pour off 16oz of the mix from a gallon of the fuel and add back 16 oz of straight castor and come up with 28% total oil in the gallon. Save the 16 ozs you poured off and when you have used up a pint from the gallon pour the pint back in and add two (2) more ozs of castor and you will still ba fine and not waste anything. That way will also reduce the nitro % a little--- about 0.6%. Not enough to notice probably If your hobby shop carries the fuel in a 10 % nitro mix, That might be a better fuel for your fox (after the oil addition)
If I can be of further help , just holler.
Bigiron
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Hi Marvin ,
Thanks for the info :D
I tried getting a ceramic P/L from RSM , but was told that the liners were warped from the factory , so the P/L's will be a while .
I'm strongly considering purchasing this type of piston and liner set up .
Again , thank you very much for the input .
All the best ,
Rob Killick
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Rob, at the recommendation of Bigiron we're using the ceramic p/l set-up...outstanding! Smoothest running Fox 35's I've seen, nice power, very consistent. If you're a Fox 35 fan, worth the effort. If you're not...oh, well!
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Hi bill ,
When you say "the smoothest running" , do you mean with a Randy Smith CNC crank and hemi head ?
Thanks for the input ,
Rob Killick
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Rob, did you get the information about the ceramic cylinders being warped from the factory or some other source ? I haven't heard that. What I heard was that they were having trouble getting good consistant ceramic coatings. Not that my information is any better or comes from a better source than yours.--- Just curious. I have purchased ten of the ceramic P & C assemblies, and none are warped.
Bigiron
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Rob, we do use the Randy crank & head on other Fox 35's, but just so happens that the ceramic p/l ones are otherwise "stock". Bigiron says the ceramic ones are very light, so I'm guessing that helps with the "smooth" run...at some point we will set one up with all the "goodies", and see how good a Fox 35 can run! By the way, our info says the quality control issues on the Fox ceramic p/l was over a year ago, all fixed now!
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[quote run...at some point we will set one up with all the "goodies", and see how good a Fox 35 can run!
Bill, I have already done that and was surprised. Try it yourself and mount the engine both ways---upright AND sidewinder. Let me know what you find and we can compare notes.
Bigiron
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In Philly we run the foxes on 22% (50/50) 5% and 10% Powermaster. Year after year. They run powerfully without wearing out. Must be our proximity to the cooling waters of the Delaware.
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If you don't do the p/l conversion what would be the fuel formula to bring it to suitable castor standards? Thanks.
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I think part of the problem with running less oil with the Fox 35 stunt is the crankpin-rod connection. I have seen problems with twisting the crank pin off when running hard and not using much oil. Fox Missle Mist would ruin a stunt 35 in short order. Course it only had 18% caster.
Hothandle