I hear they swelled, but less than the existing. If he was measuring diameter, it was about 7%. I haven't heard since. sjd
I got my Viton today, and everything fits the assembly. Here's a CAD mockup of the pump screen and pump: Image Unavailable, Please Login ...and test fit in tonight's setting sun. It fits perfectly. Image Unavailable, Please Login sjd
I didn't disconnect the pump from the hoses, so it made it super fiddly, but the pumps went right together. the bottom ring was a little tighter on the OD as the viton pad between the plastic and the pump pushed it open at the bottom: Image Unavailable, Please Login here's a view with both rings on: Image Unavailable, Please Login the bottom screen going on. The second one I put the top on first then the bottom, and it went a little easier. Some lube might have helped too, the sharp edge on the viton hung up going into the cup on both parts. Image Unavailable, Please Login Image Unavailable, Please Login Final fit together, and the return re-molded and spaced properly. I ziptied the two lines to keep the return loop from waving around. Image Unavailable, Please Login I ran out of time to fuel it and fire it up, as I changed out FPRs, too. sjd
Which Viton did you go with ? Some interesting test results here re. different specs of Viton http://www.dupontelastomers.com/autofocus/a3/af3.asp?article=stevensAltFuel This paper is a good comparison re. various elastomers https://bioenergykdf.net/system/files/Elastomer%20Compatibility%20to%20Gasoline%20Containing%20INtermediate%20Levels%20of%20Ethanol_Kass.pdf The fluorocarbons (like Viton) do very well.
It's a standard grade of FKM. Feels like Durometer 75. Seems pretty close to the mcmaster test pieces I made myself. I have a test piece of it in a jar of fuel with a sample of nylon from the clamp. There's been no swell and no change so far, per your document, it'll take 168 hours...I can't simulate the 40C. I'll check it from time to time and refresh the fuel occassionally. I'll post if there are any issues, this is an engineering experiment. Viton Type F seems to be the best for fully submerged parts. Type F is by far the best, and from my reading the hardest durometer and most durable. Did I request anything specific? no. It's a good solution, there are a couple things that I'd make changes to, and I have a supplier that's willing to make a few sets with type F. As a note, the grey electrical covers are swollen, but haven't shown any cracks or tears, and it's been two months. sjd
Runs. Drives. There's no different noise from the pumps. (I was worried that there would be less damping with the new setup and more pump noise....but nope) sjd
We can talk. I need to make a couple small tweaks to the model, and it's good to go. I have to do some analysis (basically looking at all the cars that use or could be converted), so that it's not absurdly expensive, I also don't want to be sitting on parts for the next 30 years. If you're interested, PM me, we can talk. sjd
I like that it is a pretty simply and effective solution. No need to get overly complicated. Great stuff Steve
Timeline/update: 2021: 1/15: test parts went in fuel 2/10: parts went in tank. fresh FPRs. I was so out of gas, I had to go get a 5 gallon can filled. I also had to do an ECU reset with the new FPRs in there. 2/12: fuel in test jar refreshed. still no change in nylon or viton parts. 2/15: added 7 gallons of Shell 93 (same as test jar) 3/1. +100 miles on the car. no hiccups. I think it runs better than it had. More to come. If you're interested in this solution, PM me, The big hurdle is having the viton cut. I need to do more than 1's and 2's. sjd