Technical > Spud Miller's Cave

Fuel System Protocol after the race

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denverflatheader:
Hi Spud, got a fuel question for you and would like to know how you handle with your setup.  I’ll be new user with fuel injection and nitro and was wondering what steps you take to put car away for a month or so until the next outing to protect your fi system.  Anything additional to do with the fuel system at the end of the season when the car will sit for 6-7 months?   What do you do with the leftover mixture of nitro and methanol (i.e. 25%)  Is it okay to save and if so, how long does it last?  I put new lines on too (see picture) how long do the braided lines last?  How do you check braided lines to verify they are okay?  Thank you for your time, DF 

Spud Miller:

 If you're running just methanol, you can leave the system alone over night for the next day of racing. Just fill the tank full and cap the vents. But when the weekend fun is over, you'll need to clean it out. We drain the tank, disconnect the pump inlet and outlet, and then blow all the fuel above the pump into the motor (open the barrel valve to empty it quick). Then, we'll squirt a shot of oil into the top of the pump (shut-off is open), into the hose leading to the barrel valve (then blow with a shot of air), and spin the motor with the plugs out. This gets the oil in everywhere. Lately, we've been using "AMS-Oil Engine Fogging oil" because it comes in a spray can and is easy. I then shoot some in each spark plug hole, and open the butterflies all the way and shoot some down each tube while spinning the motor over for another 10 seconds or so. Then we cap the disconnected hoses and ports off with plastic plugs.

 Because we run a high-percentage of nitro, we blow the fuel system into the motor and spin it out after every lap so none is ingested while starting the next time. Just a little bit of a high-percentage can blow up in your face. In fact, once we've spun it dry once, we squirt methanol into each spark plug hole to dilute anything left in there and then spin it dry again to be extra safe.

 As long as your jug is sealed and not seeing any sunlight, I think your mixed stuff is just fine. I always record the SG with a felt pen on the jug and I'd check it before running it to be sure it's where it was. If it's heavier, I'd pitch it. I wouldn't use anything with methanol in it that's more than a year old but I suppose the SG is the final word...if it's ok, then it's probably fine.

 I wouldn't use WD-40 because I've seen it turn to goo when exposed to methanol and left to sit. ATF is bad too because your o-rings will be the size of hoola-hoops if you take anything apart after they've been exposed to that. A really light machine oil or motor oil works great. I don't like Marvel Mystery oil for fuel pumps...just because it's a sticky mess to deal with if you have to disassemble one treated with that stuff.

 Braided lines aren't created equal, so it's hard to say when to replace them...since you can't see the rubber, you don't know if it's cracking or splitting inside. In a FED, a split hose can turn you into The Human Torch so I'd pressure test them when new and then once every season. You can pressure check them or send them out to be pressure checked. The official checking method is a "hydrastatic" test which means the hose must be full of fluid and then the pressure raised with a hand pump to test it's integrity. I know XRP sells such a tester. If you're making your own hoses, I would at least put a plug in one end and buy or make an air coupling fitting for the other end that will allow you to pressure test it with air. Putting air pressure to it is better than no check at all. You should test them with at least 150 PSI though (200 would be better) and a lot of air compressors don't go that high.

 Spud

GlennLever:

--- Quote from: Spud Miller on February 28, 2013, 06:24:33 PM ---
 If you're running just methanol, you can leave the system alone over night for the next day of racing. Just fill the tank full and cap the vents. But when the weekend fun is over, you'll need to clean it out. We drain the tank, disconnect the pump inlet and outlet, and then blow all the fuel above the pump into the motor (open the barrel valve to empty it quick). Then, we'll squirt a shot of oil into the top of the pump (shut-off is open), into the hose leading to the barrel valve (then blow with a shot of air), and spin the motor with the plugs out. This gets the oil in everywhere. Lately, we've been using "AMS-Oil Engine Fogging oil" because it comes in a spray can and is easy. I then shoot some in each spark plug hole, and open the butterflies all the way and shoot some down each tube while spinning the motor over for another 10 seconds or so. Then we cap the disconnected hoses and ports off with plastic plugs.

 Because we run a high-percentage of nitro, we blow the fuel system into the motor and spin it out after every lap so none is ingested while starting the next time. Just a little bit of a high-percentage can blow up in your face. In fact, once we've spun it dry once, we squirt methanol into each spark plug hole to dilute anything left in there and then spin it dry again to be extra safe.

 As long as your jug is sealed and not seeing any sunlight, I think your mixed stuff is just fine. I always record the SG with a felt pen on the jug and I'd check it before running it to be sure it's where it was. If it's heavier, I'd pitch it. I wouldn't use anything with methanol in it that's more than a year old but I suppose the SG is the final word...if it's ok, then it's probably fine.

 I wouldn't use WD-40 because I've seen it turn to goo when exposed to methanol and left to sit. ATF is bad too because your o-rings will be the size of hoola-hoops if you take anything apart after they've been exposed to that. A really light machine oil or motor oil works great. I don't like Marvel Mystery oil for fuel pumps...just because it's a sticky mess to deal with if you have to disassemble one treated with that stuff.

 Braided lines aren't created equal, so it's hard to say when to replace them...since you can't see the rubber, you don't know if it's cracking or splitting inside. In a FED, a split hose can turn you into The Human Torch so I'd pressure test them when new and then once every season. You can pressure check them or send them out to be pressure checked. The official checking method is a "hydrastatic" test which means the hose must be full of fluid and then the pressure raised with a hand pump to test it's integrity. I know XRP sells such a tester. If you're making your own hoses, I would at least put a plug in one end and buy or make an air coupling fitting for the other end that will allow you to pressure test it with air. Putting air pressure to it is better than no check at all. You should test them with at least 150 PSI though (200 would be better) and a lot of air compressors don't go that high.

 Spud

--- End quote ---

With an intro to the subject this would be a great article for the article section.

denverflatheader:
Spud – Thank you.  Concise details you provided, your experience and sharing with me, priceless.  Your answers way beyond my question (you’re gifted writer to explain so easily).  I read between the lines and understand your message.

One more picture of the car.  It’s fairly new owner/builder by a friend Bob from Denver, and his best friend Jerry from Castle Rock.  Another friend Wayne built engine and fi unit when he lived in Florida.  My part was easy, I just put the two together and going to have some fun with Bob’s car. 

Spud, I’ll be careful, thanks again.  Alan 

tylercrawford:
thanks for the great tips spud.

Alan, that motor looks great!

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