Purge Time for a 1984 Ford F-250 6.9l IDI

[mankypro]

I do not have looped returns. I recently plumbed in a vinyl 3/8 return hose for a few inches off my IP to accurately gauge my purge times. I waited till my engine was at operating temps and my oil was at about 160 degrees F.

I clicked my stopwatch when I hit the fuel tank selector. It took 2:58 exactly for the return fuel from the IP to be 100% #2. This was idling at 850rpm. I assume at 2k rpm this purge would take half the time.

So anyway. I wanted to post it here as I've scoured the 'Net for months trying to find out what a reasonable amount of time to purge at idle was. Now I can use a turbo timer to have the engine idle for 3-4 minutes at keyout to purge without me being there....

 

[hheynow]

I recently plumbed in a vinyl 3/8 return hose for a few inches off my IP to accurately gauge my purge times. I waited till my engine was at operating temps and my oil was at about 160 degrees F.

Returned fuel is hot. Can the vinyl handle such heat?
What a friggin' mess when it melts or bursts!

 

[mankypro]

It was simply a measure to accurately determine the purge times. It would seem to be holding up quite well, so far it has not been subjected to temps above 170F - but I do plan on replumbing it with fuel injection line in the next day or so.

 

[gonecrazyi]

Are all your fuel lines in the stock location, I assume that your returning a small amount of oil to the diesel tank when switching over.

Ive got my front tank out to put heater lines in it and plan on running new rubber hose and looping the return line back in before the selector valve. Would it be better to loop it before the fuel pump or back by the valve?

A mechanic friend of mine is replacing a mercedes motor in one of those new dodge sprinter vans. The guy was running 100% wvo and was heating it correctly with two fuel systems and seperate filters and tanks. To make a long story short, he fried his motor and is has been through 2 replacements(locked up within 12 miles on diesel).

Im waiting to see if hes going to continue running this setup, if not he might be giving me his tank, selector valve, filters, and fuel pumps. I might hang on to them and convert my truck over to electric pumps in the future.

 

[mankypro]

I've been told to loop the veg returns behind the pollack, although I don't as I reach acceptable temps without it. I go through enough #2 on short drives that I replenish my #2 tanks at least twice a month, so I'm not worried about x contamination, supposedly a small amount of veg in the #2 is good for lubricity. My powertrain is meticulously maintained and I'm fairly sure my engine is fairly young based on blowby and just the way it acts. I change my crankcase oil every 3k, I've replaced 80% of all my wear parts. I've replaced ALL my flexible fuel lines with 30R9 FI line. I think many folks expect to purchase an old benz for 1200 and start pouring veg into it without doing much to it.

I've seen #2 pumps in Montana that say "10% soybean oil" on them and this was at truck stops. So far so good.

 

[TWeatherford]

I have a different conversion than you, and my purge time is about 2 minutes. I have full return to tank for both fuels, during purge fuel is returned to the vegoil tank. It is my fourth conversion, so I knew to keep the common fuel lines as short as possible to cut down on the purge time (which is a bit hard to do with the location of the stock lift pump). I am fairly unhappy with a 2 minute purge, I usually am driving while I purge so I estimate it to be 1 1/2 minutes with a higher engine speed and call it good. I'd love 20 seconds like on my old Mercedes or 30 like on the Dodge, but I guess these motors just don't move that much fuel. I'd love a turbo timer to do the whole thing too but with a 5 spd and Ford's crummy parking brake I can't just walk away.

 

[mankypro]

Is your FSV stock? Sounds like it isn't? Separate filters?

I've considered going for a second heated filter for oil and using a 3 port to redirect my returns to the appropriate tank with a toggle on the dash.

I have a different conversion than you, and my purge time is about 2 minutes. I have full return to tank for both fuels, during purge fuel is returned to the vegoil tank. It is my fourth conversion, so I knew to keep the common fuel lines as short as possible to cut down on the purge time (which is a bit hard to do with the location of the stock lift pump). I am fairly unhappy with a 2 minute purge, I usually am driving while I purge so I estimate it to be 1 1/2 minutes with a higher engine speed and call it good. I'd love 20 seconds like on my old Mercedes or 30 like on the Dodge, but I guess these motors just don't move that much fuel. I'd love a turbo timer to do the whole thing too but with a 5 spd and Ford's crummy parking brake I can't just walk away.

 

[TWeatherford]

I have two separate filters and two three way Hydraforce valves. I would expect a longer purge time than what you posted with the stock fuel selector valve cause, but maybe not.

 

[mankypro]

I have two separate filters and two three way Hydraforce valves. I would expect a longer purge time than what you posted with the stock fuel selector valve cause, but maybe not.

I certainly expected it to be longer, alas 'tis not. I'm timed it several times, so much so I'm about to replumb the line with fuel injector line, now that the test is done.

 

[gonecrazyi]

Im planning on running my rear tank on diesel and the front on oil but seeing that the rear is bigger, I might change this. I was aslo planning on installing a third tank for vegetable oil at some point in time.

Is it easier to heat a metal tank or a plastic tank? My rear one is a 38gal aftermarket that leaves very little room on the top of the tank for hoses but has plenty of room on the sides. I was going to use some stainless steel bent piping that I pulled from some medical equipment to heat the tank.

Also, are you heating the tank and the fuel lines or just heating it at the motor?

So far Ive run over 100 gallons of wvo without heating it, but usually mixed it 50/50 when it was over 90 degrees out. But I want to it right so that I dont fry another fuel pump if the temps dip quickly again.

 

[mankypro]

the trick is to use a heated pickup, trying to heat 38 gallons of fuel is a fool's errand. I use an Arctic Fox HotFox.

 

[gonecrazyi]

How much did that little device run ya?

 

[mankypro]

I think I paid something like $160.00 for it.

 

[gonecrazyi]

Thats not to bad, I was thinking about doing something like that with what I have, except I was going to bend some stainless pickup lines around the stainless heater pipes that I have.

I might do little more research before committing though.


would you suggest using the plastic tank or the smaller metal tank?
Which one would be easier to seal?

 

[mankypro]

My WVO/WMO tank is a 45 gallon aftermarket by aerotanks, takes the place of the spare and oem 19 gallon rear tank. I don't know anything about the plastic tanks. I've heard with WVO aluminum is the way to go.

Thats not to bad, I was thinking about doing something like that with what I have, except I was going to bend some stainless pickup lines around the stainless heater pipes that I have.

I might do little more research before committing though.


would you suggest using the plastic tank or the smaller metal tank?
Which one would be easier to seal?