PRI-D and PRI-G Additives

[Langanobob]

I have numerous vehicles that aren't used all the time and I'm always looking for a better storage fuel treatment. I found PRI-G and PRI-D, but they do not seem to be very widely distributed. Does anyone here have any experience with them? Note: I did search the boards here and found nothing, and my apologies if there are already 50 threads on the topic.

PRI Website

Thanks,

Bob

 

[Donald]

Given that their products claim to "rejuvenate" stale gas, I would stay clear of them. No product can do that. They may indeed work well as a stabilizer, not sure, but I have wonder wonder if they make claims that are invalid.

Best to use (and at Walmart) are marine StaBil and Startron. Both blue in color.

 

[sdowney717]

I used some PRI-G on some 8 year old gasoline.
BUT, something to think about is old tanks with old gas means gums.
Gas oxidizes and makes gums.
So I added some PRI. The sticky gum layer sort of went away on the tank bottom.
Engine seems ok.
Now add some fresh E10 gas.
UH OH, MAJOR problems. Intake valves sticking. Injectors sticking, clogged up filters. Total disaster. Had to pull heads and do a valve job.
No more sticky gums on tankbottom, they are suspended in the fuel. I had hoped PRI would have helped dissolve the gums so they would not stick the valves, but it did not, especially after adding fresh E10 gas. then the destruction was complete.

I filtered and filtered with a 10 micron pump continually and got the tank and fuel looking clean, BUT still I got another stuck intake valve.

So, I have added marine stabil, 2 qts of MMO, 1 qt of ATF about 30 gallons of new premium gas and will see what happens. I am trying to use up 120 gallons of older gas.

 

[latenite]

Originally Posted By: sdowney717
I used some PRI-G on some 8 year old gasoline.
BUT, something to think about is old tanks with old gas means gums.
Gas oxidizes and makes gums.
So I added some PRI. The sticky gum layer sort of went away on the tank bottom.
Engine seems ok.
Now add some fresh E10 gas.
UH OH, MAJOR problems. Intake valves sticking. Injectors sticking, clogged up filters. Total disaster. Had to pull heads and do a valve job.
No more sticky gums on tankbottom, they are suspended in the fuel. I had hoped PRI would have helped dissolve the gums so they would not stick the valves, but it did not, especially after adding fresh E10 gas. then the destruction was complete.

I filtered and filtered with a 10 micron pump continually and got the tank and fuel looking clean, BUT still I got another stuck intake valve.

So, I have added marine stabil, 2 qts of MMO, 1 qt of ATF about 30 gallons of new premium gas and will see what happens. I am trying to use up 120 gallons of older gas.



I actually joined the site to reply to this. I have used PRI-G for quite a few years, and FP60 for much longer. When you have a lot of gum in the old fuel (what I would probably call varnish), we would always add toluene at 10% and dillute 50/50 with fresh gas, mixing the FP60 (and later PRI-G) into the new gas before adding it to the old gas (or vice versa -- the additives went in the new gas, toluene included). Even with very old gasoline (10-12 years, Houston summers and so forth) and old containers with old gas we never had a problem. The toluene and the 50/50 mix seemed to do it. Of course, toluene costs an arm and a leg now and it's easy for me to spend your money, but I have seen that work for 30 years. I really don't know what to say about the ATF that you added other than to suggest that any additional gas that you mix in should be premium because that ATF will probably lower your octane (I think).

As it is now, I would just mix what you have (the fuel combined with the MMO and ATF and so forth) with fresh premium gasoline at 50/50 and add 10% toluene on top of that (i.e., 10 gallons of the old gasoline mix, 10 gallons of fresh premium, and 2 gallons of toluene) and I would be surprised if you have any more sticking issues. But I would use it as fast as possible.

And to reply to the original poster, I have used PRI-G and PRI-D for years and have been happy with them. I have not found myself in the situation above, but I really think that the solution is toluene.

 

[snoboy]

So between these two (Pri-D or FP-60) which do you prefer and why? I've been using FP-60 but I was thinking of giving Pri-D a try.

 

[latenite]

Originally Posted By: snoboy
So between these two (Pri-D or FP-60) which do you prefer and why? I've been using FP-60 but I was thinking of giving Pri-D a try.


If the fuel will be sitting, PRI-G hands down. There's nothing like it. Otherwise (and what I use 99% of the time), FP+ (and I need to stop calling it FP60, it's been more than a year and age isn't that good of an excuse). So, for diesels, the same would apply just PRI-D and FP60.

Because I try to never let the tank go below 1/2 full, when I fill up and dump in PRI-G before a trip I have FP+ in already, so it has been years since I just used FP+ (or FP60 before this latest gallon).

Also, when I have seen people use PRI-D for the first time, if they have not been periodically dosing their fuel to clean out their top end you will see a lot of soot from the first tank. That does go away.

 

[snoboy]

the same would apply just PRI-D and FP60.
What if you HAD to pick only one for your diesel truck, which one would you choose?

 

[latenite]

Originally Posted By: snoboy
the same would apply just PRI-D and FP60.
What if you HAD to pick only one for your diesel truck, which one would you choose?



FP60, but I would not expect it to preserve the fuel or remove any existing carbon in the chambers that fast (although it will in time). If you are looking to add something at every fillup, I would use FP60. I did for decades, and now use FP+ and will continue to use it as long as I can get it.

That said, if you have to store fuel, I would use PRI-G/D, period.

 

[snoboy]

You use FP+ in your gas vehicles or in diesel vehicles? If you use it in diesel is it 1-5 or 1-10 rate?

 

[latenite]

Originally Posted By: snoboy
You use FP+ in your gas vehicles or in diesel vehicles? If you use it in diesel is it 1-5 or 1-10 rate?


Used to use FP60 in both with PRI-G or PRI-D as needed, now only have gas and switched to FP+ and only PRI-G as needed because I no longer needed commonality. Sorry about not being clear.

 

[snoboy]

Roger that.

 

[sdowney717]

Your likely correct on the toluene.
The price is out of sight on that stuff.

If I cant get it to work in the boat, I did find I can make it run in my fuel injected 94 Buick Wagon with the LT1 engine by diluting it 50-50 with fresh gas.
What typically happens with it in the car, is the fuel filter clogs up with a brown very fine sediment like substance. I take the filter off the car and back flush it, reinstall and it is good.

So since the boat has two 150 gallon tanks, I could pump old fuel into one tank, put fresh fuel in the other tank and pump back a small amount at a time to use it up.

It has not stuck a valve since adding the ATF, BUT not enough engine run time has gone by to really tell a difference.

 

[sdowney717]

This is what I had sitting on the tank bottom. Tanks are from 1970 MONEL, so you know a lot of gas deposited a lot of gum, and then adding E10 loosened it all up.

First filtering setup was suck the sludge off the tank bottom, pour into buckets.

Second filtering was running the fuel back and forth from tank to tank using these cartridge filters

Then I setup new filters on the boat using these WIX combined with the green fram cartridges on the suction lines
so for fuel flow it is tank, antisiphon valve, fram cartridge ccs1136, wix 24348, electric pump, an inline can filter, then carb

And bought these cheap on ebay for more filtering of the fuel.

the last ones are diesel, but used also for a few gasoline applications according to the app charts. I like these last ones, they have thick glass bowls and drains. The plastic drain could be replaced with a metal bolt. USCG likely would not like glass bowls in the engine room.

the ccs1136 are 4 micron
the wix 24348 is 10 micron
the cat filters are 10 micron

Are gums filterable? I have seen 2 micron filters used in diesel boats.

 

[latenite]

Wow. That's a lot of sludge. It looks like you are doing what I would do, less the toluene. I am not sure that I would introduce that stuff unmixed into any tank. In fact, I would try to move it to a clean tank (if you have that) and only put a 50/50 mix into the old tank to try to clean that out more gradually. I don't know if that's possible -- that's a lot of gasoline to move around.

I have always counted on the toluene with any shady gasoline, and I never had this sort of problem, or to this degree anyhow. Racor probably makes drop-in 2 micron filters for the CAT units that you have. They do work, many people use them downstream of a 10 micron filter. I don't know if it would help, but it absolutely won't hurt.

I have wondered as I have heard a lot of griping here around Houston after ethanol became required whether or not the problems that everyone with a small engine or boat seemed to have (almost immediately) were issues with the ethanol stirring things up, rather than rotting things, similar to the "false seal" problem that you have when you run bad oil for a long time and the seal dries out behind a wall of varnish. Remove the varnish with better motor oil, and suddenly the shrunken seal starts to leak. I wonder if what stirred this up was the E10 instead of the PRI-G. In that case, at least you know that when you are done with this fuel, that tank will probably be cleaned out.

 

[morris]

check out a co, B G proucts. they are here in wichita Ks. have NEVER heard any thing bad about them.

 

[sdowney717]

I found out the 90% rubbing alcohol dissolves varnishes gums etc... very very well. Wonder if you could inject alcohol into your intake along with gasoline to clean out an engine. Say on a carbed motor, you let it suck the alcohol in slowly thru a vacuum line as long as it runs, it will suck and burn the alcohol. Set it up with a 1 gallon container of alcohol to suck it up for a long time while it runs. Likely ethanol would also dissolve varnish. I think this idea is not the same as running E10, E15, E25 etc... since your adding additional alcohol, but not thru the existing fuel system. If you had a cheap source of alcohol, like made your oun, and did this in a MPFI engine, I think the computer will compensate by letting less gas thru the injectors and you would save on gasoline.