If your FPHE is downstream of the switch, you can avoid overheating the hardware. When warming up, it is heating whatever is in your primary tank (petro or biodiesel). You can switch to SVO before the FPHE output gets too hot anyway. The downside is that is shutting down. If the FPHE is past the switch, there is no way to avoid cooking your primary fuel. For me, this means I shut down on equal parts of 170F bio-petro-kero. No explosions yet. I'll keep my fingers crossed.

anyone know how bad high temp fuel actually is for a Pollak valve?
I vaguely remember a post or two linking high VO temps to Pollak failure
any more concrete info out there? (Pollak lit? heat-to-failure bench test?)

The pollak is rated for 180 degree temperatures, however I am not sure if that includes a factor of safety or not.

I actually have two 6 port pollaks in my system so I can maintain the stock configuration of the lift pump pushing through the filters. One is before my FPHE and should be fine, the other however is after and I think it will eventually need to be switched for 2 metal solenoids that can better take the temperatures.

Anybody know how the pollaks fail? Will it just start sucking air or will I start having the return sent to the wrong tank? Thanks.

quote:

Anybody know how the pollaks fail? Will it just start sucking air or will I start having the return sent to the wrong tank?

i feel the same way. with my first conversion i noticed i was using too much diesel but my return hose (being weaved plastic) allow me to see the fuel and it was golden brown. but my diesel fuel guage was dropping a little too much.

i have 3 port Pollack and i am also wondering the effects of their failure.

thanks , Evan

so FPHE pre-Pollak you fry the Pollak; post-Pollak you fry the IP with hot fuel (fuel lubes and cools the IP)
so either you replace your switching valve with more robust metal (suggestions for actual candidates?)
or do what John Galt suggests and install some kind of valve to restrict coolant flow through FPHE when switched to DSL
(John Galt, have you installed such a valve? can it be adjusted by the driver on the fly?)

I should think the IP would be able to work in 180F heat, seeing as the engine gets that hot anyway.

quote:

Originally posted by Mr Ryan Mix:
I should think the IP would be able to work in 180F heat, seeing as the engine gets that hot anyway.

yeah but
fuel actually moves pretty quick through the IP
most of it gets returned (only a little goes through the injectors)
my understanding is that the IP is designed to be both cooled and lubricated by diesel fuel
so even if the IP is 180° (or higher), it is designed to have a constant stream of ambient-temp fuel coming into it
as far as feeding hot VO into the IP goes, I would hope that what the VO lacks in cooling it more than makes up for in lubricity

quote:

Originally posted by Mr Ryan Mix:
I should think the IP would be able to work in 180F heat, seeing as the engine gets that hot anyway.

The IP can handle the temperature (the veg is around this temp going through there). The problem is sending hot diesel through it. Hot diesel looses it's already marginal lubricating properties. I would like my car to still be able to run on diesel for prolonged periods with out damage, so I don't heat the diesel. Plus the more components in the shared legs of the system the longer the purge time and more cross contamination.

I've been using the same Pollack 6 port for 3 years now, and it's always been directly downstream (about 6") from my Vegtherm 12V heater. I have never had a problem.

(The only problem I've ever had with a Pollack 6 port was with my dad's Mercedes, and teh issue there seemed to be more pressure/Vacuum related. The mech. pump was "dead-headed" against the Pollack when on vegoil. The car was always getting a bit of diesel, and teh problem worsened when the vegetable oil filter would start to get old and vacuum would increase)

Anyway, I certainly wouldn't hesitate to use a Pollack valve because of the heat issue, mased on my experience. YMMV

When's the next group buy? I'm interested in 2, possibly 3.

quote:

Originally posted by Bryan Kast:

quote:

Originally posted by Mr Ryan Mix:
I should think the IP would be able to work in 180F heat, seeing as the engine gets that hot anyway.

The IP can handle the temperature (the veg is around this temp going through there). The problem is sending hot diesel through it. Hot diesel looses it's already marginal lubricating properties. I would like my car to still be able to run on diesel for prolonged periods with out damage, so I don't heat the diesel. Plus the more components in the shared legs of the system the longer the purge time and more cross contamination.

As for hot diesel- my IP is only getting exposed to hot diesel (1/3 biodiesel) for about a minute or two on shut down. The biodiesel should lubricate it alright as long as the heat isn't a big issue.

I've been meaning to ask about the purge time added with a (16) FPHE. I'm guessing it adds about 20-30 seconds purge time. Any thoughts?

...and how about some more pictures of people's installations???

Jake- good to hear that, thanks.

Ryan- It doesn't sound like you have a problem with hot diesel. I was thinking it would could cause a problem with petrol diesel being heated by the FPHE and run through the IP for prolonged periods, such as forgetting to switch to veg. Bio-d has better lubricating properties.

If the FPHE is before the valve and only veg goes through it then purge times should not change. If it is in the shared leg it depends on the volume of fuel that the FPHE holds and the rate at which the engine is pumping the fuel.

quote:

The problem is sending hot diesel through it. Hot diesel looses it's already marginal lubricating properties. I would like my car to still be able to run on diesel for prolonged periods with out damage, so I don't heat the diesel. Plus the more components in the shared legs of the system the longer the purge time and more cross contamination.

exactly
hot DSL = poor IP lube
FPHE post-Pollak = 16 extra plates of veggie to purge

Here is mine. I still need to hook up the veg lines. The bracket it kind of shoddy, and this is the world's worst picture but...

FPHE2.jpg (48 Kb, 258 downloads)

Hot diesel thread at frybrid.com:

http://www.frybrid.com/forum/showthread.php?t=2950

Some posters over there have a temp sensor on their IP return. The diesel coming out is lower than block temp.

John- looks like you are about to cross the 1K post mark!

here are a few photo's that will not take to long to load how this helps
B.K. Hosken
Member

Posted 17 February 2006 02:10 PM
The foam around the HE is cut from a camping ground pad I had. They are $7 at WalMart or similar for a Coleman camp sleeping pad, it's closed cell foam. I assume it helps keep the heat in, since I'm getting close to the same temps out as some people with the 16 plate exchangers. I also have the heater hose going into the HE insulated with pipe foam. According to Dana L., if you insulate it's like adding 2 plates capacity to the exchanger.






Mr Ryan Mix
Member

Posted 05 March 2006 07:23 PM
I made these brackets to mount the heat exchanger, but then realized that there was no room to mount it.


Mr Ryan Mix
Member

Posted 05 March 2006 07:24 PM
It ended up fitting nicely snug on top of the transmission.


mb T

I am finding that a complete purge of the FPHE is eluding me. My bus has had a few hard starts since the FPHE installation on fairly mild days. There are new glow plugs, so I am attributing the problem to unpurged vegetable oil mixed with my start up and shut down blend (1/3 bio-petro-kero). Since the unit has a large volume of space (compared to fuel line alone), oil is not really purged out but mixed with the shut down fuel and slowly used up.

I’ll draw a picture to explain this:

so_what_i'm_trying_to_say_is....bmp (454 Kb, 172 downloads)

I installed a sight glass before the IP to check for air and see if I purged from WVO to Diesel. You can see it at the bottom of the photo, I T-ed the coolant lines together for the HE and the Dana wrap on my wvo filter. Omar
www.omarsales.com

You're not pushing diesel thru the FPHE, are you? Why aren't you switching after the FPHE? You don't want diesel in the FPHE, anyway.