I've recently installed a Wvo two tank system In a 300d with hih, fhpe and coolant lines wrapped around filter. New thermotat. Aux pump wired on.

Engine gets to 180-185. Coolant gauge reads a little less. Wvo temps right before ip are 120-140. And they climb slowly to get to 140. What should I do?

Add vegtherm? Try coolant lines in parallel (n series now)? Add injection line heaters and hope that makes the difference? Any advice is appreciated.

I could also loop the return? What would that involve?

we have been using some high-density foam (recycled sleeping bag mat) and wrapping flat plate heat exchanger with it … helps hold the heat in ...you should insulate your wvo fuel lines also
should read thru this thread

http://www.burnveg.com/forum/v...storder=asc&start=45

loop your return that will help may want to look at injection line heaters

good luck
Omar
www.omarsales.com

I have done some insulating but can try more. My hih and fphe are insulated with foam pipe insulation. Could that make a difference of the huge temp jump I need though?

quote:

Try coolant lines in parallel (n series now)?

The FPHE should be on it's own parallel loop, fed from the engine block and returned to the inlet side of the coolant pump. All the other fuel heating loads should be in series on another parallel loop.

Where would I tap into the coolant lines for the second parallel loop? Around the same place? Could I put the fphe in series and the filter and hih in parallel? Do you think this will have a big improvement on temps? Thanks.

quote:

Originally posted by kst:
Where would I tap into the coolant lines for the second parallel loop? Around the same place?

close to the engine

quote:

Could I put the fphe in series and the filter and hih in parallel?

I suppose you could do whatever you wanted. Re-read what I stated if you want more heat from the FPHE.

╔engine===╗
╠heater===╣
╠FPHE===╣
╚HOH+===╝

quote:

Originally posted by kst:
Aux pump wired on.

This won't get you more heat. I'm assuming this is a Mercedes with the Aux Pump in stock location. If so it pulls hot coolant through the heater core thus taking flow away from your veggie loop. I put my pump on a switch and turn it on only when I want heat in the cabin.


Put the FPHE on its own loop.

Loop the return to after the filter before the FPHE.


I have HoH and both of the above things and I see 160+ in sub-zero weather in winter.

If this doesn't cause the temp to rise to 160-175 there is something wrong with your plumbing.

...and yes, put on a Vegtherm, which has been shown many times to add the necessary gain over and above what can be achieved with coolant heating devices.

quote:

Originally posted by kst:
I've recently installed a Wvo two tank system In a 300d with hih, fhpe and coolant lines wrapped around filter. New thermotat. Aux pump wired on.

Engine gets to 180-185. Coolant gauge reads a little less. Wvo temps right before ip are 120-140. And they climb slowly to get to 140. What should I do?

Add vegtherm? Try coolant lines in parallel (n series now)? Add injection line heaters and hope that makes the difference? Any advice is appreciated.

Injection line heaters will probably give you your best bang for the buck. All pre-IP heat is subject to being lost to some extent as it passes through the IP and injector lines.

You may also be able to add a "balancing valve" to you coolant circuit to flow more coolant through the FPHE (and plumb it as JG suggested). For more info on coolant ccircuit configurations look HERE

A vegtherm or any other electric heater prior to the IP will help, but also keep in mind Dana's point that the vegtherm heat can easily be lost out of the Injector Lines before the fuel gets to the Injectors. Any insulation is better than bare steel, and active heating is even better, though a little more difficult on some engines (I'm not familiar with the 300D's). Omar's got some good insulation ideas to learn from.
Some engines return more fuel to the loop than others. Some injectors return more to the loop than others. These factors are significant for the amount of heat recycled or lost. If fuel loops quickly, then a heater anywhere in the loop is more beneficial than if the fuel moves sluggishly. Heat loss from unheated and uninsulated sections of tubing or piping will be greater when flow is slow. Do you have any clear fuel line in your loop where you can observe some flow activity? My VW pumps an amazing amount of fuel through the loop, but my Mazda has barely a trickle, for two extreme examples. The VW loop only has a single electric heater just before the IP, and wrapped injector lines (I'll get around to hooking up the Injector Line Heaters when I swap the rebuilt engine back in). The Mazda on the other hand needed Injector Line Heaters to run well on SVO, even though I had lots of heat prior to the IP. The heat got lost before the fuel trickled to the injectors. I never tried simple insulation though, and still wonder if it might have worked well enough.
Cheers,
JohnO

quote:

Originally posted by john galt:

quote:

Try coolant lines in parallel (n series now)?

The FPHE should be on it's own parallel loop, fed from the engine block and returned to the inlet side of the coolant pump. All the other fuel heating loads should be in series on another parallel loop.

^ Listen to John. I did and after installing a dedicated loop for the FPHE my pre-IP temps are now 150-160*F in my 300D, just where I want it.

Just a note that the injection pump on the Merc is an inline pump lubricated by engine oil (which is of course hot), so it will not be a place where you are losing any heat.

Thanks for all the suggestions! I just did some insulating so we'll see if that helps. When I get a chance I will fix my coolant routing.

As for my aux pump, my car seems to have a different coolant routing than most 300d's. That's why I ended up doing series. The line coming out of the engine goes straight to the aux pump, then the servo, then heater core and back (that's before I added anything so everything I added is between engine and aux pump).

I have a feeling that I am losing some heat because of slow fuel flow which makes me think a loop might help. To do this would I add a valve right after the return which sends it back Either to another entry on the filter or the purge valve?

quote:

I have a feeling that I am losing some heat because of slow fuel flow which makes me think a loop might help.

I don't think looping the return will speed up the flow through your injector lines. It might provide a bit higher pre-IP temp though.

I think your best low cost alternative is to insulate the injector lines as best you can.

quote:

Originally posted by Edward Beggs:
Just a note that the injection pump on the Merc is an inline pump lubricated by engine oil (which is of course hot), so it will not be a place where you are losing any heat.

That assumes that the pump is kept at the temp of the incomming VO.
Yes..the hot lube oil adds heat to the IP. But the IP also has a large surface area which can shed lots of heat. To determine if your IP is "temperature neutral" simply stick a remote thermoeter probe on the IP near the outlet. Insulate it with a bit of foam. If the temp is lower than the incomming wvo you are likely loseing a bit of heat to the IP.

But the IP is not the "big loser" of wvo heat. The injector lines are. Unless you insulate or heat your injector line expect a lot of the heat being added by ANY means to your VO pre-IP to be lost as it make the trip from the IP to the injector.

quote:

Originally posted by Edward Beggs:
so it will not be a place where you are losing any heat.

on the freeways empty car/light load especially at night and exaggerated in the wintertime ECT is frequently 140f and on downhills 120f, on long ones i have seen 100f.
what are we shooting for again - 200f?

kst: your coolant temperature 180-185 is that steady? assuming your gauge is still working accurately. also you might want to put in a fresh 192f thermostat. they do degrade after many
heat cycles. get a heavy duty one and test it in a pot of heated water prior to installation.

What I meant was that on a vehicle with an inline injection pump that is lubricated by engine oil, the engine oil is hot, so the injection pump will not be the cause of loss of heat in vegoil that has been heated prior to reaching the injection pump.

Yes, you will see temps drop on downhill runs. I noticed this about 8 years ago.

It was the main reason I started looking at adding electric heating. Your engine's coolant temp drops off on those downhill runs, and in winter, dramatically.

Add a Vegtherm.

It's easy to forget that the engine thermostat controls flow rate to maintain temperature. A dash gage only indicates temperature, not how much coolant it flowing through your FPHE, HIH, HOH, whatever. Depending on how everything is plumbed, the flow rate may change a lot as the thermostat opens or closes.
When going downhill, not only does the engine generate less heat, but the thermostat will close and reduce flow to the radiator. You may also upshift (higher gear), slowing engine rpms, which also slows the water pump, which also slows coolant circulation through your fuel system. For that matter, the engine and combustion chamber cool, too. So do the injectors (remember there's hardly any combustion taking place) These all conspire to reduce the fuel temperature arriving at the IP. Without a source of heat independant of coolant, the fuel temperature will eventually drop too much for safe operation. That's why I switch off my veggy system on long downhill stretches.

At some point, even electric heat won't be enough. Then it's time to change back to a better low-temperature fuel.

Cheers,
JohnO

In my 300D the coolant flow to the cabin heat loop is unaffected by the thermostat being open or closed. The temperature however, will vary somewhat depending on engine load and ambient temps.

It may be my car but the IP is still pretty cool at my switchover time, ~7 miles. However, after a couple miles with hot WVO going through it, it's too hot to touch for more than a second. I do need to check this out more closely.

http://genedevera.com/temp/mb/coolant-loop.jpg

Thanks, Geno

hey turbogeno, where did you get that coolant circuit diagram? i swear mine is different. for starters i don't have an expansion tank. i'd like to find if there's a different diagram for earlier models.

i haven't had much time to work on it, but i did do some insulating and it's seems to have had little effect, though some strange stuff was going on the other day. When I switched to wvo after driving for awhile the temps were around 110-20. So I turned it off. I eventually got to my destination, turned the car off for about ten minutes. When I got back in I decided to try it again and the temps went up to 176! They hovered between 160-176 for about ten minutes of suburban driving. Then they were all over the map. They went down to 130, back to 160, up and down, then all the way down to 105 and after about ten minutes they stayed between 110 and 125 so I turned it off again. then when i was running on diesel, the temp stayed at around 100 which makes me think the insulation might be doing something.