tapping into coolant lines...........

[magnus_heydoc]

On the weekend I moved my SVO project further by running 'the bundle' of coolant feed&return, fuel feed and wiring from the new SVO tank to the firewall.
I tapped into the coolant line just before the heater core with a Y and sent a branch to feed the HFPU in the veggie tank. The return coolant line from the veggie tank went into the FPHE and then the return from the flat plate heater took a Y back into the stock coolant return.
I'm thinking in series is going to get me the most consistent heat for my devices but I'm wondering if when I turn on the cab heater if I'll loose alot of heat to my coolant devices. The shorter heater core lines are likely less resistance and I'm hoping there will still be lots of pressurized hot coolant to go around. I'll have a thermometer in the tank so I guess I'll know more in time as I get some readings.

I'm wondering what plumbing designs others have undertaken and what their experiences have been?
Aaron

[Pig Bodine]

Hey Aaron,

Sounds like the swap is coming along, you'll be greasin' in no time.

A few comments. Unless I'm misunderstanding your routing I think that you are currently running in parallel, not series, which is a good idea. Series only works if you tap into a constant source of coolant flow, i.e. NOT your feed line for your heater core. This is because if your heater is off or restricted (not on full heat setting) you get no or little flow to your heat exchangers.

Second, it sounds like you are running your tee off of your supply side heater line directly to your tank and then routing the return to the FPHE. I would think about sending your supply side (that is to say, your hottest) coolant to the FPHE first, then to the tank, then route the return back to the return side. The way it is set up now, you are cooling your coolant before it gets to where it is needed most, the FPHE. In reality you only need a moderate amount of heat at the tank, basically just enough to get sludged oil into the pickup and let the heated line, HOH or HIH I assume, plus the HE do the rest of the work. On a related note, the tank temp gauge might be better located in the fuel line just prior to the IP to get a better feel for line temps just before injection. This can be done pretty easily with a 3-way female brass tee and some hose barbs. Just screw the temp sender, usually 3/8 NPT, into the tee in he middle and you have an accurate uel temp read.

I wouldn't worry about stealing heat by running your heater. Your heater core is basically a giant FPHE not exactly the most free flowing setup. Even if resistance is lower there, you can control that via the supply valve on the dash so it's only at lowest resistance when the heater lever is set on full heat, something I find I rarely do in my rig or else the temp gets to about 90 degrees even in winter.

Hope this helps,
Dave

[rtarh2o]

Pig Bodine, sounds like you have a pretty good understanding of the routing. See if you can help me out too. For my heat I have a "T" just before the heater core and another "T" just after the heater core. My thinking is that when the heat is off the coolant will bypass the core and when the heat is on it will either go to the core or the bypass. I am getting plenty of heat to my fuel lines and filter but my heater is not working. I guess the coolant is following the path of least resistance and bypassing the core even when the valve is open. Do you think maybe the core is a bit clogged or is there enough resistance that it will always choose the open bypass? I am either going to reroute it or figure out a way to maybe make a 3 way valve to close off the bypass and force the coolant through the core.
Any ideas?
Rusty

[magnus_heydoc]

Thanks for the comments guys.

That description does sound like parallel now that you mention it.
You make some interesting points which may make me re-route. Luckily, moving these coolant tap in lines around some is not difficult so experimentation and getting some readings will be an option. You may be right that it should go to the FPHE first for the reason you mentioned and the fact that I'll have a 250w electric pad heater on the bottom of the tank which will allow me some more leeway. Similarly, I'm wrapping a copper coil around an aux. fuel pump back by the vegtank. The feed&return coolant lines and fuel lines are all in the same insulated jacket that heads from the aux. fuel pump to the firewall.

I'll have 2 thermometers. One by the IP (thanks for the fitting tip as I was wondering how I might do that) and one at my vegtank. For the sake of 20 bucks I thought it might be useful to gather more temp info with another probe. Incidentally, I'm wiring the 2 probes on a switch so I can use the one monitor (cooking thermometer from crappy tire), instead of having two on my dash.
It's apparent that there will be lots more crap on my dash by the time the valve switch and gauge (greasecar), two switches for heaters, a temp monitor and eventually a new tach, and boost gauge for a turbo (next project) get homes.
I hope to be wired this weekend.
Aaron