Like the title for today says… more slow, small details. I’ve reached a point in the Boss 427 build that is becoming a bit frustrating. Lots of small things that take time, usually more time than expected. Remember, almost everything I’m doing is custom… there’s no laid out plan or directions for so many small things. You have to think about it, decide how you want it to work, figure out what you need to do it, order parts / tools / supplies, try it, realize why it wont work or how it could be better, order more parts / tools / supplies, try it again…
I’ve started wiring the engine sensors that will be used for the gauges and the fuel injection computer. One is the coolant temperature system. Now here I have both a gauge and need an input to the fuel injection system, so there are 2 sensors. The small block / 351 Fords have always had 2 places to place coolant temp sensors, but I’m using 1 of those for my heater and 1 for my FiTech fuel injection. Nowhere for the sensor to the Speedhut gauge. Research found a heater hose adapter made by Autometer that incorporates a brass tube that fits into a cut section of heater hose and has a port to install a temp sensor. Since the 351 Ford uses constantly circulating coolant in the heater system (more on that later), this can be used for coolant temp sensing. Cool!
At the same time, I’m figuring out the heater system. I’m using an electric heater control valve from Old Air Products, so that has to be plumbed in between the intake manifold, the heater and the water pump return. Found some Dayco 5/8″ heater hoses that were about 4 ft long with a 90* elbow at the end and about 7″ beyond the elbow. Bought the pieces and parts I needed, got it all together a few days later.
First thing was figuring out where to put the heater valve and how to securely mount it. Looked all over, tried a few things, then McMaster Carr to the rescue. I bought 2 padded U-bolts, 1″ wide on the inside that fit right around the tubes on the valve.
Drilled and mounted the U-bolts to the top of the passenger footbox. I loaded the locknuts up with silicone adhesive to prevent any leaks.
So this valve… why and what does it do? The heater system in the Boss is pretty simple… hot water from the engine circulates through a small radiator, and a fan blows air across the radiator, creating hot air that is pumped into the cabin. But if you turn off the fan, circulating water and ambient moving air will still move hot air into the cabin. So this valve takes the hot water and turns it back into the engine when not needed. When it is desired, just turn the heater knob to control how much hot water is allowed to the radiator, controlling how much heat you get.
Got the valve installed, started installing all the 5/8″ hoses with some nice heavy stainless steel clamps. Last hose goes back to the water pump return and… 3/4″. Sigh. Another piece to order and wait. Adapted the valve output from 5/8 to 3/4″, then finally on the water pump.
Back to that coolant temp sensor. Its a 1/8″NPT thread, so it fits right into the Autometer adapter… right? Not quite. The Speedhut temp sensor is a bit longer than the depth of the adapter… threads wont even reach. After spending a few hours researching other temp sensors that may be shorter and still have the same resistance (no luck), I looked at the Speedhut directions to get a phone number to call. Corner of my eye, I catch the words “… trim length of sensor to this point only.” What?!?! Trimming the sensor?
Yep. There’s a notch in the sensor that is the limit for trimming if needed. I need. 😉 So into the vice it goes and I go at the brass tip with a pipe cutter. BTW, that cutter was my Dad’s and I believe it’s older than I am.
I initially trimmed it short of the notch, just to be safe, but it wasnt enough and I had to go all the way to the notch. The finished sensor…
…and installed in the Autometer heater hose adapter.
Now some bright engineer types out there may take note that there’s no way the sensor will work… there’s no ground circuit. There is a threaded hole for an 8-32 screw in the side of the adapter, but I dont need it because the Speedhut sensors are 2 contact… ground is made through the wiring harness and chassis ground.
Some other things that went a bit better… got the oil pressure and oil temperature sensors installed with the help of some 1/2 to 1/8 NPT brass adapters.
and oil pressure…
Ran, harnessed and secured the wiring along the engine to get safely back to the dash.
You can see how a small item like the heater can turn into a 2 week project. While waiting on parts to arrive, I end up working on things like the headers (still do not have a good set), dash wiring (removing the harness wires for the gauges and installing the Speedhut wires) and a myriad of other small things. So I’m progressing, just not at a breakneck pace.
New update soon, I promise. Believe it or not, I can feel it all getting closer to first engine start.
Thanks for reading.