Ford 300 Inline Six

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Hmmmm... The Ford Maverick with the 250CID engine had a 9.2L coolant capacity. Terry, you're gonna have to put some BIG tanks on the radiator for this thing to get close to factory specs for coolant capacity.
 
And that's the reason why you never see IC engines continuously idling during shows like the compressed air powered steam engines. - Terry
 
Before installing the head, the crankshaft was rotated to TDC of cylinder number one and its position memorialized with a mark scribed on the crankshaft pulley next to the timing indicator. This mark will be used later to adjust the distributor timing just as it's done on the full-size engine.

The head, along with the Teflon head gasket made earlier, was then installed using fourteen 5-40 steel SHCS's. Standard length screws were shortened to obtain maximum possible purchase (6 threads) inside the block.

At this point it was possible to leak check the entire coolant system using a vacuum test. Unfortunately, it failed miserably. An easily fixed leak was discovered at the water pump where an interference with the timing gear housing prevented it from fully seating on its gasket. However, a more serious problem remained. Eventually, a leaky liner was discovered after removing the pan and flooding the bottom of the block with oil. With the coolant system now pressurized, bubbles could be seen escaping from the bottom of the liner in cylinder number two.

Although some builders use press-fit liners that are honed after installation, I prefer to completely finish mine outside the block. Since they're machined with close sliding fits inside the cylinders, they must be sealed with Loctite. With the 3/16" glue surface left around the bottom of each liner, I was surprised to discover a leak.

Resealing the liner began with a solvent flush of the coolant system to remove any traces of oil that might have been drawn into the leak during the vacuum test. After removing the head, the block was set on a pair of wood blocks with the bottom facing down. Any remaining solvent was allowed to drain through the leak for the next few hours. Using a needle syringe and working through the two transfer passages on either side of number 2 cylinder, Loctite 290 (a wicking grade) was squirted into the space surrounding the liner. The Loctite began leaking through the liner half an hour or so later. Clean paper towels under the block helped keep track of the sealing progress.

Several hours later, Loctite 609 (slightly more viscous press fit) was added. The draining slowed greatly after a few more hours, and then the block was set inside my home-made welding rod oven for an accelerated cure. With an inside temperature of 140F, the block was allowed to cure overnight.
A couple pressurized solvent flushes were used the next day to remove any uncured Loctite remaining inside the block. After reinstalling the head, the vacuum test was repeated showing the coolant system was finally leak free.

The next step is to machine and install the lifters and pushrods, but I only just discovered I'll have to order the material for them. - Terry
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Very nice I’m envious.
the race car uses light press in or pound in cast iron sleeves they use a special slide hammer to remove them when warm they pop right out but if left in and the aluminum block cools they can be a real bear to remove. Water cooled blocks ar now antiques. They are solid aluminum now we’re i to build a model engine I’d do as you have and use coolant . Most model plane engines are air cooled. There is very little issue with cylinders unless run excessively lean or with too little oil in gas 4 strokes are pretty much like lawn mower engines scaled down. Most Rc flyers use two stroke twins for big power 4 strokes twins are just too heavy for power output. Turbo and supercharging just does not work well on model motors the electric stuff is prett big too batteries are big lithium things subject to fires especially in crashes Very expensive too. . There are at least half a dozen model engines I’d like to build were my eyesight better. I’m just happy that I can work with my steamer and maybe a couple turbines . I just got one of my computers back so I’m going to see if I can revive some cad skills maybe get some 3 d printed stuff. That’s come a long ways .
byron
 
Very nice work. I still have my 1979 F150 with the 300 six in it. Pretty amazing engine.
 
The tappets and pushrods were both made from drill rod, but only the tappets were hardened. The pushrods were finished with ball ends on my little CNC lathe, and the tappets were plunge cut with a matching socket using a spherical end mill in the lathe's tailstock.

As shown in the rendering of the rod/socket model, the socket depth was made equal to the diameter of the rod. Since the rod and tappet don't remain concentric during operation, some clearance is required between the two just above the ball. This clearance is provided by a slight bevel on the top inside edge of the tappet and by an undercut on the rod just behind its ball. The resulting geometry provides space that can accumulate and retain oil. Valve lash was set using a piece of .003" shim stock as a feeler gage.

The calibrated crankshaft pulley and timing indicator were used to time the camshaft to the crankshaft. With the crankshaft positioned 15 degrees BTDC and the camshaft rotated to the start of cylinder number one's intake opening event, the driven cam gear was locked to the flange on the end of the camshaft with four SHCS's. Sanity checks made by manually turning the crankshaft with a spark plug temporarily inserted into each cylinder one at a time showed plenty of compression.

With 45 cc's of oil in the crankcase, the crankshaft webs are barely wetted. Unfortunately, dip sticks seem to be yet another thing that's difficult to scale down. I've yet to come up with one that can be reliably read. The Ford's dipstick was fashioned from a piece of 1/16" steel rod with a filed flat bottom end on which a clean oil meniscus is essentially invisible. Stippling the flat portion of the stick helped a little as did blackening with a torch to reduce reflections. Even still, oil readings are barely visible. If I were doing things over, I'd position the faux oil filter at an appropriate position on the side of the block so its threaded hole could serve as an overflow indicator.

The final photo shows the prototype spark plug I've been secretly working on. It has a 3/32 zirconium electrode that should handle a full two joule ignition. The plug's body was designed to withstand the six figure voltages that the plug's .093" gap is likely to generate during compression. The extremely long plug wires that will be required to reach the plugs will contain RFI suppression to meet CE requirements. - Terry.

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The prototype spark plug has a very long insulator.
Is this only for prototype, or did you calculate that this length is necessary to prevent arcing?
Testing has shown final design will have to be another inch longer. I'm calling it the 'Terry Plug' or TP for short.
 
Your engine is Beautiful Terry. Without anything in the picture to lend scale, I would swear that it is the real thing. I have a Ford 300 powering the tug in my hangar, couldn't tell you the color of it for all the grime-its a work horse. You make me want to steam clean it.
 
Ab Fab. Your work is always inspiring.

Just a small note for what it is worth to others. For somewhat larger engines the stainless steel
stiffener from old wind shield wiper blades makes great dip stick stock. And Free!
Appropriate for ~ 1/4 scale engines . Way too big for this beauty.
Learned from my friend Dwight Giles.
 
What started out as work on the ignition system got away from me and turned into a huge machining project. My previous assembly stopped short of installing the distributor which required the ignition system to time it. At its heart will be one of Roy Sholl's Magnum CDI's that's capable of 5 krpm on a six cylinder engine. The prank TP project is out of my system, and model engine spark plugs (Viper ZR1's, 10-40 thread, 6mm hex) will be used.

The CDI is an already potted module that I've used before, but I like to add my own front-end electronics that won't require a live ignition for timing adjustments. These additional parts along with the CDI add a lot of bulk around a small model engine. Since I want its display to be more about the engine than its running gear, I decided to hide the ignition and hopefully the fuel tank as well.

A 12" x 8" x 1/4" base plate cut from hot rolled steel will eventually be bolted to the engine through an intermediate riser block. The running gear will be hidden inside machined recesses in the bottom of the aluminum riser. The block is big enough to possibly include the fuel tank and pump, and so their machining was done as well.

For fuel delivery I prefer a recirculating fuel loop over a gravity-fed tank because of the consistent fuel level it can present to the carburetor and the flexibility it provides in placing (or hiding) the tank. There are some downsides though: 1) the fuel pump requires its own space, and 2) my pump of choice which is intended to fuel RC planes is a constant volume gear pump. Speed control of this pump typically isn't enough on its own to control turbulences inside a tiny carburetor fuel bowl. The fixes I've come up with require bowl volume, and so the Ford carburetor that doesn't even have a bowl is going to be a problem.

The riser required some ten hours of machining time, but its modeling required much more. The fuel and ignition systems were safely separated and the small signal electronics were separated from the (electrically) noisy CDI and its high voltage output. Unlike some of the other model engine control modules I've designed, I was also determined to make this one easy to assemble and maintain. The fuel tank was hogged out of the riser's left-over volume and will be later sealed with a JB-Welded cover.

The baseplate was painted with Rustoleum Multicolor Textured paint which is gas and oil resistant and
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nicely covers unprepped hot rolled surfaces. The riser was bead blasted and will be painted with a similar shade Gun Kote. - Terry
 
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first inline six cylinder with a firing order that isnt 1-5-3-6-2-4 ? , even a 'real' 300 cube ford is 1-5-3-6-2-4 , i think youll find every in- line- six ever made will run in that order , not that it 'wont ' run but vibration wise you'll find out
pretty quick , why its never done
 
first inline six cylinder with a firing order that isnt 1-5-3-6-2-4 ? , even a 'real' 300 cube ford is 1-5-3-6-2-4 , i think youll find every in- line- six ever made will run in that order , not that it 'wont ' run but vibration wise you'll find out
pretty quick , why its never done
Not sure what you're trying to say. The firing order is 1-5-3-6-2-4.
 
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For shame Terry, a 6 volt electrical system? I know that volts don't scale, but every Ford 300 would have started its' life as a 12 volt system. It looks like you've got plenty of extra room in the base to fit in a DC-DC converter, and feed it with a proper 12 volts. That way when the battery dies at a show, you can just pull the battery out of somebody's car and hook it up to your engine with a set of jumper cables.

Did I say that everything looks outstanding?

Don
 
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The fuel tank cover was sealed with JB-Weld. A machined 'o-ring' groove around the face of the tank was filled with the epoxy to ensure a continuous leak free seal. A filler neck with an o-ring'd gas cap completed the tank assembly. After installing the pump and motor, the tank was filled with gas and the entire fuel system exercised for several minutes using a dummy loop to check for leaks.

A threaded Delrin feed-thru was created to route the CDI's high voltage output through the top surface of the riser and into the center tower of the distributor cap. Just for fun, the feed-thru was machined to resemble an automotive ignition coil.

After installing and testing the support electronics around the CDI, the distributor timing was initially set to 10 degrees BTDC using the already calibrated notch on the crankshaft pulley. Eighth inch high voltage silicone plug wire was used, and the boots were fashioned from repurposed automotive vacuum fittings.
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The remainder of the engine's front end was assembled. The photos show the completed engine to date. Only the carburetor and radiator remain to finish up the 'build' portion of this project. Since the bowl design is probably going to be troublesome, the carburetor will be left until the end. The radiator will be tackled next. - Terry
 

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