Engine Swap


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There are a large number of decisions to be made when swapping engines in a TR-6. Armed with a tape measure and the measurements of a partially dressed 302 engine, I started measuring the engine bay of my TR-6 and decided an engine swap would be completed easily! I am going to return my dictionary to the seller since it has a defective definition. It defines easily as adv. 1. Without stress or difficulty - - - - HAH! Actually the swap will not be as difficult as I thought but it is not as simple as drop-in and bolt-in. Dan Masters has an excellent article on the different types of V8 engines which can be used for an engine swap. I selected the Ford 302 for its size, weight, performance, and parts availability. The 302 has been around for quite some time and is fairly inexpensive and easy to find in wrecking yards. It is also frequently used with a 5 speed manual transmission which I am going to use as part of the swap.

My search of the internet for information about TR-6 engine swaps has led to a couple of interesting pages. I won't list them individually as Dan Masters has captured most of the sites on his Conversion page. I have seen several approaches for placing the 302 into the engine compartment. The amount of cutting on the body, firewall, battery shelf, placement of engine mounts, location of the shift lever, etc.depends on where you place the engine.

Here is what is going to happen when you decide to perform the engine swap. You will look at the amount of room in the TR-6 engine compartment and compare it to the size of a 302. The light above your head will go on and you will scream "Eureka - it will fit!" All I can say to this is "Bwaaa Ha Ha Ha - welcome to the dark side!" After I regale you with my prophetic knowledge of what you WILL do, at the end of my story I will tell you what you SHOULD do. Pull up a seat and let me show you the future of your engine swap in my crystal ball.

You are going to go out and purchase a used 302 engine and associated transmission (most likely a 5 speed). If the wrecking yard has already pulled the engine and transmission, you are going to test your negotiating skills to get all of the miscellaneous bolts, engine mounts, pulleys, and ancillary items to make up a fully dressed engine. They have a tendency to throw some of the smaller parts away leaving you with the unenjoyable task of trying to figure out what you are missing. Buy as much of the engine, transmission and miscellaneous parts at the same time. It is amazing how you can buy an engine and transmission for about $650 but any additional parts such as an alternator, exhaust manifold, oil pan, radiator, driveshaft, etc. will cost $50 and up per piece! Remember - remember - remember . . . Try to get everything you need at one time, you WILL save money!!!

The wrecking yard will help you load the engine onto the back of your truck at which time you will notice the oil pan has been dented from where they dropped the engine from as high a height as possible (the dented oil pan is a standard configuration of Ford 302s coming from a wrecking yard).. After you get home you will realize the wrecking yard did not drain the oil from the block and five quarts of black, gooey oil is dripping from the bed of your truck onto the driveway. BUT you have a LBC so you are used to oil on the driveway!!!! The pain is cleaning the oil from the truck. By now you realize you need an engine hoist to get the engine out of your truck. You do have one, haven't you? Either make or buy one since you are going to use it enough times to justify the expense (trust me on this one, you need your own hoist - I built my own engine hoist - plans and details will be posted to this site at a later time). If you store the engine in your garage, any remaining oil will find its way onto the cleanest portion of your floor (buy plenty of cleaning solution and don't track the oil into your house).

Ok - you have cleaned up the oil spills, the engine bay is empty, the 302 is on the engine hoist and you are ready to slip that sucker in and have the cleanest looking installation anyone has ever seen - all within your planned time of 2 days. Ha, ha, ha, ha, ha - excuse me while I wipe the tears from my eyes and get up off the floor - my sides hurt from all the laughing. Good - you are still with me and are reading this article because you want ideas and tips for converting your TR-6. Now it is time to get serious.

I am writing the following list of issues based on a 302 with a front sump oil pan, a standard 3 pulley front crank, and normal cast iron exhaust manifolds found on 60s and 70s vintage cars. The transmission is a 5 speed Borg-Warner out of a Mustang or Thunderbird Turbo-Coupe. After I point out some of the installation and fitting problems, I will discuss the approach I am taking to alleviate the problem. There are many ways of accomplishing a conversion and my approach is just one of many. I hope this gives you ideas - and for those of you who have already performed a conversion, please let me know if you have an approach or idea that is better than what I am trying.

One other point - I am trying to keep in mind that I will have to perform maintenance in the future. As I test fit the engine and transmission, I visualize maintenance items such as spark plugs, clutch, oil pump, water pump, belts, hoses, etc. to determine if I can "easily" replace them after the conversion is complete. I do not want to pull the engine to replace the clutch, or loosen the motor mounts so I can replace the belts, stand on my head for spark plugs, and the like. I figure the time I put into determining the placement of key components now will continue to make the vehicle enjoyable to own and drive.

Here is a list of problem areas you will encounter -

  • Upon placing the 302 in the engine bay, you will find the crank pulleys line up directly over the steering rack. If you try to move the engine rearward to put the pulleys behind the steering rack, you bump into the firewall and battery shelf. Moving the engine rearward also moves the shift lever location in the driver's compartment creating some aesthetic issues.
  • The standard engine mounts for the TR-6 engine are not located in a usable location for a 302. You have to remove the existing mounts and fabricate new ones.
  • The sump of the front sump oil pan is over the crossmember. This limits how low the engine can be mounted.
  • Standard cast iron exhaust manifolds need a bit more clearance on the sides and the passenger side manifold flange dumps right onto the firewall.
  • The steering shaft and driver's side exhaust manifold may interfere with each other.
  • The starter may have clearance problems with the frame.

I didn't want to change the external appearance of my TR-6 so this required the engine be placed as low as possible to eliminate the need for a bulge in the hood. The front sump oil pan necessitates notching the crossmember in order to lower the engine. An engine mounted low has two benefits - 1) it lowers the center of gravity thereby improving handling and 2) it provides clearance between the bonnet (Hood) and the top of the air cleaner. I found that a 302 engine out of a Ford Econoline has a rear sump oil pan. This provides more clearance between the crossmember and the oil pan and reduces the amount of the crossmember that must be notched out. The front sump oil pan drain plug is directly above the crossmember which could create a mess when changing oil. The rear sump oil pan moves the drain plug to a more accessible area making for cleaner and easier oil changes. I haven't come across the rear sump oil pan and pickup tube in many of the performance parts catalogs so this is an item that is probably easier and less expensive to find in a wrecking yard.

One of the first modifications I made was to the crankshaft pulley. The engine will be equipped with a water pump, alternator, and air-conditioning compressor. This requires two belt grooves on the crankshaft pulley and the one that came with the engine had three grooves. Looking closely at the crankshaft pulley revealed that it was constructed of three separate pulleys that were spot welded together. I used my angle grinder to carefully gring the spot welds holding the topmost pulley until the pulley was free. This left me with a two groove crankshaft pulley for very little cost.

I want the cockpit to remain stock in appearance. I maneuvered the engine to where the shift lever was located in the same position as stock (upper left picture). After examining the front of the engine, I decided I had enough room to mount a radiator and air-conditioning condensor IF I used an electric cooling fan even though the water pump protruded out rather far. I also had enough room to move the steering rack forward but this would radically change the steering geometry. I will discuss in the upcoming paragraphs how I got around these problems. Another benefit was that the rear of the engine was well forward of the firewall (lower left picture) thereby eliminating the task of cutting out the existing firewall and fabricating a new one. After considering the pros and cons, I decided the engine would be mounted to align the 5 speed shift lever in the same location as the stock shift lever. I test fitted the transmission cover and found no clearance problems with the transmission. The interior of the car is going to look stock. I will fabricate a shift lever with the correct bend and thread size so I can mount a Triumph badged shift knob and hide the fact that it is connected to a 5 speed. My plan for this TR-6 to look exactly like stock, except for when the hood is up, is becoming a reality. There will be no internal cockpit or external signs of anything unusual with this car when I go out to kick-a - oops, I mean to take a nice leisurely drive around town. :) heh, heh, heh

The biggest problem you will most likely encounter is that the best position for the engine places the front crank pulleys in the same location as the steering rack. Mounting the engine to place the shift lever in the stock position MANDATES the steering rack be moved. Rather than move the rack forward to be in front of the pulleys, I am working on lowering the rack so it tucks up between the crankshaft pulley and the oil pan (see photo to left). I have cut out the mounting bracket for the steering rack and will fabricate a custom replacement once the engine is firmly mounted. The clearance between the pulleys and the rack is going to be tight and I only want to make one custom bracket. The water pump sticks out well beyond the crankshaft pulleys. I found a water pump from Stewart components that is made of aluminum and is 1.4 inches shorter. This will reduce the protrusion and save weight.

With the location of the engine fixed, I started to pay more attention to the fit and clearance on the sides of the engine. Without cutting any of the sheet metal in the engine bay, I felt I would be able to install headers, alternator, air-conditioning compressor, etc. - although it was a very tight fit. After some thought, I decided I wanted a little more room to work in and wanted to have more access to the engine for future maintenance. A little sheet metal removal and fabrication is required to provide the additional room.

The upper left picture has black lines drawn where the sheet metal will be removed and the lower left picture shows the additional space in relation to the cylinder head and starter. The cut was not as drastic as I thought it would be. When I weld in the new sheet metal, I hope it will take a knowledgeable observer to notice the modifications.

These photos were taken while the body of the car was on a rotisserie. The body is upside down at a 45 degree angle making it much easier for me to weld the panel. Another picture showing where the original sheet metal was removed.

This is a photo of the finished panel I fabricated (the sheet metal brake comes in handy for making these type of panels). After test fitting it, three sheet metal screws were used to hold it firmly in place while welding the seams (this photo was taken while the body was on the rotisserie).

All of the seams are welded and the welds have been smoothed with a grinder.

The upper right picture shows the cut I made into the driver's side of the cockpit. I did not take out as much of the firewall on this side as I did on the passenger side. There was already enough room for the exhaust manifold and I did not have to worry about access to the starter on this side. The lower right picture shows the additional space in relation to the cylinder head.

This view shows how I plan on routing the steering shaft from the cockpit to the steering rack. Since I am going to have to fabricate exhaust headers, I decided to route the steering shaft in the most direct route possible. I moved the steering rack which has forced me to rotate the rack in order to prevent the input shaft from rubbing on the lower A-arm mounting bracket. Because of the rotation of the steering rack, I will use a U-joint designed for steering columns to attach the input shaft to the steering shaft. I will mount a Heim joint near the brace for the front suspension tower to control looping of the steering shaft. I will post additional photos when I actually start the mounting of the steering rack. I will have to notch the firewall a slight bit more to gain clearance for the steering shaft. You may be able to see the outline of where I plan to make the cuts. I feel this configuration will allow me to have a safe steering system, room for an exhaust header (custom built - I don't think any stock headers will work), and easily accessible spark plugs.

These views show where I plan on routing the steering rack in relationship to the harmonic balancer and crankshaft pulleys. I am going to make it a tight fit but with enough clearance for engine vibration and belt changing.

I have mocked up the radiator and air-conditioning condensor to determine the amount of room I will have between the radiator and the crankshaft-pulley/water-pump. The water pump in this photo is the short water pump I bought from Stewart. Notice how much shorter it is than the old pump shown in one of the previous photos. I have decided AGAINST the use of this radiator. It is an older radiator out of an early Ford. What I do not like about this radiator is its use of a down-flow design instead of the newer cross-flow design. I have read articles that claim the down-flow design is more prone to overflow because the pressure cap is subjected to higher pressure due to its placement on the "high pressure" side of the radiator. The newer cross-flow radiators have the pressure cap located on the "suction" side of the radiator and are therefore less likely to overflow. This may or may not be true but I have opted to use a universal cross-flow aluminum radiator anyway. It is slightly shorter and wider than this radiator which will give me additional hood clearance. The manufacturer claims it reduces the water temperature more than a copper and brass radiator of equal size Who knows? It may or may not. I selected the aluminum radiator because I wanted a NEW radiator and it will reduce the weight by a couple of pounds. I ordered an electric fan and shroud that is sold for the Mustang 5.0 liter radiators and will use this combination in place of an engine driven fan. I will have additional freedom to mount the radiator since I will not have to worry about alignment of the fan to the radiator.

- More to come very soon -


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