A Spitfire Engine Rebuild

Part 1

Over the past few years, our 1965 Spitfire MKII has seen limited miles. I'm sure the Stag resurrection had some influence, but the real reason is the poor little guy was just worn out. At the time of the tear down, he covered over 103,000 miles. In the 25 plus years I have owned the car it has NEVER had a major mechanical breakdown! Not a single overheat problem, nothing. While there were a few hiccups along the way, this little car has been extremely reliable and has NEVER left me stranded. I intend to keep it that way.

So why the rebuild? The little guy gave me all the warning signs. A drop in oil pressure, a low frequency rumble during idle, a rattling valve train and a few more leaks than normal. The transmission whined and the rear end knocked. While racing through the roads of central Illinois staying right on the tail of a very fast Morgan +8, the rear splines of my wire wheels were just this side of being totally stripped. So it was decided to give the car a mechanical overhaul and facelift. By the way the owner of the Morgan jumped out of his car at the next stop and was amazed I was able to keep up. He asked what modifications I had done. I proclaimed none as I was running on the original 1147cc Spitfire motor. His son, witnessing this exchange, would probably never get over it.

The engine is getting a full rebuild including renewal of all the head components and even a cooling system upgrade. The transmission would be replaced by a similar unit, except that the replacement unit contains a nifty item at the back end called a D-Type overdrive. The differential will get new bearings and seals along with inspection/adjustments of the crown and pinion. While I'm at it, the driveshaft and rear axles will get all new u-joints.

Once removed from the frame, I disassembled the engine to the short block and the head. These two main parts were then delivered to Andresen's so Tom, Tim and the rest of the boys could do their machining magic.

Transmission: While awaiting the call from Tom with the list of parts, I dug into the rebuild and upgrade of the transmission. I had already rebuilt the overdrive at a previous ISOA clinic. So the only thing left was to go through a standard inspection and parts renewal of the transmission. New main bearings, synchros and a countershaft were installed. Everything went together nicely. It was very satisfying to see the overdrive mate up with the main transmission case. The only thing to finish up was a bracket fabrication and installation of the transmission switches for the overdrive. The MKII transmission has no switches. I also needed to run some new wire and add a relay for the overdrive solenoid circuit. An original overdrive stalk switch will be installed on the left side of the steering column to keep with the originality of the car.

Engine Parts: Within a week, Tom called and gave me a run down of the parts that were needed for the engine. The cylinder head was going to receive new valve guides, hardened exhaust seats and new valves. For anyone worried about running unleaded fuel in our cars, forget about it. In 25 years, I only put unleaded in this car. Inspection of the valves and seat showed little or no valve recession.

As suspected, this 1147cc motor was worn out. The mains needed .010 under and the rods needed .020 under. Not too bad. The upper rod bushings were shot, so they needed to be replaced. So far pretty typical; except the cam was too worn to be usable so a new one would be needed. The cylinder bores were very worn. Tom originally estimated that .040 over pistons would be needed. However during the actual machining operation, going 040 over wasn't going to cut it (pun intended). A call to me at the office on Monday with a request of a new piston size requirement of .060 was needed! Yikes, we're doing the assembly clinic in 5 days!

All of the engine parts were purchased from British Northwest in Oregon. Layton and Gary at BPNW are the best! I called right away Monday, and they had the pistons in stock! We were able to get new pistons shipped that day. These parts guys know their stuff and are very helpful and very customer oriented. They have nearly all the mechanical parts for our cars and their prices are hard to beat. More on costs later. Previously, I had talked with Layton about getting a new camshaft. He spent the time and explained to me the different cams they offered. I chose a cam one step above the stock cam specifications. This would still allow the car to be very "streetable" but give a minor performance boost through improved lift and duration.

Big Little Bore Spitfire: The "60" over pistons was a significant jump over the stock size. I decided to do a quick calculation to see what the displacement difference would be. So let's use some simple math here.

Stock Specifications:
	Bore  2.728 inches	Stroke 2.992 inches

displacement 	= (pi/4 x bore2 x stroke) x cylinders
		= (3.14159/4 x 2.7282 x 2.992) x 4
		= 69.95 cu inches* or 1147 cc
		 *Triumph stated 70 cu in

New Specifications:
	Bore  2.788 inches	Stroke 2.992 inches

displacement 	= (pi/4 x bore2 x stroke) x cylinders
		= (3.14159/4 x 2.7882 x 2.992) x 4
		= 73.06 cu inches or 1198 cc

Machining: When the Stagmeister does an engine rebuild, I don't fool around. It's false economy to do half a job. Besides the block getting bored, it was also decked and the cylinder head as well. The crankshaft was recut and the flywheel resurfaced. The crankshaft, rods, pistons, flywheel and pressure plate were all balanced. I always have Tim and Tom do all my shortblock assembly. As you all saw at the clinic, there is a lot of detail that goes into this part of the assembly. While Tom does not discourage you to do this work, I prefer and recommend that you pay for this to be done by them. It is money well spent for the peace of mind alone.

Rocker Arm Assembly: While Andresen's were doing their thing, I was busy with some of the minor rebuilds. The rocker shaft and arms were very worn and was the source of much of the rattling at the top end. I replaced the rocker shaft and all of the rocker arms. This will be installed when I do the final engine assembly. Which is now the rest of the story.

Assembly Prelude: I picked up the assembled short block, the rebuilt head, flywheel and all my old parts. I suppose I'll make a necklace with the old pistons. They make great anniversary gifts as they represent a constant reminder of how worn out we really are. Anyway, the Spitfire engine is very straightforward and the final assembly commenced without a hitch. The key is to remember to keep things as clean as possible and use liberal amounts of oil when putting the various parts together. A critical tool is the torque wrench. You just can't tighten things until it feels right. The torque wrench and the various torque settings are there to properly tension all the bolts and fasteners. No stripping of threads or the eventual loosening of things if they were set correctly.

The Assembly Begins: The first thing to go in the block is the camshaft. But first the front mounting plate and gasket needed to be installed. Once tightened down, make sure that the cam journals are clean. Once cleaned liberally apply oil in all the journals. The inner ones are tough, but they need to be oiled. There are engine assembly lubricants or I just use a thick oil treatment lubricant like STP or "Motor Honey". This stuff is thick enough to stay put and will provide enough lubrication when you first start the motor. Carefully slide the cam in, while you are also applying oil to the can bearing surfaces. Once in, you can install the cam retaining strap.

Next step is to install the timing sprockets and chain. But first you need to make sure that the crankshaft is at TDC as well as the rotational position of the camshaft. I had pre-marked the sprockets so that they can be easily positioned to align properly with the chain. The book describes the next step as if it were easy, but the reality in my experience it ain't so. Most of the engines I've done, the crank sprocket is tight. I'm sure some slide on real easy but most of the time they don't. In the case of the Spitfire motor, I install the crank sprocket first. You also need to verify that the cam and crank sprocket are in the same plane using a straight edge. Once set, the chain is placed around the crank sprocket, then the cam sprocket. There is enough play that the cam sprocket can then be placed at the end of the cam and tightened down. New lock washers and an amount of Loctite are applied and the bolts torqued to the proper specification.

Next step is installing the studs for the cylinder head. It's a bit cumbersome since you have to double nut every stud to tighten it into the block. With the exception of the right rear two studs, they are the same length. Those other two are a bit longer because they also hold the rear engine lift eyelet. I then put in the lifters. I apply a lot of lubricant to the cam lobe surfaces as well as the bottoms and the sides of each lifter. Next comes the head gasket. Make sure the top of the block is clean and the gasket does not have any errant contamination. The oil galley passages between the block and the head are notorious for leaking oil. Some gaskets will have a crush ring around those openings but the stock Spitfire gaskets do not. I apply a small amount of Hylomar around those oil passages on both sides of the gasket. (Blue stuff on the gasket in the picture.) This will at least give me a fighting chance of preventing one oil source leak.

Next is the fitting of the cylinder head. Wipe it down to make sure that it does not have any crud on it. This slides nicely over the studs and will sit nicely on the block. Since the block was decked square and the head skimmed flat, we are assured of a nice tight fit when everything is torqued down. Place washers on the studs and finger tighten all of the nuts. Torque setting for the head is 42-46 ft/lbs. The torque order is critical and you follow that order exactly as published in the book. I start at 10 ft/lbs, then 20, then 30 and then the final to 44 ft/lbs. Remember, follow the proper order each time.

There are six additional studs that get installed on the head. Four are used for the rocker shaft pedestals and two are for the valve cover. Good old push rods get installed through the opening of the head and into each lifter opening. Before you place the rocker shaft assembly onto the head, back off each of the tappet adjusting screws. Next take your rebuilt rocker shaft assembly and fit over the four studs. You will have to move the push rods around a bit so that they meet up with the rocker arms. Install the washers and nuts on the pedestal studs and finger tighten. This takes a while, but I tighten each nut a half turn starting from one end to the other. This assures that I'm not putting any undue strain or bending to the rocker shaft. By doing this slowly, you can also make sure that the rockers and push rods are properly joined. Once tightened down to the block, the torque wrench is used to do the final tightening sequence.

I installed the crankshaft pulley because this gives you something to grab onto for the next step. Now is as good a time as any to do the valve tappets. The motor won't be any colder than it is now and since you do those adjustments when it's cold, perfect time. The front of the motor and the sprockets were all previously marked for #1 cylinder being at TDC, so you have a base to go back to if you get lost. The Spitfire manual has a nice adjustment order for the tappets that avoids having to rotate the crankshaft more than necessary. The exhaust and intake tappet clearance is .010 so only one shim is needed to check with. Some motors have different specifications for intake and exhaust but this one is the same all around.

Next Time: This is enough for now. Part 2 will cover some of the other engine assembly steps as well as the transmission to the block mating ritual. Finally we'll get to see the finished product being installed back in the frame. I will also review costs of the entire project. You will be pleasantly surprised.

Special thanks to Andresen Engine Development who did the machining and short block assembly. Revcore Radiator for the excellent recore work on the original radiator and to British Parts Northwest in Oregon who supplied all of the engine parts as well as technical advice on cam selection.

By Joe "Stagmeister" Pawlak