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The Engine


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August 15, 2002 -- Shortly before making the decision to sell my '67 Spitfire with the high compression (9.0:1), small journal 1296 engine, I got word from another local Spitfire enthusiast that he might be interested in selling his freshly rebuilt large journal 1296 engine and rebuilt three-rail, full-synchro Type D overdrive transmission, which had come out of his 1972 MKIV. Somewhere along the way, he opted to install a larger 1500 engine and single-rail Type J overdrive, after putting roughly 500 miles on his completely rebuilt MKIV drivetrain.

Larry Holt's Speed Shop in San Diego has been building racing engines for decades on El Cajon Blvd. and is run by father and son. A visit to their shop is like walking back into a time machine to the late 1960's or early 70's.

I have to admit that knowing a good, locally rebuilt engine was waiting in the wings helped prompt my decision to sell the '67 incarnation of "Mrs. Jones". For their part, Holt and son had magnafluxed the block, confirming that it had no cracks, bored the cylinders .020 over, fitted new pistons and rings, enlarged the valves and installed hardened seats, polished the crankshaft, ported, polished and flow tested the head and balanced the complete engine. The stock MkIV camshaft was retained (significantly detuned from the earlier Mk3 engine specification for the 1296),the compression was measured at 7.5:1.

With the engine's previous owner in tow to make the introductions, I paid a visit to Holt's Speed Shop and explained to Larry and his son what I wanted done. My basic plan was to meet or exceed the specs that my earlier Mk3 engine had. The goal was to strengthen the powerplant and modernize it as best I can to strike a balance between performance and reliability. I wanted to be able to wind the tach up to 7,000 RPM on occasion without having to worry about the engine flying apart. The first thing I bought was a 4-2-1 high performance header, and had it ceramic coated. This does two things. Keeps the engine compartment cooler and keeps the exhaust gases hotter as they flow out through the tailpipe.

It took nearly two months due to their heavy workload, but in addition to the work they had done previously, I had Larry & son: install a lightened flywheel, shave approximately 125mm off the head for a new compression ratio of roughly 9.3:1, install a 4.25 lift, 275 degree cam to exceed the earlier Mk3 specs and a few other goodies. Superior ARP fasteners were obtained and used for the connecting rods, cylinder head and flywheel. Dual valve springs were fitted, and the lifters were Parkerised at the suggestion of a respected Triumph racing authority whom I also purchased the high lift cam and springs from -- and the entire assembly was once again re-balanced.

Although it was sometimes tough to convince the engine builders that the intended mods were proven and acceptable, initially at least, I think they were wondering why in the heck I would bring a perfectly well-functioning engine back for more work. Their concerns lied mainly with shaving too much off the head in case any casting defects might surface; and also with the increased lift of the new cam. They were afraid that the pushrods might be too long to provide enough clearance at the tappets, but they worked just fine. Their apprehension and caution was warranted, as these guys are used to working on high output American V-8's, not British re-engineered tractor motors...

I feel confident that my objectives with the engine have been achieved, and according to calculations by some of the engine experts on the TTN, my horsepower rating should be somewhere between 110-120 BHP, which should offer some exhilerating performance, well exceeding my previous engine's capabilities.

Larry Holt and son seemed to have done a fine job. The engine was returned painted and perfect. Since literally everything on this car is new or newly and totally rebuilt, I'm going to set the odometer to read 00000 before fitting the speedometer. It only seems fitting, and since no accurate record of the original miles exists, and it's quite legal in the state of California.

A new starter motor and generator have been purchased, but not yet fitted. The generator hasn't arrived yet (should be here tomorrow) and I lacked the spacer for the starter motor, but was able to find one on eBay. I pulled a NOS AC/Delco fuel pump with the priming lever out of storage and buffed out the top cap to a gleaming, chrome-like shine. I started by hand, but wound up using my die grinder with a small buffing wheel attached. I liked how this turned out so much, that I'm going to buff out my recently bead blasted starter solenoid as well. There's going to be a great deal of glimmer in the engine compartment. The high voltage coil is chrome, and the radiator shrouds were fashioned out of sheet aluminum for better heat dissipation and polishing potential.

Last weekend was the big day. We lowered the engine into the chassis, fitted the manifold gasket and using a rubber mallet, carefully tapped the ceramic coated stainless steel headers into place. Then, we finished lowering and temporarily fastened the motor mounts. Temporarily, because new holes had to be drilled for the rear mount to accomodate the swap from standard to overdrive gearbox. After marking the holes, we removed the front mounts and lifted the engine up a few inches again to drill the holes. Then, I fitted the refurbished Delco type D200 vacuum advance distributor.

After that, the powdercoated radiator cradle was installed, then the NOS Clear Hooter horns on freshly painted brackets.

Today, I fitted the restored, and modernized radiator. The chassis is really beginning to take shape now...

Soon, I'll be fitting the plugs, wires, Keihin quad carbs, oil filter, a new thermostat, temperature sender, etc.

8/18/02 -- I had opted to go with NGK spark plugs and picked up a set the other day, not realizing that due to the modifications to the engine, a "cooler" plug will be required (as in temperature range). There's still a lot I don't quite understand on this topic, but I've learned a lot in a short time thanks to an excellent link to the NGK website by TTN member Rob Travis a.k.a. "SloSpit". The bottom line is that my hotter cam, higher compression, etc. call for a different type of plug than the standard type in order to avoid pre-ignition and potential engine damage. As a result of my research, I'm going to be ordering a set of the NGK BPR7HS plugs.

8/19/02 -- After an e-mail exchange with a rep from NGK in which we discussed the mods to my engine, and after learning on the TTN that Spitfire cylinder heads all have a 3/4" plug thread, I settled on a set of NGK 7131 (BPR6ES) plugs. One range cooler than the standard NGK plugs for Spitfires. I've been waiting for a spacer in order to mount my starter motor, and it showed up today, along with various parts that I needed, like a valve cover gasket, a Lucas generator (I know, I know, I should have installed the Delco alternator conversion!), temperature sender, a new distributor cap and rotor, etc.

I have also installed the Pertronix 1149C electronic ignition module onto my distributor. I had a more difficult time with the magnetic collar than I think I should have had, however, and plan a call to Pertronix on the off chance they sent me the wrong one. I had to use a socket driver and a rubber mallet to drive the magnetic collar home over the distributor shaft and I shouldn't have been required to do that.

With any luck, the engine should be ready for me to start dumping oil into it soon.

4/20/03 -- I'm happy to say that the engine is complete and running in the now-finished car. I've picked up a Delco Type 200 '460 distributor, which were fitted to the high compression Mk3 engines. I haven't fit it yet, but plan on swapping distributors sometime after my new intake manifolds arrive from Carter Shore. These will have longer tubes and vacuum ports.

Several months ago, I wound up removing the electric fan when I came to realize that I had mounted the radiator on the wrong side of the mounting bracket, which among possible clearance issues with the bonnet, sat too far forward for the hoses to be connected. I opted to go with the mechanical fan for the time being, but will later supplement cooling with the electric fan out front acting as a "pushing" unit. I had wanted to install it as a "puller" behind the radiator (as shown in the photos above), but it would not clear the water pump when the radiator was installed in the correct position.

Regarding cooling, I have not yet driven the car on our hottest summer days, but have driven it in 90 degree temps and have not experienced any cooling problems, even at idle. I'm using Xerex racing coolant, which was recommended to me by a fellow enthusiast.

For the time being, at least, this project is complete!

 

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