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Blueprinting basics

3 October, 2025

Just building your engine the way it was supposed to be will unleash smooth power and longevity, then you can port and polish to gain even more
By Jim Richardson

Make sure your engine’s heads and decks are ground flat while the engine is down

You occasionally hear petrol heads tossing around the term ‘blueprinting’ when referring to an engine they have assembled, and have sometimes altered significantly.
What they are probably trying to say is that their engine was carefully machined to optimum tolerances and balanced — probably for racing. But that isn’t what the term meant originally. You see, in the 1950s  when US stock car race cars really had to be stock, the racing teams would go to the factories and rummage through the parts bins until they found components that were closest in tolerance to the original blueprint developed by the engine’s designers.

Install clutch and vibration damper on the crankshaft when you balance it

Producing the best possible engine
They did that because carefully assembling such components would produce the best possible engine, given the original configuration. It worked well, and you can do the same today. Start by finding a good machine shop. And even though you are building a stock engine for a classic, consider the specialty shops that build racing engines to machine your motor. Their services will cost more, but the speed freaks are used to working to exact tolerances.
Also, any engine will benefit from having its rotating assembly balanced. When the pistons and connecting rods weigh exactly the same as one another, and the crankshaft counter-balance weights are drilled or filled to precisely offset the weight and mass of the pistons and connecting rods, the engine will run smoother, rev higher, and last longer.

Weigh each piston and rod to make sure they are all the same

Some good tricks
Don’t forget to take along the flywheel, clutch, and clutch plate, as well as the vibration damper, when you have your engine’s rotating assembly balanced. The flywheel and clutch should always be balanced, and in some cases, the vibration damper should be too. Once everything is properly balanced at the machine shop, you’ll be amazed at how smooth your old engine will idle, and how little — even at high rpm — it will vibrate. 
Another trick that can really make a power difference without doing anything to alter your engine’s appearance is to clean up its intake and exhaust ports. Just cleaning out the roughness and slag in the ports will make a big difference to your engine’s performance. It takes time, plus a high-speed grinder and some abrasive rolls to do it, but it is worth the trouble. The point isn’t to make the ports bigger as much as it is to clean them up to eliminate turbulence. If you want to see how this is done, Google YouTube and type in ‘porting heads for power’ by Jim Richardson.
In addition to removing slag and surface roughness, you can open the valve throats (also called pockets) and clean up and open the port runners to match the openings in the gaskets for additional power. Nothing you can do to most production engines will increase performance as much as pocket porting its heads. But I suggest you practice on a scrap head before you attempt it, or have a good machine shop do the job for you.

When you reassemble your engine, it pays to use new studs and bolts

Valves
Another trick that can help your engine perform better is to do a valve job with a three-way cut.
Start with good-quality valves that can take unleaded, and if required, go to insert valve seats, and have your machinist do a three-way cut to seat the valves. This reduces drag right where it is the biggest problem, and enhances power. The cost is not much greater than a regular valve grind and is worth the trouble.
When assembling the connecting rods and mating the heads to the block, as well as the manifolds to the engine, use new bolts because your old ones may well have been stretched to their elastic limit. Also, when mounting heads to blocks, studs are a better way to go. Studs and nuts have a lot more clamping ability, and they can be torqued in place more evenly because when you tighten a nut on a stud, you aren’t twisting and clamping the stud and nut at the same time, the way you would with a bolt. ARP makes top-quality bolts and studs, and I recommend them highly.
Never use ordinary hardware store bolts when assembling an engine.

Measuring the crankshaft journals to make sure they are correct

Coaching from the bench: Casting plastic knobs and rubber parts

16 July, 2026

Casting rubber items is simple if you have a good original to work with. The item doesn’t have to be perfect. You can use plasticine to smooth out cracks, and you can even make whole prototypes out of low-fire modelling clay available from craft stores if you need to. Prototypes can also be made of wood or metal.
You will need mould dams to contain the liquid urethane moulding solution until it cures. You can build boxes out of strips of wood, but I have found that small plastic boxes and bowls such as those you would use for leftovers in your fridge work well if you spray them with a mould release agent.
Temperature is important to the chemical processes involved, so work in an area that can be maintained at around 20 degrees. You will also need adequate ventilation because the fumes can be dangerous to breathe. And you will want to wear latex gloves to protect your hands.

Fraser Cars – low flying into the fourth decade

10 July, 2026

With almost three and a half decades under its belt, Fraser Cars is one of New Zealand’s longest-surviving car manufacturers. The company first opened its doors for business in 1988, during the boom time for kit manufacturers. During the ’80s, around 40 different companies were building kits and turnkey cars for this niche market. Of those, only Fraser and Almac Cars (established 1981) are still in business today.
Most of the new kit car companies were killed off in the cradle by the threat of new legislation that never eventuated and definitively by the sudden availability of high-performance Japanese cars when the floodgates to second-hand imports were opened. The now long-retired founder of the company, Neil Fraser, first came across Lotus Seven replicas while racing Lotus Cortinas in the early ’80s. He regularly found himself racing against a little Caterham, a Lotus Seven–styled car built in England. He was very impressed by its simplicity and handling. In 1986 Fraser built his own Lotus Seven–type car, using the knowledge he had gained from several close looks at the Caterham.