Don Terrill’s Speed-Talk

123 Ignition has been around for awhile, the Bluetooth option has been available for a couple of years.
Easy way to get programmable ignition on cars with 'legacy' distributor ignition.

Street/Strip SBC or SBF safely revs to 6000 rpm How much more money and how much shorter life to build to: Safely rev to 6500 rpm? Safely rev to 7000 rpm? Safely rev to 7500 rpm? Safely rev to 8000 rpm? Bearing loads and component loads are from 2 main sources: Gas loads on piston crown : intake,ex...

Better to have bolts that you know are a little stronger than they need to be, than bolts that you wonder are strong enough than they need to be. I see ARP rod bolts for my application that are spec'd at 200k psi, vs the stock bolts that are 100k psi. Yet ARP recommends the same 48 ft-lb max torque ...

Hydrodynamic bearings only generate an oil wedge to support a load when operated with the journal center offset from the bore center. In bearing load design calculations, this offset term is called 'eccentricity', and is a fundamental factor in supporting bearing load that is generated. When eccentr...

Big time racing is Show Business, emphasis on 'Business'. and 'Show'.
Drivers and cars are the just the 'Product', it's the Money made from the Consumers that drive things.

A toolpost grinder for the lathe permits grinding precision multi-angle compound seats, plus valve head and face shaping. More time consuming than a Serdi or similar tool, but gives ultimate flexibility to do whatever you want. 5C collets can be had for any valvestem size, and clamping close to the ...

Just remember that ring gaps change by factor of Pi * bore diameter change.
So for each 0.001" of bore increase, gap increases by 0.00314".

I'd be amazed if the major OEM do not have this data. The FEA software is good enough and fast enough and cheap enough that they routinely model everything first, and then do real world testing for final confirmation of the data model fidelity. Modern 3D metrology scanning can easily detect 0.001 or...

On a water pump application, both the thermal inertia and the coolant velocity inertia should be high, so PWM frequency control should not need to be any faster than say a few per second. Duty cycles between 0% and 100% should easily handle the task. What main parameter would you use to control the ...

I made a steel tapered compresser. My application requires range of 2.900-2.950 and there were no standard ones I liked. I used a piece of steel 3/8 wall pipe. On my lathe, cut off a 2" long piece, finished outside smooth, and bored the inside to 2.950. I took a tapered inside cut over about 1....

To isolate tire friction from the floor when aligning or doing cornerweighting I do the following: Large Ziplock bag, Gallon size works well. 'Personal Lubricant' inside the bag, not too much, add just enough to make a thin wet layer inside when the bag is flat. If the floor is not flat and smooth, ...

Our oil pumps are positive displacement type (gear, gerotor, etc.) Oil is essentially incompressible. So at any given RPM, the volume of oil pumped will be the same. Eventually, all the oil drains down and winds up in the sump, to be picked up by the pump. All the restrictors do is change how much o...

A Carbon Fiber strand is very strong in tension, miserably weak in compression. The trick with it is to take advantage of it's strengths by controlling part geometry and construction. The buckling deflection of a column loaded in compression is a the critical design consideration, and CF can certain...

I first heard of this in an article 25 years ago from Car & Driver (or maybe it was Road & Track) discussing various methods. If you calculate the mass of all the steel balls vs a tubular pushrod … well, maybe the guy owned stock in a ball bearing factory. However, I've often wondered if a v...

5/16 bolts are obviously lighter than 3/8 bolts. As for strength, the tensile load limit on rod big ends is the strength of the rod bolts. So the sum of piston and rod weight times G loading at max RPM plus the max vacuum times piston crown surface are will determine what that maximum tensile load t...