Don Terrill’s Speed-Talk

Because of limited space for updraft carbs on tractor engines, I am in the midst of redesigning some of the round bore updraft carbs, that I have built over the last 7 years. Making them more compact while retaining all their good characteristics, is challenging,

This is a prototype carb. It will be run on a 540" Farmall 4 cylinder vintage pulling tractor engine. I believe that this engine will have 4.875" bores and a 7.250" stroke. 2500 rpm is considered to be screamin', for this one.

One of the next things, is to make a short oval velocity stack, and compare the flow to what was obtained with this oval to round transition pipe and round velocity stack.

I've developed an oval venturi/oval throttle bore single barrel updraft carb for large displacement vintage pulling tractors. The rules usually say that any tractor that came from the the factory with a single barrel updraft carb, must still use use a single barrel updraft carb. But there hasn't bee...

My experience has been that,black absorbs way more heat, both in radiant heat from the engine and the hot air blast from the radiator.

Or a pulling truck. About the only competition application, where deceleration pulls make sense.

Yes, 'train wreck' is an appropriate term for the distribution in many intakes, particularly 2 plane intakes. The late Harold Bettes, told me more than once, that "intakes manifolds are some of the worst devises ever invented by mankind". Once we got to using a data acquisition system with...

It depends on the combustion efficiency of the engine. For those not so efficient engines, a "flat" A/F ratio curve tends to yield the best overall power curve. For more efficient engines, a leaning trend as the rpm's increase, is usually what they like. Do not assume that BSFC numbers are...

Setting float levels with the engine off, requires you to submerge the floats much deeper in the the fuel to try to control the fuel levels. If you are using an conventional regulator, doing that with the engine off will also, most likely, give you fuel pressure that is much higher than you want, du...

What you're experiencing, is one of the scenarios that occurs when you try to set float levels with the engine not running. Also, if you are using a conventional restriction type fuel pressure regulator, fuel pressure will creep up to whatever an electric pump is putting out, if you are not running ...

A couple things to look at. 1) The 3310 bowls should take needle and seat assemblies that are 1.450" overall length. There are some assembles that are 1.500" overall length... those may not allow you to get the fuel levels up to the bottom of the sight holes. 2) Float levels should always ...

You would think we would have heard something by now. The silence is not encouraging.

Has anyone heard anything about the Race Engine Challenge or the Masters of Motors competitions for '21 ? I haven't heard anything, and neither has anyone I know. It appears that they have been cancelled again, but I hope that isn't the case.

Hi Mario. I sent some info to you in a private message. Norm/CFS

Yes Mario. The Depac tach signal generator is a stepper motor. There are many different sizes and configurations of steppers. I’ll look up the specs for the ones that work with the Depac, and get that info to you. Norm/CFS