First Time On A Dyno -- Jon's 1971 MGB "Racecar"

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A transcript, summarized by AI and edited by a human staffer, is below.

[Image: YouTube/Michigan Automotive Relic Society]

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Transcript:

Here is the cleaned-up transcript. I have removed the timestamps, filler words ("uh," "um"), and bracketed sounds to create a smooth, narrative flow.

The Dyno Day: 1971 MGB

I started doing the dyno pulls, but I didn't understand the instructions. It couldn't go that right for me. Meow. If that actually starts off at 122, I'll be pretty impressed. No way.

The Build

For context, this is my 1971 MGB that I call my race car. This engine is actually a 1976 engine, so it’s a small valve head with HIF4 carburetors off a '74. As far as the motor build goes, it has flat-top pistons, a mild street cam, dual valve springs, electronic ignition, and a balanced bottom end.

It kind of always lived its life with a Weber carburetor. I got the whole engine from a wrecked car that was a very nicely restored vehicle that was, unfortunately, rear-ended. A good friend of mine had built this motor and had it in that car for a long time, and it always ran well for him. So when that car got wrecked, I had to buy it, and the whole driveline ended up in this car.

Heading to the Dyno

It is a very rainy day in April. I have my 1971 MG loaded onto my trailer and I’m heading out to Holland. We’re going to strap it to the dyno and just see what it makes. I don’t anticipate doing too much tuning; I just want to know the numbers—just to be disappointed in them, honestly.

I got the opportunity to take it out to Eclectic Motors in Holland. Carlo was being awesome and let me do some dyno pulls so we could get a good baseline to build off of, but also just to see what it does because the thing is pretty much entirely built out of spare parts.

The Pulls & Technical Troubles

I went up to 5,000 RPM. I saw a spark fly somewhere in the front of the motor. Then the signal dropped off. Of course, the day didn’t go smoothly; that would be way too easy.

I started doing the dyno pulls, but I didn't understand the instructions. I spun the car up to 6,000–6,200 RPM, floated the valves, blew the breather hose off the engine, and sprayed oil everywhere. It was an action-packed morning.

The thing I love about going out to Eclectic every time is that I always learn a lot.

The Results

After multiple runs on the dyno, blowing the breather tube off, and spraying oil everywhere, it eventually made 61 horsepower and 73 pound-feet of torque. Max horsepower was at 4,600 RPM and max torque was at 3,200 RPM.

It was really eye-opening today to know that 60 to 70 horsepower is roughly average for an MGB. I’m glad to know that this is making actual good power for an MGB engine. It’s also reassuring to me because I’ve always had a ton of fun with this car, even when it was making a little less power before I put these other carburetors on it.

It’s just nice to know that I’ve been having fun with what most people would consider "no power" in a car. It’s plenty rowdy for me.