Don Terrill’s Speed-Talk

He needs to let it get up to operating temperature so that the water vapor/moisture burns off. Oil temp specifically needs to come up.

We called them "altitude compensators." It's an aneroid bellows, as mentioned above.

They were pretty rare, and also took up space where the mixture control solenoid was in the E4ME carbs.

I remember those! Yeah, we used them on lower division cars where the rules stated something to the effect of no machining on the heads, must have stock valve spring pockets. Or some other crap like that. Going way back though.

Agree, a bit of extra gap hurts nothing, .001" less than required does. I'd go .027" top & .024" 2nd & not lose any sleep over it. ^^this^^ As we tell the people adding boost to their otherwise stock short blocks, "Big ring gap = big catch can, small ring gap = big trash...

Use a machinists round bar. Or a straight edge will work in a pinch. Put the bar in the saddles and shine a flashlight from the backside to see which one(s) have the gap, then check with feeler gauges.

The BTCC approach is too gimmicky. Nascar, Indy Car and NHRA had legitimate reasons for slowing down the cars; Nascar reduced speeds when the cars started flying off the track and into the crowd. Indy Cars started slowing down after the Texas World Speed fiasco and drivers were close to blacking out...

Cam King had the best reply. But it's not *just* iron vs aluminum. The expansion coefficients of the valves themselves matters, too. Titanium vs the various grades of stainless vs inconel vs steel. And then there's the seat material. Iron vs steel vs beryllium copper/bronze. All have varying expansi...

Mike's right, you need to "change" the rear gear to compensate for the taller tire. We all know that a taller tire acts like a taller gear, but that was not the point. We want to see if having a larger tire contact patch will help the car hook harder and lower the et, all else equal. The o...

For the first one, my guess is those engines weren't as equal as they were spec'ed. Every camshaft lobe was measured, every port, every carb checked for fuel flow, etc? This just reminds me why stock engines in spec classes are like 3x what a complete long block MSRP's for from the OEM. I'd also th...

Regarding Hemi chambers; the spark plug is not in the center, it's offset. And when twin plugged, the standard change is to back the ignition timing off 5-10 degrees from single plug. If you look at pent roof 4 valve heads, with a decent chamber and centered spark plug, timing is indeed backed off s...

The OP never stated the application. In Stock Eliminator, the lift rule was somewhat circumvented by having somewhat softer valve springs and carefully controlling the retainer to valve guide clearance. The cam was designed for valve float (aka "loft") and knocked the valve open further th...

For reference, Calvin's "Log" header. IIRC, it only lost something like 10hp vs the best Cup car header setup. Calvin has a thread here if you're interested in going down that rabbit hole. FWIW, there are far different criteria for "success" with respect to emissions testing than...

The fluid oozing up is normal. The compensating port is still open at the beginning of pedal travel, so the fluid goes back into the reservoir before the piston moves far enough past the compensating port and pushes the fluid out of the outlet. The bleeding problems sound like a combination valve is...

The rule of thumb applies to your current type of build, ie front engine, rear wheel drive, with a live rear axle. Yes, there's theory and practical experience behind it. IIRC, the Mustang II front end had a roll center of about 7/8" from the factory. BUT, obviously changing anything will alter...

What I meant was that the height of the rear roll center is dependent on the size of the rear tire. I.E., if you have 10' wide wheels, 5-8" rear roll center is a good starting point. 15" wide wheels and you would need a rear roll center about 10" or so.