Don Terrill’s Speed-Talk

Thanks for your reply's. Seems the moderators do not have any interest on that or no time to care or respond about it. I see in online talks wording get sometimes more harsh and angry then in a real face to face situation, as body and face communication are missed. Online that get sometimes compensa...

Toyota used laser clad valve seats so they could run less valve margin, and run a larger intake valve, because with their tumble designs, they aren’t using the full diameter. The Honda paper with the 2 valve hemi does something similar. I see your point, pointing in a similar direction like the abo...

The stock 35mm valves are pretty big, but I think others have installed 36mm or even 37mm intake valves in those heads....I don’t see any meaningful penalty from larger valves in terms of combustion quality, as the larger valve reliefs can presumably be made smaller at the same flow rates. I got yo...

Like rebelrauser mentioned, it depends on many things. Just to name a few: bending of bearing axis through oscillation of load, torsion and their dynamic (vibrational) and precision of manufacturing. I run several oil endurance tests on race engines with 30 weight oils, revving up to 10,000 rpm. I g...

Why not put in the biggest intake valves that fit and aren’t shrouded and then keep the port small at valve guides? The biggest unshrouded would be around 33 mm at intake and around 28 mm at exhaust. That 4-valve head has shrouded areas already from OEM status on. May we define how much shrouding s...

Thanks

Fortunately, the vintage flathead classes don't allow EFI and certainly not DI, as I've always felt flowing dry air should help NA flatheads increase their VE and that would be a very expensive experiment with a steep learning curve. The carburettor technology went far away from the huge Venturi's,...

If you seat between the air molecules at for example 100 m/s and your body is having some weight, it is easy to understand you won't follow the bend immediately and only with some friction at your neighbour molecules. The approach to "squeeze" the port like a garden showering hose with two...

Thanks guys for your feedback. I would be interested was the Moderator team (@CamKing, @BigBlockMopar) is thinking of it.

BCjohnny wrote: ↑Sat Oct 01, 2022 4:16 am Back in the early/mid nineties when I was designing a lot of high powered geared starter motor stuff I was asked ..... by a very 'promising customer' ..... if I knew anything about alternators ......

Very nice. Which company?

After have read many documents and books i've got that One of the weak point of low Angle ports Is the short side radius. So almost all the head porters suggest tò rise the floor in order to improve the SSR and enlarge the port on the sides to achieve the correct cross section area. Rising the floo...

Earland Cox years ago did a clean sheet kind of study on ports with slices of tubing, and one thing he found that I thought was very clever was that 'the flow should be aimed at the valve". ok sounds dead simple right? But all real ports are always angled and curved so that can't be maintained...

Just thinking, higher port angle could also limit some cross flow :-k A higher port angle changes everything. You can run bigger throats and valve sizes to gain the same port efficiency. You remember the example of the I5 Volvo head for BTCC?! Yeah, you do. It changes also the tumble number as the ...

ptuomov wrote: ↑Mon Oct 03, 2022 7:41 am As small as possible is still going to be pretty big.

Stock sizes are 35/30 mm on that 4-valve head. Keeping it smallest would mean staying there just to give that qualities a number.

If they aftermarket-head drag racing gentlemen are running 14:1 CR, what's chamber volume in their head-piston combo? About 50.5-51.5 ccm. Dome volume looks like the Mount Everest. Since you're looking to make 92.5hp per 500cc cylinder at 10,000rpm, I personally think that you will also have to &qu...