Don Terrill’s Speed-Talk

I know that it does in the plenum at the drags.

I have read somewhere that a big bowl acts as a storage area for the positive waves coming down the port [DM I think], also I think it was larry M that said the bowl needs to be around the diameter of the valve [along the head] This has always worked for me.

The cam lobe doesn't know what the rocker ratio is at the other end, the lobe only knows the force generated by the spring/rocker ratio. If the spring tension is sufficient to maintain valve train control at max rpm, don't see a problem with high[er] ratio rockers. I understand nascar engines are r...

Thanks for that, I am going to have to do some thinking on this one for sure.
Makes me wonder if you had a gapless top ring combo, would the gaps in the spacer ring line up??...

Protech Racing wrote: ↑Tue Nov 05, 2019 1:05 pm Long term detonation . If the ring gaps are all lined up, it has run for a while with light detonation.

I have seen this rings lined up before, what are the reasons behind this please?

If you already have a file to copy you can change tool offsets. This will "shrink" or "enlarge" the ports without actually redesigning it. Computers only do what they are told. But you can lie to them. Everybody talks about CNC heads, what usually I ask is, who did the original ...

Tell the computer to make it a certain percentage larger? Are cnc machines now using AI to CNC? You can't just stick a head in, type in that you want this hole this much larger and let it work. That's not how cnc works. If there's a pattern to follow, someone programmed that pattern. The cnc machin...

Everybody talks about CNC heads, what usually I ask is, who did the original porting you are coping, or did you just tell the computer program to make them a certain percent larger? Just wondering why don't the sellers of CNC porting advertise who did the work the program is copying? Seems they mig...

I have an Innovate ST-12 going cheap.

Why would you waste your time checking valve lash and replacing valve springs when you can just put a turbo on a 5.3 and make 800 hp reliably? Turbos and EFI have killed the naturally aspirated engine if you want to go really fast. This sort of thinking really pisses me off, twin turbo this, blower...

We see the gauge marks on the bearings all the time when we get the engine back for a freshen. no problems.
If anyone thinks this causes a problem, well then,I have a bridge I want to sell them!

How many people here have ever ordered a cam from one of the "professionals" and realized their specs were way off or ended up buying it to only install it and find it was not what you wanted are needed? Has anyone on this thread ever tested one of the "professionals" cam agains...

This thread went around the barn and around the moon, but I thought I should close the loop. Remember, the original question in this thread was a 6,000 max RPM 3.25" stroke engine. Back-to-back dyno pulls with the only variable being the high dollar deeper pan, windage tray, baffles and scrape...

We run in all of our flat tappet engines with Lucas 30 break in oil and then run the Valvoline VR1 10W30 racing oil. Have not done a lobe in years and I do mean years.

I don't care if it's a 4 cylinder, V6 or V8. I think it makes sense to scrape the oil of a rotating assembly. Oil flowing past a bearing doesn't know what engine it's in and needs to get back where it belongs so it can repeat the procedure and not rob HP.