Don Terrill’s Speed-Talk

Looking at these 2 lobes in average inch degrees. ► 0.050 /((288-236)/2) = 0.0019230769230769232 ► (0.347-0.050)/(236/2) = 0.0025169491525423729 ► 0.050/((274-224)/2) = 0.002 ► (.359-0.050)/(224/2) = 0.0027589285714285715 ► 0.0027589285714285715 / 0.0025169491525423729 = 1.0961399711399711 - From 0....

Using Bore = 4.04", Stroke = 3.75", Rod = 5.7" Using an engine with a SCR of 15:1, and a DCR of 11.38:1 I get an IVC of 70.55 ABDC and and a cranking compression of 324 psi ======== Using Bore = 4.04", Stroke = 3.75", Rod = 5.7" Using an engine with a SCR of 10.66:1, and a IVC of 70.55 ABDC I get a...

Using Bore = 4.04", Stroke = 3.75", Rod = 5.7" Using an engine with a SCR of 15:1, and a DCR of 11.38:1 I get an IVC of 70.55 ABDC and and a cranking compression of 324 psi ======== Using Bore = 4.04", Stroke = 3.75", Rod = 5.7" Using an engine with a SCR of 10.66:1, and a IVC of 70.55 ABDC I get a ...

I come up with the same Total volume and CR. But the true CR is lower because I would also use the volume above the top ring. Let say the diameter above the top ring is 4.0" and the top ring is 0.125" down. that would give you another 0.517389 cc's for a Total Volume of 82.05572 cc's and a CR of 10....

Nut124 wrote: ↑Thu Feb 25, 2021 7:43 pm Do the calculators use total compressed volume (head, gasket, piston, deck ht) or just the volume of the chamber in the head? Big difference.

C1500SBC, what does your 64cc number include?

Most DCR calculators ask for the CR (already having been calculated).

Stan

What calculator do y'all like to use? I've used two different ones online, same exact information on both, and one gave me a DCR of 8.91:1 and the other gave me a 9.86:1. Which obviously is a confusing/worrisome issue for my current build if its the 9.86:1. It seems to run fine on 93 pump gas at fu...

For the 097 all lash is set at 0.008" lifter raise. I have 285 degrees for 0.008" lifter raise. For the 30 30 the lash is set at 0.020" lifter raise. I have 314 degrees at 0.020" lifter raise.

Stan

Not sure how good the numbers I have for the 097 are. This shows the 097 with 1.5:1 1.6:1 1.7:1 1.8:1 and the Chevy 30 30 with 1.5:1

Stan

From July 2020. I know some of you coming in here and reading this thread are saying they added Pontiac? The answer is yes we added Pontiac because I like Pontiac. I want to thank Mike / Pastry_Chef for all of his help during the development of the Pontiac version. I am, although very slowly working...

In this article he said he shifted @ 9000 RPM.

Also he was not running real high CR.

Stan

OK looking at the article again I guess my cam was not that far off. As Jack said this was a different era. My roller was on a cast core. Stan jenkings_CC_75_Cam.gif VALVE_____Lift______Opens___Closes__Duration _________________Deg_BBDC__Deg_ATDC_____________Area _________0.00000___102.52_|_102.38_|...

From an article in Car Craft Jan '75. The PDF is to large to post.

Stan

This is the Intake from my GK roller from around that time. My understanding is Grumpy's was a very steps wilder. Stan _______I__N__T__A__K__E Rocker_Arm_Ratio_=_1.500_________Valve_Lash_=_0.02400 VALVE_____Lift______Opens___Closes__Duration _________________Deg_BTDC__Deg_ABDC_____________Area _____...

The problem I am having is that I bought 6" replacements for these, and the replacements are about 1mm longer. Five of the rods in this strangely marked set are kinked, but my best rods all measure the same, about 1mm shorter than what I was to replace them with. They came milled for cam clearance ...

While it has nothing to do with lift. I did sometime ago start to add exhaust duration to the calculator. I really need to do some more work on it, maybe someday I will get to it.

http://www.magneticlynx.com/carfor/calccamb.php

Stan