The Intake Centerline -VS- Compression Pressure

[Guest Anonymous]

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[grumpyvette]

here read these

 

http://victorylibrary.com/mopar/cam-tech-c.htm

 

http://victorylibrary.com/mopar/header-tech.htm

 

 

this is some of the best basic cam info youll find so read this first,

http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm (lessons 1-8)

 

http://www.mercurycapri.com/technical/engine/cam/lca.html

 

http://ctfba.tripod.com/main/technical/cams/cambasics/cambasics.htm

 

http://ctfba.tripod.com/main/technical/cams/cambasics/GraphAttack.htm

 

http://moparjimsgarage.virtualave.net/camvalve.html

 

http://www.federal-mogul.com/speedpro/camshafts_speed_pro.html

 

look closely at the duration used for each MATCHING rpm range. ALSO KEEP IN MIND THE DCR AND OVERLAP MUST MATCH

look here

these are the valve timeing overlap ranges that are most likely to work correctly

 

trucks/good mileage towing 10-35 degs overlap

daily driven low rpm performance 30-55degs overlap

hot street performance 50-75 degs overlap

oval track racing 70-95degs overlap

dragster/comp eliminator engines 90-115 degs overlap

 

http://www.symuli.com/vw/camp1.html

but all engines will need the correct matching dcr for those overlap figures to correctly scavage the cylinders in the rpm ranges that apply to each engines use range.

http://cochise.uia.net/pkelley2/Overlap.html

 

http://cochise.uia.net/pkelley2/DynamicCR.html

[Guest Anonymous]

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[grumpyvette]

glad your paying attention

heres what it says

"Lobe Center Angle is the distance in degrees between the centers of the lobes on the camshaft.

To increase duration, cam makers grind the lobes wider on the base circle of the cam. This makes the lobes overlap each other more, increasing overlap. More duration = more overlap.

To increase overlap without changing duration, cam makers will grind the lobes closer together, making a smaller lobe center angle. Less lobe center angle = more overlap"

the "

This makes the lobes overlap each other more, increasing overlap.

 

ITS SIMPLY A mis-print it should read

 

 

This makes the lobes overlap each other less, decreasing overlap.

 

spreading the LSA decreases overlap with the same duration, narrowing the LSA increases the overlap with the same duration, look at the diagram again

 

 

as a general rule youll have a smoother running engine thats got a wider tq curve if you stay in the 110-114 LSA range, 406s and 383s with carbs and 4.56 rear gears and single plane intakes tend to gain a slight advantage from 106-108 LSAs but not enought to make up for the rotten idle in a street car!

[Kevin Shasteen]

Spiirit,

 

What is the purpose of your calculations, is it to:

 

1) Find the right Cam Duration

2) Calculate the correct Cyl.Pressures...at

a) low cranking rpms

low cranking rpms whose pressure builds when the rpms come up on the cam

c) a little of both a and b

3) Or...just for fun: learning & playing w/the duration & LSA

 

Remember LSA has two effects: one is that it aids, or detracts, from the low rpm power, and the second effect is it gives the engine a broad power band or a narrow power band. The narrow power band gives the sensation of an engine revving up quicker than the broad power band...thus a broad power band is great for a true streetable engine while a narrow power band is perfect for a Sat.Night Special or dedicated dragster.

 

If you have to retard a cam 10* is it not feasible that you have the wrong cam? As many cam grinders that are out there & as many cams that have been ground-surely there is a cam more suitable to your needs: one that doesnt require a 10* retardation: yes/no?

 

Kevin,

(Yes,Still an Inliner)

[Guest Anonymous]

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[Guest Anonymous]

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[fastzcars]

Boy Siirit, you really want to make a ruckus.