Engine Max cam lift on 302 ho engine

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GreyMare88

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Aug 30, 2020

#1

• Aug 30, 2020

• #1

I'm finally about to start on my build; I'm looking at a lunati cam with a .522 lift and I wanted to be sure of my valve clearance and I don't want to get something that I can't run in my engine....any guidance and help is truly appreciated.

 

M

Monkeybutt2000

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#2

• Aug 30, 2020

• #2

Need more details. What heads? Stock bottom end?

 

jrichker

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#3

• Aug 30, 2020

• #3

Max lift varies with cylinder head model and machining, piston top configuration, head gasket thickness, etc.
Use soft clay to determine piston to valve clearance as shown in the attached video

View: https://www.youtube.com/watch?v=4_ZdcAE67L0

Or

View: https://www.youtube.com/watch?v=Y66lvdHbm60

 

Last edited: Aug 30, 2020

G

GreyMare88

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#4

• Aug 30, 2020

• #4

I'm running GT40P heads; stock bottom end.

 

jrichker

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#5

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• #5

GreyMare88 said:

I'm running GT40P heads; stock bottom end.

Click to expand...

That still doesn't take into account all the possible variables. Do the clay method or you may wish that you had...

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

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#6

• Aug 30, 2020

• #6

Duration matter more than total lift. When the valve is full open, the piston is at the bottom of the cylinder.

so the entire valve event must be taken into consideration. You can go with pretty aggressive lift if the cam profile opens and shuts the valve fairly quickly.

You’ll need to post the entire cam events and have a cam guru (not I) make sense of it.

 

G

GreyMare88

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#7

• Aug 30, 2020

• #7

This is the one I'm looking at.

 

Attachments

• Screenshot_20200830-104434_Samsung Internet.webp

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R

Rcdgl

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#8

• Aug 30, 2020

• #8

Absolutely a must check. The clay method is cheap and pretty quick. I would do at least two cylinders. My Gt 40 heads cleared my trw forged replacement pistons. My AFR 185s with larger valves hit.

 

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GreyMare88

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Aug 30, 2020

#9

• Aug 30, 2020

• #9

Will check into it.

 

KRUISR

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#10

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• #10

I'm not a cam guru, but that cam looks okay for a stock 302. My Crower is a little higher lift and duration (with my 1.7 RRs) with no issues using 3-bar GT40s. I agree with others that the clay check method is best bet.

 

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GreyMare88

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Aug 31, 2020

#11

• Aug 31, 2020

• #11

KRUISR said:

I'm not a cam guru, but that cam looks okay for a stock 302. My Crower is a little higher lift and duration (with my 1.7 RRs) with no issues using 3-bar GT40s. I agree with others that the clay check method is best bet.

Click to expand...

Which one are you running; I was told about the 15511 but someone told me it was more suitable for nitrous than a blower?

 

KRUISR

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#12

• Aug 31, 2020

• #12

I have the 15512. It was stamped 222HR229 on the end of the cam.

Didn't know you were going with a blower. I'm naturally aspirated.

Attached are the cam specs of the 15511 and 15512. I printed them as pdf files from Crower's website.

 

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• camtag15511.pdf

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• camtag15512.pdf

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GreyMare88

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Aug 31, 2020

#13

• Aug 31, 2020

• #13

Cool; how is the power and torque with the 15512?

 

KRUISR

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#14

• Aug 31, 2020

• #14

I have not been to a dyno and not to the track. I believe I am in the 350-370 range at the crank (right around 300+/- to the wheels - I have a mostly stock AOD, upgraded VB only). This is based on running a street 1/4 mile distance. Leaving from idle, shifting at 5500, I hit the 1/4 mile distance at 4900 rpm in 3rd. Doing the math through the drivetrain (3rd gear 1:1, 3.73 gears and 26" tall tires) that puts me at 103 mph (speedo shows 165 km/h - basically the same).

Using on-line calculator, adjusting hp and weight (my car is 3750 with me in it) to get close to that speed. I am leaving at idle and the calculators probably assume drag type launches so I am likely a little better than what they come up with.