measuring cam lift with dial indicator

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Feb 4, 2012 | 04:14 PM

vjjack04

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From: Hereford AZ

measuring cam lift with dial indicator

I am attempting to measure cam lift with an in lifter bore adapter and a dial indicator....this not on and LS motor but on a 1st Gen SBC...I am getting .259 - what am I doing wrong.

Feb 4, 2012 | 04:18 PM

heavymetals

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From: Torrance Calif

Quote:

Originally Posted by vjjack04

I am attempting to measure cam lift with an in lifter bore adapter and a dial indicator....this not on and LS motor but on a 1st Gen SBC...I am getting .259 - what am I doing wrong.

Maybe nothing.

You do know there is a ratio?

You should measure the lifter end on the valve.

Feb 4, 2012 | 04:28 PM

vjjack04

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From: Hereford AZ

Quote:

Originally Posted by heavymetals

Maybe nothing.

You do know there is a ratio?

You should measure the lifter end on the valve.

Ok - I am just learning who to do this. The rockers will be 1.5 ratio.

So if I multiply that I get .3885

This is obviously a low perf stock cam....

Feb 4, 2012 | 05:29 PM

heavymetals

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From: Torrance Calif

Quote:

Originally Posted by vjjack04

Ok - I am just learning who to do this. The rockers will be 1.5 ratio.

So if I multiply that I get .3885

This is obviously a low perf stock cam....

OK!

Now check your math and measure the valve end.

(that # you gave sounds a little on the low side, but I don't know what you are measuring)

Feb 4, 2012 | 11:15 PM

vjjack04

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From: Hereford AZ

Quote:

Originally Posted by heavymetals

OK!

Now check your math and measure the valve end.

(that # you gave sounds a little on the low side, but I don't know what you are measuring)

I am using an 'in lifter bore' cam tool with a dial indicator. So it reads directly from the cam lobe. What you have said helps, but its still very slighly off, but I get it. I have a good short block 350 that when I took off the heads, hardly had any wear. So I am reusing the short block for my old 55 3100 truck. Just trying to figure out the stock info. Obvioulsy the cam is very stock. I will be changing that and the heads...

Feb 5, 2012 | 12:56 AM

heavymetals

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From: Torrance Calif

Quote:

Originally Posted by vjjack04

That sure isn't much lift compared to a LSX!

Must be a neat project.

Feb 5, 2012 | 08:06 AM

SMaster

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From: Evansville IN

Unless you're using a solid lifter your lifter may be collasping as you check it, affecting you total measurement.

In the end, take whatever you guy by 1.5 on a SBC. This is what most cam specifications are advertised by. If you're using different ratio rockers, then use that as the multiplier.

Feb 5, 2012 | 10:38 AM

vjjack04

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From: Hereford AZ

Quote:

Originally Posted by heavymetals

That sure isn't much lift compared to a LSX!

Must be a neat project.

You are right. This is an early 70s 350 and with multiplying the 1.5 that you schooled me on - and refering to some specs on the internet, it looks like a factory cam with about .390 on the intake and .409 on the exhaust. Would have been about a 250 horse 350. I am going to put a TFS top end kit on it with about .550 lift - comes with heads and dual valve springs...I am putting it in a 55 chevy truck....still a far cry from the .620 lift I have in my LS3 (in the '97 vette).

Here's what I was using to check the cam, no lifter required:

http://performanceparts.com/part/Comp-Cams/4925