CVO Technical > EVO

Compression too low for 600 cam?

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ltank:
My S&S V124LC has 10.2:1 compression. The S&S cam description "S&S 600 Cam - Originally designed for the legendary S&S 40th Anniversary engine, the S&S 600 cam has proven to be an exceptional cam in any large displacement engine with 9.5:1 to 10.5:1 compression - Good power across the rpm range - Requires high lift springs and normal clearance checks."
 I went Big Boyz EVO Calculator and figured my Corrected compression ratio is low than expected.
Will it damage my motor by being under compressed? According to S&S description I should have been good. Thanks

johnsachs:

--- Quote from: ltank on May 30, 2019, 01:01:06 AM ---My S&S V124LC has 10.2:1 compression. The S&S cam description "S&S 600 Cam - Originally designed for the legendary S&S 40th Anniversary engine, the S&S 600 cam has proven to be an exceptional cam in any large displacement engine with 9.5:1 to 10.5:1 compression - Good power across the rpm range - Requires high lift springs and normal clearance checks."
 I went Big Boyz EVO Calculator and figured my Corrected compression ratio is low than expected.
Will it damage my motor by being under compressed? According to S&S description I should have been good. Thanks

--- End quote ---
Usually the LC 124 twin cam engines are shipped with the S&S 585 easy start cams. 45 degree intake closing, and avg. 89 cc heads.
I just cc'd a new set of the 124 LC S&S TC heads for a shop when I changed the new beehive valve springs to dual springs.
If you're going to get involved, you might want to check the cc's of your heads compared to the S&S Twin Cam heads.
John

ltank:
 My V124LC custom built from S&S has the -10cc dished pistons and 585 cam but it starts running out of go about 4700 rpm. The 600 cam has more duration and should pull to at least 5500 rpm. S&S didn't add the High lift Springs or roller Rockers that normally come in the V124.  My shop added the roller Rockers and S&S but a Beehive spring failed after 477 miles and now has Fueling Endurance high lift Springs. The 600 cam runs good but I don't know if the 10.2:1 is good enough now and should consider putting in the  10.8:1 flat top pistons for a 9.3 corrected compression. Thanks

ltank:
Heads are 91cc

MCE:
Run the numbers on the BB calculator, see what the cranking compression ends up being. Should be around 190 for optimal TQ.

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