TR CheaTR Cam Base Circle?
11-15-2009, 10:48 AM
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In my experience, stock LS cams have had about a 1.53 base circle. The aftermarket cams i have measured (low 220s duration) have been 1.48 or about .050 smaller.
11-15-2009, 11:19 AM
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I found an old post of yours and a 226/230 .569/.573 cam I measured was 1.48"
My 5.3L LH6 has a Cheatr cam with stock 799 heads and gaskets. Unfortunatly I dont have the stock cam anymore to measure it and the Cheatr cam is already in.
When I purchased 7.400" pushrods for my cam swap 3 months ago, I was accidently sent 7.350" pushrods. I got them exchanged now but last night I was measuring the stock pushrods I had laying around and they measured 7.375". So which makes me believe the 799 heads also have longer valves like the 243 heads.
-Basically, im trying to figure out which length pushrods I need with the cheatr cam.-
Here is some info on LH6 799 heads...
"IMPROVED CYLINDER HEADS
The Gen IV Vortec 5300’s cylinder heads have been enhanced for improved performance and efficiency. As a result, the LH6 delivers the horsepower and combustion advantages of a higher compression engine, yet operates at peak output on regular-octane gas.
The LH6 takes its cylinder heads from the LS6 V-8 that powers Cadillac’s high-performance CTS-V sedan. Originally developed for the Corvette Z06, these heads improve airflow in and out of the engine. With their pent-roof combustion chambers and new flat-top pistons (the pistons in Gen III Vortec 5300s have a slight sump in the piston deck), the Gen IV Vortec 5300’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency and increases horsepower.
Typically, however, high compression engines require high-octane gasoline to produce maximum power, or to avoid the potentially damaging effects of spark knock or “detonation.” The Gen IV Vortec 5300 does not require premium fuel to achieve peak horsepower. The seemingly incompatible objectives of high compression and regular gas were achieved by optimizing combustion chamber design and airflow to the engine, and through advanced engine management.
With the new heads, the Gen IV Vortec 5300’s valve springs feature a new winding geometry and more durable alloy. The LH6 also uses the solid Silcrome 1 valves originally introduced on GM Powertrain’s LS1 V-8. Compared to conventional iron-alloy valve material, Silcrome 1 includes tungsten, vanadium, manganese, silicone and higher chromium content. It is harder and improves durability."
My 5.3L LH6 has a Cheatr cam with stock 799 heads and gaskets. Unfortunatly I dont have the stock cam anymore to measure it and the Cheatr cam is already in.
When I purchased 7.400" pushrods for my cam swap 3 months ago, I was accidently sent 7.350" pushrods. I got them exchanged now but last night I was measuring the stock pushrods I had laying around and they measured 7.375". So which makes me believe the 799 heads also have longer valves like the 243 heads.
-Basically, im trying to figure out which length pushrods I need with the cheatr cam.-
Here is some info on LH6 799 heads...
"IMPROVED CYLINDER HEADS
The Gen IV Vortec 5300’s cylinder heads have been enhanced for improved performance and efficiency. As a result, the LH6 delivers the horsepower and combustion advantages of a higher compression engine, yet operates at peak output on regular-octane gas.
The LH6 takes its cylinder heads from the LS6 V-8 that powers Cadillac’s high-performance CTS-V sedan. Originally developed for the Corvette Z06, these heads improve airflow in and out of the engine. With their pent-roof combustion chambers and new flat-top pistons (the pistons in Gen III Vortec 5300s have a slight sump in the piston deck), the Gen IV Vortec 5300’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency and increases horsepower.
Typically, however, high compression engines require high-octane gasoline to produce maximum power, or to avoid the potentially damaging effects of spark knock or “detonation.” The Gen IV Vortec 5300 does not require premium fuel to achieve peak horsepower. The seemingly incompatible objectives of high compression and regular gas were achieved by optimizing combustion chamber design and airflow to the engine, and through advanced engine management.
With the new heads, the Gen IV Vortec 5300’s valve springs feature a new winding geometry and more durable alloy. The LH6 also uses the solid Silcrome 1 valves originally introduced on GM Powertrain’s LS1 V-8. Compared to conventional iron-alloy valve material, Silcrome 1 includes tungsten, vanadium, manganese, silicone and higher chromium content. It is harder and improves durability."
11-15-2009, 01:33 PM
#5
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IIRC CheaTR intake is about 1.43 intake and exhaust 1.45 (LSK/XE-R), but to determine p-rod length you should measure with a p-rod checker guage for proper preload on lifters.
