Small Base Circle Cam w/383
04-28-2011, 09:59 PM
#22
LOL
You can get by with about 10% less spring pressure with a 55mm cam journal compared to a standard .900-1.050 you normally see in a standard 1.868 journal Or if you want to run the same 160/400 that everyone is doing on these hydraulic rollers, you can turn them harder and/or run a much more agressive lobe profile. We're talking a 30% increase in base circle which is HUGE for if you're trying to run radical stuff on the street. I'm not even touching on cam twist and the harmonics associated with that...
You can get by with about 10% less spring pressure with a 55mm cam journal compared to a standard .900-1.050 you normally see in a standard 1.868 journal Or if you want to run the same 160/400 that everyone is doing on these hydraulic rollers, you can turn them harder and/or run a much more agressive lobe profile. We're talking a 30% increase in base circle which is HUGE for if you're trying to run radical stuff on the street. I'm not even touching on cam twist and the harmonics associated with that...
06-03-2011, 02:15 PM
#23
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I just wanted to follow up on this thread, because I ended up going with a 1.100 base circle and put the bottom end together yesterday to mock it up and check clearances. My old cam was a 1.050 and standard (according to Comp) is 1.150. With my lobes, they couldn't grind smaller than 1.100, so that's what I went with.
Well, it was all good until I got the #6 rod in there and it just barely rubs on the cam. I guess I'll just grind a hair off the rod. I tried a different rod and it cleared, but I'm still going to massage a little of the rod.
How much clearance do you need? I mean if it clears on the engine stand am I ok, or will there be some flexing that I need to make a little extra clearance for?
Well, it was all good until I got the #6 rod in there and it just barely rubs on the cam. I guess I'll just grind a hair off the rod. I tried a different rod and it cleared, but I'm still going to massage a little of the rod.
How much clearance do you need? I mean if it clears on the engine stand am I ok, or will there be some flexing that I need to make a little extra clearance for?
06-03-2011, 02:30 PM
#24
Yeah thats a tough question to answer there without know all the specifics. Last I checked and I am going off a very shaded memory here, it was .100 minimum and I cant recall if that was for the block sides or the cam.......wish I could be of more help there.
Just to go back to the argument of whether or not a smaller base circle is indifferent to a larger base circle, one only has to look at the LSx cams to see what technology really thinks about that
Just to go back to the argument of whether or not a smaller base circle is indifferent to a larger base circle, one only has to look at the LSx cams to see what technology really thinks about that
06-03-2011, 05:13 PM
#25
Have you played with advancing/retarding the cam? .060" is a good number, you need to check it at different cam centerlines as timing chain slack/wear over time will move the cam. Obviously if there's a lot of meat you can safely take off the rod then this isn't a concern.
