comp cams has the xe230/236 with the low and high LOBE lift #s. the #s on the more common low lift intake lobe at .200 was 151 and on the high lift lobe it was 157 at .200.a much steeper ramp. would the high lift reduce valve spring life by a lot? if so are there any springs out there that would handle this as i want to get at least 60k on them because it is a daily driver.

 

if it was me i would probably go with the lower lift version of it. doesnt sound like you want to change springs very often and valve control is critical with a steep lobe like i remember the 3100 series 230 duration lobe running. i think the lift with a 1.6 rocker was something like .622 which is a bit over the top for the street. and just mho if i was going to deal with the hasle of changing springs and buying the light wieght springs and retainers and all the acompanying parts i'd just use the high lift 224 intake lobe and the regular 230 lobe for exhaust. you'll make more tq all other things being equal. the other thing i'd do would be have it cut on a tighter lsa, and have it ground straight up, that is with no advance ground in. i know that wasnt the question but i've seen cams very similar to this pull very very well given that the .200 duration of the high lift 224 lobe is right on par with the .200 duration of the standard 230 lobe. once again jmho but tq is where its at for a street driven daily driver, and a lumpy idle is cool on the weekends and at first but hammering around in traffic with ~ 10" of vacuum isnt so fun after a month.

 

Comp lobe #3315 is 230* @.050, 151*@.200 with a lobe lift of .340 (.544 @ valve with 1.6rr)

Comp lobe #3194 is 230* @.050, 157* @.200 with a lobe lift of .389 (.622 @ valve with 1.6rr)

That extra .049 at the lobe is a LOT of extra load on the valvetrain. It's also probably not for a daily driver, especially for 60K unless you are considering springs 3 or 4 times and rebuilt lifters a couple of times. That assumes you are using the BEST of each.

There's no free lunch...

 

60K is a lot to expect of valve springs in any high performance situation. But srpings are improving all the time. There are some new materials and manufacuring techniques that allow longer life with high lift/steep lobes. Look at #26112 on this page: http://www.compcams.com/Technical/Ca...04/Page-7.html for example. Of course, they are over $400/set!

Rich Krause

 

thanks for the info it helped. this will be in a 383 6 speed so i also considered the 233/239 cam from combination, i was told the .200 #s were 156/161. does this cam offer the same reliability/dependabilty issues as the xe230 low lift cam. naturally when daily driving these things need to be considered although i can also deal with some downfalls to an agressive cam. going about 200 miles a week some highway some traffic. i had done a search on the 233/239 but did not get much info and none at all in a 383, i guess cause its new

 

Jared,

Not sure when you're looking to order the cam, but I should have my motor back together in 3 weeks or so if you want to drive a 383 M6 with the high lift version of the cam to see what it's like on the street.... The 230/236 cam I have runs .600/.608 lift with the 1.6 ratio rockers and I'm running comp 977 springs on it.

I decided to fix the orginal cracked block so that's why I never ended up getting in touch with you about the machine work..... Hopefully it works out

-Rob

 

i'll take you up on that offer,thanks,good luck and shoot me an e-mail when its finished. i think you told me that you got 100 miles or so with the motor before you tore it down,do you think 200 miles a week is acceptable with your setup as far as street manners? im thinkin hard about the 233/239. thanks

 

Ok, cool. I'll let you know when I get it running again... I'd definately say there'd be no problems daily driving it. It obviously doesn't idle as smooth as a stock setup but nothing too bad. There was some cam surge around 1200-1500 rpm that was annoying but I think I can still get rid of a lot of it with some more tuning. Definatley no problems on the highway with it at all. I'm running poly engine and trans mounts to so it would even be a little smoother with stock mounts... The big test is going to be when I try to get it through emissions....