Not happy with XE256 in 401.

kaelen

I've been running a comp XE256 in my 401 for a few months now. I've not been really happy with the performance. It's got great low end grunt, but it falls off a little too quickly. I've been searching for an ideal camshaft for my engine. It's a 40 over 401 with Keith Black pistons. Around 9.6:1 compression. It's in my auto tranny 77cj7 with 31" tires and soon to be 3.73 gears. I'm looking at the comp 268H. It has a little more duration that the 256. 218,218 vs 212,218 @.050. Anyone running this cam? Also I'm not sure on the valve springs. Currently I'm running the comp 926 springs with a rate of 415. The 268 cam specs the 940 springs with a rate of 241. Should I change out my springs, I happen to have a very low mileage set of the 940 springs from a previous project. Thanks in advance.

donwag

Try Reed Cams. Tell them what you have and how you plan to drive, they will fix you up. I have a CJ7, 4.11 gears, 401, KB pistons, iron heads opened up and ported and polished, roller rockers, and other stuff. Reed cam (which one escapes me just now) Power range is 3K to 6K.

tufcj

I'd see how it acts after the gear change before swapping cams. Getting it in the correct RPM range for the load could make a big difference. I don't think there will be a whole lot of difference in what you have and the 268. Bob tufcj

kris

Reed went out of business last year. Engle was bought by "SoCal Imports" (VW parts), but still offers most of the cam catalog. Engle is my first choice. Lunati also has a cam that I would consider if the 256 isnt working for you... [url]http://www.lunatipower.com/Product.aspx?id=1482&gid=287[/url] k.

kaelen

Thanks for the suggestions. I've been doing quite a bit of looking around for different cams. I see from previous posts about cams and the 401 that MC doesn't recommend the XE256 in the 401 anymore. I'm beginning to see why. I've also read a few posts about people saying not to under cam the 401. I've looked at the K8600 and the Engle 5052. Just looking at the duration I don't think either would be an upgrade over what I have now. The problem I've found is most of the cams with more duration than the XE256 start going over .500 lift. That starts making me worry about clearance on the valves, especially exhaust to the seat. And my pushrod slots. I should have elongated the slots a little bit more. Though maybe the additional duration will be negated by the loss of lift between the two cams. I do like the 218 @.050 duration of the 268H. I think that's a good one between the 224, which would be a little too much for my gears and driving and the 212. Currently I'm running 3.54 gears, so a little more cam wouldn't hurt moving to the 3.73 (or maybe 4.11). The other reason I'm replacing the cam is I have a number of bad lifters. The shop sold me some really cheap ones instead of a name brand. They leak and collapse. I've disassembled, but can't find anything wrong. I could replace just the lifters but since I'm almost there it wouldn't be much more work to upgrade. Also I'm nervous about flattening a lobe. Some say you can do it. But I replaced lifters in a 360 once and one of them went bad, even with redoing the break in.

tufcj

The lifter problems may be due to the valve springs. They seem awfully heavy to me. Definitely go to the spring recommended by whichever cam manufacturer you go with. I rounded 2 lobes off a Crane cam by using springs that came with an Isky cam that actually had less lift and duration than the Crane. It failed pretty quickly, and I give Crane credit that they replaced it under warranty, which they didn't have to do. The second one (with the right springs) is still running in a buddies Jeep (I sold the motor to him). Bob tufcj

fuzz401

try crower cam they do not use a lot of lift but a lot of duration

kaelen

Thanks much for all the advice. I'm not sure what to do about the cam. But after doing a lot more thinking and reading on the forum I think I have a plan. First before changing the cam I'm going to try and fix my lifter problem. I'm thinking that I have at least two lifters leaking. Might still have a piece of something from when my dizzy / cam gear munched on the dyno. I tore down the engine after that but now I'm trying to remember if I disassembled all the lifters. I was looking at my dyno numbers for this setup. Unfortunately I was never able to complete a good dyno run before the dizzy went. With a out of the box untuned edelbrock carb I had 446 ft/lbs at 3700rpm and 332 hp at 4200 rpm. We tried their quick fuel 750 dyno carb on one run but I never got a printout for that run. I do remember though that it was 350+ horsepower. Torque went up to something like 460. damn, I wish I had the sheet. I never did have it dynoed again after getting it all back together. Any opinions on those numbers? I'm thinking now that the cam isn't too bad. Just get the stupid lifters fixed.

crazydog

Lunati 64502 I made 392 hp and 435 ft/lbs of torque. Here is some info on the build. [url]http://www.ifsja.org/forums/vb/showthread.php?t=121315[/url]

Dusty

intake and exhaust can hinder cam efficiency but with that compression ratio id be thinking its a combo of more than one especially if its a performer intake.... but thats just me. you'll need to change valve springs the 921s are pretty light if lift goes up you risk premature floating later in the engines life. without knowing what your valve guides are cut to clear its hard to talk about this. i had one motor that they barely cut enough to clear .480 on a wild night at the sand dunes my retainers ate my valve seals...... 3.73's is only 100 rpms up at a given cruising speed. 4.10s will net you 350 rpm more at cruising speed from current numbers so if you cruise at 2500 at 65 mph now, with 4.10s youll be cruising at 2850 +/- at 65 even if you change your cam will this be enough of a change to help you or are you battling multiple factors? understand the lifter frustration. I sure like my lunati cam 64501 smaller than the above but i am 9:1 CR and running a performer intake with TBI every once in awile i wish id gone a touch bigger i think the 64502 would have been a better match but then i take the jeep on the trail and it idles down into the 150-200 rpm range without issue, wowing everyone and still is healthy on the top end. I sacrificed HP for a heavy torque motor with a little cackle and less heat issues. Comp makes good cams the old H270 with .480 lift and 224 dur @ .050 always was a fail safe that ran pretty good nothing off the charts but healthy none the less . with an auto it ran better with the performer intake but with a stick we were able to drive around and enjoy the airgap and 4.10s, it loved the Rochester, did well with the 670 but shined with a tuned 750 double pumper, heavy octane fuel, slightly higher timing and the chance to run on sand moutain in a cherokee chief. the EX268 is a great performer also with 9:1 401 really id be a clsoe draw between the lunati 64502, a comp 268EX and an Engle custom grind 218/220+/- dur @.050 and as much lift as they could squeeze out

kaelen

Thanks, (sorry I haven't logged-in in a while) I think I'll try and stay with the XE256 for a while. Mostly because I really don't feel like pulling the front of the engine apart again. And it sure has great torque down low. For what I do that's where I need it. It's rare I hit 4000rpm. I disassembled the first two lifters tonight. I think I'm finding my problem. I couldn't believe all the crap inside them. Which is hard to believe given how much I scrubbed the block before assembly. Including running rifle brushes through all the oil galleys. The #1 intake lifter had a couple of good sized chunks of something in it. Also the disc was galled where it meets the lifter plunger. I turned it upside down on reassembly. Also I noticed the pushrods on #5 are just barely hitting the lower edge of the hole through the heads at full lift. There are some nice marks on the pushrods. They don't seem to be bent. I'll have to carefully clearance the hole a little more. I'll also check the lifters closely. Hopefully nothing's damaged. That could be contributing to some of my woes. However if I install a cam with higher lift I'm going to have to enlarge all the pushrod holes through the head. I have the small hole, stud mounted rocker heads.