Reliability of Lobes Designed for .904 Flat Tappet Lifters

[JedIEG]

I have been considering cams for my upcoming build. I am likely to go with a flat tappet due to the cost of a roller. I was wondering how reliable flat tappet lobes that were designed for the .904 Mopar lifters are and if people have experience with them? I dont see a lot of people suggesting them on threads.
The companies I see with mopar lobes are Hughes and Comp Cam's Extreme Energy HL series

For example these are basically the same duration but different lift accelerations and max lifts. I dont know why you would ever use the regular ramp rate unless there was a durability issue.
Regular ramp rate
https://www.compcams.com/xtreme-energy-230-236-hydraulic-flat-cam-for-chrysler-273-360.html
Mopar .904 tappet ramp rate
https://www.compcams.com/xtreme-energy-hi-lift-231-237-hydraulic-flat-cam-for-chrysler-273-360.html

 

[snakeoil24]

Your taking chances with all flat tapper cams

 

[RemCharger]

What I hear alot of is comp cams lifters problems.
But again, since the advent of internet, true stories are buried with the bullshit .

 

[Kern Dog]

A trusted source told me that the reason that Comp Cams gets mentioned a lot is because they hold at least HALF of the volume of sales of performance camshafts. Also, the "Fast rate of lift" cams are more likely to fail than traditional ones with slower ramps. Finally, regarding oil: Don't use a detergent oil and don't use additives. Pick an oil that is specially formulated for classic engines.

 

[Bee1971]

383/432 - 440 Source kit
Going on five years now

I put the motor together myself , in all honesty first time on a complete motor rebuild myself

Comp cams XE 275HL and lifters
Edelbrock E Street 75cc heads

10.5-1 Compression - 195 psi cold cranking on all eight

Made sure the lifters rotated fine in the bores with light oil on sides
Comp cams assembly lube on all lobes and bottom face of lifters and Comp cams 10w30 break in oil
Primer shaft for oil pump after assembly , made sure oil was flowing to all rocker arms rotating engine by hand before engine fire up

Typical start up and verified oil pressure and no leaks and 20 minute break in per Comp cams instructions

Ran the motor in the garage a few more cycles - Middle of winter in WI

Drain oil and change filter

Valvoline VR1 oil and WIX filters since day 1 the car left the garage in spring

Couldn’t bee happier , sewing machine sound at times takes a little bit getting used to

All oil filter s I cut open at work looked totally perfect honestly

There , I just screwed myself with this post

 

[justcruisin]

I ran an XE275HL in a 440 for 10 years with no issues, when I pulled it looked great with no visible wear. I changed it for a solid to work better at the track with a set of 4.10 gears. The XE275HL laid over about 5500RPM in my combo. It did kick up a bit of noise which is typical with that line of lobes.
Broke it in with a break in oil and a set of springs with 85lbs on the seat. Always used good oil and frequent changes.
Probably a good idea to check for any lifter bore wear, not sure how close the lobe comes to the edge of the lifter.

 

[Bee1971]

100% correct on 5500 RPMs

Torque and off idle acceleration for the street make up for it - Especially with 3:91s

5500 RPMs come up pretty damn fast , almost like a rev limiter

 

[beanhead]

No free lunches as they say. The faster the lobe the faster the wear, mostly from the stiffer springs needed to control the faster motion (hopefully you're using stiffer springs!) The question is really, how much more noticeable power will there be with the faster lobe of the same specs?
For example, a few years back I had a mild-ish 440 build with the comp XE 274 cam. Well I bought into all the "gotta have a fast-rate .904 lobe" hype so I swapped it for the very similary spec'd 275HL(.904 tappet design) cam...noticed ZERO difference other than it was a little noisier. Now sure, it might have showed a few more HP on the dyno...but there was no noticeable performance improvement after tuning, on the street or the track. Your results may vary of course.
In other words you can get similar power output without having to use the fastest rate valve-slamming cam in the catalog..

 

[JedIEG]

I understand there is no free lunch here. When I buy a cam I will get the appropriate spring setup. I know with stiffer springs friction will increase, but power should also increase with the increased area under the lift curve.
My target head flow would max out between .500 and .600 to meet my power targets so not lifting past .500 would not utilize the head flow.

I'm glad to hear of some success with HL cams. Has anyone tried the Hughes cams?

As an aside, I find it interesting that a sbc roller cam from comp with the same duration has less lift/ramp rate than the HL flat tappet cam.

https://www.compcams.com/xtreme-energy-230-236-hydraulic-roller-cam-for-oe-roller-sbc.html


Beanhead- I'll have to think about your comments on the lack of change. What heads did you have on your 440?

 

[66Satellite47]

I notice Bullet also has a lot of .904 lobe designs too. If you want real high rate of lift, get an antique mushroom lifter cam.

 

[YY1]

No free lunches as they say. The faster the lobe the faster the wear, mostly from the stiffer springs needed to control the faster motion (hopefully you're using stiffer springs!) The question is really, how much more noticeable power will there be with the faster lobe of the same specs?
For example, a few years back I had a mild-ish 440 build with the comp XE 274 cam. Well I bought into all the "gotta have a fast-rate .904 lobe" hype so I swapped it for the very similary spec'd 275HL(.904 tappet design) cam...noticed ZERO difference other than it was a little noisier. Now sure, it might have showed a few more HP on the dyno...but there was no noticeable performance improvement after tuning, on the street or the track. Your results may vary of course.
In other words you can get similar power output without having to use the fastest rate valve-slamming cam in the catalog..

Do you have that backwards?

You swapped out an XE series for an HL series to get the .904 profile?

The XE has the .904 profile, not the HL.

 

[justcruisin]

The comp XE cams are cut for the .842 lifter, the XE-HL is the .904 lifter grind as Beanhead said. XE274(842) - XE275HL(904)

 

[YY1]

Oh, the suffix.

I was thinking HE prefix.

 

[JedIEG]

Bullet also has a lot of .904 lobe designs

You gotta love a company that just gives you a giant lobe catalog with advertised, .050 and .200 durations and lobe lift. I'll have to give them a hard look.

 

[gtxrt]

You gotta love a company that just gives you a giant lobe catalog with advertised, .050 and .200 durations and lobe lift. I'll have to give them a hard look.

comp cams has a master catalog lobe profile too. never liked my solid lifter bullet cams had 2 of them just didn't seem to turn on fast.

 

[66Satellite47]

Comp doesn't seem to post it. Matter of fact their site doesn't give us the info it did a couple years ago. I've never used a Bullet or Ultra Dyne cam, but they do give some info to work with. My experience with Comp has been a mixed bag. The tow vehicle 260 cam was excellent, drag race 720/276 roller was poor, the reground 660/280 was the equal of my mushroom, the low 500 in my 500" motor was all done by 5500 RPM, my current 512" motor has a custom Comp low .600/248/256*. My builder took my word I would street drive it. It's clearly too small for the 512 to make real power. My bet is the 512 would really like my antique mushroom cam, especially if I switched to 1.6 rockers. Cams are a mystery until you put them on the track.

 

[gtxrt]

l down loaded it. go to catalogs then hit company on top of page, brings up master lobe catalog or they also have a reference guide

 

[66Satellite47]

I don't get that when I pull their site up. Thanks

 

[gtxrt]

here

 

[Curiousyellow71]

Right now we are running quite a few cams from different companies both .904 and .842 Lobe profiles. Tim Goolsby at Bullet has been a good contact. He doesn't seem recommend the .904 profiles for every application. There is also a Ford .875 lobe profile.
We really have been impressed with the ultradyne hydraulic and solid cams. They are quiet and perform well. A lot of the noise on the comp xe series comes from how the intake lobes are designed as they shut the valve. There is a difference between .904 profiles between companies as they can be symmetric and assymetric cam grinds. The hughes cams made by howards usually get extra lift because they are symmetric lobes. Some engines may like a assymetric profile while others like the extra lift you can only do with a symmetric profile. The area under the curve is in a different place and I would say their is a place for both.
The lunati voodoo series for mopar is also designed for a .904 lifter.