StrayDog

I have been taking my time with winter project of cam change on my 66 big/block,,,,,,,,,cam is finally out & SURPRISE it is a CRANE HMV-260-2, The engine was rebuilt by previuos owner in 1994, he was not mechaniclly incilened & advised me it was a 1966 vintage block & was a solid cam when he bought it ...he had a rebuild done &had the solid cam removed & tuned as a 390 HPL36 ,When he had the engine was rebuilt 1994.......I purchased in Feb 1995, ran great.,,,.winter project 1997 I put on Endlebrock Alum heads to reduce wieght & make unleaded fuel compatible as the pistons had TRW 2300 F stamped on them , & since the paper work reflected the same pistons I was confident on said rebuild,note moter was retammped as matching ##)but this was no concern of mine & I did not get screwed on price... anyways pulled strong & turned 13.7 @102 accordingly I shifted at 5600 RPM........My surprise :eek: surprise was finding the HMV-260-2 cam inside my 427, not a L36 Chevy cam....... due to the fact I am living with 3.08 HWY geard & staying conservative & the XE262 was my cam of choice...now :confused: I am totally confused on cam selection , my Vette is a street driver with 308 gears , looking for short duration high lift 1500/5600 with redline of 6000 rpm as my range , want fat & broad tourque curve not so much high rpm , dont konw whtt cam to go for now :confused: who has info on the HMV-260-2 CAM such as lift etc.any info from cam wizzard will be greatly appreciated :seeya The Dog :seeya


[Modified by StrayDog, 6:03 PM 2/4/2003]


[Modified by StrayDog, 6:06 PM 2/4/2003]


[Modified by StrayDog, 7:53 PM 2/4/2003]

Plasticman

Straydog,

This data is for a Crane HMV-260-2-NC for big blocks (p/n 133902). It is listed as having a smooth idle, for daily usage, off road, light towing, economy, and mild supercharger.

Max. lift @ cam: Intake = .2847 Exhaust = .3027
Max. lift at valve with 1.7 rockers: Intake = .484 Ex. = .515

Timing at .004 lift: Intake opens @ 19 BTDC close @ 61 ABDC = 260 deg.
Ex. opens @ 69 BBDC close @ 23 ATDC = 272 deg.

Timing at .050 lift: Intake opens (5) ATDC close @ 29 ABDC = 204 deg. Max. lift @ 107 ATDC
Ex. opens @ 45 BBDC close @ (9) BTDC = 216 deg. Max. lift @ 117 BTD

Power band is listed as 1500 to 4000, max RPM 6500. Crane has always been conservative on power band RPM.

Hope this helps,
Plasticman


[Modified by Plasticman, 7:15 PM 2/4/2003]

StrayDog

Plasticman, thanks For info on the HMV-260-2 , appears to be a milder grind than the Chevy L36, 390 HP Cam, with the exception of the lift , the L36 is as follows 214 intake 218 ex ........461/480 lift, the HMV -260-2 Seems to be a RV grind.......however turned 13.7 @102 MPH last year...now I am totally confused I was going with the XE 262 from comp cams for broad tourque ............ :eek: :steering: Thanks again ..

Plasticman

Straydog,

The HMV-260 has been around for a long time and Crane has sold quite a few (for many different engines). Your right about it being a RV grind, but not a bad one! The 3.08 rear gear puts you in a hole, and probably better off being conservative than wild. Note that you need a matched set of components, and your 13.7 / 102 says you are pretty close. Agree on your idea of broad torque for the street, and high lift / short duration will do that. My experience is with small blocks, so I can't say what will work best for your big block combo.

Note that Crane has replaced it with a newer profile: 260 H10 Energizer
Power band is broader (1200 to 4200), and has a symetrical intake/exhaust profile (204 duration @ .484 valve lift), which I do not like for SBC's (need more exhaust duration than intake for typical street application with closed exhaust). Crane uses "cruise" RPM to select which cam to use. Says this cam is good for a 1600 to 2200 RPM cruise for max. efficiency. Their next step up is the 266 H10, with a cruise RPM of 2200 to 2700, and a power band of 1600 to 4600. Has a duration of 210 with a valve lift of .499.

The Comp. Cam XE262 is certainly more aggressive with 218/224 duration and lift of .504/.510 (they rate it with a 1300 to 5600 RPM range, but don't try to compare their "ranges" with Cranes. Note that for a SBC, I would definately use small tube headers with this cam timing. This cam will certainly be weaker on the bottom, and loads more fun on the top. Just for comparison, a similar cam from Comp. cam to the Crane HMV-260 that you have now is the XE25H-10 (or should it be XE250H-10? - possible typo in catalog). This cam has duration of 206/212 with lift of .470/.475. "Range" is 600 to 4800. Note that it has a little more duration than your Crane cam, but less lift, so I would stick with the Crane if picking between the 2. Haven't even gotten into lobe separations & timing differences, etc. Like I said, better off finding a good big block guy! Just don't go crazy (always better to be undercammed than overcammed).

Good luck,
Plasticman

ghostrider20

Go with a good solid cam!

They are not that bad, a couple of adjustments a year, big deal.

Mark

Solidlifters

Why don't you call Crane's tech line and give them all the specs on your setup and let them help you with it. I've done a number of camshafts that way over the years and don't feel that they've ever given bad advice.

Kid_Again

...StrayDog.....i've gone over to the dark side with solid lifter/rrockers on both engines and do not regret it one bit but my street peak rpm target is a bit higher than yours - makes no difference, in practice, i believe.....

...i remember that duke replied to you once, quite a while ago, that the basic L36 cam was essentially ideally suited for what you want to do, just as a matter of perspective, why isn't that a choice for you?


...oh, and you may remember, i got a surprise with the sb when i pulled the cam....solid tappets running on a hydraulic cam - idiots :skep:


[Modified by Kid_Again, 8:34 AM 2/5/2003]

TheOman

I remember that situation with the lifters and the cam. If I ever buy one of these cars in running condition (unlikely.....VERY UNLIKELY) I am going to make this statement to the seller after an apprasial of the owners mechanical savy. "Please don't tell me ANYTHING about the car, I don't wanna know. {Most likely he doesn't know with any real certainty.) "I will decide to buy or not buy based on what I hear, see and think not based on information and purported specifications that have been handed down and embellished by God knows how many owners."

My current car was not in running condition when I got it. All I heard from the seller were words like "complete restoration" blah blah blah. Complete restorations usually run under their own power but that is anothr story about this owner and his mech. skills. Thruth to tell he got screwed when he bought the car: the "complete restoration" equalled a quick repaint of the engine while still in the car, new seat covers, some sort of greasy goop on the exhaust manifolds and a new but inexpensive top. He had no clue what he had purchased and no clue what he was talking about. Fortunately for me he had no clue how to fix anything, no money left and he just wanted to get rid of the car.

Ya just cannot trust what is under the skin on these cars when they are 30+ years old. Like Kids car and the lifters: ya just can't take this stuff as fact. Too much time since the 60's for part substitutions and too many Bubbas out there doing the substitutions.

Hope you have had all the surprises you are gonna get. As to the cam I have an XE268 in a SB car and I like it. I would suspect that with the added displacement / torque of the BB it should be very nice on the street. The power band is good for street driving, it is not cantankerous when you fire up the engine cold and it runs well up to 6000 RPM which is more than enough for my purposes at this point in my life.

Caveat Emptor.


[Modified by TheOman, 9:50 AM 2/5/2003]

Kid_Again

yup yup...i remember, vividly, when i was talking to the roadster's seller, he says the engine is freshly rebuilt, it's 0.10 over, can't find the receipts, yadda yadda yadda....my look back at him was :skep:

..yeah, it was rebuilt awright - with a siezed engine about to happen.......like you say, caveat emptor! :leaving:

Ganey

Crane 260-2 204/210 112
I replied to a cam topic you did in C3 a while back on selection. The XE262 is fine for what you want. A good min.

:cool:

StrayDog

kidagain, the L36 Cam was good 35 years ago but technoledgy & computer design have enginered new Cams design, & I wanted high lift short duration , the L36 has lift of .480 something the XE 262 , LIFT .505 & .510 with very quick ramps ....ordered the XE 262 , However I did a best ET of 13.7 @102 MPH ....WITH 308 gears & the crane RV type cam that was in my 427 ....no wonder I had 2.7 60 foot times I must have had a million foot pounds of tourque at 1,000 rpm.... :eek: will advise as to performance in 6 weeks or so.......... :steering:

66427-450

if you are at all interested in performance you need to dump those 308's, they are KILLING you. :seeya

Kid_Again

...yeah, i WAS thinking about those 3.08's...even if you stay below a 4.11 and dial in your torque around 5500 with the right cam, i think you'll be REAL happy.....

...i respect your opinions on your cam selection, and if anyone wants data - it's me, but i hafta' tell 'ya to be careful about believing the marketing hype about cams....the data i would believe for a cam are NOT the lift, duration or any other number dreamed up by the marketing department - it's a dyno run (even simulated) on a known engine as close as possible to your engine...you have decent flowing heads so i'd hate to have you dial in a cam matched for the velocities of a square port (i'm not saying you are)...though i CLEARLY don't do everything right, the way i built both engines was to work with my rebuilder, run a bunch of simulations and finally agreed on a torque curve that i wanted...he ordered the cam to match (i'm still not sure if i have the right PN in the sig, could care less)...

i hear 'ya about advances in cam design over the last 30/40 years but if you think about it, the manufacturers could have designed rapid angle of attack cams back then and chose not to - nothing new about that, frankly....in order to make the most of these new, theoretical advances in cam lobe design, you can't run stock valvetrain componenets, in my opinion , if you really want to go with an aggressive profile cam, you are much better off increasing the efficiency of the valetrain with rrockers and possibly rlifters to ensure you have a realiable performer......will it work OK without the rollers, yeah, it will...is it the best situation - no it ain't

...good luck and keep us posted, StrayDog


[Modified by Kid_Again, 1:55 PM 2/8/2003]


[Modified by Kid_Again, 1:57 PM 2/8/2003]

StrayDog

kIdagain, my heads are Endlebrock Alum, ovalports,pocket/poreted & rockers are CompCams 1.72 roller tipped..........the cam change is to accomodate the breathing ability of said heads , with a broad & fat midrange tourque............in the 1500/5600 rpm range, the cam thats being repaced "HMV 260-2 " Was even a milder grind than ,the L36, but had 505/515 lift...with this RV type trailer towing cam I was best ET 13.7 @ 102 MPH...........NO traction .. 60 foot times due to monsterous off idle tourqe way down low ..............again with 3.08 rears & 9.5 compression ratio, I feel the XE262 Is the choice for my street driver combination, as a matter of fact awainting the UPS man next week to put this together :steering: a full report will be forthcoming :auto: When will the snow melt

[Modified by StrayDog, 9:52 AM 2/9/2003] :crazy: The Dog


[Modified by StrayDog, 9:54 AM 2/9/2003]