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What's the difference between VMAX and VPRO Rhoads?
What's the difference between VMAX and VPRO Rhoads lifters?
Especially if you have used both! |
About thirty bucks :D
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Vpro are shimmed so they do not have as much stroke as the vmax. Lashed tight there is not much difference. If your setting the lashing less that .030” the vpro do everything the vmax will do.
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Jay, Would you say the the V-Max lifter would be better for a cam that had more duration in it, than a cam that was more tailored for the V-Pro lifters???
For instance, the 041 cam, 230/240 @50. using the V-Pro would possibly work. (I think you said you have built one of these?). A 238/246 @50 might work better with V-Max??? Glad to hear you have used the V-Pro lifters. Rhoads says the V-Pro's can be used on any cam with over .380" lifter. That makes it a good candidate for almost any engine...another choice for a quality lifter other than Hylift Johnson |
http://forums.maxperformanceinc.com/...0&postcount=32
I took apart a VMAX, two washers inside. Anyone got a VPRO to take apart? |
I don’t think there is any reason to run the vmax unless your cam is well into the 240s at .050”. The Vmax’s create a sowing machine symphony when lashed to were you need a Vmax (above .030”) . If someone likes sowing machine symphonies they would probably think they are cool.
If you talk to Rhoads and you run a street car they will recommend the Vpro. But if you have Vmax’s I do not think there would be a reason to switch to Vpro. But on the same token, buying new and planning to lash them below .025” there is no reason to order Vmax. Vpro might coming in sooner and have a quicker pump up rate, but I can’t honestly tell a difference. Each cam and engine combo was totally different with each type of lifter. I get them direct from Rhoads, they are priced the same. |
Something I hadn’t seen until I had a set of Vpro lifters was instructions to set the lifters by turns backing off the rocker instead of setting them with feeler gauge. I could be mistaken, but I do not recall that on the vmax instructions. At least not on the older Vmaxs. Several of the guys I did cams for using Vpros had never lashed a solid cam before. Usually they choose poly lock adjustment instructions.
Sorry I haven’t had a chance to take Vpro apart. I should mention that RA 4 stroker engine I mentioned in the other thread with the vpros and the spec-8 is a current project I am helping out with. I don’t have anything to report on that one yet. Rocky flowed the heads on it. Going to be a sweet engine in a 70 Judge. I am hoping to try some bigger 1.7 or 1.8 rockers on the spec-8 with the vpros on the SPC-8. I am collecting rockers to try on it. :) |
Jay,
I don't know if this will be of any value to you. The theoretical valve lift curves with those rocker arm ratios. Stan Rocker_Arm_Ratio_=_1.650 VALVE_____Lift______Opens___Closes__Duration _________________Deg_BTDC__Deg_ABDC_____________Ar ea _________0.00600____32.23_|__94.87_|_307.11_|__42. 08 _________0.02000____22.97_|__74.67_|_277.64_|__41. 90 _________0.05000____11.55_|__58.06_|_249.61_|__41. 45 _________0.08250_____3.00_|__48.00_|_231.00_|__40. 88 <- 0.050" lifter raise _________0.10000____-0.82_|__43.82_|_223.00_|__40.47 _________0.15000___-10.36_|__33.74_|_203.38_|__39.22 _________0.20000___-18.97_|__24.81_|_185.85_|__37.73 _________0.25000___-27.43_|__16.05_|_168.62_|__35.83 _________0.30000___-36.32_|___6.83_|_150.51_|__33.21 _________0.35000___-45.98_|__-3.04_|_130.98_|__30.11 _________0.40000___-56.94_|_-13.97_|_109.10_|__26.18 _________0.45000___-70.54_|_-27.44_|__82.02_|__20.23 _________0.50000___-91.93_|_-48.72_|__39.35_|__10.20 _________0.51000__-100.31_|_-57.07_|__22.62_|___5.65 ======================== Rocker_Arm_Ratio_=_1.7 VALVE_____Lift______Opens___Closes__Duration _________________Deg_BTDC__Deg_ABDC_____________Ar ea _________0.00600____32.41_|__95.27_|_307.67_|__43. 36 _________0.02000____23.28_|__75.19_|_278.47_|__43. 19 _________0.05000____11.99_|__58.64_|_250.63_|__42. 71 _________0.08500_____3.00_|__48.00_|_231.00_|__42. 11 <- 0.050" lifter raise _________0.10000____-0.21_|__44.49_|_224.28_|__41.75 _________0.15000____-9.57_|__34.57_|_205.00_|__40.56 _________0.20000___-17.98_|__25.84_|_187.87_|__39.08 _________0.25000___-26.17_|__17.36_|_171.19_|__37.17 _________0.30000___-34.71_|___8.51_|_153.80_|__34.83 _________0.35000___-43.91_|__-0.94_|_135.15_|__31.91 _________0.40000___-54.19_|_-11.25_|_114.56_|__27.79 _________0.45000___-66.54_|_-23.48_|__89.99_|__22.67 _________0.50000___-83.87_|_-40.69_|__55.43_|__14.56 _________0.51000___-88.87_|_-45.67_|__45.46_|__12.04 _________0.52000___-95.33_|_-52.10_|__32.57_|___8.43 _________0.53000__-107.95_|_-64.72_|___7.34_|___2.12 ======================== Rocker_Arm_Ratio_=_1.8 VALVE_____Lift______Opens___Closes__Duration _________________Deg_BTDC__Deg_ABDC_____________Ar ea _________0.00600____32.72_|__95.99_|_308.71_|__45. 91 _________0.02000____23.83_|__76.19_|_280.03_|__45. 74 _________0.05000____12.84_|__59.72_|_252.56_|__45. 27 _________0.09000_____3.00_|__48.00_|_231.00_|__44. 59 <- 0.050" lifter raise _________0.10000_____0.95_|__45.74_|_226.69_|__44. 31 _________0.15000____-8.11_|__36.10_|_208.00_|__43.18 _________0.20000___-16.15_|__27.73_|_191.59_|__41.69 _________0.25000___-23.88_|__19.73_|_175.85_|__40.00 _________0.30000___-31.80_|__11.52_|_159.72_|__37.80 _________0.35000___-40.23_|___2.81_|_142.58_|__34.87 _________0.40000___-49.45_|__-6.52_|_124.03_|__31.48 _________0.45000___-60.00_|_-17.00_|_103.00_|__27.24 _________0.50000___-73.27_|_-30.15_|__76.58_|__20.58 _________0.51000___-76.51_|_-33.38_|__70.11_|__19.06 _________0.52000___-80.09_|_-36.93_|__62.98_|__17.26 _________0.53000___-84.13_|_-40.94_|__54.93_|__15.16 _________0.54000___-88.87_|_-45.67_|__45.46_|__12.75 _________0.55000___-94.90_|_-51.68_|__33.41_|___9.48 _________0.55000___-94.90_|_-51.68_|__33.41_|___9.48 _________0.56000__-105.19_|_-61.93_|__12.88_|___3.65 |
Many thanks Stan. I can definitely use that information. I have been curious how a higher ratio 1.7-1.8 rocker arm might work with the spc-8. Looks like 1.65 to 1.8 gained about 3* @.050 and about 2.4*@.2. The big rocker will make the variable duration effect of the Vpros more pronounced. With the solid lifter like performance the using vpro’s the cam might really run with those bigger rockers.
The spc-8 cam we have has a little less acceleration. That looks really big. |
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I will have to figure out where I got those base numbers from. Can you share what numbers you have? Thanks, Stan |
I checked the cam we are using a while back it had 303* @.004” tappet am 291* @.006”, and a little over [email protected]”.
Fwiw...Melling rates the Spc-8 at 304* which is a SAE rating with 1.5s for the RA2. SAE with 1.5s is .004” tappet. Compcams version is 292* @ .006 tappet. .Both are [email protected]. Very close to what I measured. I believe the exhaust is 303 @ .006 and 315 SAE. [email protected]. I have no idea what it has at .2”. The profile that you listed Stan might be an exhaust. But it is a little puzzling that it does not have more seat timing. In that regard if looks like a more modern profile than what I have. The rockers durations should react similar though. Most of the old cams from the 60s and 70s have a lot of seat timing on the exhaust to drop the cylinder temp down when idling to pass emissions. You can kind of tell when you look at a profile and see how close the grind is to an original by looking and the SAE rating. When it has a bunch of extra seat duration, mostly on the exhaust, most folks claim it was usually a crutch for passing emission. The cam I have has 1 degree of duration for each thousandths of lifter rise at .010”. By the time the hyd lifter collapse some and the valve terrain flex’s the duration of the cam at that point Is probably more representative of the hp the cam will make. I use .009” lift out at the valve for sizing cams rather than the SAE .006” at the valve or the “true seat” numbers. Truth be told that probably neither isn’t quite open enough yet. It is probably that .001 for one degree number. A sprinitron would tell for sure :) That is part of why Rhoads work so well with the 041 cam, the extra seat timing at idle is basically bypassed, then put back in at the higher rpms when the engine is ready for it. |
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Jay,
This is from HO. It would be nice to know how close it is to scale. 068 - S 744 - H 041 - T Stan |
That graph of the T makes the S and H look pretty scrawny. Graphs look like they are to scale, kind of rough. Not easy to measure and plot the specs over the nose by hand like HO did. I use regressions tools to find the curve of the polynomial that was used for the lift curve. It is usually short polynomials segments for the section of that cam I am looking at.
I did some calculating once to get an estimate of the duration of the Crower 60919 and the SPC-8 with Rhoads Vmax lifters at different rpms and bleed down rates. My conclusion was the long seat durations were better with Rhoads. Spc-8 appeared like it would out perform the crower. The faster the velocities made the Rhoads less effective. It also appeared like a symmetrical cam and a symmetric cam would act nearly the same until the lifters were pumped up. The lash was moving the profile into the area of the cam that was symmetrical on most hft cams. Looks like the T has just under 140* at .2 on the intake. Just under 150 on the exhaust at .2.... Next time I have both vmax and vpro here I will take them apart and compare. |
Here I sit with Tinnitus from those damn things! Use regular lifters with a nice 288/302 camshaft and enjoy the street with the off idle torque that was designed into these cars as the were..
The 041 belongs on a race only car, having one on the street is pure misery.. |
I ran a 255/265 @ .050 solid lifter camshaft on the street for over 10 years, cam is still in the 400 engine, and had no issues with driving it across the state 200+ miles occasionally.
It did eat gas with the 4:33 gears though. Personally I am going to run the HO Camshaft one step above the RA-IV camshaft with the Rhoads VMAX-Pro lifters on a 455 engine and Nash 5 speed this time around. (With the Super Lube Option). I could run another Solid Lifter camshaft but want to try a hydraulic camshaft after 50+ years running solid camshafts. Tom V. |
Well we will seen how long it takes to get the V-Max Pro lifters to me so I can finish the Camshaft swap on this engine.
What will the adjustment procedure be for these lifters Jay S? Thanks before hand. Tom V. |
A cool part of these V series lifters that they hold on to the upper rpms like a solid cam, and you can change the lash to suite your desired lower rpm characteristics to your own tastes. We did some testing setting the lash from .a .010” to .030” lash range on a 455 with the Crower 60919. It idled like a 326 2bbl .030” lash, it would idle clear down at 400 rpm. The spc-8 would do very similar. How the cam reacts to the lash depends on how aggressive the cam profile is.
Tom you adjust them like a solid cam. Only the lifter has some spring preload, make sure the preload is bottomed out on the lifter and adjust it like a solid cam. I could see a cam like the HO racing profiles HC-2D and HC-3D both being great candidates for the V series lifters variable duration features. They had a good amount of seat timing like the 041. The first generation of Ultrdynes are also great candidates. They have a medium velocity compared to some more aggressive cams, when that generation of Ultradynes got converted to digital they gained some seat timing. |
Ken Crocie, when I talked to him a couple of weeks ago, was the one who swayed me to go with the HO Racing Camshaft and the Rhodes Lifters vs the Solid Lifter Cam again.
Tom V. |
Tom V. What H-O cam will you be running?
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