Indian Cam Study

11 Мар 2015 | Author: | Комментарии к записи Indian Cam Study отключены
Indian Chief Standard

Part 1: Lifters, and Press-On Cam

There are (2) factory installed combinations that were Standard, and Bonneville (Note: A known fact is that in there were optional cams available with lifters, and I have a set that I measured, and they are also here). Standard cams are tame, and as you all know, they run out of fairly quickly. This is of their short lift, and low duration.

The factory came out the Bonneville cam/lifter set to increase and RPM by increasing both the lift, and The factory had to change the lifter to accommodate the change in cam design. moved the rollers closer in the pivot shaft by nearly which moves the timing by 10 degrees on the new Bonneville lifters.

The Exhaust lifter will cam timing by 10 degrees, and the Bonneville lifter will Advance cam by 10 degrees as compared to the Standard By moving the rollers inward on the lifters, the rocker-arm ratio from .81:1 for Standard to .86:1 for Bonneville lifters. are approximate (but very figures, and the variations in shape of the that contact the bottom of the rods can slightly change figures.

Therefore, on a given a Bonneville lifter not only the opening, and closing points by 10 it will also slightly valve lift compared to a lifter. This description of holds true for the Scout as well as Scout Bonneville except that the Scout are entirely different in design, and

In fact, the lifter ratios for are lower than Chief at which required the cam lobes to be in Scouts than in Chiefs. cams have been to be more radical than but that is mostly due to appearance. need to look Higher-Lift the rocker ratio is less, and there is less valve achieved from the same cam in a Scout than if it were in a Chief.

People have used cam lobes in Chiefs with success. I have a set of lobes that I have measured have been incorrectly Shunk Hi-Lift that had sold by Charlie Mathre for but recently it has been revealed to me they were a Scout cam with the offset pin location placed. They appear to be Hi-Lift, because they intended for use in Scouts with a rocker-ratio.

They can be used in with alot of changes made to the valve spring as well as relieving metal above the valves in the heads. In a they turn out to be the most cam available.

Some performance cam have an offset pin location, the cam lobe can be flipped over to advance, or retard the lobe on how it is installed. All original Indian have a 1/4 hole drilled all the way the lobe, and gear combo. I that it was to index the cam lobe for in the gear teeth. This 1/4 is used to pin the new lobe to the gear the original lobe is ground

In most cases, I have a width of 1.125 width of the gear, and lobe combo for Scouts). The new lobes can varry in so the amount of the original lobe to be off is exactly equal to the width of the new that is going to be pressed on. can be made to this net width to add or material in order to achieve the recommended .004 to .006 play of the cams in the timing

After the cam lobes are lined up and pressed on, a .250 shaft long) is pushed through the 1/4 and staked over to lock the cam in place. This is a very job that is best left to the On some cam lobes, this 1/4 is centered, and therefore, a lobe can be over, or used on either the or rear cylinders.

You can’t get on wrong! These are the Bonneville, the known Ollie lobes, and the Sport lobes. The next (5) I describe here all have pin offset to the side slightly. recently developed cams Terry Krum provides are the same lobe as an old set of lobes I borrowed from Bob Stark’s cam that are labeled as Shunk 74.

34) I an original set of cam lobes from Breeding’s collection that are Ollie that appear to be to a set I borrowed from Bob Stark, but do not appear at all similar to the modern that are available today. 5) The set here are the before-mentioned Shunk cams that were intended for Scouts, but the pin hole was in the wrong place. They drilled for a Chief cam gear, explains the very high when used in a Chief.

All of (5) have offset pin holes, and installed on the front, or Rear the lobes can be installed in their of rotation as advanced, or retarded. As the front cam as viewed from the cam side rotates in a clockwise With the lobe pointing the pin location should appear to be to the of center if the lobe is desired to be (to the right of center if retarded).

Use some logic here! As the rotates, there is a meatier of the lobe to one side of the pin location, and if it is of the pin as it rotates, then the lobe is There has been alot of about these offset pin and their intentions.

Charlie marketed his Shunk Hi-Lift with instruction that that the lobes be installed in Retarded position. I had long with him on this, and we both are that the other guy is wrong. cams have the pin location at 9 off center, so there is a difference of 18 of timing (Retarded) if the lobes are the wrong way.

Bob Stark and I had a talk about this, and we agree that all offset should be advanced, so the intake will close sooner later allowing for more to build on the compression …. Bob even pulled out an original set of lobes where the front cam was installed advanced, and the rear cam was installed retarded. They both stamped Shunk on face.

They might installed a front cam lobe on the as well as the rear. They have incorrectly installed the cam lobe, and then stamped Regardles, this combination was not in any case.

Only one of the cam lobes was on Which one? I also a set of cams that I recently from Mike Breeding’s Dog.

They are stamped Ollie on lobes, and they are in the retarded I have a pair of lobes Bob Stark’s collection that identical to these in a bag labeled and they are stamped F, and R. If these installed with F on the front etc. they would be in the position. Which way is correct?

My job is to measure the pin offsets, and then the can be looked at and compared to known for comparable applications. Idealy, in my we need to come close to the figures for other popular and using lobes that are (as well as using Standard take us farther away the ideal opening and closing I have measured the data for cams in their advanced and I am showing the pin offset in degrees.

the cam lobe over will the same cam measurements by twice the of offset degrees! The Shunk have a 9 degree offset ( 18 if flipped, equalling (1) gear and if retarded, the intake valve close untill the piston is than half way up it’s …!

To identify a Standard measure the distance from the of the roller hole to the center of the shaft hole, and the distance is 1.460. The Bonneville lifter measure roughly 1.375 center to center. On any cam, switching over to the Bonneville the overlap increases by 20 degrees lobes centers move 10 less), and this will change the way the bike runs.

Indian Chief Standard

In cases, it will lower the of low RPM power and torque, but the higher RPM will significantly increase. My shows that the Standard are only appropriate for Standard and Bonneville lifters are the better for Bonneville, and ALL other aftermarket cams.

I arrived at this conclusion by various Indian performance measured with both and Bonneville lifter combos, and comparing the data with cams that have developed for the Harley-Davidson Panhead, and configurations. In fact, for Indian with similar duration to H-D cams, the Bonneville lifters get us to the established opening, and closing for the H-D performance cams.

Most is the closing point for the Intake The Bonneville lifter advances closing point by 10 degrees, and the piston to build more on the compression …. Again, we are the ideal numbers found in H-D performance grinds by using the lifters.

I found a handy of H-D performance cam data at ( ). All of measurements, as well as mine, taken at .053 lift off of the base circle. This is the industry standard for measurement and my figures can be used for comparison other grinds.

I have that there can be serious to the valve train when Hi-Lift performance cams Bonnevilles!), because of a potential situation when using the valve spring with 9 Please read my Valve Study here for some and advise.

Standard Lifters on and Bonneville lifters below. how the rollers are slightly closer to the shaft holes on the Bonnevilles.

On the is a Standard Chief cam. On the is a Bonneville Chief cam.

are (6) different performance press-on cam The (3) on the left have pin holes are centered, and the (3) on the right have pin holes.

Here is an example of offset pin cam that have been installed (retarded). The lower set are stamped Ollie are the same as the above, but the lobes are stamped an F, and an R. You can’t put them on wrong that you have the F, and R showing they are pressed on. The set that are on the were stamped with but not FR.

They probably incorrectly put the lobe on the rear gear,

Note: All of the measured data was at .053 lift above the cam Base Circle. This is the used today!

Note: All Pin cams were measured in Advanced State. The pin Offset is in degrees, and this amount One-Half the amount the cam would be by, if the lobes were flipped Example: The Shunk 74 has a 3.5 degree and if flipped over, it would the lobe by 7 degrees!

When Indian performance cams to H-D you will notice that by Bonneville lifters, the overlap increase by nearly 20 degrees, but the and closing numbers come closer to the desired numbers of the H-D cams.

Indian Chief Standard

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