Cams, KK vs KHK vs KR

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Cams, KK vs KHK vs KR

Postby JerrryR » Sat Nov 30, 2019 12:53 pm

Hi All,
I've had some questions about K cams for a while now and was hoping to finally get some closure on the topic. What has prompted me to write about it now is a friends recent purchase. He bought a KRM motor (in parts). It came with two cams simply marked 1 & 4 and two marked 2KR & 3KR. Here are my questions or assumptions.

1. The KK cams were simply marked 1 through 4?
2. The KHKs starting in 54 used the KK cams?
3. The use of the KK cams marked 1 through 4 continued for the 55KHKs?
4. Probably for the 56KHK since it was a floor model Harley started marking the cams with KHK?
5. My assumption has always been that the KK and KHK cams were the same?
6. I couldn't notice a "slope on the #2KR cam I have?
7. Can my friend use the cam set that came with the KRM? Can you mix KR and what I assume are KK cams?

A friend sent me the lifts he measured on KK and KHK cams a number of years ago. You can see in the table I made that the KK cams at least the way he measured them all show a slightly higher lift? I only have access to a #2KR cam. I measured its lift in the center of the lobe and listed it in the table.

Thanks and looking forward to some final clarity with these cams.

Tom D2.2.jpg
Tom D2.2.jpg (95.25 KiB) Viewed 1512 times


Tom D3.2.jpg
Tom D3.2.jpg (117.92 KiB) Viewed 1512 times


Cam Table.jpg
Cam Table.jpg (54.41 KiB) Viewed 1512 times


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Re: Cams, KK vs KHK vs KR

Postby hugoct » Sat Nov 30, 2019 3:10 pm

There was a "Hot Cams" kit available in 1952 that included WR style flat tappet cams, WR style flat tappets and the appropriate tappet blocks.
There have been stories of those cams being used in 1952 KRs, KRMs and KKs.
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Re: Cams, KK vs KHK vs KR

Postby starcain » Sat Nov 30, 2019 7:33 pm

Jerry, I got into the KK/KHK cam subject pretty heavy awhile ago. This is what I believe to be accurate.

1. The KK cams were simply marked 1 through 4? YES
2. The KHKs starting in 54 used the KK cams? YES
3. The use of the KK cams marked 1 through 4 continued for the 55KHKs? YES, JUST TALKED TO A FELLOW THAT HAD A '55 KHK AND HIS CAMS WERE MARKED 1,2,3,4
4. Probably for the 56KHK since it was a floor model Harley started marking the cams with KHK? YES, I THINK THAT IS CORRECT BUT HAVE NO PROOF
5. My assumption has always been that the KK and KHK cams were the same? YES
6. I couldn't notice a "slope on the #2KR cam I have? DON'T KNOW ABOUT THAT ONE
7. Can my friend use the cam set that came with the KRM? Can you mix KR and what I assume are KK cams? NOT QUALIFIED TO SAY

I believe there were 5 or 6 different KR cams, all with a different lift and duration. The lift on the KR cams that are in the picture ( both intake ) don't appear to be that much different then the KK cams. Duration much longer though. Seems to me that that set up could have been a workable one?

The 1953 KK's and KRM's both used the same cams as well as the KHK's. As I mentioned, I just talked to a fellow that has a 1955 KHK and his cams are simply marked 1,2,3,4. A few people through the years have claimed that they had either a 1954 or a 1955 KHK that the cams were marked KHK. So, I don't know about this for sure and have no proof either way.

I have never heard about what hugoct is referring to about the WR cams, tappets and blocks. He may be referring to the " Competition Cam Kit" that was introduced in 1953. It was what made a KK and KRM different then a standard K. It did use WR valves and valve collars but the cams were KK/KRM with light 3 hole tappets and very light tappet screws.

The lift on a KK/KHK cam is actually .375". That is the measurement that I got right off the tappet screw. I think the biggest KR cam lift is .420"

Anyway, that's what I believe to be correct but one never knows for sure!
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Re: Cams, KK vs KHK vs KR

Postby Tim The Grim » Sat Nov 30, 2019 9:14 pm

Both of your Intake Cams should have the same grind. Yours clearly do not. The radii on the #3 are smaller and will result in a more rapid acceleration of lift and a longer duration. The #2 is a more gentle profile overall with what looks like the same lift.
If it has no angle on the lobe it may be a WebCam regrind.

Back in the late ‘70s I had my KHK cams reground by WebCam and they looked a lot like your #2 with no angle. I had to grind the angle on the tappet rollers to compensate. Unfortunately my motor guy got a hair up his rear and didn’t install the tappet rollers I ground at the die shop I worked in.
The cam lobes were destroyed in a few weeks due to the mismatch. He also stole my cylinders and put a bad pair on my engine. That story involves a 1911, an oily ring on the tip of my nose and does not have a happy ending.

When I bought my’54KHK in ‘70 it had KH cams in it. I had the motor redone and paid $75 for a pair of very good used KHK cams that were stamped as KHK and were a 4 cam set. I do not know what year they came from. The KH cams got stolen from a pals garage when I had a brain fart and left them there overnight after stopping to work on his ULH.
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Re: Cams, KK vs KHK vs KR

Postby panic » Sat Nov 30, 2019 11:17 pm

The only WR retro-fit IKO is every part needed to put the WR top end including tappets, blocks, cams,covers, springs etc. on a WL lower end. IIRC the cams were plain journal since the ball bearing inners require the smaller pinion race.
I have some KR data and comments on my site here: http://www.victorylibrary.com/tech/KR-cam-c.htm
[url="http://victorylibrary.com/BTHP.htm"]H-D Flathead Breather Timing for High Performance[/url]
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Re: Cams, KK vs KHK vs KR

Postby hugoct » Sun Dec 01, 2019 12:13 am

There is a 1952 Cam Kit which uses WR style flat tappet cams. WR style flat tappets, and tappet blocks.
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Re: Cams, KK vs KHK vs KR

Postby EKHKHK56 » Sun Dec 01, 2019 12:58 am

Cams Kams. First off someone posted small hole lifters as K. All K lifters have large holes. The same part Cam set #-53 is included KK KHK through 56. My stock 55KHK had # only cams. The #-53 set is quite spunky. If someone wants to bump up the intakes a bit more thats fine. #2 & #3. However, if you are going to run different intakes you want the milder one on the front cylinder. The rear cylinder needs a bigger drink due to the difference in piston dwell on 45° V twin intake cycles. With same cams. Erik
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Re: Cams, KK vs KHK vs KR

Postby wz507 » Sun Dec 01, 2019 2:19 am

JerrryR wrote:Hi All,
I've had some questions about K cams for a while now and was hoping to finally get some closure on the topic. What has prompted me to write about it now is a friends recent purchase. He bought a KRM motor (in parts). It came with two cams simply marked 1 & 4 and two marked 2KR & 3KR. Here are my questions or assumptions.

1. The KK cams were simply marked 1 through 4?
2. The KHKs starting in 54 used the KK cams?
3. The use of the KK cams marked 1 through 4 continued for the 55KHKs?
4. Probably for the 56KHK since it was a floor model Harley started marking the cams with KHK?
5. My assumption has always been that the KK and KHK cams were the same?
6. I couldn't notice a "slope on the #2KR cam I have?
7. Can my friend use the cam set that came with the KRM? Can you mix KR and what I assume are KK cams?
JerryR


Regarding your lobe measurements to determine cam lift, you must also measure the base circle as the maximum lift is the difference between base circle and lobe height. Without measuring you cannot assume the base circle of each cam is the same or was measured the same way. On the angle-ground K Model lobes it is necessary that the lobe height and base circle measurements are made on the same side of the lobe, i.e., the tapered lobe is larger on one side and smaller on the other, thus both height and base measurements have to be made on the same side of the lobe. The image below hopefully clarifies this where the red arrows indicate a satisfactory place to measure both the height and base, as do the black set of arrows. However, you cannot mix and match a red arrow data set with a black arrow data set.

Measuring angle ground cam lobes.jpg
Measuring angle ground cam lobes.jpg (41.91 KiB) Viewed 1346 times

My ‘56 KHK has the 1,2,3,4 cam marked series in it – not KHK markings. Below are the lifts I get measuring the lobe base circle dia and height with a dial caliper at the largest end (red arrow side). Also in the table are the maximum lifts that were measured carefully in the engine for the same set of cams.

Lift of KHK cams.jpg
Lift of KHK cams.jpg (19 KiB) Viewed 1346 times

For the sake of discussion the base circle size measured above was applied to the lobe heights you measured and the resulting lift values are in the table below. I find it curious that the EX lobes are all lower lift than the intakes, which if true makes me wonder if they might be KH lobes rather than KHK? But again, we don't know how or where the measurements on the lobe were made so the lift results in the table below could introduce information that may be more misleading than informative - therefore, proceed with caution.

JerryR K Model Cam Lifts.jpg
JerryR K Model Cam Lifts.jpg (26.68 KiB) Viewed 1346 times

I think your cam images posted above are sufficiently distorted that one should be hesitant to draw any conclusions regarding how any given lobe compares to another lobe. Perhaps you could retake the picture from several feet away and zoom in to minimize the distorted view?
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Re: Cams, KK vs KHK vs KR

Postby wz507 » Sun Dec 01, 2019 2:32 am

JerrryR wrote:Hi All,
I've had some questions about K cams for a while now and was hoping to finally get some closure on the topic. What has prompted me to write about it now is a friends recent purchase. He bought a KRM motor (in parts). It came with two cams simply marked 1 & 4 and two marked 2KR & 3KR. Here are my questions or assumptions.

6. I couldn't notice a "slope on the #2KR cam I have?

JerryR

You noted that a tapered face could not be detected on #2KR cam. Are you suggesting that you could see the angle on the #3KR cam but not on #2KR? Remember that the EX lobes are ground at an angle of ~ 3 deg, whereas the IN lobe angle is ~ 1 deg, so it is much more challenging to see the 1 deg taper on the IN lobes than it is to see 3 deg taper on the EX lobes. See the image below of KHK cam lobes illustrating the higher angle of the #1 EX lobe (left) and the lower angle of the #3 IN lobe (right). I think if you look very carefully at the base circle of the #2KR and #3KR lobes you might see the angle. If not you should be able to measure a difference in base circle dia from side to side across the face of the IN lobes. If no difference can be measured then the cams are flat ground. When I slide a caliper across the base circle, from large side to small side, of the #3 IN lobe I measure a difference of ~ 0.008” in dia. If I do the same on the #1 EX lobe I see a difference of around 0.040” in dia. Let us know what you see when you do similar on the KR IN lobes.

Comparison of ground angle on #1 and #3 KHK cams.jpg
Comparison of ground angle on #1 and #3 KHK cams.jpg (114.29 KiB) Viewed 1344 times
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Re: Cams, KK vs KHK vs KR

Postby hugoct » Sun Dec 01, 2019 12:11 pm

Panic,
There is a 1952 bulletin titled "Instructions for installing "Flat Tappet Kit" on model "K" motor" it predates the bulletin you posted from 1953.
The layout of the page is identical but the diagram shows an engine with the WR style valve train components. The following parts differ 18220-30 valve spring collar, 18228-30 valve spring collar key, 18515-52R Tappet assembly, 18566-40 tappet adjusting screw, 18605-52R front tappet guide, 18605-52R rear tappet guide, 25520-52R front exhaust cam, 25521-52R rear intake cam, 25522-52R rear exhaust cam, 25525-52R front intake cam. The timing check specs are the same which would indicate that the cam timing was the same. This may be the smoking gun regarding the legend of the 1952 KRs coming with WR style cams and tappets.
Regards
Milburn
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