Cams, KK vs KHK vs KR

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Re: Cams, KK vs KHK vs KR

Postby starcain » Sun Dec 01, 2019 12:27 pm

[quote="EKHKHK56"]Cams Kams. First off someone posted small hole lifters as K. All K lifters have large holes.

Erik, are you saying that KK's and KHK's also use the large two hole tappets when you say all K lifters have large holes? KK's and KHK's use 18508-52R tappets which are lighter in weight and have 3 small holes. K's and KH's use the 2 large hole tappets # 18534-29. Just curious as to what you mean by that statement?

Stan
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Re: Cams, KK vs KHK vs KR

Postby starcain » Sun Dec 01, 2019 1:01 pm

Had a request for a larger image of the Competition Cam Kit/ Special Roller Tappet kit.
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Re: Cams, KK vs KHK vs KR

Postby starcain » Sun Dec 01, 2019 1:08 pm

hugoct wrote: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


That is very interesting. Any chance you could post an image of that said Bulletin?
Thanks,
Stan
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Re: Cams, KK vs KHK vs KR

Postby hugoct » Sun Dec 01, 2019 2:54 pm

I could scan and Email it. Your Email address?
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Re: Cams, KK vs KHK vs KR

Postby starcain » Sun Dec 01, 2019 3:27 pm

Milburn, I sent a PM to you but not sure if it went. My email address is:

[email protected]

Thanks, I appreciate it.

Stan
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Re: Cams, KK vs KHK vs KR

Postby wz507 » Mon Dec 02, 2019 1:06 pm

hugoct wrote: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

The cam discussion here has brought a new question to mind, specifically, a question relating to cam part numbers. I am familiar with cam set part numbers due to the various on-line sites and manuals that provide such information (Patrick’s KR/XLRTT, Panic's Victory Library, factory KR/XLR manuals, etc), and in the majority of cases see the cam sets listed as 25499-XXR part numbers, where XX is the year of the part, and the earliest set being 25499-53R. However in the quoted text above the cam part numbers end in -52R, which is the earliest -R cam part# I know of. Was there a -52R cam set for K Models, and if so, might anybody have the factory specifications for the -52R flat tappet cams?

Circling back to the original subject of what cams, labeled KR2 and KR3,might be in Jerry’s friend’s engine, it would be interesting to know the lobe height and base circle dia of these cams so we know what lift they are. From the -53R KR cams going forward all the KR cams had at least 0.395” lift. Makes me wonder what the lift of the -52R cams was. I’ve heard it suggested around the camp fire that the KK/KHK cam was the same as the early KR cams, yet the early KR cam, 25499-53R, is listed as having 0.395” lift and KK/KHK cams do not have this high a lift. Did early KRs actually use the KHK cam?

More questions than answers, but hopefully we can make a dent in it.
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Re: Cams, KK vs KHK vs KR

Postby hugoct » Mon Dec 02, 2019 2:56 pm

The 52 "R" cams and the the 53 "R" cams have the same timing check specs which may indicate the same timing specs.
Intake opens at 7/16" before top center and the exhaust closes at 1/2" after top center.
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Re: Cams, KK vs KHK vs KR

Postby panic » Mon Dec 02, 2019 3:28 pm

If the lift vs. duration curves of 2 cams with identical duration and lift were compared, one with a flat tappet and the other with a roller tappet, the plots would only overlap at zero lift at both ends. The actual motion is quite different.
[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 » Mon Dec 02, 2019 4:26 pm

Jeff, If you want a copy of the flat tappet cam kit bulletin send me an Email at [email protected] and I will send a scan. :)
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Re: Cams, KK vs KHK vs KR

Postby EKHKHK56 » Tue Dec 03, 2019 1:30 am

Of course the early Ks were deriviants of the WR. The first hot rod K was the KK with WR Valve Train. Erik
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