Camshaft wear

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mikenixon
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Camshaft wear

#1

Post by mikenixon »

Image

You're looking at a camshaft lobe, and though this is a surprising amount of wear for the mileage, it's not catastrophic. In fact it's not even excessive wear. Yet this wear is more than most people would expect in just 4900 miles. That's right, 4900. It's normal. The fact is, camshafts in vintage Hondas can be observed to wear their cams at a rate between 0.001 inch to 0.003 inch per thousand miles.1

Japanese motorcycle cams are fairly soft. With very few exceptions, any of these cams can easily be drilled with a standard HSS drill bit, the kind you can pick up at the bargain table at the hardware store. And the resulting chips experienced machinists recognize instantly as cast iron. Yup. Very soft. Below Rockwell 52 in fact, for you metallurgists. 2

The result is that vintage bikes with 20,000 to 40,000 miles have some significant wear on their cams. Enough to make the bikes perform signicantly below their potential, not the least of which because the wear changes valve timing by 5 to 10 degrees.

Two facts emerge. First, folks who swap in aftermarket cams are in most cases seeing gains not from the supposed advantages of said "high performance" products but rather from the simple elimination of the stock part's wear or misadjustment. 3

Second, this has prompted aftermarket cam suppliers to offer stock-spec cams. They're very useful and very timely products. How else can you restore the performance level the machine exhibited almost 50 years ago? A used stock cam won't get it -- most are worn as much or more than yours. A remanufactured cam is a huge boon.

Don't overlook the camshaft.

Notes:
1 This is not a guess. This is a documented, widely corroborated fact.

2 There are a very few cams that are not cast iron. The chromoly cams found in the ZX-10R and similar hyperbikes are among the few exceptions.

3 I have proved this countless times with all sorts of parts. The stock minimally-worn part properly installed and maintained out-performs the so-called performance part every single time.
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Re: Camshaft wear

#2

Post by Track T 2411 »

I can certainly attest to this! I have two sets of 1100 cams that look horrible compared to your pic. However, I've never seen ANY aftermarket cams offered for these engines. Maybe I'm not looking hard enough? Any suggestions/links/info on where to look?
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Re: Camshaft wear

#3

Post by Old Fogey »

Track T 2411 wrote:However, I've never seen ANY aftermarket cams offered for these engines. Maybe I'm not looking hard enough? Any suggestions/links/info on where to look?
Web Cams and Megacam use to (still do?) offer a 'sports' spec cam on your cores (last time I looked was about 5 years ago - around $400 if I remember right). I used to think they would build it up and regrind; if these are cast iron, that would not be possible. So I guess it would be just a regrind with a smaller base circle if the lift was to be increased.
Flat follower cams (as opposed to roller) need the zinc that most modern oils have practically got rid of, except for some diesel oil. Hence the popularity of Rotella.
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Re: Camshaft wear

#4

Post by mikenixon »

There are at least three companies that will weld, harden, and regrind to stock specs. Likely there are more. I have had it done on many bikes. They also insist on doing the followers (rockers, won't guarantee otherwise) and in fact the followers cost more than the cams. Stock, the followers are flash chrome plated. To reiterate, steady wear, not galling from lack of oil, is endemic in non-sport model Japanese motorcycle cams. They are very soft. Most never notice, no bad effects in other words. Then when during a resto one measures the cams the Honda way and checks against the manual, holy crap! They're 0.050 inch below minimum spec. No wonder this bike won't accelerate like it used to!

As for aftermarket cams for Wings, Jim Dour who founded Megacycle practically started with Gold Wings.
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Re: Camshaft wear

#5

Post by mikenixon »

Megacycycle in Calif
Web Camshaft in Calif
Delta Camshaft in WA state

These are the "three" that I mentioned that not only repair stock cams back to stock spec, but very importantly, give them the harder-than-stock finish that is beneficial AND do the followers similarly. There are many other companies that will make any kind of cam you want, Crower, for example. But I know of only these three above that will do the hardweld, to OEM spec, and do the same to the followers.
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Re: Camshaft wear

#6

Post by Track T 2411 »

Thanks for the info. I was wondering about the followers, as they are noticeably worn as well...
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Re: Camshaft wear

#7

Post by mikenixon »

Track T 2411 wrote:Thanks for the info. I was wondering about the followers, as they are noticeably worn as well...
Good. But remember, we're not talking about damaged cams due to oiling issues or other failures within the engine, though those cams and followers can be rehabilitated the same way as simply worn cams and followers. If your parts are extremely "worn", this is damage, not wear. Meaning you heed to find and correct what caused this.
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Re: Camshaft wear

#8

Post by Old Fogey »

mikenixon wrote:Megacycycle in Calif
Web Camshaft in Calif
Delta Camshaft in WA state

These are the "three" that I mentioned that not only repair stock cams back to stock spec, but very importantly, give them the harder-than-stock finish that is beneficial AND do the followers similarly. There are many other companies that will make any kind of cam you want, Crower, for example. But I know of only these three above that will do the hardweld, to OEM spec, and do the same to the followers.
Curious as to how they do 'hardweld' to cast iron.
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Re: Camshaft wear

#9

Post by mikenixon »

Old Fogey wrote:
mikenixon wrote:Megacycycle in Calif
Web Camshaft in Calif
Delta Camshaft in WA state

These are the "three" that I mentioned that not only repair stock cams back to stock spec, but very importantly, give them the harder-than-stock finish that is beneficial AND do the followers similarly. There are many other companies that will make any kind of cam you want, Crower, for example. But I know of only these three above that will do the hardweld, to OEM spec, and do the same to the followers.
Curious as to how they do 'hardweld' to cast iron.
Dunno.
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Re: Camshaft wear

#10

Post by taunusrainer »

For european members http://www.imotecgmbh.de/ is a good address.
They regrind the camshafts to stock specs or to more (or less) radical curves. Then they nitrate and harden the surface.
Prices are acceptable, quality is good.

To avoid or reduce camshaft wear (and main bearings wear, big end bearings wear, cold start wear) I add MoS2 to the engine oil.
This sometimes requires harder aftermarket clutch springs, but also with brand new Honda springs the clutch would not slip
on my bike.
MoS2 is the only additive I recommend, it was already developed in WW2, so quite proven.
Available from different brands, for example LiquiMoly
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Re: Camshaft wear

#11

Post by gltriker »

Sometime around 1969, I ordered a copy of this same publication from WEBER Speed Equipment. Somewhere in California. [attachment=0]s-l300.jpg[/attachment
Why?
I had purchased 2 1953 Harley-Davidson Servi-cars ($150each) and soon afterwards became interested in the current chopper magazines' experimentation with SU carburetors . They were Cheap and plentiful back then to purchase 2 or 3 different ones to experiment with.and although I had no idea if there was any good reason to spend $100 for the service, why not remove and send the 4 individual camshafts out of the 45c.i. sidevalve engine to WEBER somewhere in California for some "modifying," too. tumb2

The lobes were built up with, if my memory serves me correctly 50+ years later, a nickel alloy weld treatment, then reground to a customer's profile selection.

After opening the side cover to gain access to the 4 camshafts, I was surprised to find roller camshaft followers. And, that was how the engines were originally designed.

The aftermarket air cleaner assembly I bought locally for the SU carburetor was manufactured in,
Woolloomooloo, Australia . :-D
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Re: Camshaft wear

#12

Post by 5speed »

this is what the lack of zinc phosphate in oil did to the lifters and cam in my Z28. shaved 3 lobes off the cam.
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Re: Camshaft wear

#13

Post by mikenixon »

Ouch! Wow.
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Re: Camshaft wear

#14

Post by rcmatt007 »

makes me wonder what the 140k (plus) cams look like on my 78
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Re: Camshaft wear

#15

Post by 5speed »

mikenixon wrote:Ouch! Wow.
it was made worse by the loose nut behind the steering wheel.
When I heard the noise it sounded to me like a broken rocker arm and since I was heading to the town my brother was working in as a heavy equipment mechanic, I decided to go there, pull the valve covers, remove the broken rocker arm and limp it home.
we didn't make it.. :(
Did I mention it was a hot day in july..my camaro is black with a t-roof and I had both kids with me!!
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