Camshaft run in procedure and cam wear

+1 Nigel, run it in like you mean to ride it!!!
I had an XR 500 RD Honda, I ran it in like I rode it, it got some pretty harsh treatment riding through South East Asia, flat track raced it, then it ended up doing long distance offroad in Australia .Never gave any grief from running it in with a heavy hand.
I ended up giving it a freshen up and a hotter cam, the bore and original cam had no noticeable wear after all that hard work.

Plenty of clean oil though throughout.
Regards Mike

I'll definitely be running in any new cams from now on - it does seem like doing anything else is courting potential disaster.

Interesting reading all of this a 18 months after fitting a new cam, and not bedding it in anything like described here - will be interesting see whether i have something else to do in my spare time sometime in the near future.

Iain, how did you run it in?
Regards Mike

FWIW, we ran-in engines on the dyno though you can do the same on the drag strip or other location where you an safely get up to suitable speeds in higher gears. That's pretty difficult (and unsafe) in the real world unless at a race track/strip. That could be a prime reason for the long break-in manufacturers usually prescribe. It probably wouldn't go over well with the lawyers/law-makers if Suzuki, for example, suggested you take your new Hyabusa out and do full throttle runs in top gear to redline on Interstate 40 at 2AM!

Here's what we did: After setting timing to TDC and pre-lubing the engine, we started it and did a 30 minute cam break in. We then changed the oil. Next we set the timing to the spec and did 10 pulls including coast-down working up from 1/2 way to red line on the first run at about 1/2 throttle, working up to WOT to redline on the final two pulls, monitoring for appropriate temps/oil pressure. Then we changed the oil again and determined the optimum timing using the dyno to find the setting that produced maximum power. At the end of that, engine was ready to run however the owner wanted to run it. There was no other "break-in" required.

Note that since coast-down is a critical part of the bedding-in, if you do it on a dyno, it has to be a load-dyno, not an inertial dyno. I have never understood the point of an inertial dyno other than for Sunday-afternoon bragging at a local Harley meet over lots of beer but that's another subject...

NTS8 - if your cam lasted this long, it's fine! It's like a lot of things, despite there being an "optimum" method, much of the time engines manage to do just fine without it. Look how many engines in the world are surviving without incident running grocery-store or Jiffy-Lube oil!

Hi Mike,
we were fiddling with multiple things, including an at that point unsolved electrical gremlin, and i gave no thought to a cam needing to bed in so it had multiple starts and short low rev runs on the work bench followed by some short runs around town before some open road work. It did then do a Sth Island tour for last years rally so is well run in now, and not yet worn out

Ok thanks Iain

I understand the theory, but the practicality of being able to start a newly rebuilt motor readily & have the carbs set about right to be able to ride it almost straight away I feel is difficult to say the least.
The fan option.... not quite sure what a carpet drying fan is though.... as we don't normally get our carpets wet from our local hire centre is certainly an option

I went thru the text book break in procedure for my new Thruxton in 2016.
It's not as described above ( running to red line)
It's very Rev limited , starting with a 4000 Rev limit and gradually increasing in 500 rpm increments every 300 kms to 7500, the Redline.
It seems to have survived this pampering
Doesn't use any measureable oil between changes, 16,000 kms interval.
That is the first new vehicle I've seen in years that dictated a break in procedure of any kind. I was surprised at how long they wanted revs kept down.
They did also advise to vary rpm, pretty common in break-in.

So I'm not sure you have to beat the daylights out of a new engine.
I've always used lots of throttle as in quick acceleration, but kept revs well below redline and run times short ( not too much heat)

Glen

Here is the Breaking-in procedure from the Commando Riders Handbook, 1975.
It's very similar to the information on "Running-in" listed in the 2005 and 2016 Triumph Owner's Handbooks.
About the only difference is the use of the Term " Running-in" vs the Norton term "Breaking-in"




I have to admit that I've never been quite this gentle, although I would generally follow this procedure, especially the RPM limits.

Glen

"Breaking in" has "negative connotations".

John Bloor &Co. are savvy marketers.
Fortunately they also build very good products to go along with the marketing.

It's surprising how close the two sets of instructions are with 41 years between print dates.

Has anyone to date considered or indeed carried out an oil feed from the rockers down to the front of the crankcase and by use of a fitting through the crankcase facilitate some kind of nozzle to spray the cam lobes with oil.... Sorry thinking out loud again..... message to self

worntorn said:

John Bloor &Co. are savvy marketers.
Fortunately they also build very good products to go along with the marketing.

It's surprising how close the two sets of instructions are with 41 years between print dates.

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Maybe it doesn't matter that much so there's no need to change it?

olympus said:

Has anyone to date considered or indeed carried out an oil feed from the rockers down to the front of the crankcase and by use of a fitting through the crankcase facilitate some kind of nozzle to spray the cam lobes with oil.... Sorry thinking out loud again..... message to self

Click to expand...

Yes; Comnoz. He gun-drilled the cam, and fed oil through the left-hand case, bleeding out through holes in the lobes. As I recall, he didn't see any value added. Jim, please clarify, as I most likely got the details screwed up...
For my money, I'd like to see the cam tunnel recreated like the prior-to-Commando style, where the tunnel wrapped around the back of the cam, acting as a reservoir that the lobes could dip into from the git-go.

Nathan

Nater_Potater said:

Yes; Comnoz. He gun-drilled the cam, and fed oil through the left-hand case, bleeding out through holes in the lobes. As I recall, he didn't see any value added. Jim, please clarify, as I most likely got the details screwed up...
For my money, I'd like to see the cam tunnel recreated like the prior-to-Commando style, where the tunnel wrapped around the back of the cam, acting as a reservoir that the lobes could dip into from the git-go.

Nathan

Click to expand...

I have seriously considered creating that trough with aluminum sheet metal & JBWeld, but the idea of metallic particulate accumulating in there deters me.

swooshdave said:

Maybe it doesn't matter that much so there's no need to change it?

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The manufacturers must think it matters a lot in order to include such a detailed procedure in the handbooks. It's reassurring that the two seperate companies give the same instructions decades apart. Or do they have it all wrong?
Triumph also pastes a break-in decal on each speedo that lists rpm limits at each interval of break-in mileage.
This is for the 75% of owners who won't be bothered to read the handbook.

I'm thinking the rpm limits are a good thing.
An example of the opposite method comes from the Vincent world.
A well known Aussie Vincent mechanic built a hotrod 998 around the same time I built my hotrod 1360.
He and I used the same Terry Prince /Fritz Egli MK5 race cams.
He went racing with the bike after about 10 minutes of running.
I went thru a new Norton Commando/ new Triumph type break-in procedure for 1500 miles.
I questioned his lack of rpm limited break in time on his race engine and he responded " I think I know my engine".

His engine is ruined after 1 short season of 5 races, less than 100 miles covered. He informed me that the MK5 cams Terry sells are crap as his are ground down to nothing just from that small usage. All of that metal has gone thru the engine, which took out main bearings, big ends, main shafts, everything. Even the valve guides and valves are shot, as are the rings and bores.

I disassembled the 1360 at 1500 miles for crank rebalance and it was spotless in there, everything perfect, cams included.

So we do what works for us!

Glen

Pride goes before a fall.

concours said:

I have seriously considered creating that trough with aluminum sheet metal & JBWeld, but the idea of metallic particulate accumulating in there deters me.

Click to expand...

That's what the crank trap is for!

Glen, the Norton blurb talks about limiting the throttle to 1/3 opening. I’m not able to test this right now, but I’m pretty sure this’ll be in excess of the 2,500-3,000 cam break in range won’t it?

I’m thinking we might be crossing arguments here... the Comnoz cam break in comments never sugegsted red line runs.

Still seems to me that keeping a Cdo below 1/3 throttle would most likely constitute the kind of ‘normal use’ scenario that should lead to good cam break in?