Backyard cam dialling

[lambs]

That camshaft has been built-up and re-profiled to restore or increase lift.   Race engines usually run stiffer valve springs and higher ramp rates, totally changing the wear characteristics.    OEM camshafts are straight cast iron and rely on work hardening 'skin effect' for wear resistance....and plenty of good quality oil, of course.   

I started mucking about with Camshaft Dialling in 2013 after the Ivan Tighe camshafts (2532 grind) I had made and fitted "wore out".
I had a winge to Tighe Engineering, and spoke to MP who let me know that after 10 years of service I could expect those lump sticks to be knaffed - indeed, when racing, the camshafts are swapped out regularly.
This is what they looked like, they had developed a flatish spot and a wave crest at the top of the lobe.

[lambs]

In fact I Put the old camshaft back in and it ran sweet again......

So assuming the marks lined up with the old camshaft in place, either there is some important difference between the EX camshafts or having the marks more-or-less line up is important.....or maybe both.....

As the son of a builder I know that tradies are valuable people 

[AussiXS11G]

I started mucking about with Camshaft Dialling in 2013 after the Ivan Tighe camshafts (2532 grind) I had made and fitted "wore out".
I had a winge to Tighe Engineering, and spoke to MP who let me know that after 10 years of service I could expect those lump sticks to be knaffed - indeed, when racing, the camshafts are swapped out regularly.
This is what they looked like, they had developed a flatish spot and a wave crest at the top of the lobe.



I never dialled the Tighe cams.
I swapped the Tighe cams for a pair of OEM 1978 sticks, slotted the sprockets, and with the help of #2 son, and the advice of Gary Thomas, the man who had ported and flowed my head, set out to dial these cams to Gary's recommended "110 lobe centres"
Unfortunately, the slots in the sprockets only allowed us to get to 105 lobe centres, and this stayed so until May 2016 when I freshened the engine for the bike's current evolution.
I had a fresh set of sprockets slotted to let us get to 110 lobe centres.



These are the numbers from 2013 efforts - I can't find the current details



I have a few word docs that explain lobe centres, and camshaft dialing and they can be found in this dropbox folder (the most recent Dyno sheet 2018 states the Tighe cams - not true OEM '78 cams dialled as discussed) I haven't been back to the dyno since I fitted the TPS and updated the IgniTech software - something to look forward to 

https://www.dropbox.com/sh/erzsdzkmj0bqesm/AACQ2NmpePWEUokvjmJPWMDXa?dl=0

It's an interesting topic for sure

[Jonesy :-)]

As far as i know the later model cams had more lift but same duration?
Truth be told, I couldn't get it to run properly with this slotted set up, it either wouldnt idle and die or with the slightest touch of the idle adjuster the revs would take off. Makzy your bricklayer version of timing setup makes sense to this son of a plumber . In fact I Put the old camshaft back in and it ran sweet again, if I get keen I might have another go with the marks setup from the pre slotted photo. I didnt try to run it before I slotted it

[makzy]

Well your both half rite, there were changes to the later models, mainly valve timing, for emissions purposes, profiles changed a bit but unless your using a degree wheel to set actual valve timing you might be defeating the purpose because with chain and sprocket wear the marks will nearly always be a little out, the marks on the cam you put in might differ but the slight difference in lineup is irrelevant, it will be right for the cam but not quite rite with the marks if ya get what mean? A degree wheel is really the only way to get what the book says but in reality they were never exactly what the book says! A degree here or there was good enough back then, you just have to look at the indicator marks on the sprockets and cam caps of pretty much any engine from the period to see they weren’t perfect.
I think one of my cams was nearly half way between teeth so but it to the next tooth on the advance, runs great!
With slotting the holes and lining up the marks you might actually be putting the valve timing out by a degree or so. But what do I know? I’m only a bricklayer!

[lambs]

I know there are differences between early and late heads, so wouldn't be surprised if there were also camshaft profile changes.   What you've seen suggests differences in cam lobe angle given that only the EX cam was changed.

[Jonesy :-)]

Recently had a problem of the dots on the cams wouldnt line up after doing an exhaust cam transplant.
The only way I could achieve proper timing was to slot the sprocket holes.
Does anyone know if there are different cams for the 11?




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