Changing Cams Evo and TC

[Spanners39]

If any of you are considering a cam swap and have made the mistake of reading how to do it on a USA forum and been convinced you can't do it (especially if it is a Twin Cam....sooo much BS about crank runout on the USA forums) I can talk you through it if you have the skills to at least attempt it but here are the main points our Yankee cousins will spout that may put you off and my responses:

• You can't put a gear drive cam set in a TC without taking the crank out and truing it - Not true, you just need more than Zero lash at the two tight spots on the crank pinion, the excess lash on the loose spots makes no difference to anything important except maybe your OCD
• You must fit a high-output oil pump if tuning a TC (or an Evo) - Not true, but do look inside your oil pump to make sure it hasn't eaten a load of gravel (more important on a TC as if the tensioner pads explode it can crack the gerotors), Evo oil pumps can run very well with some fairly serious scoring inside
• You can use an old camshaft to drift the new inner cam bearings into place - Yes, you can but you really shouldn't do it unless you absolutely know why it isn't a good idea and can work around it
• You need lots of expensive special tools....you can make most of them and the cam bearing removal/insertion tools on Ali Express are perfectly OK but may need a quick modification with a grinder to make them easier to use

I'm full of useless info and in 2009 built a 130HP/130 ft/lbs Torque 120 cube Twin Cam....it was a hoot but alas I had to give it back to the owner once run in.

[Baggger]

Great write up! Thanks for the info. 🙌

[Slowpoke]

If any of you are considering a cam swap and have made the mistake of reading how to do it on a USA forum and been convinced you can't do it (especially if it is a Twin Cam....sooo much BS about crank runout on the USA forums) I can talk you through it if you have the skills to at least attempt it but here are the main points our Yankee cousins will spout that may put you off and my responses:

• You can't put a gear drive cam set in a TC without taking the crank out and truing it - Not true, you just need more than Zero lash at the two tight spots on the crank pinion, the excess lash on the loose spots makes no difference to anything important except maybe your OCD
• You must fit a high-output oil pump if tuning a TC (or an Evo) - Not true, but do look inside your oil pump to make sure it hasn't eaten a load of gravel (more important on a TC as if the tensioner pads explode it can crack the gerotors), Evo oil pumps can run very well with some fairly serious scoring inside
• You can use an old camshaft to drift the new inner cam bearings into place - Yes, you can but you really shouldn't do it unless you absolutely know why it isn't a good idea and can work around it
• You need lots of expensive special tools....you can make most of them and the cam bearing removal/insertion tools on Ali Express are perfectly OK but may need a quick modification with a grinder to make them easier to use

I'm full of useless info and in 2009 built a 130HP/130 ft/lbs Torque 120 cube Twin Cam....it was a hoot but alas I had to give it back to the owner once run in.
 

I've been starting to do a lot more on my bikes myself, I'm looking at doing a set of cams in a 103 t/c soon, do you have one of those Ali Express bearing tools and do you actually rate it? Or is there another you would recommend as better bang for buck? (i don't mind paying a bit more for something decent but don't want to sell a kidney for the top of the line tool I'll only use once a year.)

[Spanners39]

I have the Ali Express tool and rate it 10/10, I did have to modify it as it needs a cutout on the top edge so you can see what is going on, 5 mins with a grinder fixed that. Mine came with both pre-2007 and post 2007 heads. You will also need the correct blind hole puller and guess where I got mine? 

There is no such thing as a Chinese copy of anything, they make stuff for most of the planet and just sell genuine gear in a white box in contravention of their supply contracts. I have bought stuff on Ali Express that is listed on the USA EBay site, from a USA supplier, for 3 times the cost and both vendors use the same pics and advert content.

[VonGruff]

For those of us who dont have the mechanical knowledge that many have I found this series of videos on understanding cams and the charts etc to work out what I wanted as far as a cam  goes quite informative.  Part one is very basic but does give what I found to be easily understood information as the follow on videos play though. 












 

[Dave]

Excellent content as always @VonGruff