How to Measure Crankshaft Runout When Choosing a Harley Cam : Weekend Wrenching

Looking to add some horsepower to you trusty Harley? Well then a cam is probably in your future and one of the choices you will have to make if you have a Twin Cam or a Milwaukee Eight engine is whether or not to use gear drive or chain drive cams. One of the determining factors in making that decision is figuring out if your crankshaft is in spec enough to be able to use a set of gear drive cams. The process is pretty straight forward and since you will be taking your cam chest apart for the cam job you wont be doing any of the work twice.

#TwinCam #MilwaukeeEight #Cams

[paulwalker]

this applies not only to gear drive cams, but to any billet cam plate. if total pinion runout is .005 or more DON'T use a high tolerance billet plate. my SE billet plate is now trash because the .009 total runout (.005 flywheel and .004 main bearing ) caused the oil pump to trash the surface of the cam PLATE. going back in now with s&s crank and tc3 plate/oil pump and gear drive cams. not cheap but hopefully it lasts

[MidnightExpressMC]

Very concise tutorial covering all angles with great delivery. Also a superb illustration of how bean counters rule at H-D nowadays. Thank you, sir!

[opel]

Great video, first time I knew about this procedure but now I know how to go about it. Thank you.

[Grunt]

Thank you! Harleys are not always well engineered, but they are always harleys!

[timwilsononline]

Hey Patrick, firstly thanks so much for these videos - they're just incredibly well made and informative and I'm learning heaps. Keep up the great work! Q: (maybe an obvious question) Is crank runout the reason manufacturers use chain drive in the first place? e.g. because the chain / tensioner system providesa mechanism for absorbing that minute movement in the crank?

[-MrRichBiker]

love it, Pat. Awesome vid, as usual. i have a 2005 fatboy, i did install gear drive cams, Andrews 37 g, with a brand new crank from S&S, from the factory it had .003 runout, which then spread to .005, . the gears sound like a 350 old chevy, banging away. love the power, but i do hear those cams cha-cha-cha, esp at idle and WOT. Am i ok? no damage in 3 years, no metal at all on any drain plug, either. just the old twin cam sound?? help..lol ty again, pat!!

[superplumber]

I feel lucky having .003 in both my twin cams 02 RK. 09 Dyna. The wobbling of the crank only gets worse with centrifical force and time. .006 is gonna wear out the oil pump a little faster.

[dougfresh]

Top quality vid and info. Appreciate your work.

[mikeberry]

i have a friend who replaces the chain to gear drive and installs the new oil pump also. after watching this, I have never seen him measure the crank shaft runout. does that mean some may last and some may break due to skipping the runout test?

[jigglestickdave]

Excellent video. Showed me exactly what I needed to know. 👍🏻

[jeffcollins]

What is the maximum runout to run the S&S cam plate and oil pump for a96 twin cam I will be using chain drive cams

[jonkalm]

What is the process if you want that runout back down to below .003 ? New flywheel ?

[bigwu]

Band-aid on an open wound. Chain drive is your friend. As is belt drive on your primary
Slack not necessarily but looser tolerances absolutely.

[nathanschwartzengraber]

So does this mean I shouldn’t put cams in my 103 if the runout is out of spec then? Or just gear drive, I thought mine was chain drive.

[davidmatias]

Can you still a cam if your run out is more than specified ?

[jerichobargas]

What about " truing and welding" it, can u put in gears then?

[Kyle-ueuj]

So if you are over that number is it fixable?

[creigmacc]

So in other words, just use chain drive cams.

HD

[allanable]

This is not how S&S say to check, it the backlash on the gears and if not in limits you can get under or over sized gears

[vernegibb]

Damm shame hd put that junk in the m8 too. Guess they did not like miles engines evos rock.