megamannz123 Posted July 21, 2014 Report Share Posted July 21, 2014 Hi all, just received my Rollmaster cam timing kit, does anyone have fitting instructions for these, or experience setting them up. The Crank gear only fits one way, the cam gear has a middle hole, and then 6 holes either side for advance and retard. That would make 12 holes for 360deg meaning 30deg per hole? doesn't sound right? Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted July 21, 2014 Report Share Posted July 21, 2014 Remember the crank shaft does 2 laps for every one lap of the Cam. From memory the mark on the crank cog needs to essentially point towards the mark on the Cam cog (central one) and vice versa. Pretty sure there is a mark under the crank cog too. Iirc each hole on the Cam cog should give you 6° advance or retard. PS did you get your Cam today? Quote Link to comment Share on other sites More sharing options...
megamannz123 Posted July 21, 2014 Author Report Share Posted July 21, 2014 G'day mate, Yes thats right! I will call the guy I ordered from and see if they know exactly. yup the cam turned up today, can't believe the post was so much! should have the motor assembled soon. Cheers Quote Link to comment Share on other sites More sharing options...
GJM85 Posted July 21, 2014 Report Share Posted July 21, 2014 Pretty sure each hole number is a value of degrees. Not in relation to the centred hole. They relate to the teeth on the cog. If you want 2 degrees advance then the 2's on outer and inner rings on the gear should line up with the marking on the crankshaft gear. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 21, 2014 Report Share Posted July 21, 2014 Yes, the holes are related to the cam teeth, so you go forward a hole, forward a hole, then forward a tooth and back a hole. Well, that's my Datsun experience, I have never had an adjustable K camwheel. What you need is the head on, the cam in place with only two rockers in a cyl and a dial guage on a valve collet top. You put a circular protractor on the crank pulley and turn from TDC. When the cam lobe opens you will see it instantly on the dial guage and read it off the protractor. That will let you set it up according to the cam cutter's specs, and then you change it a coupe of degrees either way once you have it all running and want to change the power band. You might as well build the little steel fitting that holds the dial gauge on the head somewhere, and we drilled the pulley bolt and tapped it for the circular protractor. That way you are set up for doing this for decades to come. Quote Link to comment Share on other sites More sharing options...
GJM85 Posted July 21, 2014 Report Share Posted July 21, 2014 (edited) I'm at work so I banged this up real quick. Unless your cam grinder gave you specifics to advance or retard the cam, you'll need a degreeing wheel to set this properly. NB: In this hastily scrawled diagram, the cam gear is 180 degrees out. Edited July 22, 2014 by GJM85 Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted July 21, 2014 Report Share Posted July 21, 2014 You can also measure it with a dial guage with the head off. Just zero it sitting on top of the number one lifter. That's what i did when i dialled mine in. Just remember to take the valve clearance into account. Quote Link to comment Share on other sites More sharing options...
megamannz123 Posted July 22, 2014 Author Report Share Posted July 22, 2014 Aha, all starting to make sense now, cheers! Quote Link to comment Share on other sites More sharing options...
GJM85 Posted July 22, 2014 Report Share Posted July 22, 2014 (edited) The decision where you set your cam is really yours. A general rule of thumb is, the more advance you set, the earlier the cam comes on. Effectively increasing low end power but if you've a lot of overlap you lose efficiency The more retard you used, the cam comes on higher in the rev range giving greater top end. Would you be willing to share the cam specs with us? Edited July 22, 2014 by GJM85 Quote Link to comment Share on other sites More sharing options...
Clapped out Posted July 22, 2014 Report Share Posted July 22, 2014 http://www.ebay.com.au/itm/COMP-CAMS-CAMSHAFT-DEGREE-WHEEL-SPORTSMAN-9-CO4790-/360920749666?pt=AU_Car_Parts_Accessories&hash=item54088d9662 Quote Link to comment Share on other sites More sharing options...
megamannz123 Posted July 22, 2014 Author Report Share Posted July 22, 2014 Got it fitted today, engine is starting to take shape on my home made engine stand! ha. Cam specs... | Advance Ground on Cam: 2 Lobe separation: 110 | | .050 VALVE TIMING | | Inlet opens: -1 BTDC Closes: 35 ABDC .050 Duration: 214 | | Exhaust Opens: 39 BBDC Closes: -5 ATDC .050 Duration: 214 | | ADVERTISED VALVE TIMING | | Inlet opens: 32 BTDC Closes: 68 ABDC ADV Duration: 280 | | Exhaust Opens: 72 BBDC Closes: 28 ATDC ADV Duration: 280 | | Inlet lobe lift at TDC on the over lap:.045 | | ----------------------------------------------------------------------| | Valve lift Inlet: .4427 Inlet Rocker Ratio: 1.50 | | Valve lift Exhaust: .4427 Exhaust Rocker Ratio: 1.50 | | Quote Link to comment Share on other sites More sharing options...
megamannz123 Posted July 22, 2014 Author Report Share Posted July 22, 2014 Pics Quote Link to comment Share on other sites More sharing options...
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