2 replies to this topic

[ASeriesPower]

Hi all,

sorry if this has been covered before but i can't find a solution to my exact problem. 

It's my first timing replacing/timing a camshaft and i'm replacing a standard midget cam with a kent md266 cam. cam timing of the MD266 is 106 degrees ADTC, compared with the original 110 degrees on the standard camshaft.

I have a minisport vernier cam gear for accurate timing, and today I thought i had it accurate at 106 based on reading various forum posts and watching youtube videos.

However, it has dawned on me that i may have the cam 180 degrees out due to not finding true TDC. I had to rotate the crankshaft almost a full turn before no1 inlet is at full lift. By my reckoning, 106 degrees is just under half a turn (180 degrees) of the crankshaft ADTC. I read on anothwr forum that that when finding tdc, no1 cylinder must be reaching the top of the cylinder on its compression stroke, and not on its "secondary" lift where no4 fires. Is this true? I'm suspecting that I've unknowingly set TDC 180 degrees out. The minimania video i watched on youtube shows the guy turning the crank not far from TDC to no1 inlet full lift...for me its over 180 degrees without measuring, ovwr half a turn of the crankshaft. 

I'm aware that the cam sprocket being much bigger means a whole turn of the crankshaft means a smaller turn of the camshaft...but my novice brain is now doubting itself.

Is there a way to know if i've effed up? 

Any insight greatly appreciated.

[sonscar]

is the no1 firing position defined by the camshaft?If the no1 piston is at the top and the cam fitted properly it defines the firing order then,it does not matter how many turns you do on the crank.Or am I mistaken.Steve..

[Steve220]

First of all, are the dots alligned? Or have you inadvertently alligned the cam sprocket's woodruff slot with the crank pulley?

Edited by Steve220, 25 August 2021 - 11:08 AM.