QuestionHoward, I have a 69 Spit MK3 '1300' that I'm rebuilding.
I had to replace the cam sprocket, chain,and crank pulley, there were no marks on these new parts. I would like to know the correct procedures for alignment of crank and cam timing. I enjoy reading the questions and answers on this site,never thinking I would need your expertise. Gratefully
AnswerHi Hurbert,
If the new sprockets do not have any marks on them you will need to use a wide accurate setting of the valve clearance on the intake and exhaust valve on #1 or #4 cylinder and set both exactly the same (.040" or .050")(to get off of the transition ramps) And put a degree wheel on the crankshaft and a pointer for TDC.
Note that the cam sprocket has four mounting holes, This gives you four different possible settings (two on each side of the sprocket)
First start out by setting the crank at TDC and use two of the bolt holes in the cam sprocket to mount the sprocket and set the cam so as to be in the middle of "Over Lap" (if the valve clearance were set to specs both intake and exhaust would be open) Yours are not both open because you set them at a wide gap (.040" or .050")
Now hold tension hard on the chain tensioner side so as to take up all slack in the chain and rotate the crank to a point that the push rod gets snug (either valve) and note the degrees on the degree wheel. and write it down as first try and mark with a magic marker on the sprocket which two holes you used (I usually write a #1 next to each as that is my first try)
Now rotate the crank back the other direction (holding hard tension on the chain) until the other pushrod gets snug. Now write down the degrees of that side. If the two degrees are the same then you are finished (no such luck)
If not exactly the same remove the sprocket from the chain and rotate it until you can use the other two mounting holes which you should mark #2. Repeat the above process and if the two degree readings are the same you are done. If not remove the sprocket again and flip it over and repeat the process and mark those holes as #3. If still not exact you will need to try #4 holes. When the cam is about in the correct position you will be able to see a dot punch mark in the cam through the open bolt hole that is at about 11 O'clock.
Which ever set of holes make you exactly split in the middle then use them as your timing and I would punch make the sprocket so if you ever have to go into the engine at a later date you will not have to go through this again.
let me know,
Howard
