I'm trying to put on my Rollmaster adjustable timing set, and gonna test and measure my valve clearances. Here's the deal. The timing set is adjustable in 2-4-6-8* incriments either adv. or rtd. My original plan was to try to take it to a local performance shop to flycut my pistons and have them degree it in. But that guy is damn near impossible to get ahold of. So I had another idea. TR claims there should be .070" clearance between the piston and the intake vavle (.090 exhaust). I was just gonna mess with adjustments of the timing set till I get to .070 and .090 and just skip the flycuting, and just run a thicker gasket. Good idea, bad idea? I couldn't find modeling clay, but I did pick up some playdough I'm hoping it'll work the same.

The adjusting part is kind of confusing me though. if you look in the pic. at the #1 arrow, this is 0* adv or rtd. the instructions say to move it (the key) one notch to the right for a 2* rtd. So I did that (arrow #2), Now here's where they lose me. I just assumed I lined the dots back up, cam dot down, crank dot up. Well, it looks like waaaaaaay more than a 2* adjustment. I'd guess more around 30-45*.

Can you guys have a looksee at the picture to tell me if I'm way off track or not. Thanks.

 

looks like its half a tooth off, which is acceptable for a 0* advance

mike

 

I just installed my Rollmaster as well.

I agree that just looking at the notches on the inside of the sprocket it appears to be more than two degree increments.

My only thought was that this is the incremental change needed at the crank to produce the two degrees of timing change.

At least that is the only thing that makes sense to me!

My $0.02 worth!

Steve

 

Once you advance or retard the cam using the crank sprocket, you have to make a new timing mark on the crank sprocket. DO NOT USE THE TIMING MARK THAT IS ASSIGNED TO STRAIGHT UP!

 

That makes more sense. Thank you. So it appears that I'm gonna have to have someone degree it for me, as, eyeballing it isn't gonna work. BTW, this is for a TReX cam.

 

You can make a new timing mark that is over the same # of teeth that the current one is from the keyway mark. Do a search, there is a thread that Jason from Texas Speed posted a picture of the corrected timing mark that you could go from....

 

You do NOT put it back DOT to DOT. That's only used if you retain standard timing. The DOT on the cam sprocket will remain at 6:00 regardless whether you use standard timing or put in some advance or retard. The crankshaft will have to be moved SLIGHTLY if you use timing other than standard, but only a very small amount. Advancing the crank has the effect of retanding the cam and vice versa. The instructions that come with the Rollmaster are not much help because they are written in Australian. If the keyway in the crank has been moved very much from the standard position because you are advancing or retarding you have gone TOO FAR. 2 degrees is a VERY SMALL AMOUNT. Be careful and be sure you understand the relationship between the cam and crank. The Keyway you select in the sprocket to add advance or retard is aligned with the crank keyway and the key is installed to lock them together. Then the crank has to then be turned slightly to make the timing change. Just putting the sprocket on the crank at the position you select in and of itself does NOT change the timing. Turning the crank slightly one way or the other does. Only one shaft is turned to change timing, not both. Either the cam or crank to accomplish a timing change and in this case it is done by moving the crank.