OK. I installed a RB underdrive pulley on a 90 N/A a couple months ago on a motor I bought second hand and never had running in the first place. Well the CAS isn't timed right and since I didn't save the instructions on the RB pulley I have no idea what the timing marks on the pulley reference. What mark needs to align with the timing indicator when you drop the CAS in and which marks should align with the indicator when you're using a timing light on the leading and trailing wires? Also, just to be sure what connector do you ground when checking the timing? The manual says the green single wire connector. The only one I can find is the green connector with orange wire near the leading coil. Is that the right one? Thanks for the help.

Chris

 

It has marks at 20 and 10 degrees BTDC, O BTDC, and 10 degrees ATDC.

 

Ok. That's a start but this pulley has 5 marks. I'll call RB on that tomorrow.

The whole story is that I bought an Atkins motor second hand. The guy I bought it from said it never pulled very well on top end. Well I finally get everything installed in my ITS roadracer and it's all wacked out. The setup: all emissions crap removed, no BAC, thermowax, IAC, basically every acronym is removed and it has an open dual-outlet header on it right now. The rest of the exhaust should go on this week and I expected some problems running the car with the open header but wanted to fiddle with it anyway. It idles fine but acts way lean when you stab the throttle and anything over 3500 rpm calls for a serious miss, kinda like the secondaries aren't firing...but they are. This could be caused by the header. Anyway, we decide to check the timing and nothing made sense from there.

The first problem in checking the timing is that the lowest the motor will idle is 1500rpm. I have all three throttle blades set to open together and that might be why it's idling so high? Will that high of an idle make it impossible to get an accurate timing reference? First we tried checking the timing and we were getting the same reading for all four plugs. The light indicated the last mark on the RB pulley for all four plugs. Not knowing what that meant we removed the pulley and referenced it to a stock pulley. As best we can tell the yellow mark on the stock pulley references to the second mark from the left on the RB pulley. The red mark on the stock pulley doesn't quite line up with the first mark on the pulley but it's close. Having established that we reinstalled everything and that suddenly seemed correct because the CAS went back in the same and we ended up with the same reading on the timing light. Now assuming that the second mark on the RB pulley is TDC and each mark is 10* as 13BAce says (probably real close), we're running all four plugs at 30* BTDC. Still ran the same.

Being one to tinker I just started turning the CAS to see what we could get. We went full advance without removing it and it ran much better and could pull above 3500 somewhat. Took the CAS out, advanced it one tooth and centered it on the adjustment slot and the car ran very well. Pulls all the way to 7000+. Set the light on it and it is about 15-20* advanced past the last mark on the pulley which would mean we're something like 50* BTDC. And all four plugs read the same.

Ok. So it runs well but now it scares the hell out of me because we really don't know where the timing is. Seems we're missing something in the procedure when we check it even though we're doing it with a factory manual and it's hard to screw up a timing job. Still am curious if we have the right check connector. It's possible there might be one mis-marked pulley (you hear about it all the time), but two that are mis-marked and then match? Anybody got a clue? Any discussion might help!

Chris

 

My bad. The pulley does have only 4 marks.

Chris