running rough

[ninescarz]

89 civic dx... changed the head, adjusted the timing (match the existing mark), new distributor... still running rough... is the timing still off?? How do I catch it if the mark that is there is wrong? Also, any distributor wire diagram available (just to be sure)?

[FrodoGT]

did you use the same head, or one from a different engine? And you did do the ignition timing right? AFTER you did the cam timing.

[Christ]

When you change a head, the first things to do after installation is to adjust/set the cam timing. There are certain instances where the timing will constantly be off, especially in the case of head/block milling and using diff cams than what came w/ the engine.. remember, just b/c it fits, doesn't mean it's going to work.

After you've properly set your cam to THE CAM'S TIMNG SPEC *not the head's* you must set/adjust your ignition timing. On some of our cars, the procedure involves jumpering a connector that has nothing attatched to it on the d-side of the engine bay, on the inner fender, next to the strut tower.. it will have a white rubber cap on it, and it's a 2 pin connector... jumper this connector, and while the engine is operating at normal temps *operating temps*, adjust your timing w/ a reliable inductive timing light to the exact spec of the manufacturer, keeping respect to the approx degree that the cam is off (if any)

In other words, if your cam is 4* advanced, set your ignition timing 4* retarded (from the spec... so if it's supposed to be 12* advanced normally, you'd now set it to 8* advanced.) This will keep the spark at the proper duration, and keep it happening when it's supposed to in the crank cycle.

Also, keep in mind w/ cams, if you can't get it dead-on, figure out which you want more... if you want top end power (generally) you retard the cam, and if you want low-end (off idle) power, you advance the cam.

But the ignition SHOULD NEVER be adjusted by the cam's degreeing, it should ALWAYS be timed in relation to the crankshaft. (Piston position.)


**By the way, when I said to adjust your cam to the cam's timing spec, I mean, like in the case of using a A6 cam on a B2 head, you'd have to adjust the cam's timing marks the same way you would on the engine it came from... i.e. using the same timing mark as the Si engine does, instead of leveling the dual timing marks on the cam's gear w/ the valve cover mating surface, as you would w/ a stock B2 cam.

**I've come to believe that this is where my problem is in my own engine.. I'm pretty sure we put the cam in @ the B2 engine's timing spec.. like idiots, of course, not realising that the degreeing of the cam was totally different than the B2 cam was.

EDIT: After re-reading what I've posted here, I've realized that the way I described setting the ignition timing on your car may have been slightly misleading... if you're using an inductive timing light you don't need to worry about advancing or retarding the dizzy for proper timing, just do it normally... if you're setting the timing w/ a dwell tach (NOT RECOMMENDED) you'll need to set it to make up for the cam degreeing.