248/248 s13 cam question (yes I searched thoroughly)

[coupe92]

So I've never installed cams before.

I have a 1992 s13 ka-t, I have a spare exhaust cam from a 91-93 s13.

I want to run my spare exhaust cam on the intake side with the sprocket 3 teeth CCW.. But what does that mean exactly? Do I take the stock cam out, then turn the gear 3 teeth ccw, then install the new cam in stock position? Or do I take the stock cam out, put the spare exhaust cam in, THEN turn the cam gear WITH the whole cam 3 teeth CCW?

I searched, a lot... Cam install guides, write ups, all of that, and there's nothing that answers this exact question. This guide Do it yourself dual exhaust cam swap for KA24DE engines (http://www.nicoclub.com/archives/cam-swap-ka24de.html) says " Install other exhaust cam on intake side and rotate cam gear 4 (I'll be doing 3) teeth counter clockwise" but does the cam turn WITH the gear? Or do you just turn the gear, and leave the cam where it is?

IDK wtf I'm doing. And to think I turbo'd this thing myself. No idea how I managed.

[godsmack]

Ask yourself this question.

What is going to happen if I just turn the sprocket and not the cam?

But to answer your question.

Put engine in TDC. Mark the chain and sprocket. Remove cam then seperate from sprocket. Install sprocket on new cam as normal. Then put cam in and adjust so that the 2 marks are 3 teeth apart. Sprocket will be to the left 3 teeth.

[coupe92]

Thanks a lot for the reply. I went at it before seeing that and what I've done is remove the stock cam, marking the sprocket position, and the 3 teeth ccw position, and then I turned the sprocket to that position, and then I put the new cam in (still separate from the sprocket). So Now all I need to do is connect the cam to the sprocket, so I believe it's exactly as you said, only I'm connecting the cam/sprocket after they're already in, rather than doing it before installing the cam. If that makes sense.

So as long as in the end, the cam pin is in the sprocket slot, and the sprocket slot is 3 teeth ccw from where it was with the stock cam, then I did it right, correct?

Thanks again, this is my first time dealing with cams so actually doing it helps to get a grasp on what people are talking about.

[godsmack]

Yup just as long as the pin is where it's supposed to go it'll work the same way.

[WOTandSDWYS]

How come some sites/write ups say 4 teeth and others say 3? The most common I see is 3 teeth, but 4 seems to pop up a lot.

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[coupe92]

The correct amount is 3.5 teeth, which obviously isn't possible without redrilling the cam gear.

3 teeth generally is said to have better low end compared to the 4 tooth method, though both are known to have more top end with less low end than the stock 240/248 cams, or, even 232/232 stock cams from an s14.

Also, 3 teeth ccw tends to have more of a "lope" to it, which I like the sound of. See youtube for that.

[coupe92]

Got it running, idled VERY rough at first, would only idle on its own for maybe 10 seconds before dying. Adjusted idle up to about 1000 and it holds there, until I'm on the brakes while driving in neutral, that's when it dips dangerously low to like 300 rpm, sometimes stalls. Pulls good, not much difference from stock, but sounds incredible at both idle, and cruising. Pretty rough at low rpms but not horrible.

The one big issue now is that it pulls next to no vacuum at idle, no idea why. It used to have like 15 mm/hg at idle, now it's pulling 3-5, which means that the BOV doesn't work right, and it has next to no torque from 1000-2000 rpms, I half to half throttle it just to get going. Any ideas?

[godsmack]

Try switching it over to 4 teeth. Maybe that'll suit you better. And might also have a vacuum leak somewhere. Did you check for one yet?

[WOTandSDWYS]

Yeah the cams definitely did not cause that running issue. There is another problem somewhere.

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