Cam timing 101: Will this engine run?

[Spider951]

I know this has been covered many times on this site, but I need help understanding cam timing so as not not to screw up. I'm basically back to the question I asked back in April ("Cam gear 180 off"). I want to replace the '81 engine that came with my '81 car with an '82 engine, but I am still concerned about the camshaft (more specifically the exhaust cam) timing. Both engines are currently out of car.
The cam timing on the '82 engine appears to me to satisfy the following: (1) with crank pulley at approx. TDC (crank pulley notch where it's supposed to be relative to pointer down below), the intake cam hole marker and pointer line up OK , (2) with cam box covers removed, cam lobe noses on both intake and exhaust cams point somewhat "inward" (ready for combustion) on cylinder 4, and wooden dowel in cylinder 4 spark plug hole at approx. TDC (compressed), exhaust valve poised for next step: exhaust, (3) distributor rotor lined up correctly to fire on cylinder 4, (4) manual rotation clockwise of crankshaft pulley results next in cylinder 2, then cyl 1, and finally cyl 3 - each cylinder showing same configuration as described above for cylinder 4 and each being matched with distributor rotor in correct position for each combustion stroke. [I replaced oil seals on both camshafts, aux gear, and crankshaft so I know cam pulleys are correct, i.e. no mixed up pulleys]. In short, everything (crank, cams, valves, rotor) moves and appears in correct position for each phase (4 strokes) for each cylinder. I can turn over engine manually repeatedly and no interference or perceived problems. So what's the issue? The pointer hole (and therefore dowel pin) on exhaust cam is approx. 180 deg off; does not match pointer ( or "bump" on exhaust cam housing right behind exhaust pulley). What am I missing? How is this possible (assuming stock camshafts, etc)? In short, is this a problem??

[rebar1111]

I am not sure who's instructions you are following, but if they are mine, please note that the cam dowel pin/hole and the cam sprocket hole are not the same. The dowel pin and it's hole can only be seen with the sprocket mounting bolt removed. The other sprocket hole has no pin and is a see through hole for alignment with the pointer for belt installation alignment.

[Spider951]

Thanks. Yes, I'm aware of that. Below are photos the camshaft ends (with dowel pins highlighted by arrows, as seen looking at front of engine) and the pulleys (intake on the right and exhaust on the left) I removed. The timing marker hole on the exhaust pulley for the exhaust cam is about 180 off from the pointer when pulley is installed (this configuration is how I found them when I removed timing cover to replace cam oil seals and new timing belt, and this is the arrangement I have now re-installed).

[tima01864]

That is confusing, Do you have one pulley marked exhaust and one marked intake?

[Spider951]

There are no obvious markings (at least to me) that say "intake" or "exhaust", but I have read several posts from this site that indicate the pulleys are the correct ones, e.g. "the timing marks are offset to the dowel pin hole....as the cam rotates [clockwise], on the inlet cam the dowel pin leads the timing mark, on the exhaust the dowel pin lags the timing mark. Mick." (sorry, Mick, I didn't save the date of your post, but thanks for your help). This is also the arrangement of the holes on the pulleys sold by VAS and marked as "I" (intake) or "E" (exhaust).
Steve

[ORFORD2004]

Exhaust cam way off. Put your pulley back. It's the outside hole that you use for timing to pointer. Middle pulley to 1 o'clock. Crank pulley to 0. Ignition to #4. And vroum.

[Spider951]

OK, but when I do that and then rotate the exhaust cam 180 so that the outside hole matches the pointer the cam lobe nose for the exhaust cam will no longer be in combustion position to match intake cam's position. Below is the way the cams are configured now with intake and exhaust noses for cyl 4 pointed up and somewhat inward (compressed), dizzy rotor pointed to 4, but cam timing mark 180 off.



I hear what you're saying, though; I have been reluctant to rotate the exhaust cam alone without belt on (should I even do that?). Turning everything (with belt on) clockwise the way it is now only comes back to the same spot no matter how many times you go 'round.

[Spider951]

OK, but when I do that and then rotate the exhaust cam 180 so that the outside hole matches the pointer the cam lobe nose for the exhaust cam will no longer be in combustion position to match intake cam's position. Below is the way the cams are configured now with intake and exhaust noses for cyl 4 pointed up and somewhat inward (compressed), dizzy rotor pointed to 4, but cam timing mark 180 off.



I hear what you're saying, though; I have been reluctant to rotate the exhaust cam alone without belt on (should I even do that?). Turning everything (with belt on) clockwise the way it is now only comes back to the same spot no matter how many times you go 'round.

[tima01864]

So at TDC ##4 lobes are off the valves having fired, #1 is in position to detonate?

[Spider951]

In the picture above of the camshafts (sorry for posting it twice) cyl 4 (farthest to the left) is at TDC (actually a few deg before as per the crank pulley and its timing mark, therefore at combustion position for 4; dizzy rotor is pointed at 4 in distributor cap. Isn't that as it should be? Next cyl "at bat" is no. 2 cylinder.
In short, through all this, it appears to me that everything is in correct working order and in correct sequence (4-2-1-3) except that pointer on exhaust cam is 180 out of sync. Either I am not comprehending what constitutes each stroke or there is something very different about the exhaust cam. I have used the '81 engine (which runs but leaks oil from virtually every seal and gasket) as a guide to help me understand: '82 engine matches '81 except for ex cam timing mark on '82.

[Spider951]

Just to reiterate my last point (and to beat this dead horse some more....make sure it's dead enough already) below are photos of the '81 engine camshafts and its newly-installed camshaft pulleys (I put small nails in timing holes so they would show in photo). Compare the '81 camshaft photo with the '82 - virtually identical configuration. Cam pulleys, however, are in contrast to orientation in '82. In both cases, distrib rotor pointed to #4. [ I keep expecting someone to say that the '82 engine exhaust cam must be from some "well-known" aftermarket cheapo manufacturer that makes cams from the finest alloy of pot-metal and re-cycled tuna cans and have the life expectancy of a bottle-rocket].

[aj81spider]

I'm no expert, so take this with a grain of salt. However based on where the dowel pins are on the cam shafts it doesn't look like a pulley problem. Your dowel looks like it's 180 degrees out.

Is it possible you have an incorrect cam shaft in the exhaust?

[Spider951]

I have wondered that also. I have thought about removing the exhaust cam to take a look, but I don't know what to look for. Are there numbers or other markings to identify them? If so, where do I look?

Thanks

[ORFORD2004]

I have the original cams for my 83. i'll take a look tonight.

[Spider951]

That would be great. Thanks.
One other piece of info that just occurred to me after staring at my photos, and then I verified by measurement: the cam lobes on the '81 engine are wider [approx. 25 mm (about 1") wide on '81 vs. approx. 19.75mm wide (about 13/16") on the '82 engine.] I think I read somewhere that OE cam lobes are wider on later engines, further advancing the notion that those aren't OE for the '82 engine (??).