Timing

[BrotherJoseph]

When I removed the (very) old timing belt from my 1608, the marks did not perfectly line up, as in the cams seemed to be one or two teeth off of being lined up to the marks, compared to the crank. I manually nudged the cams just a little to make all three of the marks line up perfectly. Was there possibly a reason for their being a tooth or two off, or was it just a previous mistake or old belt? There seemed to also be a painted mark, like two teeth off of the factory mark, but that may be the mark for a timing light, as it is an interesting color (I've never used a light). The car definitely runs with no interference, and revs up fine, runs quite strong above 2000rpms, and now that the butterfly in the carb is actually doing something, it idles, but it still sputters and misses quite a bit beneath 1600-1700 rmps, and it seems to idle at about 2100. I believe the high idle is just a carb being too rich issue, but I'm wondering if timing could have anything to do with it idling so rough. And I don't know ANYTHING about ignition timing/distributor stuff. Any ideas?

[mbouse]

that i recall, the cam pulley has a postive alignment to the cam itself, so the answer should not be an improperly assembled cam wheel.

yes, the old belt could have slipped, the previous owner might have improperly installed the belt.

when you get all four timing marks aligned properly, pull the plugs and give the engine at LEAST two full revolutions by hand.. by hand.. before you torch off the ignition switch.

certainly timing will cause rough idling. but, there are other sources of that rough idle.

[BrotherJoseph]

Four timing marks...I don't recall being able to determine where the aux shaft pulley is supposed to be. I didn't make out any mark on it, but assumed it would be ok. I did give the engine two revolutions, but I being a noob, didn't pull all the spark plugs, and turning the engine was EXTREMELY difficult, and ended me up feeling dumb and with a bloodied knuckle. The engine seemed harder to turn over by hand with the new belt then it did with the old(and slightly off timing), if that means anything. The belt package had a disclaimer that said something like "this belt is only good for being tensioned once", leading me to believe that I can't take it off and try again? That doesn't quite make sense to me, but I'm still a relative novice...

[mbouse]

the aux shaft should be timed when the crank is at 0° and the cam gears positioned to their markers. the aux shaft should be set to one o'clock, as determined by the mark on the aux shaft gear.

if you've bloodied your knuckles on the engine, you can no longer call yourself a noob. you are now experienced. sorry about that.

i have recently read substantial debate on the issue of tensioned once only for our T-belts. most of the debate revolved around belt life and change intervals, and most agreed that you would be perfectly fine in this case for resetting the belt. personally, i'd not pull a belt with 5,000 miles and retension it. 1,000...only in an emergency. but, yours has not been run yet. I believe you would be completely safe.

[manoa matt]

This diagram should help: http://www.flickr.com/photos/bigtimes_f ... 7/sizes/o/

Removing the spark plugs and placing the car in neutral will make turning the engine over by hand a snap.

I switched out some cam pulleys three weeks ago. The timing belt was about 2 years old and on my daily driver, no problems since the switch out. I know its a big no no, but I'm switching out the engine shortly and I'm confident in my work.

If you are just setting up the engine and installing the timing belt, I don't see any problems with removing and reinstalling it several times to get it right. I believe the concensus regarding the tension is that the spring provides enough tension on the belt. There is no need to pry on the tensioner while tightening the pivot bolts to provide additional tension.

[BrotherJoseph]

Thanks so much for the advice and diagram! I've run the car quite a few times, just through working on the carb, and showing it to friends and family (haha), but never for more then five minutes. I'll double check it all now to that diagram. Why are there 5 and 10 degree marks?

[manoa matt]

Set the timing as per the diagram with the crank pulley at Top dead Center lined up with the 0 mark on the timing cover. Start and let the car warm up completely and let the fan go through two cycles. When it switches off you can adjust the timing with a timing light. Loosen the distributor hold down nut (17mm) and adjust the distributor so the light flashes and the timing mark on the crank pulley lines up with the 10deg BTDC mark. Tighten down the dizzy nut.