Cam timing marks

[BigMacDave]

Hello friends

So today i am replacing the timing belt. The PO made some silly white paint lines on the back of the gears which when i first looked i thought were ok, however, after i was looking at the bible, it talks about marks on the front that the timing arrows point at which in the picture you can see i do not have. (totally black with no markings) I do have two little holes on each one, but they aren't even close to the marks the PO made on the back.

Does anyone know how i can verify if i have them lined up right. The belt is very hard to put on and i rather not do it again or worse, blow my machine up




Thank you

David

[BEEK]

no. You are about 180 degrees out. the holes line up with the pointers. that is a starting point. But the little cast on marks on the back side of the pulleys (actually on the cam housings should be used) the pointers can be off a bit. just turn the cams easily if they bind back off the crank or the other cam, you could hit valves or a piston. just be real easy and you will be fine

[BigMacDave]

ok, thats what i was kinda thinking. The crankshaft looks pretty much dead center with the TDC mark on the block and the 3 lines on the crank pulley (probably timing marks for a light if i had to guess). so i think I'm ok with that. its just the cams marks (or lack of markings) that sent a red flag up.

just to clarify,

So i rotate the cams around, so the two holes line up with the obvious tab on the cam shaft housing. is that correct?

[ORFORD2004]

Crank must align with the top notch to be TDC. It's 0-5-10 degrees. Also back off the engine 90 degrees so all the pistons will be mid course before you turn the cam wheel. Auxiliary wheel at 1 o'clock.

[BigMacDave]

Crank must align with the top notch to be TDC. It's 0-5-10 degrees. Also back off the engine 90 degrees so all the pistons will be mid course before you turn the cam wheel. Auxiliary wheel at 1 o'clock.

Thank you for that quick tip. I was wondering how to keep the valves from banging when turning the cam. But other than that, do the two holes that are on each cam sprocket need to be turned so they are lined up with the arrows and or the casting tick on the cam towers themselves? is that correct.

I just want to double check because i rotated the engine around until the crank was TDC and the weird white markings the PO made are lined up. But as you can see, the "real" timing marks for the cam gears aren't even close to where they should be.

Right now, the crank is at 5 degrees and the white lines (looks like grease pen) on the back of the cam gears are lined up. Sounds like they didn't have a clue what there were doing.

Thank you
David

[bobplyler]

Because the cams move at half the speed of the crankshaft, the cams will have two possible positions when the crankshaft is at TDC.

[BigMacDave]

Because the cams move at half the speed of the crankshaft, the cams will have two possible positions when the crankshaft is at TDC.

ok that makes sense. so they probably moved the crank to TDC and marked the cams. ill just back the crank off a bit and rotate the cams to the factory timing marks. and them move the crank back to TDC

[JohnMc]

I have a 1970 so may not apply but I have large folding washers on the cam bolts that fold over and lock the cam in place once the cam bolt is torqued down so it cannot unscrew. Maybe you have something else or I am not looking at it right.
Maybe someone what that year can comment.

[BEEK]

yes on the early cars they used a folded over washer instead of a lock washer

[BigMacDave]

Ok, so best i can tell i think i have it all right now. can someone confirm that? the holes do not line up perfect with the arrows, but are dead on with the cam casting mark in the back. Also, the manual shows the crank pulley lined up with the first tick (like in my picture) but should i move it to the middle?

thank you

David

[zachmac]

First tick on the crank is 0 degrees (where you want it for cam timing). Middle and last tick are 5 and 10 degrees respectively for ignition timing.

[ORFORD2004]

First time I see timing marks on the pulley.

[BigMacDave]

First time I see timing marks on the pulley.

I wasn't confident about that either. But since i know cylinder 1 and 4 are the ones for TDC, i did the ole, put 4 dowels in the spark holes trick. When the line farthest right (0 i think) is at the block line, that is for sure TDC and the dowels are at the highest point. if i keep moving forward, to the second or third line (5 and 10) , the dowels start to fall in cylinders 1 and 4 so i know the stroke is going down and cylinders 2 and 3 start to rise.

[rebar1111]

I hope the following for a 79 2L will confirm the initial position of the crank/cam relationship
The final adjustment should be done according to the belt installation instructions using the valve position.

Chilton's indicates that the intake sprocket when face from the front, should have the dowel {under the mounting bolt) located at 11:30 with the hole at 11:00 while crank is at TDC. The exhaust sprocket dowel is at 12:30 with the hole at 1:00 and crank at TDC.

[phaetn]

Looks like you're on the right track.

Since no one else has mentioned it, make sure that you turn the engine over by hand at least three revolutions before even thinking of ever starting it to make sure there's no interference between the valves and pistons and to ensure everything remains properly aligned. 1.8L engines are interference but the 2.0L one are not, I believe. It's easy for the crank to be on a half-tooth of the belt and slip if you're not careful.

Take the spark plugs out and turn the crank by hand. I found it easiest to do with a 38mm oil filter socket on a 3/8" ratchet wrench so there was clearance to the rad , but that may not fit on other engines/cranks.

As someone else also mentioned, if you have a mechanical fuel pump (or if the car originally came with one even if it has been later updated to an electrical one) then the auxiliary shaft may have a lobe on it that can interfere with a connecting rod so it needs to be aligned at 1 o'clock when engine is at TDC. Some people have had these lobe ground off during engine rebuilds if they went to an electric pump to avoid the above danger.

Finally, in case you haven't seen the instructions elsewhere, start with the timing belt at the crank and make sure there's good tension on both sides (like you're holding it as a U shape), then install the belt on the intake cam pulley with no slack, then over to the exhaust cam pulley; the only slack should be *after* the exhaust cam, and should be taken up once you release the tensioner to spring back into position.

As I mentioned earlier, turn it over by hand a few times. I can't stress this enough. This makes sure that if there was slack in the wrong place it doesn't affect the synchronization of four elements: crank, aux shaft, intake and exhaust cams. If the cams are off by even one tooth it can have surprisingly deleterious effects on power.

Cheers,
phaetn