Need help! Timing after Timing Belt Replacement

[topdownstl1978]

I did quit a bit of research on replacing the timing belt on my 78. I started off great. Got all the parts, timing belt, tensioner pulley, seals, water pump, etc. Trouble is that when I loosened the bolts for the cams and the nut for the crank, things moved. Not a lot, but enough to concern me. I have replaced all of the seals, water pump, tension pulley. I need help on how to allign all of the cams and crank. Do I work from #4 cylinder just before TDC? What are the timing marks on the cover? They seem contrary to the manual diagrams that show timing marks to the left of the crank pulley on some pointer that I do not have on my car. Help!!!

[131]

Do I work from #4 cylinder just before TDC? What are the timing marks on the cover?

The cams line up with the pointers when 1&4 are at TDC. The timing marks on the cover are for ignition timing, not really required for timing cams. The pointer on the auxiliary shaft points to the 13mm bolt on the tensioner. Ignition timing is 10 deg before TDC on 4. If you do a forum search you'll find what you need, the topic comes up quite often.

[topdownstl1978]

I have more to tell. I did find this information on the forum. Aligned the cams with pointers, aux with 13mm bolt. All when #4 was at TDC. When I rotated the crank two complete revolutions, the cams did not come back to pointers and 13 mm bolt. I am using the crank nut to turn the shaft. I have a couple of washers as spacers, but the nut may have moved. Is there a better way to do this? Also, I put the New belt on thinking I had everything correct. The belt seems loose on top between the cams. If I push it will touch the pointer bolts. Is that correct? I neglected to install the belt around the tension pulley last. Since there is tension on the belt now, do I need to get another belt and start all over? Sorry for all the questions, my first time and I do not want to damage the motor.

[wizard124]

No, you don't need a new belt. I made a few adjustments before I got it right. No issues.

I needed to rotate the crank 10-15 degrees BTC, put the belt onaround the aux pulley, then the cams. Then turn the crank, taking up the slack. Check that the timing marks all align. Rotate to check for interference and alignment.

[topdownstl1978]

I changed the tensioner bearing. I have read the following:

"NOTE: If the tensioner bearing needs to be changed, the spring must be flicked out of its groove by a large flat-blade screwdriver, remove the locking bolt and washer, and don’t
lose the tensioner spacers and hardware.

Refit the tensioner onto the stud, fit the washers and spacers, fit the locking bolt (this is the one with the groove for the spring), to refit the tension spring, use a large screwdriver with a notch in the blade to lever it back into position"

I was able to get the bearing replaced without doing the above. Could this be part of my loose belt issue. Or do I just need to keep working it to get the slack out?

[azruss]

This is my tried and true method. loosen the tensioner and push it as far as you can to the exhaust side and tightened. This requires a long screwdriver to pry it all the way. The bearing hole will stop on the stud. Tighten it to hold the tensioner at this position. Line up the crank to TDC. I use a straw or something like that down spark plug hole #1 to see when the piston is all the way up. Each cam should be on their marks. The indicator on the front works the best, but each cam housing has an indicator as well. Align the aux shaft as stated above.
Start with putting the belt around the crank pulley making sure it is in the grooves. Pull tight on both side to engage with the aux pulley. there should be no slack on either side. While keeping belt contact on both side of the aux pulley, pull the belt tight to the intake pulley. adjust the pulley so it picks up a tooth and rotate it counter clockwise to hold belt tension. Now pull tight from the intake to the exhaust pulley, adjusting the exhaust pulley to pick up a tooth, rotate ccw to hold tension between the intake and exhaust. Slide the remaining belt over the tensioner and release it to put tension on the bolt. Tighten down the tensioner bearing nut. You should have tension between all components at this point. If you don't, start over. Rotate the motor by hand for several revolutions check the timing marks as they go by. If you are hitting the marks, then you are done. If not, you get to start over. The problems usually come from having slack between the crank and the aux pulley, as the belt engages on both sides of the pulley. It is hard to keep both sides engaged while doing the cam pulleys. As others have mentioned, this is just cam timing and not ignition timing.

[topdownstl1978]

Should I be doing something for ignition timing during this process? Sorry, but I feel overwhelmed...

[131]

Should I be doing something for ignition timing during this process? Sorry, but I feel overwhelmed...

Ignition timing is a separate, related process. Cam timing has to be correct, finish that first, before you move on to ignition timing.

[topdownstl1978]

Ok, I had to provide an update. Got everything back together. Everyone's help is very much appreciated. I found that removing the tension bearing assembly and cleaning it made the belt installation much easier. No interference and belt is nice and tight.

Now I am working on the ignition timing. I set the timing at 10 degrees, and had some issues with small backfire on deceleration and some sluggishness between 1st & 2nd gear. I read that I should have disconnected the vacuum advance first. I will try that and retire. Any other helpful hints?

[topdownstl1978]

I'm back... I have driven the car after replacing the timing belt and have tried and tried to set the timing to 0 degrees btdc ( as per the owners manual). I get it to idle ok (around 9-10k) and timing set at 5 degrees advanced, but there is a very noticeable hesitation when applying the accelerator and there is oping and a deep growling in the exhaust that was not there prior to replacing the timing belt. There is also a very noticeable loss of power in all gears.

Any advice? Could I have the cams slightly out of sequence with the timing belt install? Could it be the carburetor (no real issues prior to belt replacement). Would a compression check tell me if the belt is off a bit.

Ant and all help is appreciated.

[azruss]

You may want to go back in and check the cam timing. This can be done without removing the coolant hose. There are casted index marks on the cam towers and you can see the timing holes from the back of the cams. not as accurate as the pointer, but if you are off, you will be able to see it. check TDC with straw or something like that in the #1 spark plug hole. rotate the motor til the piston is all the way up. If all that is ok, then reset the ignition timing to #4 per manual. If all is ok, then start looking at the centrifugal advance and vaccuum advance.

[RoyBatty]

I didn't read the whole thread so I don't know if the was already mentioned.
When turning the crankshaft to check alignment of your marks always go ONLY in the direction of normal engine rotation. Clockwise when viewed from the front. If you back it up while the tensioner is loose, it will only serve to loosen the belt on the pulleys. Those could lead to your timing slipping a tooth or more.

[topdownstl1978]

Couple of questions:
I was told that a compression test could also help verify cam timing. Is that correct?

I do not have any vacuum lines attached to the distributor, so does that mean I do not have a vacuum advance?

Thanks for the help guys!

[131]

I was told that a compression test could also help verify cam timing.

Use a timing light, off plug 4. From the back of the cam the cam timing marks should just lead the pointers or cast reference points on cam boxes.

[azruss]

If you have all your normal cam timing pointers, there is no need to do a compression check. Cam timing is static. That just sets your cam locations to the crankshaft location. Ignition timing is variable. This sets the spark timing in relation to the cams. Your dizzy has spring loaded pivoting weights on the top of the dizzy just under the rotor. you can move these by hand to make sure they move easily. If your dizzy is old, wear marks can hamper the movement of these weights. Some fiats had an additional vaccuum advance. This would be connected directly to the dizzy with a vacuum line going to it. Just because you don't see a vacuum line, doesn't mean your dizzy isn't the vacuum advanced type.