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Rick, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 426
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1988 pontiac sunbird: sprocket..indicator

Resolved Question:

I am replacing a timing belt on a 1988 pontiac sunbird overhead cam 2.0 litre engine. When I put the timing mark on the vibration dampner pulley alinged with the 10 btdc on the timing mark scale the top mark on the cam sprocket does not line up with the indicator to line it up with. I used a new timing belt and allready tried a second dampner pulley.
Submitted: 8 years ago.
Category: Pontiac
Expert:  Rick replied 8 years ago.

hi Customer

with timing belt off have to move upper pulley to align to mark on rear cover before belt put on, then belt and lower pulley...Rick


NOTE: O.E. manuals do NOT provide images of the timing marks, however, the alignment marks are located on the camshaft and crankshaft gears and the rear timing belt cover.


  1. Battery ground cable, then partially drain cooling system.
  2. Serpentine, A/C and/or P/S drive belts (if equipped).
  3. Raise vehicle and remove crankshaft pulley.
  4. Lower vehicle and remove coolant reservoir.
  5. Timing belt cover.
  6. Loosen water pump bolts and remove timing belt.


  1. New timing belt.
  2. Crankshaft pulley.
  3. Check if the mark on the camshaft sprocket lines up with mark on the rear timing belt cover. The timing mark on the crankshaft pulley should line up at 10°BTDC on the indicator scale. CAUTION: Do not turn camshaft. Use only crankshaft nut to turn. Turning the nut on the camshaft directly can damage the camshaft bearings.
  4. Adjust timing belt to specifications using tool J-26486-A. With gage (tool J-26486-A) installed, tension to within band shown in figure 4. Adjusting the tension with the gage installed on the belt will insure an initial over-tensioning with the new belt.
  5. Crank engine (without starting) approximately ten revolutions. As the new belt takes a set position, a substantial tension loss will occur.
  6. Recheck tension with gage on belt to within prescribed band on gage. NOTES:
    • If reset of tension is required, it is imperative that gage be removed from belt before the readjustment is performed. If gage is left on belt during the reset of tension, the reading will be incorrect. In other words, the gage must not be installed during tensioning due to a possible over-tensioning effect.
    • The timing mark on the camshaft gear and rear timing belt cover must be aligned during the final tension recheck or reset.
  1. Tighten water pump bolts to 24 Nm (18 lb ft) .
  2. Timing belt cover.
  3. Raise vehicle and install crankshaft pulley.
  4. Serpentine, A/C and/or P/S drive belts (if equipped).
  5. Lower vehicle and install coolant reservoir.
  6. Battery ground cable and fill cooling system.
Customer: replied 8 years ago.
I realize that you have to line up the marks. But the problem I am having is when all the marks are lined up on the cam sprocket and its alignment mark and the bottom is on 10 btdc, the belt is about half a lug out, that is to say that the mark on the cam lines up with the center of the lobe on the belt and you have to move it on way or the other to get the belt on and by then you are at 4 btdc or approx 16 btdc.
Expert:  Rick replied 8 years ago.
hi, once engine is turned over as instructed 10 times, belt will stretch or seat better and marks will line up better, make install and turn engine over couple times and will see is getting closer...rick
Customer: replied 8 years ago.
actually I worked on it last weekend and this weekend with my son driving it in between time and when I took it apart again today it does not line up any better than it did the first time I tried it.
Customer: replied 8 years ago.
If I cant get it to line up with 10 degrees and I could get it to line up with 14 degrees or so would this work.
Expert:  Rick replied 8 years ago.
hi, you must have belt in right position if he is driving it, any timing issues , lack of power? if it was off by a tooth would notice issues with running or possible noise, coulb be belt manufacturer not perfect, not sure, ones i've done were close, but have always used belt from dealer...Rick
Customer: replied 8 years ago.
Accelerates when you step on gas easy but when you floor it and shift it into passing gear no power which is why I checked timing belt to start with and it is out about 4degrees, ( when cam is lined up with mark on cover I am at about 6 degrees btdc) which accounts for lack of power but can not get belt to line up. I have another engine which has a cracked head and I tried that belt and the new belt I bought from uap napa auto parts and same thing.
Expert:  Rick replied 8 years ago.
if belts are same should be right, cam gear alignment peg was ok on camshaft, gear did not slip on cam? maybe other problem for your accelleration , lack of fuel, i will out out see is another expert has any clues or has seen this...Rick
Customer: replied 8 years ago.
I checked cam gear today and alignment peg is fine. I have also replaced fuel pump and did fuel pressure test. which o.k. I thought maybe I was missing something or overlooking something. I did get it to about 8 degrees on one of my attempts to fix this and it worked for about 5 mins but I must not of had the belt tight enough and it slipped and I am back to the same position I am in now where I can not get it to line up. When I tried the other belt from the other motor, with a cracked head, I compared vibration dampners and when you line up the key way slots the marks on the pulleys are not in the same place so I used the other one which is on the engine with the cracked head and no luck same thing.
Expert:  Rick replied 8 years ago.
hi, trying to get others to help you out also, will hear from someone shortly...rick
Customer: replied 8 years ago.
O.K. Thanks
Expert:  Rick replied 8 years ago.
your welcome , maybe someone else has an idea....
Customer: replied 8 years ago.
Does any one else have any ideas.
Expert:  Rick replied 8 years ago.

hi ,

no other ideas yet, we are still going to try, trying to get others to review...rick

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