timing belt problems

revolution · 02-06-2006, 03:30 PM

im in the middle of changing the hg on my 7mge and im having a bit of trouble getting the crank at 0 and the cams in line. i installed a new tensioner and belt but its a half notch almost everytime. is there a trick or just persistance? any advice would be greatly appreciated.

revolution · 02-06-2006, 06:55 PM

cam lock tool. did the trick

rnoswal · 02-07-2006, 02:35 PM

Well, if you get the head milled, then the timing marks are going to be off a little bit. In the book the cam marks line up with the marks and the back plate behind the cam. The cam and the gears have three holes in them. The initial setup for the cam is to put the pin in the middle hole and put the cam gear on the cam using its middle hole. If the #1 piston is at top dead center then that is when you put the belt on. Now if it is off, that is where the other holes in the cam and cam gear come into play. Make sure the crank pulley timing mark lines up with its mark on the timing cover. Now if the cam gears are lined up with their marks but the belt won't fit, the you pull the gears back off, start with the intake cam gear first and put the pin in another hole and try a different hole in the cam gear. Experiment with it until you get the combination that makes the belt tight.

You have to be careful with that part though because once you find and position that make the belt tight, your marks on the cam gears no longer line up with the marks on the backing plate. I have done this several times and usually put the car in gear, 1st, and carefully move the parts around. Stuff a rag into the cover so you won't drop a pin in there. You should be able to do this and get it tight. After the intake cam then do the exhaust cam gear the same way. When you are satisfied, tighten things back up, let the tensioner back on the belt. With a marker, mark the new spots on the cam gear. Then turn the crank over with a ratchet and see if the marks line up and the belt is tight.

You may have to try it a few times, but don't worry about valves hitting anything, they won't! If something moves before you get it where you want, just put the gear back to its normal spot, get it lined up again and try it again. You will feel your way to how much tension you can put on the gears before they turn to get the belt on the gear tight. All you have to do is turn the crank gear just a bit, clockwise< to see if you had any slack in it. If not you are ready to go, if so, then try it again. It should only take a half hour or so to do this procedure.

The reason I think this is better than getting a thicker head gasket is because with the head milled you get a little higher compression and thus a little better performance. If the head hadn't been milled previously and you know exactly how much was milled and can get a head gasket think enough to make up for that difference and if you get a new belt, then putting it back together with everything in its stock locations is just as easy. This way though you get to play with the car a little and get a little bit more performance from it. You could even experiment a little bit more and figure out how many degrees you can advance or retard the cam gears and get either a little bit more low end or a little bit more high end power.

Good luck and don't let this part scare you, unless you don't feel at all comfortable in trying this alone. Let me know if you have anymore questions.

Russ

02-06-2006, 06:55 PM	#2
revolution Stock Join Date: Nov 2005 Location: ohio Posts: 20	cam lock tool. did the trick __________________ love my chev but it hates me

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02-06-2006, 03:30 PM	#1
revolution Stock Join Date: Nov 2005 Location: ohio Posts: 20	timing belt problems im in the middle of changing the hg on my 7mge and im having a bit of trouble getting the crank at 0 and the cams in line. i installed a new tensioner and belt but its a half notch almost everytime. is there a trick or just persistance? any advice would be greatly appreciated. __________________ love my chev but it hates me

02-07-2006, 02:35 PM	#3
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	Well, if you get the head milled, then the timing marks are going to be off a little bit. In the book the cam marks line up with the marks and the back plate behind the cam. The cam and the gears have three holes in them. The initial setup for the cam is to put the pin in the middle hole and put the cam gear on the cam using its middle hole. If the #1 piston is at top dead center then that is when you put the belt on. Now if it is off, that is where the other holes in the cam and cam gear come into play. Make sure the crank pulley timing mark lines up with its mark on the timing cover. Now if the cam gears are lined up with their marks but the belt won't fit, the you pull the gears back off, start with the intake cam gear first and put the pin in another hole and try a different hole in the cam gear. Experiment with it until you get the combination that makes the belt tight. You have to be careful with that part though because once you find and position that make the belt tight, your marks on the cam gears no longer line up with the marks on the backing plate. I have done this several times and usually put the car in gear, 1st, and carefully move the parts around. Stuff a rag into the cover so you won't drop a pin in there. You should be able to do this and get it tight. After the intake cam then do the exhaust cam gear the same way. When you are satisfied, tighten things back up, let the tensioner back on the belt. With a marker, mark the new spots on the cam gear. Then turn the crank over with a ratchet and see if the marks line up and the belt is tight. You may have to try it a few times, but don't worry about valves hitting anything, they won't! If something moves before you get it where you want, just put the gear back to its normal spot, get it lined up again and try it again. You will feel your way to how much tension you can put on the gears before they turn to get the belt on the gear tight. All you have to do is turn the crank gear just a bit, clockwise< to see if you had any slack in it. If not you are ready to go, if so, then try it again. It should only take a half hour or so to do this procedure. The reason I think this is better than getting a thicker head gasket is because with the head milled you get a little higher compression and thus a little better performance. If the head hadn't been milled previously and you know exactly how much was milled and can get a head gasket think enough to make up for that difference and if you get a new belt, then putting it back together with everything in its stock locations is just as easy. This way though you get to play with the car a little and get a little bit more performance from it. You could even experiment a little bit more and figure out how many degrees you can advance or retard the cam gears and get either a little bit more low end or a little bit more high end power. Good luck and don't let this part scare you, unless you don't feel at all comfortable in trying this alone. Let me know if you have anymore questions. Russ