Timing Belt replacement
nymorey
12-30-2004, 10:53 PM
I am going to change the timing belt, tensioner and idler pulleys on my 94 Lumina Z34, 3.4 DOHC.
I have been reading the forum threads, instructions on 60degreeV6 and the Haynes manual.
My question is whether or not I have to do the cam timing as part of the install. I'd rather not deal with the special tools. The manual leads me to believe I can line up the timing marks, clamp the cam sprockets and then replace the belt.
Any tips?
Thanks
I have been reading the forum threads, instructions on 60degreeV6 and the Haynes manual.
My question is whether or not I have to do the cam timing as part of the install. I'd rather not deal with the special tools. The manual leads me to believe I can line up the timing marks, clamp the cam sprockets and then replace the belt.
Any tips?
Thanks
cadgear
12-31-2004, 12:22 PM
Make sure you TDC #1, and ensure alllllll the marks are lined up properly. I'd use the tool to secure the sprockets but hey, that's me. Other than that, best of luck to you.
dwalmop
12-31-2004, 01:33 PM
I agree with cadgear, your life will be much much easier with the sprocket tool. there is just too much crap to line up easily. but have fun, glad to hear somebody's actually keeping up with maintenance
nymorey
12-31-2004, 08:41 PM
I tried to find a tool but no one has them. I'll make one as described on 60degreev6.com. Do you need a special tool to get the sprockets to freewheel?
Can I assume that when I line up the flats on the front cams and secure them with the tool that I am at TDC?
Can I assume that when I line up the flats on the front cams and secure them with the tool that I am at TDC?
nymorey
01-01-2005, 06:15 PM
I'm confuser regarding the timing marks. I have everything apart, the flats are up on the front bank and I see only one timing mark on the crank. Is that what I am looking for?
cadgear
01-01-2005, 10:03 PM
The one timing mark on the crank should be pointing to another mark in the front cover. That's TDC for #1, and you line up the marks on the cams, make sure the intermediate sprocket is lined up with the cover's mark. When that's done, you're at TDC Exhaust for #1, which is how all the marks are made.
nymorey
01-01-2005, 11:08 PM
Ok. I lined up the crank mark with the mark on the housing and clamped the front bank cams with the flats up. Which I assume is TDC exhaust.
There are no other marks anywhere else on any other pulley or sprocket. I put a paint mark on the intermediate sprocket lining up with the cover timing mark per the book.
Then I loosened the front cam cogs and spun the crank until the rear bank cam flats are face up (with the front cogs freewheeling), which, not surprisingly, put the crank mark real close to the mark on the housing for TDC exhaust. I clamped the rear cams and replaced all the pulleys and have the paper clip in the tensioner ready to install the new belt tomorrow
There are no other marks anywhere else on any other pulley or sprocket. I put a paint mark on the intermediate sprocket lining up with the cover timing mark per the book.
Then I loosened the front cam cogs and spun the crank until the rear bank cam flats are face up (with the front cogs freewheeling), which, not surprisingly, put the crank mark real close to the mark on the housing for TDC exhaust. I clamped the rear cams and replaced all the pulleys and have the paper clip in the tensioner ready to install the new belt tomorrow
nymorey
01-02-2005, 08:41 PM
Well I finished the job. Next time I definitely need to get the tool that holds the sprocket while you loosen them up. That was probably the hardest part of the whole job. (other than putting the inlet plenum back on, yuk)
Also noted that you have to be aware of the location of the tab on the tensioner pulley. When I installed it the first time and pulled the paper clip from the tensioner it didn't apply any tension to the pully. The problem was the tab on the pully that mates up with the tensioner was not lined up properly. Luckily I noticed it and reinstalled correctly, however I had to use a wrench to hold it up while I pulled the pin.
Also noted that you have to be aware of the location of the tab on the tensioner pulley. When I installed it the first time and pulled the paper clip from the tensioner it didn't apply any tension to the pully. The problem was the tab on the pully that mates up with the tensioner was not lined up properly. Luckily I noticed it and reinstalled correctly, however I had to use a wrench to hold it up while I pulled the pin.
cadgear
01-02-2005, 11:32 PM
Congrats on a job complete, the DOHC's major weakness is the belt (IMHO). If you don't keep on top of it, you're SOL very shortly. Glad you finished everything okay.
nymorey
01-03-2005, 09:39 PM
Thanks, I appreciate it.
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