98 timing issue
- Thread starter pjt
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TheDurk
Elite Member
First off, the belt has nothing to do with ignition timing so I'm not sure what you mean by spark check marks. The belt is responsible for valve timing, which is totally different.
If the marks you are talking about are on the timing belt, disregard them. They only serve when you initially install the belt. After that, they only line up again every 210 years--or something like that.
If you are talking about the hard marks on the three pulleys not lining up at TDC, then you may have a problem. Remember, the crank pulley turns twice for each of the turns of the camshafts, so the cam pulleys line up only every other turn of the crank.
sorry, left out some commas. what i meant is i check for spark, pull a plug wire, and grounded the plug, crank the motor had spark. The three timing marks will not line up, the cam marks will come up together but not with the crank, now i'm going by the mark on the crank pully, when its on 0 degree, thats tdc, right?
541joseph
New member
Should be but don't go by that. Go by the mark on the timing cog itself and the one on the block. And if the cam cogs and crank cog don't line up but the two cams do pull the belt off turn the crank whatever direction needed to get it lined up then put belt on cranking it over 2 times by hand and check marks again.
ok, took off the pully and rotated the crank, its is out of time. the timing belt must had jump time, everything looks good, there is nothing broke, like i said i had belt,water pump replaced two years ago. now since it jump time do i just line up the three marks? is the crank mark always TDC, or is it every other revolution.
TheDurk
Elite Member
Something is wrong. They don't just jump time for the fun of it. Pull the timing sprocket and check the key and key way. It may have been left loose and the sprocket turned on the crank and split the key. I hate to say it, but pull your tensioner and check that, too. You will have to recompress it anyway in a vise (slowly!!!!) and put an Allen key in the holes to hold the piston back. Crank mark is always TDC, it's the cam pulleys that are 180° out every other rev of the crank. So when you are sure all is well, use the marks on the sprocket and pulleys and line them up, reinstall the tensioner and then the belt, and pull out the Allen key. Rotate crank twice and recheck. I would not use the compressor tool because you really need to verify function on that hydraulic tensioner to be sure it doesn't happen again.
we were thinking the same thing, it jump for a reason. the crank cog looks good, the key way looks like nothing has move, i did not pull the cog but i have changed a lot of keyways at work, and this one looks good. pull the tensioner and put it in a vise, it was pretty tight, i'm thinking maybe its not working properly. like i said everything looks good. the place that changed the belt, changed the waterpump, the top bearing but they did not changed the tensioner or the bearing, the belt was made in italy. I'm about to roll the cams over by hand and see it i can feel if anything feels wrong. i can't mess with it this weekend, but i will get back with you. i appreciate your help, thanks alot.
just to wanting to let you know, what i thought was just dust in about four of the splines on the crank cog, was hard dry mud, i had not drove this truck for about a month, it was a dirt dobber nest, i found the rest of it on the bottom of my water pump, put it back in time, runs like always.
