Timing Belt Walk On New Motor

[jtalton626]

Good day,

I am the proud owner of a 1990 Plymouth Lazer GST. 5 spd, FWD. I have a brand spankin' new motor in it, and have driven it now past it's 500 mile break-in period. The motor has quite a few mods done to it, both inside and out. Bottom line, the engine runs like a champion...but I have one problem, which is turning out to be pretty typical with this car. There's always ONE MORE problem. But here's the deal.

I change my oil at the 500 mark and notice my timing belt is now riding almost halfway off the cams. When I drove it at first, it was walking about 1/8'th of an inch off the cams but now it's going a LONG way off. I have noticed that when I turn the car off, the belt goes slack between the rigid pulley and the intake cam...quite slack. After a short restart, the whole belt is tight. I thought that perhaps the lack of a cam gear cover may be the issue, and after purchasing and installing said cam gear cover my timing belt ate through it within 10 miles. It is coming off AWAY from the motor, which REALLY concerns me because I am quite aware what happens if that belt comes off. Any ideas?

I do have two other cars, so this can remain parked until I properly diagnose the problem. It is quite a pain in the arse though, seeing as how it's been off the road for over a year. I have now driven it for 9 days, and now I have to look but not touch AGAIN! I am truly beginning to develop a love/hate relationship with this car. I drive a speed demon for 9 days and then it's back to a crappy 2.2 liter ECO-tech cavalier. Ugh.

 

[92AWDHX40]

have it done again.

 

[vanilla gorilla]

I say, re set the timing system, and make sure you tension it properly.

 

[MichaelSuch]

Was the tensioner replaced? If not replace the tensioner and line the belt back up where it needs to be. Definately don't drive it until the issue is resolved. Make sure you set the tension correctly, follow this guide.

 

[khartley]

The tensioner is supposed to be replaced with the timing belt. Even if that turns out to not be the culprit, I would replace it anyways to help prevent future problems.

 

[DSM1G90]

1990 Plymouth Lazer GST

(...must had an Eclipse before his RS..)

Agree: check the assemblies mentioned above. Bet something is horribly off alignment.

 

[quattro527]

Your tension is not set properly.... RE-DO it before you skip teeth. Goto vfaq.com which also gives you instructions. The idler pulley must be properly set so that the hydraulic tensioner has a given gap. vfaq.com uses the drill bit technique to measure the gap between the tensioner piston, and the arm of the idler. This is VERY important. I easily overlooked it on my first belt change (after the old belt snapped and cost me a new head), and skipped 2 tooths.

 

[jtalton626]

Well, it looks like I may well earn the dumbass award of the day. I decided I was going to attempt taking off the balancer and re-adjusting my tensioner. My brilliant ass forgot to clip the belt to the cams, mainly because I did not think it was this loose. When I went to take the bolts out of the balancer pulley, the crank spun and the cams did not.

Great! Here's my idea. If there is anything wrong with this idea, I would like someone to tell me by tuesday. I am going to remove my number one plug and place a notched metal rod on top of the number one piston. I will rotate my crank until the number one piston reaches TDC, ie. the notched rod reaches full height, then adjust my cams to level with the top of the head and re-apply the belt. This time being sure to follow the timing instructions. I doubt the tensioner is the problem, as the one I used was brand new and shows no signs of being defective. I think it may have to do with my idler pulley. I ordered a new idler pully and tensioner pulley today. They should both be here on Tuesday.

Well, this is the first time I have ever fully rebuilt a four banger motor with no training whatsoever. I did it alone in my driveway with four children running around me stealing tools and parts faster than I can find them. I don't feel too bad that this is the biggest mistake I have made so far but it does frustrate the hell out of me that I made such a noob mistake. Oh well, at least I slipped the teeth manually and not while it was running.

 

[jtalton626]

Ok...I read the "How-to" set timing on this motor. Now I know what failed. I did not adjust the tension on the tensioner pulley itself. I have worked on american cars all my life and I have never seen a vehicle that had an offset bolt on the pulley. I suppose now I know why that looked so funny, and why my timing belt felt the need to run so wild and free. Hmmm.

Well, I suppose on Tuesday I shall re-set the timing on that. I'll have to order the specific tool for it on Monday from O'Riellys. At least I learned something for free by this lesson. Usually they are quite a bit more costly. I will tell you one thing though, I have learned that mechanics are great and all...but I would rather personally know what I screwed up than have no idea what someone else screwed up.

 

[DSM1G90]

I'll have to order the specific tool

Save your 20 bucks. Go buy a length of 8mm rod and two 13mm nuts. Take a hacksaw and cut down the rod down to a foot and spin on the two nuts and jamb them together super tight so that a 13mm socket can fit on top.

Makes a great adjuster tool. See this page that I posted on this...http://www.dsmtuners.com/forums/newbie-forum/299561-question-about-battery-tie-down-belt-tensioner-tool.html

-DSM

 

[quattro527]

Ok...I read the "How-to" set timing on this motor. Now I know what failed. I did not adjust the tension on the tensioner pulley itself. I have worked on american cars all my life and I have never seen a vehicle that had an offset bolt on the pulley. I suppose now I know why that looked so funny, and why my timing belt felt the need to run so wild and free. Hmmm.

You are lucky you didnt jump some teeth and bend some valves... because it has happened to the best of us.

Regarding adjusting of the tensioner/idler pulley... it is just another one of the "love/hate" things on the DSM. That...along with that stupid balance shaft.

 

[jtalton626]

Well, luckily I had the foresight to install a balance shaft eliminator kit, so I no longer have to actually time everything. It's a fairly simple process getting the time right on it. I have aftermarket fully adjustable AEM Cam Gears, so the etched lines help. As far as setting time on the crank, I just put a rod on top of my #1 piston so that I can see it while I turn the crank. When it stops going up, your at TDC. Put the belt on and tension. The tensioning is where I'm having difficulty. And the dude talking about the rods and hacksaws and stuff...um, I'd rather spend the $20. I have learned the value of the RIGHT tool after many busted knuckles and gashed wrists.