Only the crank jumped timing

[DakotaPSI]

I just finished my build and the car was running great, then after school one day with 150 miles on the rebuild, it jumped timing when i started the car, i shut it off immediately. When i got home and took off the timing belt cover to see what had jumped and why, i found that there was proper tension in all places and that the only thing out of time was the crank ( and the everything connected via the balance shaft belt went with it). The cranks off 5 teeth and when the cams are lined up, the oil pump sprocket does to??? how could the crank be the only thing that jumped, and especially 5 teeth??? bout when i saw that it was 5

 

[DSM90AWD]

I just finished my build and the car was running great, then after school one day with 150 miles on the rebuild, it jumped timing when i started the car, i shut it off immediately. When i got home and took off the timing belt cover to see what had jumped and why, i found that there was proper tension in all places and that the only thing out of time was the crank ( and the everything connected via the balance shaft belt went with it). The cranks off 5 teeth and when the cams are lined up, the oil pump sprocket does to??? how could the crank be the only thing that jumped, and especially 5 teeth??? bout when i saw that it was 5

The Crank Pulley is two pieces connected by a rubber elastomer to dampen crankshaft harmonics. It's quite likely that this pulley separated as this is a known problem with older crank pulleys (yours is 14years old).

The only other things I can think of is that you did not reset yout auto tensioner correctly, allowing too much slack in the T-belt; you had oil or other debris on the belt; or what I once did, tried to turn the pulley the wrong directino (counter-clockwise) .

 

[ddavisaf]

The Crank Pulley is two pieces connected by a rubber elastomer to dampen crankshaft harmonics. It's quite likely that this pulley separated as this is a known problem with older crank pulleys (yours is 14years old).

The only other things I can think of is that you did not reset yout auto tensioner correctly, allowing too much slack in the T-belt; you had oil or other debris on the belt; or what I once did, tried to turn the pulley the wrong directino (counter-clockwise) .

Not the pully, the sproket.
He took the pully off, and was going by the timing marks on the trigger plate and front case.
Auto tensioner was brand new and set correctly.
Oil, possibly.
Turning the pully in the wrong direction. Nope.

 

[ddavisaf]

I'm going to go over his house either tonight or tomorrow (hopefully) and help him take a look at the problem. However any added ideas would be helpful.

 

[wolf20043]

I just finished my build and the car was running great, then after school one day with 150 miles on the rebuild, it jumped timing when i started the car, i shut it off immediately. When i got home and took off the timing belt cover to see what had jumped and why, i found that there was proper tension in all places and that the only thing out of time was the crank ( and the everything connected via the balance shaft belt went with it). The cranks off 5 teeth and when the cams are lined up, the oil pump sprocket does to??? how could the crank be the only thing that jumped, and especially 5 teeth??? bout when i saw that it was 5

Not too sure as to why, but keep in mind, The crank is what turns the assembly, moving everything else with the timing belt. If the cams happen to stick for some odd reason, the crank will continue to turn while all the parts held by the belt could stay stationary as you have 3 gears with teeth holding them in place. The crank will only have one. I would start by seeing if for some reason the cam shafts froze or something to that effect or if something held them up long enough for the crank to go out of time.
Mike

 

[DSM90AWD]

Auto tensioner was brand new and set correctly

Took me several tries (4) my last T-Belt re/re to get my tensioner to the correct setting. I assume you helped so the routine of adjustment + pull tensioner pin + wait 15mins + 6-revolutions + recheck was followed?

Are both the tensioner and idler pullies ok?

 

[ddavisaf]

Took me several tries (4) my last T-Belt re/re to get my tensioner to the correct setting. I assume you helped so the routine of adjustment + pull tensioner pin + wait 15mins + 6-revolutions + recheck was followed?

Are both the tensioner and idler pullies ok?

Yes, although we waited about 30 minutes before the re-check.
The pullies were used, however spun freely with no signs of binding at any point in the rotation. I have not gone down there yet to see exactly what caused the jump in timing. I did talk to him on the phone last night and got him to where he's at right now.
Right now where he's at is the auto tensioner is out of the vehicle and is going to be re-pressed today. While the belt is off I'm going to inspect the pullies to see if any went bad, or if they were not torqued correctly. Then we'll set it back to the correct timing and compression test it to see how bad it is.
What bothers me is I've never had a car jump timing on me like this before. And I've done a timing belt or two in my day.

 

[Old Mitsu Tech]

HMMM....... Depending on where the cams were at when it jumped 5 teeth. I just had a 2g nt jump 4 and did not bend valves, but you never know.

If nothing is seized up, it almost always boils down to the auto tensioner being set improperly. If you pull the covers, see where the hole in the auto tensioner is. If it's fully extended, then that likely is the problem.

Let us know.

 

[ddavisaf]

I should be going down there tonight to work on it. I'll let you guys know what I find.
I talked to Claire and she said not having the CAS bolted in with the 2 bolts will also cause it to jump. This car only has one nut securing the CAS.

 

[DSM90AWD]

I should be going down there tonight to work on it. I'll let you guys know what I find.
I talked to Claire and she said not having the CAS bolted in with the 2 bolts will also cause it to jump. This car only has one nut securing the CAS.

Just to be clear, we are talking about valvetrain timing right As the CAS is only relevant to ignition timing (on 1Gs) and has nothing to do with the timing belt slipping / or TBelt alignment at all

 

[ddavisaf]

No. She said one of her cars' timing belt slipped due to the CAS.

 

[ddavisaf]

Or maybe I understood her wrong.

 

[Old Mitsu Tech]

I cannot see how the cas being loose can cause a belt to jump as it is not a part of the tensioning or guiding.

Besides, it's on the opposite side of the head and the cams are held in line by the caps.

Or maybe it's just me.

 

[DakotaPSI]

I would also like to note that the crank was x number of teeth out of time in the counter clockwise direction ( opposite of what it revolves) If that helps.

 

[DSM90AWD]

I would also like to note that the crank was x number of teeth out of time in the counter clockwise direction ( opposite of what it revolves) If that helps.

The only way this could of happened would be if
1.) you slipped 19teeth clockwise (285degrees of crank rotation) guaranteeing bent valves. The starter would most definitely do this if the tension was way off.
2.) Rotated the crank pulley counterclockwise either manually (which you say you didn't do) or bumpstarting in reverse.

I jumped three CS teeth once and definitely heard the piston/valves smacking , luckily I shut down immediately and nothing was damaged. Reset belt and was good as new.

Hope you get thru this without having to pull the head

 

[Drifter27_04]

I didn't come out that lucky with mine.

After a few laps around the block I heard my pistons / valves smack each other and that was it for the car. Me and my mechanic gotten out and check things out and notice nothing to be out of the ordinary which it was 12 o'clock at night to when we was looking. He got a ride back to the shop and gotten his jeep to pull it back to the shop where we than still found nothing. It was late and we decide to call it a night and come back first thing in the morning. He made a phone to our local mishi dealership and he told the mechanic there what happen and they said something about the hydraulic belt tensioner was bad and what had happened was that when you let the out of the gas the motor gives a backlash or something of that nature and the tensioner is bad and it lets the timing belt jump a few teeth before it can react to the slack. We asked how much for a tensioner and when he told us how much one was for we about fell ($300). By this time we went back to the shop to find that the belt was really freaking loss, the cam gears was fine but the crank jump 5 teeth "ouch". I got on the phone to SBR and told them what had happen and what we have found and who ever I spoken with (can not remember) pretty much said the same thing. I asked him if there was a way to check the tensioner and he said take it pitch it in the trash can and buy a new one, so that's what I did. Bought the tensioner from SBR for $70 not $300 from the mits dealership. We than did a leak test to find out we had one and pulled the valve cover off to find out that some of the rockers was not the way they should be and than pulled the head and found out that we bent all of the intake valves. I took it to the machine shop to have them "cut out" and on the phone with someone local about ordering new SS valves. By the time the head work was done the tensioner came in the mail and installed everything once again and been running since than.

For the thought I would look at the belt tensioner system and make sure everything is working right and I would buy another tensioner to be on the safe side. You could have bought a faulty part and not know it. Than needless to say I would do a leak down test of each cynlinder and if you hear air through your intake and intercooler piping you have bent some intake valves and if you hear something from the exhaust you have bent some of the exhaust valves. Hope for the best that you did not do any damage. If you take the head off most definitely inspect the tops of each piston. Hope this helps.

 

[DakotaPSI]

I retentioned the tensioner. Im gonna pull the pin on it with it unbolted in my hands and measuer how far the plunger comes out. Does any one know how far it should come out?? Like in millimeters, and where to measure from, (i.e. top of the base part of the tensioner.

 

[mujgy]

Its not so much how far it will extend, moreso if it maintains a certain pressure and position. This is why you must do the routine of adjustment + pull tensioner pin + wait 15mins + 6-revolutions + recheck as DSM90AWD posted. Either the tensioner is good or its going bad. I would imagine it would be possible to do a leak down test, similar to a valve lash adjuster test, to find out if the tensioner has any leakdown. But if its a new tensioner it should be good.

All in all about the only things I can think of that would have allowed the TB to slip so far on the crank sprocket is not setting the tension pulley correctly or the mounting bolt was not fully torqued.

Depending on the DSM gods being in a good or bad mood that day will decide the fate of your valves.

mujgy

 

[ddavisaf]

Looks like the tensioner pully slipped a bit.
We re-timed it. Rotated it 6 times and now it's sitting. We're going to rotate it again tomorrow. Then we'll run a compression test on it.

 

[Mark90gst]

the cams seized in the head,crank kept going cams stopped, you lucky you didnt bent all brand new valve like I did and waste alot of money on it the head.

 

[ddavisaf]

I've seen that happen before. Actually, that happened to the guy I got my 6 bolt from. It's never fun wasting money. Sorry to hear that.

 

[DakotaPSI]

Just wondering, but how tough should it be to rotate the crank by hand. I had a regular sized ratchet with a 3/8" drive with a 3/8" - 1/2" attachment. Is it suppose to be easy all the way around, or is it suppose to get tought for a second (im guessing when it hits the tops of the cylinders for each pair???) Cause with one rotaion it gets tougher two times. Just a question.

 

[DSM90AWD]

Just wondering, but how tough should it be to rotate the crank by hand. I had a regular sized ratchet with a 3/8" drive with a 3/8" - 1/2" attachment. Is it suppose to be easy all the way around, or is it suppose to get tought for a second (im guessing when it hits the tops of the cylinders for each pair???) Cause with one rotaion it gets tougher two times. Just a question.

Yes, this is normal. You're simulating the compression stroke on the engine with two cyls compressing 1L of air.

I would at the same time check the valves (cover off) to make sure they are not sticking and the followers are all seated correctly on their perches

 

[DakotaPSI]

well it shouldn't be compressing, i dont have spark plugs in?? just wondering if it got tought when the rods got to full out on the crank and then switched sides.???

 

[ddavisaf]

Yes, this is normal. You're simulating the compression stroke on the engine with two cyls compressing 1L of air.

I would at the same time check the valves (cover off) to make sure they are not sticking and the followers are all seated correctly on their perches

Valves weren't sticking. Everything was moving smoothly.