1hz Timing Belt Change (1 Viewer)

[mudgudgeon]

One thing to keep in mind when removing the cam, you need to try and position the cam so there is no load on the cam lobes while you unit the journal caps.
If the cam is loaded, you can bend the cam as you un-bolt the caps

 

[Hicksey000]

Yeah the engine was running when the belt gave way. Half of the teeth on the belt have been stripped off. I haven't yet pulled the head off to check for damage, I was trying to line the marks up on the pulleys to see if anything would bind up while setting the marks correctly. The chances of getting away without damage seem a little on the impossible side.

 

[Hicksey000]

Just about to put her all back together. 6 bent valves and a cracked head. Brought a new complete head to put back on. I was just wondering if anyone had tips on how to time a 1hz from scratch (this is the first diesel ive pulled apart so I don't know much). Do i just align the cam pulley timing mark to TDC and same with the injector pump, put the timing belt on and should be good to go?

 

[mudgudgeon]

Just about to put her all back together. 6 bent valves and a cracked head. Brought a new complete head to put back on. I was just wondering if anyone had tips on how to time a 1hz from scratch (this is the first diesel ive pulled apart so I don't know much). Do i just align the cam pulley timing mark to TDC and same with the injector pump, put the timing belt on and should be good to go?

Not quite.
The injection pump drive gears have match marks, you need to line them all up.
There's timing marks on the crank and cam pulley to set the cam timing, it's not done from TDC.
Follow the steps in the factory repair manual

If you don't have an engine repair manual, download it here
https://2fiftycc.com/cruiser/1PZ 1HZ 1HD-t Engine 1990.pdf

You need to get the pistons and cam in the right spot before putting the head on, or you'll be back to square 1.

Was the fuel pump removed? Or just the drive gears? If the pump is still on the engine, put the gears back with all match marks lined up.
If the pump has been removed, you need to get it positioned properly first or you can damage the shaft seal in the pump

 

[roscoFJ73]

Yeah the engine was running when the belt gave way. .

Was it being driven hard or was the belt overdue for a change?
Its a pretty rare thing to happen, yours would be only the second I have heard of.

 

[Hicksey000]

The belt was just really old. I bought it off a bloke that had assured me it had been done. I took the old belt off and it was hard and brittle. By him saying it had been replaced when it hadn't cost me close to $1000 in parts. I should have checked it myself to be fair.

 

[Hicksey000]

So if I line the cam pulley and the injector pulley to the BDC marks it should be alright? then after the new timing belt is on, crank it by hand and see that the Cam, injector and crank pulleys all line up to TDC? That's how it seems in the manual, I just wanted to be certain before I tackle it.

I didn't remove the injector pump, only the head.

 

[mudgudgeon]

So if I line the cam pulley and the injector pulley to the BDC marks it should be alright? then after the new timing belt is on, crank it by hand and see that the Cam, injector and crank pulleys all line up to TDC? That's how it seems in the manual, I just wanted to be certain before I tackle it.

I didn't remove the injector pump, only the head.

1 - Turn the crank so the mark on the crank pulley/Harmonic balancer lines up with cylinder 1 at BDC
2- Check that the bottom cam timing gear match make also lines up at BDC.
3- BEFORE you put the head on the engine, Rotate the cam so the match mark on the cam pulley also lines up

Recheck cam timing marks both line up before fitting the timing belt

 

[roscoFJ73]

The belt was just really old. I bought it off a bloke that had assured me it had been done. I took the old belt off and it was hard and brittle. By him saying it had been replaced when it hadn't cost me close to $1000 in parts. I should have checked it myself to be fair.

Bastard, the belts can be had for $30. He could have bought one and said it needs doing.
There are reports of them, lasting 300000klms, so it must be old.

 

[Hicksey000]

Yeah. It would have a whole lot cheaper if he'd told me it had to be done.


I have one last question and hopefully the poor thing will live to see another day!

I just put the new timing belt on and lined all of the marks up where they need to be and cranked the engine over. It fires which is good but the timing belt keeps slipping off the cam pulley, does anyone know what could be causing it?

 

[mudgudgeon]

Doesn't sound good.

Do you mean it's slipping off, as in it's shifting forward off the pulley? Or coming right off? Or skipping teeth?

Did you replace the tensioner pulley, and tensioner?

 

[Hicksey000]

Yeah its just shifting towards the from of the pulley, coming about half way off.

I haven't replaced the tensioner or pullry but I do have another one in the mail on its way

 

[mudgudgeon]

I think hold off running it until you have changed the pulley and tensioner

 

[Locked79]

Post up a photo mate. Something sounds a miss. The cam pulley shouldn't allow the belt to wander. Are all pulleys parallel?

 

[Hicksey000]

No worries, I'll take a picture in the morning and post it. It looks like all of the pulleys are lined up well but the belt just keep moving the the edge of the cam pulley but not quite enough to make it come off.

 

[Hicksey000]

So im not sure if these help at all. When I crank the engine over by hand the belt starts to shift off the pulleys but every seems to be lined up very well. Any suggestions at all?

(Ive made sure the belt is on both pulleys and the idler/tensioner perfectly straight before cranking the engine by hand)

Thanks

 

[Locked79]

At a quick glance, looks like the idler is misaligned. Is the plate it bolts to (pivot point) slightly bent? Eg pulled away from the casing. Any slop in the pivot point itself?

 

[Hicksey000]

This is the back of the idler, ive looked into it and it seems that there are supposed to have a white spacer but mine didn't have one. The bolts that hold the idler on are both tightened up but there's still a gap in the back casing.

After the belt breaking while the engine was running might have caused the idler assembly to stress and bend so ive ordered a new one just to be safe anyway

 

[mudgudgeon]

I would replace the tension spring on the idler too. They are around $14 from Toyota. Given the failure you have had, I wouldn't risk having that spring failing, or not having enough tension in it.
The spring doesn't usually come with the idler pulley kits .

Did the cam pulley go onto the key way properly and get torqued down?

 

[Hicksey000]

Yeah that was the plan. The bearing in the idler seemed alright so I just wanted to start the engine to make sure it all runs and swap the idlers out when the new one comes in the mail but i'll just wait seems the belt keeps almost sliding off. hopefully replacing the tentioner and spring should fix that issue.

yeah the cam pulley is on the key way properly when it's torqued