Oh s***, that was stupid

[Feistl]

Hey guys,

Just ****ed up, been a long time since I’ve made such a silly mistake.

I’ve been overhauling my 1HDT and I had removed the timing belt (was doing some custom brackets etc so hadn’t put it back on yet). Anyway the weather was nice today and I had some assistance from the misses so I removed the engine from the cruiser (to install new clutch etc).

Anyway in the process of removing the flywheel bolts I managed to spin the motor over without a timing belt installed. I only noticed when the motor suddenly stopped spinning “freely” which I assume is piston making contact with valves. (Edit spun as in by pressure from the socket/ratchet trying to loosen the bolt, NOT using the starter motor).

Now I didn’t put much pressure on so I doubt I’ve done much damage (I’m really hoping not) but what’s the best way to “reset” the timing? Should I remove all the rockers and spin the motor back to the timing mark and start from scratch?

I’m going to pull the injectors and try and put a scope/camera down to inspect the pistons just to be sure

So annoyed at myself. I’m usually very methodical and logical but I was under a bit of time pressure and just didn’t think it through

 

[mudgudgeon]

Chances are its all fine if you didn't force it once it stopped turning freely.
If valves made contact with pistons, it's happened without any real force.

I'd turn it back slowly to the TDC mark with the front crank bolt and continue with the t- belt replacement.

 

[Feistl]

Thanks mate, I have read/been told to never spin a motor counter clockwise... (I never understood why not), so was hesitant to do that. However it seems like a better option than pulling the cam off (I shouldn’t have said rockers earlier, spent too much time on pushrod V8s and my 12HT). This is my first overhead cammed engine...

Cheers

 

[mudgudgeon]

You won't do any harm turning it backwards.

I was told not to turn an engine backwards too, but more in the context of setting timing

 

[roscoFJ73]

I had to turn a 1HZ backwards once upon a time for the same reason. No problems at all. But you need to turn it back and then forward again to take any slack out of the engine.

 

[Feistl]

chickened out and decided to remove the camshaft instead. Considering the motor was out it was just 14 bolt which took 5 minutes. Decided to change the cam bearing (strangely there’s only one) and change all the valve seals. For the $100 in parts and relative ease seems like a no brainer. Still kicking myself though

Cheers

 

[Dilspec]

Eh you should be fine, might have been an issue if you cranked it with the starter and it moved at a higher/faster rate.

 

[Nz Nath]

I think the issue with turning engines backwards is the cam belt/chain tensioners. They take up the slack on the run after the crank, the belt/chain isn't driving anything on that run. If you turn the engine backwards you're putting a lot more force against the tensioner that it's not designed to take, and depending on the design of the tensioner might put slack into the belt whilst turning it if the the tensioner doesn't 'lock off'.

 

[roscoFJ73]

If you turn the engine backwards you're putting a lot more force against the tensioner

I have played around with the tensioners on the 1HZ and wound engines back a few times and there are no problesm you can have with these. The tensioner has more room to move than it needs to when you turn it backwards. You just need to go back a little further than you need and then go forward to bring the tension back onto the timing belt ect. Its a no brainer.

 

[Feistl]

Hey guys,

Just putting the motor back together tonight, followed the FSM and got the cam back in after changing valve seals... all went smoothly.
I put the timing belt back on (aligned the markings on the cam and fuel pump) and spun the motor over, everything feels nice.
However during a final check I’ve noticed that the CRANK markings aren’t aligning with the fuel pump or camshaft... is this an issue?

Just to confirm the fuel pump (which hasn’t been removed) and cam markings are lining up correctly and the motor spins freely, but the main crank markings are out by like 20 degrees. I can take some photos if required...

I’m just worried the engine is going to be say 180 degrees out of phase, eg the pump is injecting during the exhaust phase.

Thoughts?

 

[Feistl]

It looks like its out by 1.5 teeth. Now the pump has been rebuilt by the previous owner, so it may have been reinstalled incorrectly. The cruiser was running (and running pretty well) when i purchased it, could it run being that far out?

 

[Nz Nath]

You had the timing belt off, and turned the crank during that time? So to put it back together you'd set all the sprockets on to their marks and then install the belt...

So I must be misunderstanding something? It's the crankshaft that's not on its mark? So how did you decide it's position before you put the belt on?

 

[Feistl]

So from the start...

I pulled the timing belt off in anticipation of changing. I turned the motor over until the camshaft and fuel pump marks were in alignment, i didn't check the crank as i didn't initially realise it had a marking as as i wasn't planning on turning the motor over i didn't really matter.

Then the plans changed and i ended up removing the engine from the car. While trying to get the flywheel off (to get machined) i accidentally turned the motor over. So rather than spinning backwards i decided to just remove the camshaft altogether (so i could replace the cam bearings and valve seals).

I've replaced the bearings and seals and went to put it together. I spun the motor over until the fuel pump mark was at the top and bolted the cam on with the timing mark at the top (essentially the same as what it was originally).

So after bolting everything up i was just doing a final read of the factory service manual and it says on the last page to check all 3 timing marks (including the crankshaft).

This is when i've noticed that the crank and fuel pump aren't in alignment. As they are a 2:1 ratio it doesn't matter how many times i turn it they don't line up. Now as the fuel pump is gear driven it must mean that the timing was out originally (unlikely?) or maybe the timing mark on the pully is wrong? (Maybe someone has change it previously?)

Now i know the fuel pump was removed and rebuilt a while back by the previous owner, I'm wondering if they've installed it wrong and been a tooth out (causing the timing issue). Will a 1HDT run when out of alignment like that?

Cheers

 

[Nz Nath]

Okay I didn't realise the fuel pump was gear driven. Is it possible to adjust the static pump timing enough to compensate for being that far out on the gears, as an option on what the previous owner might have done.

It seems strange that the procedure to fit a cambelt involves aligning a mark on the pump when that doesn't have anything to do with the belt. If you take an injector out would you be able to see into the cylinder to physically confirm TDC?

 

[Feistl]

The camshaft is driven by a belt from the fuel pump. The fuel pump is gear driven (internally) by the crank. You can see why i only bothered lining up the fuel pump/camshaft initially....

There is a small amount of adjustment in the fuel pump but i dont think enough to compensate that much. I thinking i may have to pull the pump out . My biggest fear is for some reason the crank markings are wrong and its actually currently in alignment, then i pull it all apart and adjust it to be out of alignment and it doesn't run.

 

[mudgudgeon]

Don't remove the pump.

Recheck timing marks on the crank etc.

It's possible the harmonic balancer has separated and the outer ring may have shifted out of position which screws up the timing mark.
Removing number 1 injector is one way to be able to verify TDC

If the pump timing is wrong, you'll have to remove the timing case and the pump drive gears then reinstall the gears with the timing marks lined up correctly.

 

[Feistl]

Really good tip, thanks mate... So the outer ring has separated but looks like when the previous owner changed the front main seal he forgot to install the key into the keyway... so the balancer was just bolted on. As a result it has moved in relation to the crank, however i suspect it moved during installation (tightening of the main bolt) and not been spinning on the crank itself. And if it was, there isn't any damage...

So I'm thinking time for a new balancer(s), new bolt and new seal (After reading that the balancers have a fairly short life span and do real damage if/when they go for the $500 its probably worth doing now).

For the record i put the balancer back on in correct alignment (as per the keyway) and it lines up with the timing mark/fuel pump/camshaft. So your tip saved me pulling the pump off, really appreciate that.

Ill write up a guide on changing the balancer when the new one arrives. Just trying to work out whether i go genuine toyota (Cira $600 for both balancers) or aftermarket (powerbond) for $450ish...

 

[mudgudgeon]

I'd go OEM for the balancer.

 

[Feistl]

ok, and is it worth trying to fit one of the later model balancers? (the 4 bolt version). I know toyota redesigned this due to failures in the early models, but not sure if it impacts anything else...