Cambelt Timing Marks?

[stuzbot]

I don't want to get ahead of myself here, since I still have to sort out 'The Case of the SumpPlug Made of Cheddar' but, while I was out yesterday, I also thought I'd take a pre-emptive peep at the cambelt, since I have a new belt and tensioner waiting to fit. Just to check the old one wasn't looking like it was about to disintegrate in the meantime. [I haven't got the cambelt warning light on the dash or anything. But, given the hidden surprises I've found so far, I wouldn't put it past the previous owner to have cancelled it, if it did come on].

Anyway, old belt looks OK for another while, but I'm a bit confusticated as to where the timing mark is for the cam shaft. I can see the one on the pulley. But there doesn't seem to be an obvious one on the back-plate:

This, I reckon is lined up pretty much where you'd expect TDC to be....

As confirmed by this, which I'm assuming is the mark for the crankshaft pulley...

Actually, the crankshaft pulley seems to have a whole selection of timing marks. These ones look to have been added later. But thankfully they all agree with each other....

So, where is the timing mark for the top pulley hiding?

 

[BobMurphy]

Well, here we go, with some pics I prepared earlier (2010 as it happens - where does the time go ).

Setting the crankshaft:

Setting the camshaft:

Checking the lower cambelt pulley (its geared to the crank):

Compressing the tensioner:

Lock the tensioner open with a pin - A Pop Rivet stem works well:

Make sure the marks are aligned with the drive-side of the belt tight:

I'm sure you know all this but it might be of use to someone.

Both pulleys turn at half engine speed so the load on the belt isn't high. At 3000 RPM you can read the markings on the belt !

The first time I did this I found the idler pulley pivot to be seized and the belt a bit slack so its worth keeping an eye on it.

One of the easier jobs .

Bob.

 

[stuzbot]

Cheers Bob.

Where's that spike thingy in your first photo located? I didn't notice anything like that when I had the cover off.

I did [correctly, as it turns out] suspect the wee ridge in the middle of the casing, which is lining up with the notch on the pulley [visible in my first pic and your second] might be the timing mark for the camshaft. Looks like mine has had the paint rubbed off, or it's only partially painted and the painted area is hiding behind the cambelt in my pic.

The first time I did this I found the idler pulley pivot to be seized and the belt a bit slack so its worth keeping an eye on it...

Wilco. I've got a new tensioner to fit too. So I'll make sure everything's moving freely. I've given the belt the old 'accurate to ten decimal places' measurement by twisting between finger and thumb and the tension at the mo' feels about right to me. So I'll aim for similar when fitting the new one. At least the Toyota one is pretty much self-tensioning thanks to the spring loaded tensioner. Other ones I've done, the tensioner pulley is on an offset spindle, so you have to adjust it yourself.

One of the easier jobs .

So I've heard. And so it looks [at least as regards access]. As I've mentioned before, I've previously done one on an old VW LT35 and that was a complete arse of a job involving: Making a special tool to lock the crank shaft. Removing radiator, fan, power steering pump, alternator, crankshaft pulley [and probably a couple more bits I've forgotten]. So this looks like a piece of piss by comparison. I'm almost looking forward to it.

[Hopefully that hasn't tempted fate!]

Oddly enough, when I was questing for a new 4x4 all those months ago, I did also consider the Nissan Pathfinder, as it has a really good flat load space in the back for making it into a mini camper. But, after watching a video on YouTube of a guy changing the cambelt on one of those, I thought "No way, José!". It looked nearly as much of a palaver as the LT ones.

 

[stuzbot]

Oh. While on the subject of all things cambelt-ian:

I noticed that, when I had the cover off, there was a smear of oil here [Apologies for hijacking your photo @BobMurphy ] in the area marked red:

It wasn't an alarming amount, just an oily smear and there was none on the belt or pulleys. I just wiped it off with a cloth for now. But just for future reference [I'm not going to do anything with it just yet. I can't be bothered pulling all the pulleys off etc for this belt change], what is behind there that might be leaking?... or is the backplate itself the culprit? I presume it's attached to the engine with a gasket?

 

[BobMurphy]

What is behind there that might be leaking?... or is the backplate itself the culprit? I presume it's attached to the engine with a gasket?

Right . . . Are you sitting comfortably? . . . This might take some time.

With the rear plate of the cambelt cover removed you can see that the front camshaft bearing cap sits close to a flange on the camshaft. I assume this is an 'oil-thrower'.

Any oil getting past the thrower will end-up in the recess behind the belt cover where it can drain down into that large square hole and drop back into the sump.

Proof that it works :

There is an oil seal in the back of the rear cover, and there has to be a bead of silicone sealer around that square hole to prevent oil spill from leaking out:

The oil in your cambelt cover may also be coming from the cambox cover gasket. I would start looking there - you really don't want to be removing all the stuff from the front of the motor on a hunch.

Oh - That spiky "Crankshaft Timing Pointer" is on the front of the block below the Timing Belt cover - visible here:
You will need to ensure that the motor is on the correct stroke (i.e. both Crank & Lower Pulley marks line-up) and there is much finer adjustment on the crank (as it goes around twice for each timing pulley's once). You can't alter the relationship between the two (unless someone has had the Injector Pump off and screwed up).

Hundreds of pictures . . . But never quite the right one .

I wouldn't worry too much about the potential oil leak.

Bob.

 

[stuzbot]

Cheers. I'm not too worried about the slight oil leak. As I said, it's just a smear and not soaking the belt or anything. So no need to attend to it any time soon.

I'm going to have to get the crank-case cover off sometime though to see what's going on in there. I stuck my finger in the oil filler hole one day and had a swirl around and, when I pulled it out, the oil on it was like black treacle. So I reckon that needs a good cleaning out, if the recent oil & filter change doesn't gradually thin it down and shift it.