First if it is lose on the exhaust cam sprocket it would be lose on the intake sprocket as well since it is one big chain. You would have to have catastrophic failure on the one sprocket and not the other. The chain and the sprockets wear at similar rates because they are all exposed tot he same oil and the same loads chains and belts can be based on pushing or pulling depending on the system design. The tension does not have to be identical at all points along the length of the chain in a machine.

To measure chain stretch you have to have the chain off of the engine to measure.

To add insult to injury the chain tensioners in the engine work off of oil pressure they have a tiny amount of spring pressure internally but most of the tension comes from oil pressure. When the engine is not running you are not seeing it as it would be with positive oil pressure!

If you do not have any sludge or a very dirty engine and your not hearing any timing chain noise and your guides are in tact when you look down into the timing cover you are likely fine. On the other hand a dirty engine with neglected air filters or oil changes is a prime candidate for valve train wear!

If the car is well maintained the guides or a tensioner will usually fail before the chain does.

For the record the tensioners and guides work on the long aspect of the chain not at the top of bottom of the chain.

 

Awesome information! Thanks. Engine is clean, and well maintained. Don't see any sludge, Andi have been in it to where I would have seen any. I removed the vvti oil filter plug looking thing last year and it was clean.

When I start the car it is noise free and sounds great. When I go into reverse or forward, I heard rattling noise from the front of the engine. It's not an exhaust leak or loose exhaust part. I have checked that extensively.

I did the screwdriver stethoscope test around the front and passenger side of the engine block. Really sounds like it's coming from there.

So I figured I would seedo the timing chain and see if that fixes the rattle. Easier than doing the balance shaft assy. I don't think it's anything related to balance shaft assy.

I will take pics and measurement when I'm in it this weekend.

Enjoy!

 

Makes noise only when gear? I would think exhaust shields, but if you have ruled that out, I would think mounts and/or anything close to the engine.

 

All new motor mounts, except for the trany mount. I did check that one and it seems good. I bought a new transmission mount and I compared the old one to the new one and they both felt the same. I get what you're saying for sure. I've just started the unbolting slash removal procedure. Of course I waited till it's hot as you know what in Tampa florida.

 

Don’t mess with the cam gears like that, you can cause timing to jump and then you’re really SOL. The best way to check for chain stretch is to pull the front cover and inspect how far the plunger has moved out of the tensioner body. The tensioner is applied with oil pressure, so it’ll never have full tension on it with the engine off


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Finally some time to update this. I replaced the chain etc, with the parts from the Cloyes kit. Nice stuff!
I also replaced the cam phaser on the intake cam. Probably did not need to do this, but what the hell since I was in there.
I thought replacing the chain would eliminate a rattling noise when I put the car in gear, but it did not.
What it did do though was make the car idle super smooth when in gear and stopped at a light. It had a slight vibration before replacing the chain.

The old chain and the new chain were exactly the same size.

Thanks!

 

We told you that the chain was not the issue if the engine has been maintained and seen decent oil change intervals. If it was going to be anything it would have been guides and tensioner!

Most Toyota timing chains with proper maintenance can do 300K+ miles but tensioners and guides seldom make it much past 250K. So you will hear a rattle on cold start that goes away once oil pressure is up. The came phaser solenoids last the longest with good synthetic oil and freq. oil changes but trying to pin down a millage for them is difficult. They can fail on the oil side of things or the coil in them can fail on the electrical side of things. Almost no one ever seems to take the time to figure out why theirs failed and report it to use so.......GreasyMechTech could probably nail that one down since he works on these things day in and day out!

 

Reviving this because I have a related question. Just replaced my timing chain and put front cover back on, put in new tensioner as well (whole set from Cloyes, same engine as above). It seems like the timing chain is tight between the crank gear and each cam sprocket, but the space in between the cam sprockets has a bit of slack - the chain sags a bit, in that I can pick it up maybe a quarter inch or so and it will drop again. I can see as I rotate the chain that the tensioner moves in and out a little bit, but it is unhooked. Rotating the crank ccw further has no effect.

I see above @BlackCamSe mentioned that the timing chain won't have tension on it with the engine off - does that mean this slack will go away when I fire up the engine for the first time after its back in the car? Or is this little bit of slack something I should address now? I should note, doing a couple of full rotations both ccw and cw, it doesn't go out of time at all.

 

The tensioners have weak spring and rachet mechanism that slowly pushes the guides in as they wear our. When the the engine starts up and has positive oil pressure an additional externally changeable tensioner places more pressure against the guides. The ones that are only changeable with timing cover removeable are there only for when you start the car up with no oil pressure. Not all designs have externally changeable ones some have those internally too or make the internal ones do double duty both static and hydraulic pressure. Some companies use an actual steel flat spring like an old colt Single Action Revolver. I have not had the timing cover off of the 2AZFE or looked at the timing parts to know how they have done it. Point is at start up only spring pressure is holding guides against the chain and only after oil pressure comes up which should be up inside of 30 seconds before you get full tensioning of the chain. As the guides wear or the o-ring on the tensioner hardens the whole system can hit a wall were it can no longer do it's job and some maintenance is in order.

Usually if the chain is worn you will see fluctuating timing data in real time mode on your OBD2 reader if it has real time data.

 

I just went to Rockauto to look at the part and it looks like it only has one hydraulic tensioner and it is externally changeable with just 2 bolts needing to be removed. The one inside looks to be nylon cam with simple wound spring and not an item that would wear maybe break but not wear. It looks like you install it collaped then go in from valve cover and release the arm holding the piston in place. Check the guides though for wear if the piston is fully out a new tensioner will do nothing with out replacing the guides.

 

I replaced pretty much all timing components, including chain, tesioner, guides, and the same for the oil pump too (the nylon cam you mentioned is to tension the oil pump chain and was also replaced). The toyota service docs said to install it with the hook on the piston, then rotate the crank counter clockwise after installation to release it and tension properly. Those are the steps I followed, it can't even really be reached from the valve cover area (you can just barely see that the hook is on or off). It definitely did get tighter to a degree following the steps, but again the only slack I see in the chain is between the intake and exhaust sprockets. If the tension on the chain does increase with oil pressure, I can't imagine its going to be an issue, but I just wanted to be sure its nothing to worry about and that I installed it correctly.

 

Good to know. The last Toyota timing set and tensioner I replaced was on a 3RZFE? the Tacoma 2.7L I4. All it needed was the Tensioner but since it is such a pain to replace I did everything including sprockets. That was at something like 300K miles. It was the internal one that went bad. The cylinder head and oil pan had to come off to get the timing cover off so even though all the old parts were like new except the internal tensioner I did not want to do the job twice! I used all Aisin and Denso parts and I think one or two Toyota parts at the time!