Tapping, rattly top end idle

[MrT]

Hello folks. Sounds like my valve clearances are needing some TLC. Engine has done over 120k so not unreasonable. Any advice on checking/changing them please? I didn't find a how to do if you know of a decent thread explaining the procedure please shout up.

Also, any other work I should think about whilst the can cover is off? Timing chain dare I say it? I've got a new tensioner waiting for service time next week.

Thanks in advance.

[Carolyn]

I've been intending to do a 'how to', but every time I get stuck in to lifting cams I get too involved to stop and take pics.

I'd start by changing the tensioner.  It can make a massive difference to top end noise at low rpm.

If you're still not happy, you will have to measure all your valve clearances and note them down.  This is fiddly.  Helps to have a couple of sets of feeler gauges so you can measure each one twice without having to fiddle with changing feeler blades.

Put the engine to TDC on #1.  You'll need to clean off the marks on the bit that sticks out from the timing cover.  I find it helps to mark the notch on the pulley with an engineer's white pen (which will also be handy for marking the chain and sprockets).

Take the cam cover off.  Mark the chain and a tooth on each cam with the engineer's pen. Mark the horizontal timing marks on the sprockets.

Remove the chain tensioner.  There's a cast-in hexagon halfway along each cam, they are there so you can hold the cam steady with a big spanner.

Using the Hexagon, hold the exhaust cam steady while you undo the bolt that holds the sprocket to the cam.  Take the sprocket off.  You cam let the chain drop in its guides.  You can't loose chain position on the bottom sprocket...There's a casting in there to prevent that.

Unbolt all the cam bearings.  Keep them in order (they are numbered just in case).  The big double bearing at the front is #1 and they count back from there. (e2, e3 etc).

Once the cams are loose, lift the inlet cam, slipping the chain off as you go.  Now lift the exhaust cam. 

One-by-one lift the buckets and measure with a mic.   Keep the buckets in order.  Now figure out how much you need to adjust to hit target clearance,  (.20 inlet and .30 exhaust.)  You'll be able to move some buckets to new holes and you'll need some more (usually 3 or 4) to end up with a set that gets you very close.

Ask Spit nicley to send buckets you need.  Return any you won't be using to Spit.  He keeps the bucket bank.  It helps if you clean the buckets and write their actual value on them.

Once you've got the right buckets in the right holes, put the cams back in.  Make sure you put the chain over the VVTI hub as it goes in.  Make sure the cams are sitting with the horizontal timing marks level with the top of the head.

Bolt the cams down.  Go slowly and in a bit of a 'sequence' as you'll be compressing springs. 

Use the spanner on the hexagon to position the cams precisely.  They will have moved a bit as you've bolted them down.

Position inlet cam first, both with the chain marks and the horizontal timing marks.

Put the exhaust sprocket into the chain, aligning the chain mark to the sprocket tooth, and offer it up to the front of the exhaust cam, again positioning the cam with the big spanner.  Bolt the sprocket back on to the cam.

Re-install the chain tensioner.

Using the bolt in the middle of the bottom pulley, rotate the engine clockwise until the tensioner releases. 

You can then rotate the engine 720 degrees and check the horizontal timing marks against TDC on the pulley.

The chain marks won't now be in the same position (that's ok)

If all is still timed up, give it all a good squirt of engine oil and put the cam cover back on.

Don't even ask about the chain!!!

[m1tch]

My engine is on 176k miles, fitted a new (used but lower mileage) tensioner, engine seems fine and the cam chain was still tight when I checked it last, pretty sure the valve clearances are out after all this time but will be swapping in the project engine at some point soon.

Also worth noting that there is also a VVTI oil filter in the head, although its usually ok, think its a bit fiddly to get to with all the ancillaries on etc.

[J03]

The aux belt tensioner can rattle quite a bit as well & give the impression of engine related noise.

[MrT]

Thanks folks. So check vvti filter and valve clearance but change tensioner first?

PS only checking clearances. Will decide what to do if I find a large clearance. Can somebody confirm clearances for intake and exhaust please, in international units(metric), or have I misunderstood, thanks Carolynne. And is there a range or tolerance?

[m1tch]

Thanks folks. So check vvti filter and valve clearance but change tensioner first?

PS only checking clearances. Will decide what to do if I find a large clearance. Can somebody confirm clearances for intake and exhaust please, in international units(metric), or have I misunderstood, thanks Carolynne. And is there a range or tolerance?

Here you go:
link to copyrighted information removed, sorry folks

[Carolyn]

Inlet:  min .15 mm    max .25 mm

Exhaust min .25 mm max .35 mm

[MrT]

Brilliant thank you