Re-Torque Heads before valve adjustment

[Red_Hen]

Hi Gang,

My valves are clacking away - loudly.

I do have a nice snap on torque wrench - my question: when I re-torque the heads (the right head was replaced @ 500 miles ago to replace stripped out head thread).

Is the proper re-torquing procedure to loosen and re-tighten or not loosen and check for proper torque, following the sequence pattern in the Clymers manual and just check for the "click"?

Thanks much.

[Bob_Roller]

I think just a re torque would be sufficient .

I don't know the value you are tightening to, but the value has been revised downward from I believe the original value was 29 ft/lbs, to 25 ft/lbs .

[Barry]

I believe the usual procedure is to back off and re-torque.

If it was me though I'd do as Bob sugests and just re-torque but I wouldn't go above 25 ft/lbs and in practice I'd probably chicken out at 23 ft/lbs.

If 23 does the job why risk higher.

[wilcom]

I agree with Bob & Barry. Hear it click  and stop. Our cases are a weak point and I don't want to lay a wrench  on them any more than necessary.

I don't re-torque at all. Never had one back off and fall out or a blown head gasket,...... but that's just "old shadetree me"

[Bob_Roller]

If you've had the head off and replaced the head gasket, it will probably be on the low side the next time you check it .

But after the gasket is compressed, the torque shouldn't change much at all .

As with the valve clearance adjustment, this is done on a 'cold' engine .

[Red_Hen]

Thanks for your suggestions!

[Justin B.]

I actually torque mine to around 20 lb/ft.   Barry is correct on the procedure, just back off a bit then set to the proper torque.  In the future, now that you will have the new head gasket re-torqued you don't really need to do any more in the future...

[tvrla]

Ken - I don't think I'd loosen them, though that's the recommended procedure. If they're at 25 already I'd just leave em.

Also, what's the range on your wrench? Be careful if it's a 100lb or larger! It's best having your setting in the middle of the range - in this case a torque wrench with a max reading of 50lb.

[Red_Hen]

My torque wrench is a snap on - I just dial in the value and that's it - it's pretty simple to use and seems to be accurate.  

What is the RX on minimizing the travel on our rocker arms - if I'm saying this right.  I've got my Clymer at my side - so will review.

I'm capable to do this - just want to review so it goes smooth and like Perzig says, I'll do it when I'm in my "zone"

[nhmaf]

Ken - just be careful of your torque wrench is a high torque (100 or more lb-ft) unit as they aften aren't that accurate at their low end settings.   Repeatable - generally yes, but accuracy is different.

I have a lower range beam unit that I use - but a quality clicker can be OK - I just don't trust them that much.  And yes - if you've recently replaced the head gasket it will likely need to be retorqued, but after this time, should be pretty stable and not necessary to repeat except for the rare check every 10K-20K miles or so.

Is your question about end-play of the rocker arms?
If so, there are a couple methods to tackle that.   But before we dive into that, did you have rocker shims installed in the heads when you had them worked on?   If you're still running "old school" - the method I've settled on involves a large pair of channel lock pliers.

[Red_Hen]

Hi Mike - no shims on rocker arms

[tvrla]

Ken - if there's play in the rocker arm, loosen the lower head stud, pull them together with your fingers and tighten. It's nothing complicated, the shaft just needs zero play but not binding. Guys also use large ChannelLocks and C Clamps, but not much force is required.

As for the torque wrench situation - the deal is that they're most accurate mid range. It doesn't matter how expensive your torque wrench is, the rule of thumb still applies. When we're talking about a few pounds making a difference, that could be the tolerance of your wrench in that area. If your wrench goes to 150 lb, 25 lb is at the extreme low end and quite a ways from the median. Hopefully it's erred on the low end rather than giving you higher torque than asked for.

[nhmaf]

I think that the clearance is "nil" or "oil film" clearance for the rocker arm to pivot block distance - if you look carefully while you slowly squeeze (I loosen both upper and lower studs so as to try to get both to move inward equal amount) you should be able to see a thin oil film barrier/meniscus come and go at the interface gap between the rocker arm and the block piece.  If your eyesight cannot determine that, you can use a feeler gauge - if a .002" won't quite fit but a .001" will, I'd say that is good.   You REALLY don't want them to bind as that will cause problems.

As wirespokes said - it doesn't take a lot of force.  I use the Channellocks or a large C clamp so I can eyeball the oil film and/or check with my feeler guages and tweak the pressure accordingly before I re-torque the nuts holding the rocker blocks and the head together.

[tvrla]

I've heard it's best to remove the push rod, or back off the adjustment to the extreme and check the rocker movement through its full path as it could bind at the end of its travel.

[nhmaf]

+1 - yes I back off the adjustment quite a bit to check for binding prior to resetting the valve lash again - it can all be a bit "finicky" sometimes, but I think it can pay off when done right.   Once I do this once, I generally don't redothe rocker block adjustment thing unless I have to.