Does cam removal change valve clearances?

Hi all,

I checked my valves this weekend and accidentally turned the engine while a shim was removed (was trying to swap two shims).

I put a little gouge on the inner diameter of the valve lifter/bucket.

I’m thinking I’ll pull the camshafts so I can inspect the camshafts, clean everything, and do my shim adjustments easily. I’ll also replace the bucket I put a gouge in.

My main concern with removing the cams is my valve clearances. I don’t want to mess up my valve clearances which are currently all within spec.

If I remove and reinstall the cams, will it change the clearances? Does it take time for the engine to settle back in? I imagine there’s a chance for some oil or dirt to get between some surfaces and change my readings at least temporarily.

Any tips would be much appreciated. The actual removal I can do no problem since I have the FSM and found some nice videos too.

 

No. The valve assemblies and their shims are part of the head.

 

Nope, it won't change anything. The parts that set the clearances are are within the head itself. Just make sure its clean and take your time.


That said - why are you removing the head? Sounds like you need to pull the cams.

 

Whoops sorry I just woke up. Yes I meant cam removal.
Thanks so much for the help.

I edited to correct my mistakes

 

Does it change the answer if the question is not about the whole head removal, rather the cam shafts?

 

Better get your hands on a factory service manual, don't just go yanking the cams out without reading it first. It'll save you a lot of headaches...

 

The only part that the camshafts touch are the ends of the valve stems.

The valve shims are between the ends of the valve stems and the valve springs. Removing the cams do not affect the shims at all.

 

i can see where they're coming from though. the shims are set up based on a seated cam, but once you unseat and reseat the cam you've potentially upset the previous conditions.

i would be of the mind that while you're in there, it would take very little effort to slip a feeler gauge in before and after your pull the cam (if you have to pull it) just to sleep easy that it's the same. to be thorough, after you place the cam back in, torque the cover down to spec, then undo it so you know the cam has been pressed tightly into place before you slide the feeler gauge in to spot check.

 

^^^^This guy.

In the real world you'll often see some 'shift' of the measurements. Like a thou. Some cars have a shim design where the only way to change them is to unbolt the cams and pull the buckets. When you put everything back together and remeasure, it's all different even though it shouldn't be. Bottom line: If you unbolt the cams and put them back in, don't be dismayed at a little measurement shift.

 

This then begs the next question... if the measurements shift, will they stay at the shifted value, or will they settle into a new value after a few thousand miles?

 

Hence the specification window. Shoot for the adjustment spec, end up in the window. All good.

 

Yeah I suppose it won’t be anything catastrophic. I’m trying to shim most of the valves to a smaller range than the manual specifies so the truck will run well and have longevity. I guess worst case if I find things did shift I may want to go in and check again after some time, instead of letting it go a really long time like I did until now.

I’ve got it

There’s also this video which clearly seems to be based off the FSM instructions. https://youtu.be/sVWn4ENiyUc

 

i think this is where torqueing the cover down after replacing the cam and then pulling it again to check the clearances is necessary, you'll re-seat it.