I know stuck nuts are a common issue on old cars but has anyone got any suggestions how to free up the locknuts on the rocker arms?

I thought it was about time to check the gaps (they are out but the engine seems to be running OK) and adjust. However I can't move the nuts at all so can't adjust the gaps. I don't want to use too much brute force for fear of doing more damage.

Is it easier to take out the whole assembly to get them loose first?

Thanks as always.

Hi Andrew, yep they can be VERY tight. I'm afraid that you have to make sure your spanner is a good fit and use an extension to give more leverage. Taking the lot off would be a faff. You could try some penetrating oil but be careful not to contaminate the engine system, bags of leverage should do it

Ian.

Hi AndrewRL. Were you thinking of taking the head off? Bit surprised that all the gaps need adjusting. Not trying to teach your grannie to suck eggs but are the gaps that much out? As the car is running ok I would say "if it ain't broken leave it alone". However I must admit I have taken cars to bits in the distant past just to find out how things work.

Andrew, taking the assembly of is relatively easy, but you have better leverage in situ. You may also end up unwinding the studs an possibly damaging the threads in the head.
The nuts and rocker screws get overtightened and seem to be like many bolts on modern cars in that they may have a slight "stretch" built in, so they are really torqued even with a relatively small amount of tension. A good fitting 11mm spanner and a tap on it with the heel of your hand or a soft hammer should shift them. Some one may have thread locked them.

Thanks all. More effort/brute force will be used at the weekend (will check the websites for replacement parts just in case ). I am assuming that these are "normal" and don't have some confusing reverse thread so I am trying the wrong way (so righty tighty, lefty loosey )

I don't think all need adjusting but, unless I am measuring it wrong, a couple are slightly out. I know the engine is not the smoothest around but I am wondering if getting the gaps right may also reduce some of the noises a bit.

I could just leave it but as I am still learning my way round all things mechanical I want to be able to do this. I also paid a huge amount (not) for the adjusting tool so need to use it!

Cheers!

What is the best tapper adjustment tool to buy ?

TBH I have no idea. I just saw one on the VdL (or may have been FD Ricambi) website and bought it along with some other parts I needed as the Haynes and other manuals talk about using a special tool. Haven't tried it yet (and may not do so if I can't release the nuts!). It isn't very high tech and it looks like simple pliers would do the trick as well.

Hi Andrew. Please don't use pliers on any nut. I have always used an open ended spanner on the lower nut and a ring spanner on the top nut and with your third hand adjust the adjuster lol. Being less frivolous, it's not a difficult job. Once you have set the gap and as you tighten the top locknut there is a tendency for the gap to close so you may have to play about a bit. When I worked on the old Mini there was a tolerance on the gap. I think it was minus 2% to plus 8% before any appreciable difference to the efficiency of the engine.I do not think there are many left hand threads on most cars. If a bolt /nut is properly torqued it will not come undone. It's the way to learn, doing it is far better than just reading about it (wait for the comments)!!!! Meant to say, new gasket for the rocker cover after any bits the old gasket have been removed.

My procedure for setting tappet clearances is as follows. Good quality 1/4" drive socket to loosen the four nuts. Guess I should mention that 5 is the key number as you set no 1 tappet when no 4 valve is open. Adjust the clearance then I found that holding the tappet screw with a spanner was difficult so I took a small cheap socket and shaped it in the vice to fit the screw top. It was then easy to hold the screw in position and tighten the lock nut with a ring spanner. I would never use an open ender.