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Valves

2K views 15 replies 4 participants last post by  Juney70 
#1 ·
I was trying to adjust my valves but the nuts are jammed on tight and I mean jammed. Does anyone have any idea how I can get these off? Can I heat them? Any feedback is most appreciated
 
#2 ·
Juney70,
They should be pretty tight. Heating might help but over heat, and nuts/rocker could become weaker.

I would suggest a long (~25mm/10") six point box end wrench. A six point socket on a 3/8 drive ratchet or 1/2" drive ratchet could also work. I suggest six point because if the nuts are that tight, you don't want the socket or wrench to slip off or the nut points to get rounded.

If the nuts still don't come off, take off the rocker arm assembly and put it in a vice, and use a bit more force. I would not recommend using excessive force while the rockers are attached to the head, as the head is magnesium/aluminum and you could damage the studs that attach the rocker shaft to the head.
 
#8 ·
Juney70,
They should be pretty tight. Heating might help but over heat, and nuts/rocker could become weaker.

I would suggest a long (~25mm/10") six point box end wrench. A six point socket on a 3/8 drive ratchet or 1/2" drive ratchet could also work. I suggest six point because if the nuts are that tight, you don't want the socket or wrench to slip off or the nut points to get rounded.

If the nuts still don't come off, take off the rocker arm assembly and put it in a vice, and use a bit more force. I would not recommend using excessive force while the rockers are attached to the head, as the head is magnesium/aluminum and you could damage the studs that attach the rocker shaft to the head.
Thank you so much for your reply, I had to take both the rocker arms off as the whole 8 of the bolts were seized so I ordered new screws and nuts , are they easy enough to put back on?
 
#4 ·
Two nuts hold it on. When you put it back on, make sure you get the four pushrods seated in the engine and seated in the rockers. You will want to leave the rocker adjusters backed out a little so when you tighten the rocker shaft nuts, the rockers will not push the valves in too far.

Once the shaft nuts are tight you can start adjusting the valves with a screwdriver and wrench. Use a feeler gauge and you should set the clearance to not less than .004 (.1mm) probably .005 (.125mm). Don't exceed .006 (1.5mm) or the rockers will make a lot of noise when the engine is hot.

Engine must be completely cold when you adjust the valves. If you are curious why, the pushrods are made of aluminum tubes and will grow in length when they get hot, making the adjusted valve clearance approach .002" which provides some clearance and quiet operation. If you set the valves with the engine hot, the valve clearance will stay close to the adjusted level and make a lot of noise when the engine is hot and the oil is thin. Additionally when the engine cools off and gets cold, the clearance will be closer to .010" after the pushrods shrink and make a real racket when cold.

Good luck with your valve adjusting adventure.
 
#6 ·
Two nuts hold it on. When you put it back on, make sure you get the four pushrods seated in the engine and seated in the rockers. You will want to leave the rocker adjusters backed out a little so when you tighten the rocker shaft nuts, the rockers will not push the valves in too far.

Once the shaft nuts are tight you can start adjusting the valves with a screwdriver and wrench. Use a feeler gauge and you should set the clearance to not less than .004 (.1mm) probably .005 (.125mm). Don't exceed .006 (1.5mm) or the rockers will make a lot of noise when the engine is hot.

Engine must be completely cold when you adjust the valves. If you are curious why, the pushrods are made of aluminum tubes and will grow in length when they get hot, making the adjusted valve clearance approach .002" which provides some clearance and quiet operation. If you set the valves with the engine hot, the valve clearance will stay close to the adjusted level and make a lot of noise when the engine is hot and the oil is thin. Additionally when the engine cools off and gets cold, the clearance will be closer to .010" after the pushrods shrink and make a real racket when cold.

Good luck with your valve adjusting adventure.
Thanks very much for your reply
 
#5 ·
To be clear, you are taking off the two nuts that hold on the entire rocker shaft, which holds the four rockers. You should not have to take the rockers themselves off the rocker shaft. Thinking about it a bit more, I suspect the valves might have been adjusted when the engine was hot making the adjustment nuts really tight when the rockers got cold.
 
#7 ·
Tight nuts? Can you possibly reach with an impact wrench and right sized socket? Alternatively, a suitable socket and half inch strongarm. Hit the end of the strongarm with a rubber hammer. Or, extend the strongarm with a length of steel tubing. Just be careful not to round the nuts. I suggest doing it with the engine at operating temperature. Good luck.
 
#15 ·
Once you take the rocker shaft assembly off, the individual rockers should move very smoothly. They may even move based on their own weight. If this is not the case and you have to apply pressure to get them to move something is wrong. There may be some rust or crusty burned oil holding them tight. You might soak the rocker assembly in gasoline to see if it gets looser. If you decide to disassemble the shaft assembly take a before picture and layout the parts in order on a cloth so you can put them back together in order. Check the surfaces where the rockers rotate and see if that area is galled or rusted. In this case you could try to use some 400 to 600 grit sandpaper to smooth the surface as a short term fix. If not, you may want to invest in a new rocker assembly or pick one up at a wrecking yard.
Now if you need to put it back together, make sure you put the washers back on the right sides of the rockers, based on your photos.
Any photos you can provide will aid in diagnosing the tight rockers.
 
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