Broken Rocker arm adjusting nut-500efi
 

I broke a adjusting nut on my roller rocker arm on my 2002 500 EFI labor day. Luckly I caught it before it did any other damage to the engine. As I was checking the others, I found another one broke. They both broke right below the adjusting nut head. I think I should replace all 16 of them now. Anyone have any thoughts about this problem. I have about 200 hours on the motors.

I have considered changing valve springs out also. Does anyone have any Part numbers for springs, retainer, and what manufacturer to use. Crane etc...
thanks

Re: Broken Rocker arm adjusting nut-500efi
 

Don't forget to do the lifters also....They are weak at 200hrs.
I've had an adjusting nut from Crane break like that also...I hear its common along with rocker studs.

Re: Broken Rocker arm adjusting nut-500efi
 

I believe the part #s are

Springs comp 929-16
Retainers comp 741-16
Keepers and locks comp 612
Seals comp 505-16

Maybe someone could verify if i am correct.....

Re: Broken Rocker arm adjusting nut-500efi
 

I do appreciate the help!

Re: Broken Rocker arm adjusting nut-500efi
 

I would use the US seal, light blue ones.


I have never heard of a nut breaking on a 500efi can you take some picks?????

Re: Broken Rocker arm adjusting nut-500efi
 

Strip My digital camera is history. I will try to get you some pics. They cracked all the way around the top of the adjusting nut, right below the hex head. It was weird how they broke.

Re: Broken Rocker arm adjusting nut-500efi
 

That does sound weird

Re: Broken Rocker arm adjusting nut-500efi
 

I'm a shade tree mechanic. Does Mercury use Crane Rollers or Comp Rollers. I hav been on both websites looking for all the proper part numbers. I guess I will call them. I think I will replace springs, retainers, rockers, and nuts on both engines this winter. I would like to get all the parts before I tear into them. Whos the best place to buy performance parts? I know mercury wants a arm and a leg!

I remenber when you went through you engines a winter or two ago Strip. I appreciate your help.

Re: Broken Rocker arm adjusting nut-500efi
 

Cool ...I am doing it again this winter :eek: The rockers are crane. They have redisinged them from whats on your motor now, I think the nuts are imported . some of the new ones I had I had to retap them :mad: the rockers look good though.Teague had a good price also ,Scoggins and Dicky in Texas was good.I bet your rockers are ok though

lifters are crane 16535-16,dogbone style 456.00..you might ck with RM builder on some of his ,but you might have to change the push rod length?

valve spring sets up at 1.880 at 150lbs

you going to take the heads off?



929

Re: Broken Rocker arm adjusting nut-500efi
 

I'm going to do mine also, should i do head gaskets?