Rocker Arm nut losening

[cookiedoh]

My father just installed a new head gasket on his 1996 v6 4.3 mercruiser. He didn't do the rocker arm adjustment, he just torqued them all down. He tried to start it and it wouldn't run (suprise) I adjusted the rocker arms 1 turn past zero lash following the seloc manual procedure. Ran fine for about 2 mins, developed a bad ticking noise in the valve cover. Pulled the cover and the rocker arm nut is loose again. I'm thinking that when he tried to start it with the valves tightened down it bent a valve? Any other ideas?

 

[buggiedad_67]

Re: Rocker Arm nut losening

try a nut they are lock nuts and can wear, also it is possible that when he torqued it down he may have pulled the stud and broke it loose and every time you adjust it the stud pulls up just a little, but try the nut first.

 

[Don S]

Re: Rocker Arm nut losening

Get rid of the Seloc manual, and go to the OEM manual (link below) then turn to page 3A-27 and torque the rockers to 20 ft lbs.
Your Dad was right on how the valves were done.

http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/18/18covr2.pdf

 

[Coors]

Re: Rocker Arm nut losening

Seloc strikes again.

 

[cookiedoh]

Re: Rocker Arm nut losening

Why does the seloc and a bunch of posts here talk about 3/4 to 1 turn past zero lash?

EDIT: nevermind, found this post by Don S
that may work great on some older V6's but if his has stepped rocker studs that the rocker pivot torques down against, then it doesn't get adjusted that way.

 

[Don S]

Re: Rocker Arm nut losening

Why does the seloc and a bunch of posts here talk about 3/4 to 1 turn past zero lash?

Because they are for a different engine than you have.

 

[Maclin]

Re: Rocker Arm nut losening

I read that as his dad just torqued them down all at the same time without regard to the cylinder being at TDC on comp stroke...?

 

[Coors]

Re: Rocker Arm nut losening

They just torque down.

 

[Coors]

Re: Rocker Arm nut losening

Until they hit the step.

 

[Don S]

Re: Rocker Arm nut losening

I read that as his dad just torqued them down all at the same time without regard to the cylinder being at TDC on comp stroke...?

Read my first reply. Download the link and read.

Just like the big blocks.

 

[Coors]

Re: Rocker Arm nut losening

I just went back and read that pdf; pretty comprehensive. Not a Seloc.

 

[Maclin]

Re: Rocker Arm nut losening

Thanks, I did think better after I posted and loaded that one up to see. It took a while to load in, but I understand the geometry better now, makes more sense...please ignore the red-faced poster behind the curtain (ME:redface.

 

[Don S]

Re: Rocker Arm nut losening

I've had to use the :redface: icon many times.

.
.

Sure am glad to be a part of the human race that is allowed to make mistakes.


Oops, sorry. Forgot some other posts. Marine mechanics are supposed to be perfect :redface:

 

[Coors]

Re: Rocker Arm nut losening

But still a bbc with stepped. I never understood why GM did that except to sell more parts, or take adjustments out of the hands of shade tree.(gotta take this to the dealer, old adjustment method didn't work)

 

[cookiedoh]

Re: Rocker Arm nut losening

You guys are awesome. My marine mechanic came out and adjusted the rocker arm nuts once. They losened, I adjusted them, then you guys told me the CORRECT way. The marine mechanic didn't even know.. scary.

The distributor wasn't all the way down, the timing got disturbed when we tried to start it. Now I have a timing question. I believe it is a Thunderbolt IV, which doesn't need to be ground out right? We had it running it was set closer to TDC then the 8* the manual says. When I rotate the distributor to get it to 8* you can hear the engine slow down a little bit. Should I do it by ear or by the timing marks?

Also, I'm getting a white goo up in the valve cover and in the hose coming off the cover. The new head gasket had a pre-applied white rtv sealant. I think it might be that, but maybe not?

 

[Don S]

Re: Rocker Arm nut losening

The new head gasket had a pre-applied white rtv sealant.

There are so many places to get both good and bad head gaskets that it's totally impossible to tell you what that is. I have never seen anything like that on a head gasket.

Should I do it by ear or by the timing marks?

Go by the marks, from the sounds of things, I don't think your ear is quite trained to set timing just yet. When you set timing so it runs the fastest, it's WAAAAAAAY off.

 

[Bondo Again]

Re: Rocker Arm nut losening

I'm getting a white goo up in the valve cover and in the hose coming off the cover.

Ayuh,.....

That's either condensate, or just plain ole Water......
Is the Oil Level rising,..??