Rocker arm issue! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

240lab · 05-22-2010, 11:44 PM

This is a all stock s13 sr head. i just rebuilt the bottom end of the motor and didnt mess with anything on the head. in the proccess of rebuilding it i did bleed/repack the lifters full of oil since they had been turn up side down. so i know they are nice and solid. so the car ran fine for a day the next time i started it up it started missing and had low vaccum. took off the valve cover and the 2nd cylinder exhaust rocker arm had come off. i took a look and the guide shim had been sheered off on the side facing the front of the car. double checked lifters all where hard to where i was not able to push any down by hand. raplaced the guide shim and the car was running great all day until later on it happend again while driveing took off the vlave cover and the same thing happend 2nd rocker arm on the exhaust side came off and the guide shim was broken again in the same spot.

are there any ideas? has anyone else had this problem. i mean i havent changed anything on the head its all stock and built to spec. so whats the deal the only thing that i can think of is a weak valve spring causeing one side of the rocker arm to move more then the other cause it to get tweaked a little?

please any help would be appriciated.

240lab · 05-23-2010, 10:14 AM

even if you know of any shops that would be willing to give me some advice, i will be calling mazworxs monday and enjuku to see if they cant help me out.

thanks

240lab · 05-24-2010, 11:12 AM

update, none of the shops that i called never had this issue. the most helpful was 240sx motoring i think i talked to jeff and he said that he has seen a rocker arm slightly bent then eventully fail. and he also mentioned to make sure the guide is on the right side. my guide shims on the intake side are facing the front of the car with no issues and the guides on the exhuast side are facing the firewall and only cylinder2 is breaking the guide shim. i thought they where both grooved and that you can put it on either side? but i will double check. any how ordered a rocker arm just incase and a shim. i will let you know how it goes.

ezzie240 · 05-24-2010, 04:36 PM

The rocker arms are machined on the sides of the finger that goes with the guide shim. If memory serves, the guide shim should be to the front on the ex. side and the rear on the intake. Have you checked that the shim height matches the guide with a dial indicator? There is a tool for this, or you can make one using an old lash adjuster (lifter). Good luck!

240lab · 05-26-2010, 08:05 AM

Quote:

Originally Posted by ezzie240

The rocker arms are machined on the sides of the finger that goes with the guide shim. If memory serves, the guide shim should be to the front on the ex. side and the rear on the intake. Have you checked that the shim height matches the guide with a dial indicator? There is a tool for this, or you can make one using an old lash adjuster (lifter). Good luck!

thanks for the help ezzie.
i was out in the garage yesterday and found the same thing.i first looked in the FSM but it never mentions anything about what side they go on, so when i went to go remove the other rocker arms i realized that the guides where stuck to the rocker arms. then i got them off and looked at it and realized how i made a stupid mistake. but i figured this could be good information to others if they have the same issue. so here are some pics of what i did wrong.

None machined side

Machined side

None machined notice how the guide shim wont go all way down thus causing mine to break.

Machined side, slides down nice and easy!

i hope this helps out a few people if they had any questions.

P.s yes shims where mic' and are same.

thanks all for looking

sr24det · 06-19-2010, 11:17 AM

I had this issue when I put my motor back together. i didnt get my number 2 intake arm sat in just right and so it jumped off and i replaced it. and it jumped off again and i did it a third time. but what i finally found out was happening is the first time it jumped off it made a spring get loose and it then bent the valve stem very slightly almost unnoticeable.
so when i kept putting it back on the cam would press the arm down and one of the valves would get barely stuck down and would create a little gap between the cam and rocker and it would eventually jump off.
so check that, may be just coinsodince but who knows may help

Foolish · 01-12-2013, 12:56 PM

This may be a little off topic on the discussion, but while I was working on the rockers, the guide shim came off the valve spring, can't seem to locate it anywhere inside, is there a secret hiding spot I should look first or should I just tear the head apart looking for the rocker guide shim?

Mikester · 01-12-2013, 07:27 PM

Pretty sure this thread died a couple yrs back- but it's nice to see someone at least did a search =)

*fliprayzin240sx* · 01-12-2013, 07:46 PM

Quote:

Originally Posted by Foolish

This may be a little off topic on the discussion, but while I was working on the rockers, the guide shim came off the valve spring, can't seem to locate it anywhere inside, is there a secret hiding spot I should look first or should I just tear the head apart looking for the rocker guide shim?

Well, take the cams off and start inspecting inside the head. It might have fallen down to the oil pan already at the front if you cant find it in the head. How many are you missing?

Mikester · 01-12-2013, 09:03 PM

Quote:

Originally Posted by fliprayzin240sx

Well, take the cams off and start inspecting inside the head. It might have fallen down to the oil pan already at the front if you cant find it in the head. How many are you missing?

He's all set brotha... http://zilvia.net/f/s-chassis/497880...ml#post5086828

05-22-2010, 11:44 PM	#1
240lab Leaky Injector Join Date: Jan 2009 Location: ILL Age: 32 Posts: 71 Trader Rating: (1) Feedback Score: 1 reviews	Rocker arm issue! This is a all stock s13 sr head. i just rebuilt the bottom end of the motor and didnt mess with anything on the head. in the proccess of rebuilding it i did bleed/repack the lifters full of oil since they had been turn up side down. so i know they are nice and solid. so the car ran fine for a day the next time i started it up it started missing and had low vaccum. took off the valve cover and the 2nd cylinder exhaust rocker arm had come off. i took a look and the guide shim had been sheered off on the side facing the front of the car. double checked lifters all where hard to where i was not able to push any down by hand. raplaced the guide shim and the car was running great all day until later on it happend again while driveing took off the vlave cover and the same thing happend 2nd rocker arm on the exhaust side came off and the guide shim was broken again in the same spot. are there any ideas? has anyone else had this problem. i mean i havent changed anything on the head its all stock and built to spec. so whats the deal the only thing that i can think of is a weak valve spring causeing one side of the rocker arm to move more then the other cause it to get tweaked a little? please any help would be appriciated.

01-12-2013, 07:27 PM	#8
Mikester Nissanaholic! Join Date: Jun 2007 Location: Kathleen, GA Age: 50 Posts: 1,941 Trader Rating: (0) Feedback Score: 0 reviews	Pretty sure this thread died a couple yrs back- but it's nice to see someone at least did a search =) __________________

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05-23-2010, 10:14 AM	#2
240lab Leaky Injector Join Date: Jan 2009 Location: ILL Age: 32 Posts: 71 Trader Rating: (1) Feedback Score: 1 reviews	even if you know of any shops that would be willing to give me some advice, i will be calling mazworxs monday and enjuku to see if they cant help me out. thanks

05-24-2010, 11:12 AM	#3
240lab Leaky Injector Join Date: Jan 2009 Location: ILL Age: 32 Posts: 71 Trader Rating: (1) Feedback Score: 1 reviews	update, none of the shops that i called never had this issue. the most helpful was 240sx motoring i think i talked to jeff and he said that he has seen a rocker arm slightly bent then eventully fail. and he also mentioned to make sure the guide is on the right side. my guide shims on the intake side are facing the front of the car with no issues and the guides on the exhuast side are facing the firewall and only cylinder2 is breaking the guide shim. i thought they where both grooved and that you can put it on either side? but i will double check. any how ordered a rocker arm just incase and a shim. i will let you know how it goes.

05-24-2010, 04:36 PM	#4
ezzie240 Join Date: May 2009 Location: Ontario, Canada Posts: 1 Trader Rating: (0) Feedback Score: 0 reviews	The rocker arms are machined on the sides of the finger that goes with the guide shim. If memory serves, the guide shim should be to the front on the ex. side and the rear on the intake. Have you checked that the shim height matches the guide with a dial indicator? There is a tool for this, or you can make one using an old lash adjuster (lifter). Good luck!

06-19-2010, 11:17 AM	#6
sr24det Join Date: Apr 2007 Location: mississippi Age: 35 Posts: 37 Trader Rating: (2) Feedback Score: 2 reviews	I had this issue when I put my motor back together. i didnt get my number 2 intake arm sat in just right and so it jumped off and i replaced it. and it jumped off again and i did it a third time. but what i finally found out was happening is the first time it jumped off it made a spring get loose and it then bent the valve stem very slightly almost unnoticeable. so when i kept putting it back on the cam would press the arm down and one of the valves would get barely stuck down and would create a little gap between the cam and rocker and it would eventually jump off. so check that, may be just coinsodince but who knows may help

01-12-2013, 12:56 PM	#7
Foolish Join Date: Oct 2012 Location: Killeen, TX Posts: 14 Trader Rating: (0) Feedback Score: 0 reviews	This may be a little off topic on the discussion, but while I was working on the rockers, the guide shim came off the valve spring, can't seem to locate it anywhere inside, is there a secret hiding spot I should look first or should I just tear the head apart looking for the rocker guide shim?