Rocker arm guide came of L18

[racerx]

Engine was making weird noise and hardly any power and sounded like it was missing,  so I took off valve cover and noticed that one (intake) of the Rocker Arm guide came off. So I put it back and now there's too much play with the valve adjust.  So here are the questions?

 

 

 

1). Is this a head job that needs to be done?

 

2). If valve is bent, where is the best place to get valves and what else should be replaced?

 

3). Has this happened to you guys before and what is the likely cause?

 

Thank you,

 

RacerX

[Draker]

If the valve is bent, which I doubt.. it would be stuck open. When the rocker arm falls off the valve stays closed.

 

I've heard if the valves are not adjusted correctly, they can pop off. Is the valve adjustment too loose now? Does the head have brass valve seats?

[wayno]

Did this vehicle sit for a long period of time?

I had a rocker arm keep popping off on #4 cylinder, it happened a few times, in my opinion it was because the vehicle sat so long that the gas got stale, once I put new gas in the tank it quit doing it, it happened when I was turning it over to start it.

You may have had the lash pad fall out and that is why it is so loose, look around for the lash pad in the area it fell out.

[banzai510(hainz)]

just put rockerarm back on if the lash pad didnt fall off then adjustd it a bit tighter.  I do mine .006in .008 exh

 

 

 

so as I loose a clynder I ck the plug wire by getting shocked.and remove it from plug and see if the car runs the same or worse to get the cylinder thats bad. 

then I pop the valve cover. This has happen about 3 times to me. 

 

 

But you can take it to a garage and Im sure theyll say you need a rebuilt head 1200$

[shacks510]

I had a rocker pop off once. I had just adjusted the valves. Valvetrain was still super noisy but I drove it anyway. I was driving and felt a "pop" and lost power but knew exactly what it was. I must have forgotten to tighten the nut. Has never happened again.

[racerx]

Car does not sit for long periods.  It's my DD.  Can't adjust, the space between rocker, cam lobe and valve is too wide.  Tried to go either way with adjustment nut and could not adjust.  The spring is much lower than the other valve springs. Yes, it has hardened valve seats. Definitely I will look for the lash pad.

[Doctor510]

Probably broke the inner spring!

[banzai510(hainz)]

most times the lash pad is near the spring if it didnt work its way to the back or the front and drop in the oil pan.

 

most times the valve lash tightens over time and valve seat wears to the point one can not adjust anymore and new seats are needed or swap out another head. Datzenmike has a halfass fix for this by thinning down the hex nut to get a few more threads in to lower the Ball to lower the rocker to get the feeler gauge in there.

[wayno]

If that spring is lower than the others, the seat came out or the valve got bent, either way your going to have to remove the head.

[shacks510]

I think you can still get valves at Nissan for pretty cheap, if need be.

[racerx]

looking at the specs for valve adjustment on intake and olddatsun says .08 in but read somewhere it's .008 in. 

[DanielC]

.08 is definitely a misprint.

From Nissan service manual. Cold:  intake, .2 MM, exhaust, .25 MM.  Hot Intake, .25 MM Exhaust .3 MM.

.2 MM =.0079 inch

.25 MM =.0098 inch

.3 MM = .0118 inch

[Roadster-ka]

Wayno is correct.

If valve retainer is lower than other, head needs to be removed and inspected. Valve bent or seat has fallen out.

[racerx]

thanks to both..yep double check and olddatsuns at.08 is a misprint, yes agree that head needs to come off.