My Rockers seem to be a little off, or I'm off my Rocker(s)

[Zed Head]

Third to last post here has pictures of my original 1976 rocker arms.  They have the trapezoid.

http://forums.hybridz.org/topic/118926-engine-woes-read-on-if-you-dare/?tab=comments#comment-1122036

Here's one.

Edited September 23, 2018 by Zed Head

[zKars]

After going through a couple hundred, there are only two types of markings. The ones with the Trapezoid always have a single letter on the opposite side, and a variety of numbers and dots next to the trapezoid.

The ones that start with S have NOTHING on the other side.

I can't see any structural or size differences between the two types other than the markings.

Given all the stock engines I've harvested them from, I guessing they are ALL Nissan rockers. Not exactly a statistically rigorous study, but a decent sample size. 

I do remember a couple of points from a variety of threads on hybridz about rockers. The first point was that Delta didn't always do it right so check every one for even parallel grinding. The second point was that there seems to be a bit of variety in overall rocker arm lengths. I don't remember if they measured the actual ball center to lash pad contact points for consistency but the overall castings can vary. Try to use a set of same-ish length ones if you can of course.

Edited September 24, 2018 by zKars

[wheee!]

I know the buyer appreciates all this pre-sale inspection and maintenance....
[emoji6]

[240260280]

An optimistic spin would be: the craters hold more oil ?

You helped me with a problem with Delta ground cam and rockers that ate each other on Dr 240z's 240z

[240dkw]

14 hours ago, wheee! said:

I know the buyer appreciates all this pre-sale inspection and maintenance....

So we now know where your getting your stroker from.

[wheee!]

So we now know where your getting your stroker from.

Whaaaa? Who told you that? [emoji51]

[wheee!]

So I asked a couple of my mechanics at work to have a look at the rocker pics and they are convinced that the cause of this pitting is due to the engine not being run often enough! The oil gets up to the valve train, sits and slowly drips back down to the engine. The rockers eventually start pitting around the oil spots (not on the part of the pads that are under contact with the valves), and the next time it is started, the corroded metal falls off into the engine and probably into the oil filter. Basically they are saying the engine needs to be run and used more often to avoid this happening. Neither of them saw this is having any real effect on the engine as long as the oil gets changed regularly. This is good to know!

[zKars]

That sounds like a possible contributing factor. The car gets used for big trips and very little for day to day use. It sits a lot.

I had another member discuss the possibility of acid buildup due to non-use of a PCV system but I've always had a working PCV system on the car, either with triples or with SU's and I change the oil very often, like every 2000km. But this damage appears corrosive in nature, not mechanical. 

I use Shell Rotella Diesel oil. Maybe I should have used synthetic all along.

[wheee!]

I think the lesson here is we all need to drive our cars more! Especially in the frozen wasteland of the north....!

I use AMSoil 5W30 full synthetic in the 370, but now I may be doing the same in the 280Z (or should I say 310Z)!

[240260280]

The eroded patches seem to be more on the passenger side of the pad where the pressure is greatest and the lift starts.

[zKars]

Delta Cam's is a wonderful business.

Ignoring the fact that postal service delivery took 20 days to get there and back, they turned around 132 rocker regrinds in 48 hours (once they got there...)

Every one looks like the 12 randomly selected rockers below. 

They look like they have some kind of coating on them, applied everywhere. Hardening process or the result of a polishing or tumbling step to make them look pretty? I suppose I could just ask...

 

 

 

[wheee!]

Oooooo... my precious...!
Dibs on 12....!