Need Help With Rocker Arm / Valve Lash

[m240]

I am working on a 71 engine. The engine doesn't run well at all. I thought it might be the timing so I adjusted it to no avail. I pulled the valve cover thinking it might be a stretched timing chain and I found a rocker arm twisted completely off the valve spring. I found the collet next to it but no lash pad. Should I A) buy a lash pad and try to put it back togather, take the head off my 73 parts car and swap it in, C) get proffessional help? Could there be damage to the valve that I can't see? I am waiting for the valve adjusting tool from motorsport ( I gues I should have adusted the valves before trying to run the engine) so I am trying to weigh my options. Any help is truly appreciated.

Mark:stupid:

[2ManyZs]

Has to be some reason for the lash pad being off, I think you might want to pull the head and check out the valves. Lot of different possibilities, but usually a lash pad won't come of for no reason. Was the spring holding the lash pad broken? Does the valve spring look OK compared to the rest of them? Since you have another head you might want to think about swapping them and take a good look at this one to see if the valve is seized in the guide or if there is something else wrong.

If the spring retainer that holds the lash pad in place was broken, you should be able to just replace the spring and lash pad and see how it goes from there.

[m240]

If I swap the heads do I need to use a new head gasket or can I use the old one?

[hmsports]

I would recommend replacing the head gasket. I think they compress when torqued and you may not get a good seal if you don't put a new one in. I don't remember what my rebuild book says about this.

I've had rockers pop off from missing a shift and over revving the engine. Usually only if the valve springs were old and softer.

[m240]

So even if I swap heads to get it running it might be a good idea to take the head with bad rocker in for new springs and maybe seats since they are probably original. Any idea how much this would run?

[hmsports]

Take a look at the head you may swap it out with. Look at the seats of the valves that are open -- and you can turn the cam with a large adjustable wrench (just make sure to support the ends of the head on 2x4 so you don't hurt the valves). If they are looking mushroomed or rounded then it could only help by having new seats and a good quality valve job performed. You can also see if there are deposits on the backsides of the valves (indicative of oil leaks and other internal problems).

You can change springs yourself -- once the head is off the car. New springs from Nissan are less than $100 I think.

It's so hard to guess at what a freshened head would cost. You can get a rebuilt head from MSA for $450. I would think it'd be hard to beat that at a local machine shop.

[Ed]

Don't forget you have a lash pad roaming around the engine somewhere (hopefully in the bottom of the oil pan). You don't want that getting stuck in your timing chain.

[m240]

I've been thinking about that. I found part of it and i hope the rest is in the oil pan. I'm going to try to stick a magnet by the timing chain to see if anything is in there.

Thanks