Cylinder head questions.

[flatcat19]

So I've tons of searching, here and on the rest of the internet, for answers to my questions. Nothing.

 

I got a closed chamber A87 awhile ago from someone for 30 bucks. It was basically the bare head, and a box of parts. No rocker arms. No rocker arm springs, No lash pads. Cam, towers, and cam gear were just rolling around in the box. I took a trip to a Pick N Pull awhile ago and snagged me a full set of lash pads, rocker arm springs, and rocker arms. Which brings me to today...Started tearing this thing apart today out of boredom. Came apart fairly easy. I put everything into labeled bags corresponding to which valve everything was removed from. And then tapped out all the holes too. Put a straight edge on top and bottom. Straight. When I get everything in order, I plan on taking it to a machine shop to make sure all is straight. It was dirty as all shit. (That's why no OIC's. Sorry.) Wondering if this dude ever changed his oil. Anyways, tearing it apart I found a couple of things off...Found one of the springs broken. And a couple of the valves were whitish?

 

So now come my questions.

 

What is my next step with everything?

 

I can get my hands on a full running W58 head from a friend; Can I just swap every piece straight across, and have it work for me?

I ask about this because of just replacing broken parts.

 

When putting everything back together, should I be putting in new valve guides? Seats? Where can I source these from?

 

Is there an alternative/upgrade to these parts from another Datsun to avoid spending big bucks for hi performance stuff?

Like I've read about Z car valves or Roadster springs.

 

I mentioned that a couple of valves were whitish in color. Are these in fact burnt?

 

I'm sure I'm forgetting something-I'll add it later when I remember.

Thanks for any help guys.

[Guest kamakazi620]

So I've tons of searching, here and on the rest of the internet, for answers to my questions. Nothing.

 

I got a closed chamber A87 awhile ago from someone for 30 bucks. It was basically the bare head, and a box of parts. No rocker arms. No rocker arm springs, No lash pads. Cam, towers, and cam gear were just rolling around in the box. I took a trip to a Pick N Pull awhile ago and snagged me a full set of lash pads, rocker arm springs, and rocker arms. Which brings me to today...Started tearing this thing apart today out of boredom. Came apart fairly easy. I put everything into labeled bags corresponding to which valve everything was removed from. And then tapped out all the holes too. Put a straight edge on top and bottom. Straight. When I get everything in order, I plan on taking it to a machine shop to make sure all is straight. It was dirty as all shit. (That's why no OIC's. Sorry.) Wondering if this dude ever changed his oil. Anyways, tearing it apart I found a couple of things off...Found one of the springs broken. And a couple of the valves were whitish?

 

So now come my questions.

 

What is my next step with everything?

 

I can get my hands on a full running W58 head from a friend; Can I just swap every piece straight across, and have it work for me?

I ask about this because of just replacing broken parts.

 

When putting everything back together, should I be putting in new valve guides? Seats? Where can I source these from?

 

Is there an alternative/upgrade to these parts from another Datsun to avoid spending big bucks for hi performance stuff?

Like I've read about Z car valves or Roadster springs.

 

I mentioned that a couple of valves were whitish in color. Are these in fact burnt?

 

I'm sure I'm forgetting something-I'll add it later when I remember. Www

Thanks for any help guys.

Whitish valves mean it was running lean ass for valves guides they didnt puts them in till unleaded gas late 70s at least in american cars I say take it to a good shop and get an estimate and if its too much deniro sell thats head to me!!

[DRIVEN]

they didnt puts them in till unleaded gas late 70s at least in american cars

I think Kami meant seats, not guides. (Judging by the time stamp on his reply--easy mistake :wacko: ) If the oil changes were neglected it's a safe bet the guides are shot. You probably aren't going to be replacing those at home. It needs to go to the machine shop for surfacing, guides and a valve grind. The white is from running lean but will appear worse due to oil consumption. A burnt valve will have a black trail/spot where exhaust gases have been leaking past the seat in the early stages. The later stages are pretty obvious.

If you want to swipe used parts from other heads this gives a run down on valve sizes...

http://www.datsuns.com/Tech/510/L4_cyl_heads.htm

As far as swapping all the parts; you can probably use all the pieces from the W58. You'll still need to have the machining done for it ti be right. One other thing. You mentioned that you grabbed rockers from the wrecking yard. Don't use them unless you get them resurfaced. Much like using mismatched used lifters and cams, you run a very high risk of wiping out the cam lobes. They need to be a matched set.

Sorry dude, looks like your cheap head just might cost you some money.

[datzenmike]

Test fit the valves to see if they are the correct diameter... they likely are. The guides may be all right. Set the valve in it's guide and wiggle the top end where the keys go. If it deflects by more than 0.2mm (0.008") they are worn and need replacing. That's easy enough to do. Inspect the valve face and seat. There should be no pitting and the surface should be straight and not concave. Excessive seat wear will allow the valve to sink into the head. In any case the valves will need to be lightly lapped to increase their contact surface and make a better seal.

 

Cam, when installed in the cam towers should spin freely before rockers are added. If it does not, the head could be warped, or the cam towers out of alignment. (never remove them. If resurfacing the head mark them so they go back in the same position and X fingers) Rockers can be surfaced by hand using 800-1200 wet sandpaper and a small sheet of glass in a sink. Draw the rocker over the wet paper in a sawing motion until a new even surface shine is achieved. I've swapped many rockers that were even and in good shape with no ill effects but if yours show any pitting or obvious low spots or grooves or anything you could see with the eye that could be called "wear' don't use them. A very shiny contact area is not the same thing as worn and this can be polished away.

 

Do NOT forget the metal washers below the valve springs. They protect the soft aluminum.

[flatcat19]

All good stuff guys.

I know about not using the rocker arms unless resurfaced. When I grabbed the set I have, I did it just to have them.

 

Anyone know a good cheap up grade on springs?

[nismo dr]

Anyone know a good cheap up grade on springs?

 

 

tsk tsk tsk

 

cheap, fast, reliable, pick two. Now who is always telling me that?

[datzenmike]

Frowned on but shimming them is cheap.

[flatcat19]

tsk tsk tsk

 

cheap, fast, reliable, pick two. Now who is always telling me that?

 

You started that shit. Not I.

Kids, school, unemployed, unemployed wife.

 

I pick fast and cheap.

Meaning I want to get this thing running fast. And I have no other option but to be cheap.

 

Ed, you know me. If I could, I would own stock in Kameari.

Gosh!

[flatcat19]

Oh...lash pads.

How do I know which lash pads I need?

Does that really only come into play when I start putting nicer stuff on?

[Sealik]

Oh...lash pads.

How do I know which lash pads I need?

Does that really only come into play when I start putting nicer stuff on?

 

 

You have to check the wipe pattern with the cam....has to be centered on the rocker.

You can use your stock pads to determine actual thickness of lash pads needed.

Just cut up a .010 feller gauge into small round pieces, place 1 under the lash pad then do a wipe pattern.(rotate cam)

Keep adding pieces of feeler gauge until the wipe pattern is perfectly centered.

Stock is around....130ish...?....so add that to what you stuck under the lash pad, gives you a heads up before you buy a whack of pads that you might not need.

 

Nissan.cc sells valve springs...about 10 bucks a set.

 

http://www.nissanparts.cc/

 

PN....M-99996-M1046 VALVE SPRING

 

Edit

 

If it's a reground cam...try starting out with .150+ lash pads

Valves can be of a different length in an engine... meat/stem above the keepers, which will reflect on lash pad size.

 

As shown here....both lash pads are .150

 

 

I cleaned up my rockers with some 1500-2000 grit

 

Edited April 17, 2011 by Sealik