ZCar Forum banner
Status
Not open for further replies.
1 - 8 of 8 Posts

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #1 ·
Yes this is the same head that has the good port work on both intake and exhaust. The ports are also matched to the gasket. And yes, the head has hardened seats, and good guides. Yes the head has small hairline cracks in 2 of the waterjacket holes and one between the valves on the #1 cylinder. The head was pressure tested and there was no leak in that chamber. You might lose very little torque on the low-low end because of the exhaust, but that is mostly dependent on what type of cam you will be running. No this head has no towers, but you can remove the towers off of any of the 70-83 Z heads and they should all be interchangable. The towers that were on the N-42 were actually directly transplanted from a P-90 head. Do not worry about losing any low-end torque, you will not be racing at 2K RPM. This head will give you considerably more power, I guarantee it. It also comes with the Stainless Steel exhaust valves so you will not need to do any valve job work on the exhaust. I am not sure if you will even need to do any valve job work on the intake seats when you put in your intake valves. I was quoted today $125 to weld all the cracks and resurface the head another .003".
 

·
Registered
Joined
·
355 Posts
RE: Dustin, I answer to money!

Ok thanks for all the answers that clears up a lot. What would u charge for the head, having the cracks fixed and sell the HKS 2 MM gasket too me?? Would would u seel all that for??

Dustin
 

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #3 ·
<b>RE: Dustin, I answer to money!</b>

The head and SS exhaust valves are for $175. SS valves normally run about $16 per valve. If you want my machinist to repair it, the charge will be what he charges me. I got a quote from a local machinist, but my machinist in Houston gives me great deals and has experience with Z heads. He builds the shortblocks for Hennesey Vipor. As far as the HKS, I paid $155 and I will sell it for $90. It was only used for 4-5 months and can be reused up to 5 times. The gasket is in perfect condition and the best part is you will never blow it out.
 

·
Registered
Joined
·
355 Posts
RE: Dustin, I answer to money!

Ok one more thing... If you had your machinest fix the crack and put on the intake valves and seats, so all i would have to do is add the cam(and componets) and the towers it would be ready to rock what would u charge me??

Dustin
 

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #5 ·
<b>RE: Dustin, I answer to money!</b>

Just a thought, but aren't cam towers inline bored at the factory to match the head? I just don't want to see anyone sinking all sorts of money into a head and after they get it and put cam tower from a different head on and they end messing it up. I have never checked this out, but it is what I have been told(i am no expert). Well at least make sure you have a matching set of cam towers and that you keep them in the exact same order. To check it out you could install the cam towers with a lubricated cam without any rockers...if the tolerances are OK, the cam should spin freely by hand. That make any sense?
 

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #6 ·
<b>RE: Dustin, I answer to money!</b>

I really don't want to get involved in any aspect of the head assembly. Once the cracks are fixed, the head is ready to be assembled and used. If you need help finding a shop to set up the head I can put you in touch with someone.
 

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #7 ·
<b>Thank you concerned citizen.</b>

Like I said before the cam towers that were on the head were transplanted from a P-90. Yes, you need to be sure that you keep the towers in the same order when switching from one head to another. Even when you remove the towers from one head and place them back onto the same head, you will need to align the towers with cam in place as you tighten the bolts. I do not think they would line bore the towers while it was bolted to the head, that is not a very stable setup, I could be wrong. Let me ask a few shops and get their opinion. I will post my findings tomorrow. Actually, I might be able to get the towers that were originally on the head. I will keep you posted.
 

·
Registered
Joined
·
107,695 Posts
Discussion Starter · #8 ·
<b>Found a great article on the subject.</b>

Found this article on the subject. Just passing it along. It contains the part on the cam towers.


L6 Engine Cam Removal & Installation
>I am about to take the head on my car (74' 260) to a local machine shop to have it resurfaced. First I have to take the cam off. I understand this isn't difficult, but has to be done exactly right or the engine, once it's put back together, will go bye-bye. Any hints or tips? >Mike Palma

Mike,
If you are intending to re-use the old cam and rockers I would suggest the following;

The main concern when removing a Z cam before head work is to take the time to mark all of your rockers so that they can be re-installed matched up with the cam lobes that they have previously established a wear-in pattern with. I use a # stamping kit to number them 1 through 12 starting with the #1 cylinder at the front of the engine. Do this BEFORE you remove the retention springs to make the job go smoothly.

(Rocker Removal Tool)
Afterwards I use a tool made out of a high-tensile steel phillips screw driver that has had its phillips tip cut off and ground down to a tight fitting taper so it will fit into the hole drilled into the pivot end of the rocker. By inserting the tool deep enough into the hole and then levering toward the cam you can cause the ball and socket end of the rocker to lift up and to the side of the ball, thus enabling you to easily remove all of the rockers without a valve spring compressor. This tool also is excellent for checking rocker wear on a used engine before doing a valve adjustment in the field. Try to keep each rocker's lash pad matched up to it's original rocker tip, but don't # stamp the lash pad surface. This last precaution is not too critical to reassembly, but it never hurts to follow it.

The next precaution regards the removal of the sharp-edged forged steel cam through the soft aluminum cam towers. Slide the cam toward the front of the engine very slowly so as not to have the steel cut a nasty gouge in the aluminum bearing surfaces. Be sure to oil the bearing surfaces well before sliding the cam out.

Lastly, the removal of the cam towers from the main head block is somewhat controversial in some Datsun engine rebuild shops. Several rebuild manuals recommend against the practice because the cam towers were originally factory line-bored to exact tolerances. If this inline center cannot be re-established at reassembly time the cam will bind causing the rapid destruction of the cam tower's bearing surface.

On the other hand, many excellent Nissan engine re-builders that I deal with, have no qualms with removing the towers, because there is a technique to re-aligning the bore centers that works well for them. But they are experienced. A less competent beginner might be wise to not remove them if the resurfacing shop does not require it. Either that or let them take the responsibility.

Valve removal is usually accomplished by using a valve spring compressor of which there are 2 prominent types, the overhead and the "C" clamp type. The overhead type must be used BEFORE you remove the cam from the towers. Both types can usually be rented at your local tool rental store.

Reassembly of the whole head is a reversal of what I have just described with all the precautions still applying. Often the head shop will do the reassembly for a small fee. At least if something really comes apart at start-up time you can blame the shop instead of yourself and maybe get your money back!

There is one important check to make at this point. After a Z head has been shaved (surfaced) it will sit closer to the crankshaft of the engine causing the cam center line to be close enough to the crankshaft center line as to cause a worn cam chain to have too much slack. If this slack is too great it could cause havoc in a fast revving engine, not to mention throwing off the timing of the cam and valves. The common solution is too reassemble the cam towers with the proper thickness of shims installed at the base that are specifically made for the Datsun L-series engine. It is the inclusion of these shims that often can make it difficult for an beginner to align the towers properly so be careful.

You might want to consider several other great improvements to your head and performance potential when going to the time and expense to do the necessary head and valve job. While you have the head off, doing some clean-up of the casting obstructions in your intake and exhaust ports and around the backside of your valve mating surfaces is an excellent way to improve your heads air flow and engine performance. Just don't get carried away with a die grinder or you will do more harm than good. Especially in your intake port. Don't do more than lightly clean up the casting bumps and match up the inline surfaces of the port and the matching manifolds and gasket. For good gas mileage you need the rough factory casting inside the intake port. The exhaust port can be ground and polished to a greater extent without penalty, but making it larger than the intake is not much help.

Recently, I acquired several new Nissan rebuild gasket kits for Datsun 4 & 6 cylinder L-series engines as well as about 15 Nissan intake/exhaust manifold gaskets. All are OEM new Nissan factory gaskets from a dealership. The kits are in original Nissan boxes. If any of you are going to be installing headers soon or doing an engine rebuild you might want to check out what I have. Some of the kits have not arrived yet, but if you let me know what engine kit you need I will have the inventory checked and reply to you in a couple of days.

Go to this URL to see the entire list of gaskets in stock http://www.jps.net/zparts/tables/gaskets8298.htm

Eric Neyerlin - Z PARTS
 
1 - 8 of 8 Posts
Status
Not open for further replies.
Top