Head Job

[imtb]

I am wanting to put a different head on my L20B. I a have a u67 open chamber and Upgrading to A87 Closed chamber with a bigger cam and valve job.

 

Do I need to do anything special with the new head. I want to do it with the engine still in the car.

 

1. Put engine on TDC. Compression stroke

2. Drain fullid. Anit freeze, oil?

3. Remove intake and exhuast maifold

4. Pull valve cover

5. Put block of wood to hold up timing chain

6. Loosen cam gear.

7. Loosen headbolts.

8. Remove Head

9. Install new head gasket and put new head on

 

If you have any suggestions please let me know. I am trying to prepare myself for the surgery.

[ggzilla]

The most important part -- the part that causes the most problems -- is in the details of your Step "install new gasket":

 

In general, to avoid a "blown" head gasket:

* Don't use Easy-Fit/Printo-Seal gaskets (my opinion)

* Clean *all* grease and gasket residue from block deck and head surface

* Use ether to clean the surface. It should be absolutely dry with no oil on it

* Torque the head bolts in the factory-recommended three stages

* Use a torque wrench to torque to specifications

 

For more details see my article (which is for Datsun A-engine, but most of it applies equally well to Datsun L-engine): Changing Head Gasket

[mike]

...A piece of green garden hose about 2 feet long folded in half with the loop end shoved down towards the tensioner works better than the chunk of wood, and its easier to make. Also chase the holes in the head with a thread chaser, especially the one between 2 and 3 cylinders on the intake/exhaust side. Make sure that the head bolt threads are clean and free of the residual buildup crap on the threads. If everything is in good shape you can just blow out the holes for the headbolts with compressed air to make sure that they are clean, if you dont have compressed air (Like last time I did this) I sprayed PB blaster in the threads and turned the headbolt in and out (without the head installed) soaked up the liquid that came out around the bolt with a rag. I kept doing this until the thread depth was sufficient depth to reinstall the head. A side benefit to doing it this way is that the threads are clean when re torquing. It is important to make sure that there is as little liquid/oil/dirt in the holes to ensure as this stuff doesnt compress and also adds unnecessary friction which will cause bad torque readings and possible premature failure of the head gasket.

 

Also on disassembly (as per the HAINZ vid) loosen your cam gear and all that stuff before you set it on TDC. If you do happen to lose TDC while assembling, mark the cam gear and chain in 2 spots with a screwdriver or something that wont rub off and also mark which hole (1, 2, or 3) you are putting the cam pin in (Do this before taking it apart!!!). Line everything back up on reassembly and youre golden.

 

When youre ready to start it pour some oil on the cam and lifters prior to turning it over if everything is dry or hasnt been run in a while.

 

When you get it running post a smoky burnout vid. Good Luck

[imtb]

I was wondering if head height will be an issue.

 

Old head milled(shaved)

 

New head just decked to clean up.

 

Will this effect chain length.

 

Gardon hose sounds like a pretty good idea(do you place between the tensioner and the chain.

 

I was also thinking of using some bailing wire to hold the chain onto the cam gear along with the garden house.

 

Thanks for all the tips so far. I just need to build up the courage to getrdone.

[datzenmike]

#3. Remove intake and exhaust manifold : Well I leave them on... take the head off with manifolds attached.(carb off, or on if you don't turn upside down) Easier to take apart on a work bench. Way easier. Easier to put together and put back on the engine. Way, way easier.

 

 

 

#6. Loosen cam gear. Should be before: #1. Put engine on TDC. Compression stroke: It's almost impossible to lock the sprocket and break the bolt loose without jerking the chain up and loosing the timing mark. Loosen, then TDC, then remove sprocket later.

 

 

 

#7. Loosen headbolts.: Loosen in the opposite sequence to tightening... from the ends toward the middle.

 

 

 

#2. Drain fluid. Anti-freeze oil?: Don't need to drain oil but you could change it AND the filter, why not?

 

 

 

#9. Install new head gasket and put new head on: Be damn sure the head has the number one cylinder cam lobes set at the TDC position, with exhaust at 2 o'clock and intake at ten o'clock. Any random position could bend a valve against a piston top on 1 or 4 when torquing the head down.

Edited January 11, 2009 by datzenmike

[imtb]

Still pondering the project.

 

Do the temp gauage sensor just unscrew out of the head?

[datzenmike]

It unscrews out of the thermostat housing which is bolted to the head. :D

[ggzilla]

There is no need to remove the temp sensor to change a head gasket. If it's working I suggest don't touch it cause it might break coming out.

[imtb]

Another question.

 

How can I make sure I am on the compression stroke at TDC. I know the Exhuast vavles 10 and intake valves 2.

 

thanks

mike

[banzai510(hainz)]

watch this about 100times

 

http://www.guba.com/general/search?query=hainz&set=5&x=28&y=10

[DaTsUn72WaG]

Do not let the tensioner fall out lol. datsun should have put a retaining screw in it so it cant pop all the way out. also dont let dumbass friends make sure the timing chain is chocked. check those valve stem seals and make sure valve clearance is set. those clicky noises are annoying. we dont want a deisel! XD