Am I crazy for wanting to replace head gasket?

Post by **justinae** » Tue Mar 02, 2010 6:49 pm

I've got a 1980 King Cab with a blown head gasket. I've been quoted at $700. I thought I might try it myself. Here are the reasons I shouldn't:

I'm a carpenter, not a mechanic.I'll end up with the engine torn apart and it'll cost me twice as much at the mechanic.It'll take me thousands of hours.

Is there any reason I should attempt this? How difficult is it?

thanks,Justin

Post by **PEZi** » Tue Mar 02, 2010 7:59 pm

i'll see if i can get you a DIY on it.... for someone with some basic skills like you and carpentry... it should be easy with the instructions in front of you... but its not easy by any means

Post by **justinae** » Wed Mar 03, 2010 9:19 am

PEZi720 wrote:i'll see if i can get you a DIY on it

That would be cool. Thanks!

Post by **PEZi** » Wed Mar 03, 2010 5:55 pm

here ya go... there are two articles in here... one for removal and one for installation

zerothread/474226

Post by **justinae** » Wed Mar 03, 2010 9:20 pm

Thanks so much for the link. My engine is the L20, not the NAPZ. Is there a tutorial for this engine?

much appreciated,Justin

Post by **seang** » Thu Mar 04, 2010 6:09 am

Here is the Datsun factory service manuals (FSM's). zerothread/379438 It is the same as the sticky, I just posted it for ease of navigation. Step by step instructions should be in here.

You might need to buy some tools and rent ones you don't need to use more than once. I know Autozone and other places rent tools for free, you just pay a charge that you get 100% refunded when you return the undamaged tool. I don't know, though, it depends on what kind of tools you already got.

I would not want to pay 700 dollars just to find out that something else was wrong. Hopefully nothing is, but don't get discouraged just yet. I would rather you do perform the job youself.

If you lived closer I would probably help in person.

Another edit. The one thing I can see messing you up is rusted/oxidized fasteners that just shear off as soon as you torque them. WD40 is your friend. Proceed with caution, extracting broken bolts is something else entirely.

Modified by seang at 11:17 AM 3/4/2010
Modified by seang at 11:21 AM 3/4/2010

Post by **PEZi** » Thu Mar 04, 2010 8:53 am

justinae wrote:Thanks so much for the link. My engine is the L20, not the NAPZ. Is there a tutorial for this engine?

much appreciated,Justin

ah... i always forget that anyone still has the L20 in a 720... but what sean posted should help ya out

Post by **justinae** » Thu Mar 04, 2010 11:33 am

Thanks Sean,

I saw a PDF for an L20B engine but it said it was for the Datsun 200SX. Does that matter? I don't mind renting some tools. Yeah too bad you're not close by, that would be a great help. I'm still not sure I can do this, but I'm getting more confidence.

cheers,Justin

Post by **datdude** » Fri Mar 05, 2010 12:12 am

go for it!!! whats the worst thing that can go wrong? you pay someone a few bucks extra to finish the job?

there are not very many special tools you will need torque wrench long allen socket (head bolts)a timing chain tensioner tool i used to use a screwdriver for that i had one that fit just right. As a carpenter you can build that yourself out of wood all it has to do is keep the tensioner from expanding. if you let the chain tensioner fall out you double your work so pay attentionbent feeler gauges when you get done and adjust the valves other than that it is all wrenches sockets and common hand toolsif you need to bend a wrench to get a hard bolt just do it

be careful when you remove the head dont sit it flat on a bench you will bend a valve if the cam is still in !!! good luck and enjoy your project

Post by **justinae** » Fri Mar 05, 2010 6:29 am

thanks man. I had a guy offer my $1000 last night for it, which is what I paid, but I'm kind of interested in trying this out. I don't know brands when it comes to engine parts so here is what I found at Shucks:

http://www.oreillyauto.com/sit...10206

If I'm going to save $700 I don't mind splurging for a good gasket set. But what all do I need?

Also, while I have the head off, what are other jobs I should do?thanks,Justin

Post by **justinae** » Sat Mar 06, 2010 1:54 pm

I've been doing more research and feeling better. One thing I'm confused about. Do I have to take apart the whole valve/camshaft/lifter assembly? Or do I just lift off the head, still assembled, and have that resurfaced?

Once I start I'll document with pics.

thanksJustin

Post by **PEZi** » Sat Mar 06, 2010 8:44 pm

you definitely want it resurfaced... and might as well do a mild shave on it too for a little more compression... it'll run a little stronger if you do

Post by **justinae** » Mon Mar 08, 2010 7:09 pm

what's the difference between resurface and mild shave?

what are your thoughts about the head assembly? Does it stay assembled or do I have to disassemble it all?

Post by **Charlie69** » Wed Mar 10, 2010 9:08 am

Bonzai Hainz's Lmotor Video link

http://www.guba.com/?query=hai...build

Post by **PEZi** » Wed Mar 10, 2010 12:40 pm

justinae wrote:what's the difference between resurface and mild shave?

what are your thoughts about the head assembly? Does it stay assembled or do I have to disassemble it all?

it can stay assembled.... but it would not be a bad thing to disassemble it and replace everything

a shave will take some of the head surface off.... 'tightening up' the combustion chamber and thus giving you higher compression.... higher compression equals a little bit stronger motor

Post by **justinae** » Thu Mar 11, 2010 7:13 pm

Charlie thanks man that's cool. The best was when he said "this is easy, not like those L20s which are really hard."

PEZi I thought about doing that, I assumed it would be a royal pain. You're essentially talking about rebuilding the head right?

Post by **Charlie69** » Thu Mar 11, 2010 7:29 pm

You are Welcome. The L20 is confusing the first time but after that it is easy just take your time and use the wood tool to hold Chain tension on the Hydraulic Chain Tensioner. Bonzai Hainz is better known as "The L Motor God".

Post by **justinae** » Mon Mar 15, 2010 11:42 am

I can see why he was called the L motor God. That was a sweet video.

I think I'm ready to order parts. I checked out the Nissan parts link but it didn't have any actual parts to buy. I'm sure I'm missing something.

So what do you guys recommend:Fel-ProBeck/ArnleyROL

Should I get the set or just the head gasket? Napa has a set that has a ton of gaskets, called a Cylinder head gasket set:http://www.napaonline.com/Sear...99999

overkill?

thanks,Justin
Modified by justinae at 5:12 PM 3/15/2010

Post by **justinae** » Mon Mar 15, 2010 8:34 pm

Ok we started. Here are a bunch of pics to document the process as promised. You can see we have all the most important tools.

I hope you guys don't mind me picking your brains cause I don't think I'll be able to do it without you. So here's a few questions:

1. I was told that with a blown head gasket you would get milkshake like evidence. I saw a little bit that that, but it was a really small amount so just wanted to verify before taking more of the engine apart. I had thought it would be all over the place. The truck has been sitting for a few weeks now if that matters.

In this one look below and to the left of the chain in the picture for what looks like more milkshake evidence.

2. My manual is geared more toward the Z22 than the L20B, so is it possible to take the head off completely assembled, while maintaining the tension on the chain?

3. The steps in the book to get to TDC are all about turning the crank at the bottom. But I don't have access to it because I'm only doing the head gasket. Am I missing something?

Thanks a ton you guys,Justin

Post by **Charlie69** » Mon Mar 15, 2010 8:47 pm

Watch Hainz's video over and over. yes you can take the head off complete

Here is a link to Mike Klotz's site scroll down and you can download a scanned Factory Service Manual. He has a 1974 & a 1978 available. You will do fine. What does the oil on the dip stick look like?

http://www.olddatsuns.com/620tech.htm

Post by **justinae** » Tue Mar 16, 2010 8:01 am

I couldn't get a very good picture, but the dip stick came out clean. Well the oil needs to be changed, but no milkshake like stuff. Should I be considering that something else is wrong?

Post by **Charlie69** » Tue Mar 16, 2010 2:29 pm

Do you see any signs of water/antifreeze where the head & block meet?

Did you have water in any cylinder? Pull spark plugs, turn motor over & watch for water coming out of spark plug hole. Do a compression test. Drain the oil and check for water.

As little milky residue as you are seeing it could be condensation.

Why do you suspect blown head gasket?If you do pull the head do not pull the cam towers off of the head. If you do you will have to have the line bore checked by a machine shop when you put it back together

Post by **breadbox** » Wed Mar 17, 2010 5:46 am

take neg batt cable off.

Put motor to TDC.

Remove intake and exhaust.

Remove VC, make the wooden wedge of grace.

Take off cam bolt, keep chain tight and wedge the stick into the chain so it doesnt move and carefully unbolt and remove head.

Replace gaskets and install in reverse order and hopefully it is timed correctly.

My head got rebuilt cleaned leakdown pressure tested and decked for $250

New gasket and seals is like $40 or so from Bap Geon. So for $300 you got a new looking head, perfectly set to run at factory specs.

Post by **breadbox** » Wed Mar 17, 2010 5:48 am

yeah if its not milky try other stuff, however you could re-torque the head by loosening the bolts and re-torquing them to spec.

Although I can see some evidence, so you might as well rebuild the head, for a learning experience and to have a solid motor, That you know runs cuz you did it..
Modified by breadbox at 11:54 AM 3/17/2010

Post by **justinae** » Wed Mar 17, 2010 6:06 am

Charlie,the original symptoms were:

-Massive amounts of white smoke out tailpipe-Lost interior heat-Lost antifreeze-Engine overheating quickly

I called the mechanic who did my initial compression test when I bought the truck and he said that sometimes the antifreeze mixes with the oil (milkshake) and sometimes it gets into the exhaust and you wouldn't see as much milkshake. That could explain why there was so much white smoke.

Breadbox,

Thanks for the list of steps. When I take the cam bolt off, how do I keep tension on the chain and remove the sprocket at the same time?

Yesterday we removed the carburetor. Who was the genius that put the 4 bolts in places that are practically unreachable. I'm guessing a 90 degree wrench would help. Here are some pics:

Thanks a lot guys,Justin

Post by **justinae** » Wed Mar 17, 2010 1:40 pm

I've hit my first snag. In the process of removing the intake manifold I can't loosen the nut that fastens the EGR tube to the manifold. In case you're wondering, I did use a second wrench on the smaller nut to pull against the larger one. I didn't have any luck where it connects to the exhaust manifold either. I sprayed a bunch of WD-40 on them.

Any suggestions?

Modified by justinae at 4:55 PM 3/17/2010
Modified by justinae at 4:57 PM 3/17/2010

Post by **justinae** » Thu Mar 18, 2010 2:13 pm

Tried for 3 hours today. Tried liquid wrench, then later tried Freeze Off. We tried a 3 foot extension on the wrench, no luck. So we tried the lower nut where it connects to the exhaust. No luck there either.

So, is it possible to get an EGR tube anymore? I didn't have any luck online. I was also thinking I could cut the tube, then solder it back together, or splice it with a heat resistant connector.

Maybe I can find one in a junk yard, but I image that I'd have the same issues trying to remove it.

Post by **seang** » Fri Mar 19, 2010 4:05 pm

I think that tubing can be welded. If so, then cut it so you can continue with the disassembly. Then, after you get situated, try and remove it if you can and weld it, or have someone weld it, back together.

Or, maybe you can just have a length of metal tubing bent and use that if it will work with the stock fittings, I'm not sure about this one.

Post by **Charlie69** » Wed Mar 24, 2010 4:36 am

Take a torch & heat it up that should make it towhere you can loosen it. be very care ful that you do not cause a fire. Aim the flame down and if you get the fittings glowing red from heat let them cool down (til the red glow is gone) before wrenching on it but while it is still plenty hot.

Also if you do need one for replacement post an add on Ratsun's parts warted section with a picture of the tube as ther are different shapes of the EGR tubes.

Post by **justinae** » Wed Mar 24, 2010 1:44 pm

Thanks guys. I cut it today. I'll look into having it soldered if I can remove the ends. But now I can't get the intake manifold off!

I've removed the 4 bolts that attach it to the head. I've practically stripped this thing down and just can't see anything that would still be holding it on. I've used a wood block and hammer to tap (ok maybe hit) but nothing.

Is there a commonly known missing screw/bolt?

Here's a pic:

Am I crazy for wanting to replace head gasket?

Am I crazy for wanting to replace head gasket?

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