Why rebuild? Because it's there!

[copacetickid]

Background: bought my '79 620 long bed from DatDoug a little over a year ago (still don't know if I got yanked or not :rolleyes:) and it was basically love at first sight. I originally bought it because I was looking for a small economic vehicle my partner and I could sleep in the back of (comfortably). After doing some work to make it road trip worthy -- or so I thought -- we drove south with everything we owned in the back under a bed platform. ...Basically it's not a good vehicle for trippin' in and by the time we reached southern Cali, it had eaten 4 quarts of oil, 1 in the last hundred or so miles. So that's the somewhat legitimate reason for doing a total teardown/rebuild, but really I'm doing it so I can learn about my truck. Engines are fascinating!

 

So yesterday we started, and I was gonna just rent a hydraulic hoist for $40, but my dad had this cool chain pulley lift. I wrapped a nylon belt around the center ceiling joist and when we put the chain pulley on, it wasn't going to give enough vertical clearance to get the engine out. I wanted to start anyway so we used another electric hoist he had.

 

 

I bought the load leveler at harbor freight. Thank god for that!

 

it was a bitch getting the rear of the transmission past the crossmember

 

 

at this angle on the load leveler, the hoist was pulling the engine towards the cab, and the truck was on stands. I had to muscle it forward and I dented bay in two places. Then the weight of the engine started back-driving the gears in the hoist and it would slowly sink (rated at 500 lbs!). One person had to keep jerking the engine up after it had fallen while the other turned the handle on the leveler and maneuvered the engine. Next time I'm renting the hoist!

 

 

with the trans still on the engine the hoist couldn't handle it, so we worked fast. Not so fast we couldn't snap a pic though :D. Finally, with the trans off the hoist could take it.

 

 

except one of the bolts wasn't long enough to use to mount it. That and it wouldn't fit without the clutch and flywheel removed. Off to home depot at 9:45pm! We used two breaker bars levering off each other to break the six bolts on the flywheel. What a bitch! (I'm sure you'll all tell me what I should have done, but where do you learn this stuff at??) When the last bolt came off, the wheel dropped about 2 feet to the concrete... is that bad? (too bad?)

 

 

finally mounted, time for bed

 

 

here's a shot of the EGR outlet on the exhaust manifold. The one that was in there before shot out on out road trip in portland, OR. It forced us to stay in a hotel for a night; even JB Weld Quik takes a long time to cure when it's 20 degrees out!

 

 

today I started disassembling the engine.

 

buncha good stuff

 

 

this is only half the zip loc baggies that are on the bench now

 

 

getting the crank pulley bolt off required locking the crank, but the flywheel was already off. will a piece of wood work?

 

 

nope.

 

 

metal is better.

 

 

with all the ancillaries removed. The last person who had this out did the world's worst paint job, with some shitty paint to boot. What do I get to take the paint off?

 

 

looks like I have a U95 block and a W58 head. Anything I need to know about these?

 

 

Ahhhh! Springs! Gears! Cams! Levers! Chains! I love motors:D

 

 

Almost didn't have a 10mm allen for the head bolts... nobody told me! Found one at last though

 

pistons look... well like pistons. This is the first time I've ever actually seen them in person, so you guys tell me, is a bit of carbon buildup ok?

 

 

heck of a lot of buildup on the chambers 2 and 3.

 

 

crank looks great, smelled a little cokey when I opened it up though...

 

 

if I had to guess, I'd say that the timing chain and tensioner are brand spankin new. I've read a bunch of places that you always get a new timing kit when you have the chance, but shit, do I need it? Doug, did you do a timing job? Bad pic, I'll have a better one up tomorrow.

 

 

I started getting tired when it came time to get the pistons out. The first one came out fine, but the second one got a little stuck, and I don't know how but it dropped out and hit the engine stand :cursing: It took a bit of the orange paint with it, but I didn't see any damage at first glance.

 

I was amazed at how easy it was to get all of the big end bolts and main bearing cap bolts off... how the hell did they stay on? Right now though, I'm stuck. I don't have an extractor like it says in the manual, and I can't get the middle bearing cap off. Any tricks? I'm afraid of cleaning all the nicely-coated-with-rust-preventing-oil parts because they'll... rust. Even in southern california, where it's so dry my washingtonian nose bleeds daily, any and every piece of exposed metal corrodes. What do you all do? Damn it's 2am.

[copacetickid]

stupid photobucket said it was making all the pictures 1024x768. it lied.

 

when I took off the oil/dizzy worm drive gear with a puller, I found these in a drawer. how many pullers do you need?? the upper left one is homemade by my grandfather.

 

[datzenmike]

I usually have trouble with the rear cap. Lightly tap forward and back while lifting up, get it to wiggle. You can thread a bolt into the top of it to hold onto. I admit it takes a bit of work but I've pulled 5 or 6 motors apart in the last couple of years and used no puller on it.

[denveratsun]

Have fun man! Looks like a nice truck.:)

[Phlebmaster]

Looks like fun! Did you get a chance to see Hainz's video yet? Look it up..:D

[tdaaj]

did those leaf springs help at all with the trip?

[DatDoug]

That is more than likely the original paint on the motor. I personally never dug into it. There was no reason to as far as I could see, hear, & smell it was tip-top. As for getting the paint off, I wouldnt worry. Just get it as clean as you can and make sure all the flakey stuff is off. I use a good degreaser and spray it on and let soak for a good 15 min. and then spray off.

I did put a new clutch in rite b4 I sold it but you still should replace it with a new one since you have it apart. You should also think about getting a weber carb 4 it too. While you have the motor out you can also give the engine bay a good scrubbin as well. Good luck:D

[datzenmike]

stupid photobucket said it was making all the pictures 1024x768. it lied.

 

when I took off the oil/dizzy worm drive gear with a puller, I found these in a drawer. how many pullers do you need?? the upper left one is homemade by my grandfather.

 

 

How odd. Every motor I have ever taken apart, I have never used a puller on the pulley or any of the crank sprockets. I just tap the back of the pulley with the 27mm socket I used to remove the retaining bolt, comes right off.

[rat tail dragger]

i use oven cleaner spray a shit load on the painted are and let it sit then spray off or use a aresol can called bumper stripper get from your automotive paint supplier works killer

[sanitys]

if your rebuilding it just get it dipped.

[copacetickid]

didn't work on it today, think I'm getting sick. yesterday though got the crank out and I cleaned up a lot of parts. I was hoping to get it all to a machinist before the weekend, but I didn't get the rear bearing cap off until 3pm on friday. I did the wiggle thing for a half hour before finally deciding to make a lever. should have done this to begin with!

 

I found a pipe with an elbow that slipped onto the end of my jack lever nicely. a cap in the elbow with a hole in it fit perfect too, just slipped the bolt in, screwed the cap on and screwed the bolt into the block. made a fulcrum out of some scrap 4x4. lifted out like butta!

 

 

finally everything is on the bench, completely disassembled

 

 

started cleaning parts and found that the oil pan gasket was made of cork? I'm starting to wonder if this thing has ever been opened up before...

 

 

after cleaning the bearings

 

 

all the bearings showed some wear. here are the front, middle and rears

 

 

I know I can't get that accurate, but I measured the crank with some calipers and every journal and pin were at the very top end of the tolerances and I couldn't find any out of roundness or cupping. The only imperfection I found was on one journal there are the tiniest scratches. I have no idea how they got there, but it must have been me... I didn't check for straightness but the even bearing wear tells me it's prolly pretty straight. It's like this thing is brand new! As long as I have it out though it's going off to the machinist with the block and head. Can they just polish the journals without taking off a significant amount of metal? As for the block, I'm not even going to try to measure it.

 

I haven't called any machinists yet, so what should I expect to be a reasonable price and turnaround for all the work? I'm kinda scared it's going to be pricey... :( I'm also starting to look at where I can get parts from. From hainz's video I checked out mr-auto-parts.com (nonexistent?), nissanparts.cc/nismoparts.com which I can't search for parts pre-1980, and importedcarparts.com. The last one is the only one I could find prices for things on:

 

Main Bearing Set std. Taiho $45.85

Rod Bearing Set std. 4-cyl. Taiho $27.20

Timing Gear Kit Japan $79.10

Oil Pump Japan $78.95

 

No piston rings or even pistons. The down side to this is you have to buy all the gaskets separately, (no water pump, dizzy, themo housings, etc.)

 

Cylinder Head Gasket Set Ishino $30.89

Oil Pan Gasket Ishino $5.24

Oil Pump Gasket Ishino $0.30

Valve Cover Gasket Ishino $3.71

Crankshaft Seal Front Ishino $16.33

Crankshaft Seal Rear THO $6.45

 

How do these prices compare to what you guys have found? The valves and rocker guide prices seem reasonable, but they are selling rockers for $43!!! The only other stuff I've found is on ebay: gasket sets for $50 and timing sets for $45, but no bearings that aren't oversize, no big end bearings and no oil pump. I read in a post that the usa nissan central parts warehouse is in compton, ca? That's 15 minutes from me, so if it's true and they have an office... anyone?

 

So right now I'm taking apart the head and got stopped on the springs. I don't have a spring compressor, and can't really come up with something quick that will do the job. I think I'll just rent one at autozone tomorrow. If the valves are too pitted, I won't have new ones to give to the machinist yet so I guess I'll have to do the seating myself... I'm nervous of abrasives. The other thing is that after I saw hainz's vid today I realized that I've been resting the head on the valves the whole time!! @%#$! I hope it didn't mess them up too bad, at least it was on a layer of cardboard and a rag.

 

Ted: thanks again for helping me out before I left, I can't thank you enough. they did the job great, although now for some reason the rear of the truck is listing to one side hard... don't know why, I hope it's nothing serious. did you ever make use of any of those parts I gave you?

[datzenmike]

If you are replacing the oil pump with a new one get the hi output one from a 240sx or a D-21 Hardbody with KA24E motor. This pump is also used in the D-21 with the Z24i motor. The internal rotors are 14% longer and identical in outward shape and fit for the L series motors. I had one from a used Z24i motor on my 300,000Km L20B motor and it raised the hot oil pressure from 17 to 29 pounds! with no other changes. Good insurance.

[ppeters914]

stupid photobucket said it was making all the pictures 1024x768. it lied.

 

800x600 would be fine and cause a little less scrolling. Just a thought....

 

Nice job. I'm hoping to avoid it, but won't know til I'm running again. :(

[Phlebmaster]

I see you have alot of extra parts there...what are ya going to do with them??

 

 

JK!! Looks like you are on the right track, post pics of the assembly. What brand of bearings are you using? :D

[copacetickid]

It's amazing how much you can learn in such a short time, reading my first post I sound like an idiot.

 

Right after my last post I got everything back from the machinist and had 5 days to reassemble the engine before flying back to Olympia, WA. I did end up getting it back together, but it was rushed (better than leaving it all apart in my parent's garage... I think). I was only able to take it out for a round-the-block before I had to leave. I had to be back in WA to move into a new apartment and look for a job. Since then I've been busy finding a job, then working my ass off at it. So here's how everything went:

 

I basically gave my firstborn to the machinist. The final tab was over $600 for this:

 

hot tanked block

bored cylinders

polished crank

4 "new" pistons

jet washed head

2 new intake valves

4 new valve guides

valve seating (I wanted to do this myself, but he did it anyway)

 

Don't know how badly I got cranked, and I don't want to know. It's done. Should have thrown in the timing cover for a jet wash though -- what a bitch to clean! I reassembled the head myself to save $30, and because I wanted to do as much as I could.

 

I did clean the engine bay while the block was away

 

 

This is what the block looked like after it came back from the machinist. First timer here, don't know if I should have complained about how rusty it was.

 

 

Since I was going to paint it, I spent a solid 3 hours with an assortment of drill mounted wirebrushes getting off as much as I could. My dad was shaking his head the entire time "You can never get it all off.... It'll rust under the paint no matter what". He's probably right, but I figure I bought myself at least 5 years.

 

I also unfortunately followed the advice of a few websites and washed the block with hot water and detergent (I used simple green, mistake?) and then dried it with compressed air. What I was left with was a layer of soap scum that no amount of brushing would remove. I'm baffled. Probably not wise to paint over it, but there's no turning back.

 

 

Masking everything was tedious, but not too bad. Use an exacto knife to cut off excess tape.

 

 

I used a can of duplicolor low-gloss high-heat paint from autozone. Didn't really know where to find something better. Low-gloss my ass.

 

 

While washing it, this also came out of the water jacket (not the quarter). Part of the casting process?

 

 

I decided to check the bearing clearance, not that I wasn't going to use the crank and bearings anyway, it's just to know. I put the bearings in the block, laid the crank in, put some plastigague on each journal, put the caps on and torqued them. Here's the caps:

 

 

And one of the journals:

 

 

They were all between .0015 and .002, so it was time to lube them up and put it in for good.

 

 

When the crank came back from the machinist it was covered in oil (as it should have been), so I wiped it off. However, even though I was using a "fiberless" towel, it left fibers ALL OVER the thing. Nothing I could find didn't leave fibers on it. The best was a synthetic microfiber cloth my mom had for cleaning the house. It still left fibers though, so I ended up just saying fuck it, and put it in. Hope I don't find out later that it's going to kill the bearings. Damn I'm paranoid.

 

The pistons I got from the machinist looked good, no dings on the critical surfaces.

 

 

You may have noticed at the top I listed them as "new", well here's why.

 

 

Hope that doesn't mean what I think it means. I'm trying not to think about it.

 

Before you all ask, YES I gapped the rings. Good thing too, a few were too tight (not by much, but what does 'much' mean anyways).

 

I borrowed a piston ring compressor from a friend of my dad's. They went in WAY easier than I was imagining. Just *tap* *tap* and they were in.

 

 

Here's the head when it came back from the shop:

 

 

The wood block in the background with the notch on the bottom was part of my valve spring compressor tool :) I must have used the lever arm from the floor jack for 10 different things. I don't have a picture of it, but we cut a piece of thick PVC to seat on the spring retaining ring and used the lever arm to force the springs down. After the 7th set of keepers I got good at putting them in :rolleyes:

 

 

I don't have any pictures of the reassembly cause I was getting down to the wire. The Haynes manual says in about 4 places "DO NOT REMOVE CAM TOWERS". Well, I didn't, but the machinists did, and when I mentioned it he got a little prickly. I guess they do know what they are doing.

 

Time to put the head on the block.

 

 

So putting the timing chain on an engine that's sitting on a stand couldn't be much easier, and I followed the advice of Hainz in his video and put the chain guides on so the chain would make a nice arc. I also see why it's impossible to get the tensioner back in it's home after it's popped out. The bad news here is that I forgot the factory manual is on olddatsuns.com and I didn't have time to write a post asking anyone, so I put the cam sprocket on the number 1 position. Here's where the mark lines up with the notch:

 

 

Also, that marker plate has a lot of play on the first cam tower, so I don't know how much information it gives anyway. I tried to get it on there as centered as possible.

 

Here's the timing cover gaskets stuck on there with permatex 2. I used the stuff on basically every gasket in the engine. (used the right stuff on the oil pickup to block, the distributor housing to timing cover, and the radiator hose connector to timing cover) I don't know if you can get away without using it in most places, but I didn't really know, so better safe than sorry. It will be a royal bitch to drop the oil pan or remove the timing cover if I have to though.

 

Also, what the hell is that oval hole in front of the timing chain on the head for?? All I can imagine is there's some tool you stick through there so that the chain doesn't lose tension when adjusting the cam sprocket.

 

[copacetickid]

Oops, post was too long, gotta break it into two.

 

So I got the old head bolts off with a regular allen wrench, but when I was putting the new ones on, I didn't have time to run out and get a 10mm hex socket. I just cut off the end of the allen wrench as I'm sure most of you have done before. This little piece of metal turned out not to be my friend.

 

 

On the last bolt of the second round of torquing, I removed the socket from the bolt and the little shit fell down into the timing cover. WOW. :mad: It was pretty late, but I hadn't had a beer for a couple hours, and I kept thinking "how the....". I remained calm however, and in one of those moments that makes you believe in karma, I miraculously fished it out with a magnet.

 

I highly suggest stuffing a rag down there as insurance. I'm lucky nothing else fell in.

 

 

So after a valve lash adjustment, which I found out is a fine art (and how the hell do you know what torque you are tightening the locking nuts to?), I bolted everything back up to the engine that I could.

 

 

Also, it turns out that the threads of the EGR outlet on the exhaust manifold are the same as an oil drain plug. This is a great spot for an 02 sensor for my next project, just have to do some drilling on the plug.

 

 

Since the block had been on the stand this whole time, I couldn't get the rear bearing seal in or the flywheel on. I couldn't find anything that was the same diameter as the seal, and so started tapping it in with a rubber mallet a little at a time on every side. I got anxious because it wasn't going in (you should oil it first) and I grazed it with the mallet, cracking the rubber. I debated for a long time about getting a new seal, but I didn't have time and the crack wasn't TOO big. I packet it with permatex 2 and finished tapping it into place. You can't really see the crack, but it's at about a 7 o'clock position.

 

 

It was at this point that I realized that I didn't mark the flywheel's position on the crank when we took it off. I don't know how critical this is, because I've heard of cranks and flywheels being balanced together, or separate. I couldn't detect a single marking on the crank and fly that would indicate it's original position. I mean nothing. I didn't have much of a choice, so I just eeny-meeny-miny-moed it. Also very important to have is a clutch alignment too. Perhaps the only perk to living in a suburban wasteland is that there are about 10 box autoparts stores within a 15 minute driving radius. 1 out of the 4 autozones had the right one.

 

 

I didn't replace the clutch because it had about 1.2 millimeters of material above the rivets. Also, I'm planning on ditching my 5 speed when I get back to WA with it, so I'll have another chance to replace it.

 

For reference (because of the rear seal crack), this is how clean the bell housing was:

 

 

So here she is, ready to go in.

 

 

This time I didn't mess around with no winches, I got a hydraulic hoist. And I realize why it was so hard to get out too: I didn't unbolt the steering crossmember! This time I did, and it went in without a hitch.

 

 

The saga wasn't quite over, it turns out I put the engine mounts on the wrong sides, so I had to hoist it back up a couple inches and swap them (the oil filter wouldn't fit) I had even gone in the house and scoured the forums for a pic of which side they went on. I finally found a pic in one of fineline's posts. I guess he has two right sided mounts.

 

Here it is, back where it belongs.

 

 

After all of this, I had a really hard time tuning my weber, and left before it ran right. I think it was because I timed the ignition at a point in the carb tuning process and assumed that the timing wouldn't have to change with the carb adjustments. My dad finally figured out that I had it set way too lean.

 

I was going to drive it home, but I read that article datsunmike linked to about breaking in an engine, so I left it with my dad to break in on surface streets. I figured the worst thing I could have done was take it on a 1100 mile road trip.

 

I'm flying home for christmas, and my girlfriend and I are going to drive it back up to WA. I'll finally have my truck back! But I have a big decision to make while I'm down there: do I change the cam sprocket to the number 2 position, or do I just leave it?

[Phlebmaster]

Nice work! I will be doing this to my L20b that I swaped in, maybe next summer. Thanks for the walk through! :D

[slodat]

Nice work man!!!

[motavated]

I heard on an l20b it has to be on #2? I heard this from Hainz... He also says it in the movie I think...

 

Really nice work man!

[Llittle_Llama]

wow, that is a NICE walkthrough, i want to drop my motor now, lol. but.... might be selling the ranger and need the datto as backup :D

[datzenmike]

L16 and 18 are set on the #1 position. All L20B and Z series engines were set on the #2 position at the factory for emission purposes I believe.

[copacetickid]

What's the performance impact of the number 1 position? Power doesn't matter as much as fuel efficiency to me. My dad who is driving it says it's running beautifully.... I guess I just don't know the effects of a more advanced or retarded cam timing.

[banzai510(hainz)]

set to #1 position.???????????

 

Dont worry about it!!!!!!!!!!!

 

good write up.

 

I dont put the water pump on untill last so it clears the core support when installing.

[]2eDeYe]

Well done, looks like a new truck under the hood now :D

[datzenmike]

What's the performance impact of the number 1 position? Power doesn't matter as much as fuel efficiency to me. My dad who is driving it says it's running beautifully.... I guess I just don't know the effects of a more advanced or retarded cam timing.

 

As long as the V in the sprocket is to the right of the etched mark in the cam thrust plate, it's fine.

 

A retarded cam favors low speed cylinder filling and power/torque. An advanced cam favors higher RPM cylinder filling and power/torque. This is a very general statement and there are other factors to consider, but very generally this is the case. Perhaps some weekend you could try advancing it and see if there is any gain/loss in mileage/performance or driveability.