Montana Datsun Revival

[sick620]

12 minutes ago, datzenmike said:

If an '81 and up that had a Z series engine in it the Z24i and 5 speed will fit. Transmission will be a little short and I don't know about the transmission mount location.

 

Did the 720 have a carburetor? The intake and carb, the distributor and the drive spindle will have to go into the Z24i to convert it to Z24.

It’s a 1980 720 with l20b 5speed… 

 

and a 1987 hardbody with z24i and rare but not preferable 4SPEED… 

 

driveline should work but is just a little short for this transmission length correct? Could front shaft be taken from hardbody perhaps?

 

and yes it’s a carbed l20b In the 1980 720.. I have an extra z20 spindle and distributor and intake with a Weber to convert it to carburetor. 

 

 

Edited April 21, 2022 by sick620

[sick620]

Head torqued, timing set on, front cover on. Just have the oil pan/pickup, flywheel/clutch, rear freeze plug, and all the bolt ons... Just about ready to go back in the truck. cant forget to adjust valves and put oil in it... 

 

Ive never timed an engine from scratch but it was soo easy... bottom at top dead center, head with cam dowel at 12oclock... cam gear at 1. bright link lined up with the one on outer edge of gear.  other link lined up with mark on crank gear. very easy I am 99% it is correct.. 

 

I only lapped the valves for a minute a piece or so and didn't really focus on making them perfect, used a drill. Didn't want to wear the seats too much.. Never did a leak test with water or anything but most of the pitting was gone and they looked pretty uniform with a nice little flat surface corresponding with the seat... 

 

I was worried when I looked at my extra l20b and saw it had a oiler behind timing cover, and this block didn't have it.. thought maybe I needed to install one, but realized zseries engines don't have them or a place for them... Was afraid I was going to have to take it back apart, thank god for ratsun and all the info on here. 

 

between ratsun, hainz videos on youtube, and how to rebuild your nissan datsun book this has been fairly easy.. hardest part was cleaning gross parts. 

 

Edited April 22, 2022 by sick620

[sick620]

[sick620]

almost 2 days straight of working on it but she’s in. New starter, 50 amp alternator, matchbox dizzy, and radiator. waiting on cap, rotor, plugs, and wires… needed a bigger belt so I’ll have to get that tomorrow… valve cover gasket is cheap and does not fit good so we need a different one… still need to add oil, antifreeze,fuel lines then it’s pretty much ready to fire up! 

[sick620]

Running great! 
 

new Chinese radiator puked all of its fluid out the fan side though! factory dud 😞… 

 

might be a bit before we get it going now couple more weeks atleast 

Edited April 28, 2022 by sick620

[slowlearner]

i love my chinabay radiator. Sorry your's is misbehaving.

[sick620]

15 hours ago, slowlearner said:

i love my chinabay radiator. Sorry your's is misbehaving.

Dang wish I could have got a good one think we are just going to bite the bullet and get a koyorad

Edited April 29, 2022 by sick620

[sick620]

Getting the truck slowly road worthy 

got the back brakes put back together finally now it starts drives and stops it even went around the block a few times…

 

problem … gas gauge and temp gauge stopped working out of nowhere.. I suspect that voltage regulator on the cluster any ideas on what I should try first to get it to work? 

[datzenmike]

Replace with the one that someone is selling or take the old one apart and clean the contacts.

[sick620]

This is a closed chamber head correct? It’s a w58 off of a 1980 720…

 

how much compression does the z20 rebuilt block with peanut head make? When I freshened up the head I figured it was open chamber and didn’t even think about it being closed chamber, just realized that I had read 1980 720 had a rare closed chamber w58 … had to go back and look at photos … I may have just built a high comp motor and had no idea lol 😂 no it’s probably not all that high but I believe z20s pistons have slightly less dish than l20b pistons so maybe hight 8’s at the most 9 to 1 compression? L20b with closed head makes like 8:8 to 1? 

 

also update: truck is in the exhaust shop getting 2inch pipe to a cherry bomb… lots of popping  before We took it in I hope was just from a leak a foot or so from the collector or from the collector itself, new pipe should remedy that we hope… I did see a poof of smoke come from the exhaust manifold where it meets the head a few times when turning truck off, but i tightened the manifold bolts and didn’t see anything recently but wasn’t really looking for it either, so hopefully we don’t have a warped exhaust manifold and it’s leaking at the head and that’s the reason for the popping …

Edited June 21, 2022 by sick620

[datzenmike]

It's a closed chamber W58 head, probably from an import engine. This was cheaper than rebuilding the original open chamber one. These would not have passed emissions standards and been allowed into North America on any vehicle. NOx emissions would have been through the roof.

 

L20B with closed chamber head would have an 8.9 compression.

 

A Z20 block with a closed chamber head would have a 10.68 compression and need premium octane gasoline. The higher compression would be more efficient and on a good day worth maybe 8 extra HP.

[sick620]

30 minutes ago, datzenmike said:

It's a closed chamber W58 head, probably from an import engine. This was cheaper than rebuilding the original open chamber one. These would not have passed emissions standards and been allowed into North America on any vehicle. NOx emissions would have been through the roof.

 

L20B with closed chamber head would have an 8.9 compression.

 

A Z20 block with a closed chamber head would have a 10.68 compression and need premium octane gasoline. The higher compression would be more efficient and on a good day worth maybe 8 extra HP.

Is this the z20e or z20truck engine (carbed) we are talking about tho mike? I know the z20e with flat top pistons and different length rods would have a higher compression/ horsepower but remember I have a z20 from a truck with dished pistons, dished pistons that are just slightly less “dished” than a l20b… if you go back a page in my thread here you will see the picture of our rebuilt block with the new dished pistons, they seem to be a bit less dished looking than a l20b piston, but certainly not flat top…

Edited June 21, 2022 by sick620

[datzenmike]

 

 

Z20E and Z20S pistons. E have the shorter pin height to allow the longer N8500 long rod.

 

 

Z20S dish. It is similar to the L20B but does look slightly smaller.

 

If just slightly less than the 11.36cc L20B pistons then just slightly more compression than the 8.9. I don't have the dish volume but if you can find it I can re compute the compression. Safe to say about 9 or slightly more.

[sick620]

Ok awesome, I have no idea where to find the dish volume.. but if in the 9’s on compression also pretty safe to assume running regular octane will be fine and probably making an extra 1 or 2 hp with the peanut head… 

 

We should have cut out the exhaust liners and port and polished the head while we had it out, I had no idea this was atleast a little bit of a desired head… will be due for a top end overhaul in a few years probably try to squeeze a little more power out of this thing…

Edited June 21, 2022 by sick620

[sick620]

We got the exhaust done. 2inch with a cherry bomb… exhaust leak at collector for sure, we need to cut off a stripped nut and 2 stripped studs replace them with nuts and bolts and replace the gasket…

 

The truck did not do good on the way home…3 major problems so i decided to just call a tow truck after we lost power and had to pull over 10+ times.. 

 

it’s not getting good gas. it has 12 gallons of new gas but it’s getting dirty fuel up at the filter clogging it… limped it for an extra mile or two but I either need to figure out a way to clean it out ourselves or just take it to a radiator shop and pay for a clean and re seal… 

 

also brakes locking up slightly pedal hard to press and hanging up a little making truck hard to push but not locked up all the way, e brakes aren’t the issue because it’s disconnected from the rear drums… 

 

lastly clutch leak at slave cylinder probably. hard to get into gear with full press of pedal 3/4 press of the pedal and it gos into

gear… 

 

this has been an ongoing issue with the truck, you fix one thing and 3 other problems arise… sorry about sideways pics I’ll adjust later..

 

 

Edited June 23, 2022 by sick620

[datzenmike]

Buy several cheap fuel filters and change them as needed till tank is used up. (or till tank has self cleaned itself) There is a drain plug so drain the tank and remove. You would have to do this anyway if sending it out to be cleaned. Take the sender out. Put 3 or 4 heaping hand fulls of clean washed driveway gravel in and shake and roll it around on the lawn. Empty out and rinse thoroughly with garden hose. Let bake in the sun till dry. Install with new filter. Certainly faster and less work than taking it somewhere.

 

 

Brake hanging could be the pedal play is missing. Push on pedal with your thumb. It should move easily about 1/16" before there is firm resistance. If there is no play the push rod can't return to it's resting position and allow all the brake fluid back into the reservoir. Pressure is trapped in the lines.

 

Clutch slave rod should move 1.18 inches if working properly. Clutch should also have about 1/16 inch pedal play. Any chance the release bearing collar is the wrong one?

 

[sick620]

13 hours ago, datzenmike said:

Buy several cheap fuel filters and change them as needed till tank is used up. (or till tank has self cleaned itself) There is a drain plug so drain the tank and remove. You would have to do this anyway if sending it out to be cleaned. Take the sender out. Put 3 or 4 heaping hand fulls of clean washed driveway gravel in and shake and roll it around on the lawn. Empty out and rinse thoroughly with garden hose. Let bake in the sun till dry. Install with new filter. Certainly faster and less work than taking it somewhere.

 

 

Brake hanging could be the pedal play is missing. Push on pedal with your thumb. It should move easily about 1/16" before there is firm resistance. If there is no play the push rod can't return to it's resting position and allow all the brake fluid back into the reservoir. Pressure is trapped in the lines.

 

Clutch slave rod should move 1.18 inches if working properly. Clutch should also have about 1/16 inch pedal play. Any chance the release bearing collar is the wrong one?

 

 

I ordered 5 fuel filters and I'll try this method. I think you are right about the brake issue, it has pressure at the very start so probably adjustment will fix it. 

 

No the clutch collar is for the sure the correct one... I'll check distance of travel and pedal play, it was working good so I figure its the fact that it has a leak at the nipple so now the pressure isnt enough to push the fork...  need to look into it. 

[sick620]

we worked on the truck today/yesterday, tomorrow is import face off at firebird raceway near Boise Idaho. We registered the truck in the non judged show and even though its been having some issues I would feel like a failure if we didn't drive it.. 

 

We put a new fuel filter on it and we have 4 extras with us if it gets clogged again, ran for a little while and cant see any dirt or rust or anything yet.

 

adjusted brake pedal, now it takes a pump to make them work and they engage way near the floor, so I'm going to adjust it back a little bit... hope our brakes don't fail we have no E Brake if they do... 

 

plan to adjust slave cylinder in the morning, realized clutch works great if I only push in pedal a tiny bit so its obviously adjusted to where its pressing way to hard on the fork (moving it too far) 

 

Exhaust leak at the collector is not great, there is only one bolt holding it together, so at the very least we need to get one more nut on the only other stud and see if that helps it a bit, otherwise soon we need to remove the studs and replace with bolts, and install a new gasket...

 

So as long as I can get the clutch adjusted, get the brakes working a bit better and they stay working, and the fuel lines don't get plugged lol we'll be at the show.

 

washed the truck, pictures don't do it justice.. patina looks really cool we think... 

 

PS temp gauge and fuel gauge issues ended up being our fault cluster was not installed back tight and thus not grounding well. After tightening it back in all was fine.

 

Some other things that need to happen soon- Pop dent out of front corner as best as possible, straighten front end, re-install grill/bumper, Install fender mirrors, Replace front brakes and wheel cylinders, fix blinkers (need one bulb) and brake lights (none of them work), Install new steering wheel adapter (so we can install a horn button), install stereo, make some door cards and the truck needs a new upper control arm bushing bad so we just need to go through all of the suspension bits soon and replace all of the wear items... Hope we can put off king pins for a while... So basically just trying to get all of the bugs worked out and get it comfortable to cruise in this summer.. we will do some larger projects on it in the winter... 

 

 

Edited June 26, 2022 by sick620

[datzenmike]

1/16" pedal play will not cause the brake to work near the floor. You either have....

 

air in the system.

brake shoes are not adjusted close enough to the drums.

[sick620]

5 minutes ago, datzenmike said:

1/16" pedal play will not cause the brake to work near the floor. You either have....

 

air in the system.

brake shoes are not adjusted close enough to the drums.

ok I was thinking this to be a possibility... I'll bleed the system as well.. not really sure if we have 1/16in pedal play maybe somewhere closer to an 8th inch, possibly 1/4 inch... would not enough stroke at the master cylinder cause that issue or probably drum adjusters or not bled properly in your mind still the cause? 

[Tdaaj2]

On 6/21/2022 at 5:30 AM, datzenmike said:

It's a closed chamber W58 head, probably from an import engine. This was cheaper than rebuilding the original open chamber one. These would not have passed emissions standards and been allowed into North America on any vehicle. NOx emissions would have been through the roof.

 

L20B with closed chamber head would have an 8.9 compression.

 

A Z20 block with a closed chamber head would have a 10.68 compression and need premium octane gasoline. The higher compression would be more efficient and on a good day worth maybe 8 extra HP.

Hmm, every 80 720 I’ve run across had the closed chamber w58 head so.. not exactly sure where you are getting your info mike.

[mklotz70]

If you have air in the system, the pedal will be spongy.

 

The shoes need to be adjusted so that they rub a tiny bit.  Adjust them so that you can't turn the wheel with your hands. Then, back them off until you have just a little scrubbing left. Typically, you'll have the scrubbing in just one spot as it rotates.  The drums don't stay perfectly round unless you've just had them turned.  After you adjust each one, activate them with the brake pedal 4-5 times and check they still have a tiny bit of rubbing.  Activating the brakes with the pedal causes them to re-center.  Make sure the sliders are working. If the adjuster is frozen into one spot, you'll have a really hard time getting them adjusted correctly.  The tiny bit of rubbing will go away, but it lets you know the shoes are close.  If they don't have any rub, they could be a 1/4" away....no way to tell.  If your drums happen to be round and you get constant rubbing through the entire rotation of the wheel, back off the adjuster a click or two.....do the brake pedal a few times, check again.  You want the shoes as close as possible.

The pedal push rod.  Do you have the return spring on the pedal?  It should be pulling the pedal all the way up so that it doesn't apply any pressure to the m/c. The specs for how far the pedal is off the floor and how to adjust it are in the factory manual....which you can download online in multiple places....including my site.  http://www.bluehandsinc.com/manuals.html  With the pedal all the way up, you should be able to wiggle the push rod a tiny bit.  Not so loose that it can bounce around and rattle, just easily twist a bit between with your fingers.  Any looser and you're losing effective travel with the m/c.  Any tighter and it's holding the m/c piston in and it should not be.

 

When driving it, slowly push the pedal down......not very hard, just enough to start activating the brakes.  If you feel the front want to pull to one side, that side is engaging before the other .....check the fronts again....you want them to activate at the same time.  If the side that it's pulling to is rubbing more than the other, loosen it a click or two or make the other side rub the same.  The rears are harder to tell with.....maybe if you have  dirt road you can tell which one is activating first.

 

If you've got new shoes, you're going to want to google how to "bed" them.  Typically, longer, slower stops....no panic stops.  You need the shoes to heat up so they "cook" a bit.

 

Anyway.....hope some of that helps. Good luck.

[datzenmike]

7 hours ago, sick620 said:

ok I was thinking this to be a possibility... I'll bleed the system as well.. not really sure if we have 1/16in pedal play maybe somewhere closer to an 8th inch, possibly 1/4 inch... would not enough stroke at the master cylinder cause that issue or probably drum adjusters or not bled properly in your mind still the cause? 

 

 

If the brakes are not adjusted, a lot of pedal travel is moving the shoes out to contact the drums.

 

 

6 hours ago, Tdaaj2 said:

Hmm, every 80 720 I’ve run across had the closed chamber w58 head so.. not exactly sure where you are getting your info mike.

 

Ted you are quite possibly correct in this. All '78 and '79 L20B heads (used on S10, A10 and 620) are 11041-W5880. The '80 720 was the last year any L20B was used and the part number is 11041-W0381. I'm using a Nissan parts counter parts call up search and compatibility system not found on line. This is what the Nissan parts department Manager uses or did use 20 years ago and covers everything from '66 through 2004. You can look up a bolt and it will show every year and vehicle that it was used in including it's first use. Strictly speaking we know the the heads are interchangeable but this says they are not precisely the same. So no, I can't say for sure that the '80 720 used an open chamber W58 head.

 

A possibility is that back in the '80s it was more cost effective to use a low mileage import head rather than rebuild the original. Import L20B head from Japan were a likely source for closed chamber heads. I can't see Nissan sending '80 trucks here with a mixture of open and closed chamber heads on it.

 

You would think the closed chamber head would make more NOx and the higher compression would require a different ignition timing going from 8.4 to 8.9. Emissions standards tend to get tighter every year not less, how did this head pass? 

 

   

[sick620]

Truck broke down a couple times on way to show.. the bad gas issue is more than just filter getting clogged seems to be lines or plugged in the tank… we broke down near a guys shop he helped us blow air into the tank to push gas back up to the carb then it fired back up.. made it to the car show, broke down half way home.. eventually had to call the tow truck again… guess I’m dropping the tank soon…

 

adjusted brakes and the stopping got a bit better so that’s good … still need to replace all the front stuff soon probably…

 

 

[sick620]

On 6/26/2022 at 1:34 AM, mklotz70 said:

If you have air in the system, the pedal will be spongy.

 

The shoes need to be adjusted so that they rub a tiny bit.  Adjust them so that you can't turn the wheel with your hands. Then, back them off until you have just a little scrubbing left. Typically, you'll have the scrubbing in just one spot as it rotates.  The drums don't stay perfectly round unless you've just had them turned.  After you adjust each one, activate them with the brake pedal 4-5 times and check they still have a tiny bit of rubbing.  Activating the brakes with the pedal causes them to re-center.  Make sure the sliders are working. If the adjuster is frozen into one spot, you'll have a really hard time getting them adjusted correctly.  The tiny bit of rubbing will go away, but it lets you know the shoes are close.  If they don't have any rub, they could be a 1/4" away....no way to tell.  If your drums happen to be round and you get constant rubbing through the entire rotation of the wheel, back off the adjuster a click or two.....do the brake pedal a few times, check again.  You want the shoes as close as possible.

The pedal push rod.  Do you have the return spring on the pedal?  It should be pulling the pedal all the way up so that it doesn't apply any pressure to the m/c. The specs for how far the pedal is off the floor and how to adjust it are in the factory manual....which you can download online in multiple places....including my site.  http://www.bluehandsinc.com/manuals.html  With the pedal all the way up, you should be able to wiggle the push rod a tiny bit.  Not so loose that it can bounce around and rattle, just easily twist a bit between with your fingers.  Any looser and you're losing effective travel with the m/c.  Any tighter and it's holding the m/c piston in and it should not be.

 

When driving it, slowly push the pedal down......not very hard, just enough to start activating the brakes.  If you feel the front want to pull to one side, that side is engaging before the other .....check the fronts again....you want them to activate at the same time.  If the side that it's pulling to is rubbing more than the other, loosen it a click or two or make the other side rub the same.  The rears are harder to tell with.....maybe if you have  dirt road you can tell which one is activating first.

 

If you've got new shoes, you're going to want to google how to "bed" them.  Typically, longer, slower stops....no panic stops.  You need the shoes to heat up so they "cook" a bit.

 

Anyway.....hope some of that helps. Good luck.

Thanks for this information will be very helpful