Rebuilding my L20B

[flatcat19]

I hear some of these guys take the running engines out of their Datsuns, for alternator changes... just to put some paint on them and show off how fancy poppa smurf blue they can be... all while having a bad ass project engine slowly maturing on the side.

Lagoon Blue, asshole.

 

 

 

Yes. I have the motor out of mine with the intention to only do a 5 speed swap.

 

One thing after another, it's been a month and a half that my truck has been down. And it's driving me nuts not being able to drive my Datsun.

 

Rather than build on my spare motor I pulled my running motor. Fix a leak...paint the block...clean all the mounts...wait for parts...this and that adds up.

 

 

Don't be that guy. Er...don't be this guy.

[ErickwithnoK]

You know... there are old timers on here that are speaking from experience on the "build the engine on the stand" while leaving a running one in the truck.

 

It gives you perspective and it will help keep you interested in the build. For instance, I have a non-Datsun project that I recreationally drive. I have a completely done engine on a stand, ready to go in whenever. In the meantime I'm killing the stock engine learning how to properly drive the thing. So, I have the best of both worlds. I got to build the next level motor, and, I get to enjoy the vehicle so I don't burn out on the project.

 

I hear some of these guys take the running engines out of their Datsuns, for alternator changes... just to put some paint on them and show off how fancy poppa smurf blue they can be... all while having a bad ass project engine slowly maturing on the side.

You started an awesome conversation. My reluctance to build an engine on the side is because it's more money, not because I don't believe you old timers when you say it makes things a lot easier. The only reason I'm on this forum is to get advice from folks like you, I'm not in the business of ignoring it.

[ErickwithnoK]

I'm very project oriented, I get obsessed with whatever I'm building at the time. I'll be leaning on that a little.

 

I also live with my dad, who is not only great help with any project I have but also a great source of motivation.

 

I'll post here often, probably daily pictures as i will try to do at least a little something on it every day.Thanks for the suggestions.

 

I already stare at my Datsun at least twice a day and imagine what I'm going to do to it next. Bench seat needs redone, water is getting in somehow, I want the alternator swap, wheels are ugly, needs moar low, exhaust tip, carpet, 5 speed, center console, rhino the bed, fender mirrors, new rear view mirror, visor clips, blinkers act funny, exhaust downpipe gasket is leaky, window squeegees...can't wait to spend ten grand on this thing over the next 5 years.

[Soundline]

Lagoon Blue, asshole.

Yes. I have the motor out of mine with the intention to only do a 5 speed swap.

One thing after another, it's been a month and a half that my truck has been down. And it's driving me nuts not being able to drive my Datsun.

Rather than build on my spare motor I pulled my running motor. Fix a leak...paint the block...clean all the mounts...wait for parts...this and that adds up.

Don't be that guy. Er...do that be this guy.

  

 

Actually Eric, as you can see this was the best advice I could give on the topic, mixed with a clever dig at Gato who is an actual good mechanic. I did this to show you what pulling the engine and losing the funist part, driving the Datsun, slows things down. I've seen a lot of people in the car culture fallout, and lose that drive because of extensive down time.

 

I just don't want to see you stuck in that sinkhole because I'd love to see this 620 in person in 2022, when it mirrors your vision for the end product.

 

You started an awesome conversation. My reluctance to build an engine on the side is because it's more money, not because I don't believe you old timers when you say it makes things a lot easier. The only reason I'm on this forum is to get advice from folks like you, I'm not in the business of ignoring it.

Yep, no harm no foul. I just try to keep people out of rabbit holes I've found myself in before. In the end, you make 100% of the final decisions on your truck. You do you, most of us will back you regardless of what you want to do to your truck.

[ErickwithnoK]

  

 

Actually Eric, as you can see this was the best advice I could give on the topic, mixed with a clever dig at Gato who is an actual good mechanic. I did this to show you what pulling the engine and losing the funist part, driving the Datsun, slows things down. I've seen a lot of people in the car culture fallout, and lose that drive because of extensive down time.

 

I just don't want to see you stuck in that sinkhole because I'd love to see this 620 in person in 2022, when it mirrors your vision for the end product.

 

 

Yep, no harm no foul. I just try to keep people out of rabbit holes I've found myself in before. In the end, you make 100% of the final decisions on your truck. You do you, most of us will back you regardless of what you want to do to your truck.

 

That's awesome. I'm not saying I'm against the idea of it, I just don't want to spend the money. I see that it's more convenient, more fun, and keeps my truck running to get a second motor to build on a stand while I drive my Datsun  :thumbup: . If I see an L20B for cheap that has the head I want (which head do I want? I have a U67 which I was told earlier has larger valves, but also an open chamber design. Do I want a closed chamber head? Is the Peanut head the only closed chamber?) I'll totally scoop it up and do what you all want me to do.

 

I hope it becomes what I want and I get to show it to Datsun folks like yourself.

[wayno]

It all depends on what pistons you are using, if you use flat top pistons then in my opinion the U67 head is the best head, if your using dished pistons like I use then a closed chamber head(peanut head) with big valves is the best head to use as you want around 9 to 1 compression ratio to run this crap they call gas these days.

The only closed chamber head with big valves and large intake ports is the 219 head(V912), some A87 heads have a 219 cast into the front of the head, and these heads are very expensive, any other closed chamber head has to be modified to make it a 219 head, but with flat top pistons and a U67 head with big valves and large ports you basically have the same engine I have but didn't spend the money I did to get there.

I say just build an engine on the side if you can with all the best parts you can find for a reasonable price, and install it in one weekend and reap the benefits of you hard work.

I hate having a vehicle that doesn't move under it own power, it drives me crazy, so I do everything possible to do what I can on the side and then take a weekend and remove and replace whatever I am changing out, but by Sunday night it has to be done and moving again.

[ErickwithnoK]

It all depends on what pistons you are using, if you use flat top pistons then in my opinion the U67 head is the best head, if your using dished pistons like I use then a closed chamber head(peanut head) with big valves is the best head to use as you want around 9 to 1 compression ratio to run this crap they call gas these days.

The only closed chamber head with big valves and large intake ports is the 219 head(V912), some A87 heads have a 219 cast into the front of the head, and these heads are very expensive, any other closed chamber head has to be modified to make it a 219 head, but with flat top pistons and a U67 head with big valves and large ports you basically have the same engine I have but didn't spend the money I did to get there.

I say just build an engine on the side if you can with all the best parts you can find for a reasonable price, and install it in one weekend and reap the benefits of you hard work.

I hate having a vehicle that doesn't move under it own power, it drives me crazy, so I do everything possible to do what I can on the side and then take a weekend and remove and replace whatever I am changing out, but by Sunday night it has to be done and moving again.

 

Hey thanks for the info. 

 

I'll keep my eyes open for an L20B with an A87 or U67 head to work with. I'm willing to do what you all tell me to do even if I don't want to, I believe you all when you say it's tough to work on a motor for a truck that can't roll under it's own power. Time will tell what I do for my application

[wayno]

You already have a U67 head as I recall, and the A87 head with the 219 mark on the front is as rare and expensive as any 219 SSS race head, there are lot of A87 heads without the 219 mark, some have big valves, some have small valves, some are open like your U67, some are closed like the W53 and 219 heads.

It's hard to tell you what you need and keep a straight face when I know all these parts are drying up, a couple years ago there were 2/3 620 trucks in the wrecking yards all the time, 5 years ago you could find almost anything you needed, now Datsuns are a rare find in the Portland area wrecking yards, even Nissan 720s are hard to find now.

I don't recall now what your existing engines issues are, I will keep saying this, if all you need is a head gasket, then put one on it and get it back on the road.

[Soundline]

This is why when I finally decide I'm done Datsuning... my 620 will go where all good 620s go to die....

 

 

....on gato's front lawn.

[hobospyder]

This is why when I finally decide I'm done Datsuning... my 620 will go where all good 620s go to die....

 

 

....on gato's front lawn.

no

 

Please

 

Don't

 

 

I'm actually serious the last one that sat at gatos is now at my house

[flatcat19]

Unless it's a ball joint king cab...

 

 

 

[ErickwithnoK]

You already have a U67 head as I recall, and the A87 head with the 219 mark on the front is as rare and expensive as any 219 SSS race head, there are lot of A87 heads without the 219 mark, some have big valves, some have small valves, some are open like your U67, some are closed like the W53 and 219 heads.

It's hard to tell you what you need and keep a straight face when I know all these parts are drying up, a couple years ago there were 2/3 620 trucks in the wrecking yards all the time, 5 years ago you could find almost anything you needed, now Datsuns are a rare find in the Portland area wrecking yards, even Nissan 720s are hard to find now.

I don't recall now what your existing engines issues are, I will keep saying this, if all you need is a head gasket, then put one on it and get it back on the road.

I do already have the U67, but if I was going to build on the side I would need another head.

 

It probably just needs a head gasket but there's oil coming out of the spark plug on cylinder 2 so it's possible it needs rings as well. Either way I'm going to rebuild the thing while I have it apart because it should be a great learning experience and a lot of fun, then I'll end up with something I can be proud of.

[flatcat19]

Diagnose first. Compression test, dry. Get readings. Compression test, wet.

 

Concern verified.

[ErickwithnoK]

Diagnose first. Compression test, dry. Get readings. Compression test, wet.

 

Concern verified.

Do I need to do a compression test if I already plan on new pistons/rings anyway

[flatcat19]

No. But wouldn't it be nice knowing?

[ErickwithnoK]

No. But wouldn't it be nice knowing?

It would be interesting to find out, plus I could learn how to do it before doing a test on my motor after I build it

[Soundline]

Unless it's a ball joint king cab...

I'd just be returning your parts...

 

....besides... Hobo clearly has room in his stable for more 620s...

[flatcat19]

But that means I'd have to see him again.

[hobospyder]

I'd just be returning your parts...

 

....besides... Hobo clearly has room in his stable for more 620s...

 

really i don't unless you want to take some non dattos off my hands

 

But that means I'd have to see him again.

and who wants to do that right?

[datzenmike]

 

It probably just needs a head gasket but there's oil coming out of the spark plug on cylinder 2 so it's possible it needs rings as well. Either way I'm going to rebuild the thing while I have it apart because it should be a great learning experience and a lot of fun, then I'll end up with something I can be proud of.

 

 

Oil is likely dripping down from the valve cover gasket or blowing back from the front of the engine. My guess is the fuel pump gasket. If oil is coming out the threads then the plug and the combustion chamber will be wet with it and there will be a blue cloud following you down the road. Nothing should be able to get past the threads. Do you have NGK plugs??? Spray down the area with carb cleaner and let dry. Check every time you start it and find out where the leak is. I've seen lots of oily plugs and it was just a leak. It's always a leak.

[hang_510]

Isky makes cams? Will contact them, they probably could tell me what I want. Thanks!

 

They were extremely helpful, every time I called.

 

 

I think Isky has new cams on the shelf last time someone ordered!

Shhhhhhh!

[hang_510]

 

2/ Weld up your own intake and run bike carbs.

 

3/ It'll take 5 weeks just to find a Z22 crank

I have #2 available. First gen. Everything! Is ready to bolt on tune & go.

 

3/ that's optimistic don't ya think?

[ErickwithnoK]

Oil is likely dripping down from the valve cover gasket or blowing back from the front of the engine. My guess is the fuel pump gasket. If oil is coming out the threads then the plug and the combustion chamber will be wet with it and there will be a blue cloud following you down the road. Nothing should be able to get past the threads. Do you have NGK plugs??? Spray down the area with carb cleaner and let dry. Check every time you start it and find out where the leak is. I've seen lots of oily plugs and it was just a leak. It's always a leak.

Haven't changed the plugs since I got it or it would have NGK's. I cleaned the motor and after that found the only two wet spots are drivers side head and around the threads on the second cylinder plug. It's dry above the plug and on the front of the motor

[ErickwithnoK]

I have #2 available. First gen. Everything! Is ready to bolt on tune & go.

 

3/ that's optimistic don't ya think?

I might call isky before I'm ready to buy a cam just to pick their brain about things I'm probably missing.

 

By #2 you mean an r1 manifold? Yes please...

[ErickwithnoK]

Hey guys. I'm trying to install a 1200 tach I bought at Canby. My truck is a '76 so I have the factory plug taped to the wiring harness near the tach. My plan is to cut off the plug and use the wires from the plug to wire in my tach with connectors, since the 1200 tach doesn't have a plug. I like the idea of not running any wires through the firewall. 

 

So far I looked through my wiring diagram in my manual to see where each wire in the plug runs, and I came across something that might throw a wrench into things.

 

The newer style tach (with the plug) has one wire running to the coil, whereas the 1200 tach I have has a slack loop that is wired "between the coil and distributor". 

 

My question is, can I wire my 1200 tach into the factory harness, or do I need one wire from the tach to my engine bay in order to get between the coil and distributor. 

 

This is the thread I am referencing: http://community.ratsun.net/topic/17937-what-factory-tach-will-hook-up-without-mods-for-my-74-620/ 

 

Here is my tach, the lights are out of it because I have them wired into the plug-harness already. 

 

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Here is what my manual's wiring diagram shows. (L is blue, B is black)

 

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Here is the current state of my wiring

 

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My diagram shows one blue wire going to the coil, and one black green wire going to ignition on the fuse block. If you look closely at the photo of my wiring you will not find a blue wire, but two black green wires. ??????\

 

I have a multi-meter, but don't know how to use it effectively.

 

I've never done any electrical on a car. Help.  :blush: