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Saying Hello to Ratsun

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Hello all,


I wanted to introduce myself. I’m a recent member to this awesome forum, although I’ve been ghosting information frobm it for months concerning my most recent acquisition, a ‘78 620 extended cab. I’ve been wanting a Datsun for the past 10 years, and by chance and luck I was able to find this one. Perhaps it found me.


My first truck was a red ‘94 Nissan Hardbody. I still own it now, after 15 years. It was a stock 4x4 at the time. Now, it sits on 35” tires with a Dana44 front end, built axles, an exo cage, and a KA24E engine from a 240SX that I hand built myself. You could say that I like doing my own work.


I had a Subaru Outback for awhile, it was fun but unfulfilling. I sold it for a black ‘97 Hardbody King cab, my first extended cab truck. I loved it. After some basic repairs, it ran like a new rig off the lot. 


Here is the funny twist in my truck story.  I got a call from the young man that sold me this truck. He was stuck up in the snow on Larch Mountain. It was around 10pm on a Saturday. I loaded up my gear and went to pull him out. And as I was shoveling snow from about his rig, a new Ford came sliding down the mountain and obliterated my parked Nissan.


I was dismayed, but the insurance payoff was huge. I bought a $800 truck and was reimbursed $4K. With some financial leeway, I decided that it was time to find my Datsun.


I did a quick craigslist search, and found a freshly painted ‘78 king cab in Springfield, Or. I decided to jump on it. My lady and I drove down there on a Sunday with snow in the weather forecast.


I could tell that maintenance was needed on the truck, but it ran and drove. Snow was falling heavily. It’s hard to inspect an engine bay in a snow flurry.


It was cold, it was snowing, and I didn’t want to leave with nothing after a 3 hour drive. I paid in cash and drove her home.


The next day, I heard that Springfield got over 6” of snow and the roads were blocked. Timing is everything.


Now I am the proud owner of one of my dream trucks, which my sarcastic friends have aptly nicknamed Pikachu.


I have come to realize that it takes a community of knowledge and resources to keep this truck on the road. I’ve been refreshing and restoring this truck for a few months, and finding parts and knowledge is a task. Most of it I have gotten from this form. So I thank you all, and I hope to be a resource to everyone as well.

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The cam was my fault. I was reassembling the head this weekend, after a full gasket and engine bay refresh. The head looked beautiful, and I was reassembling it after some cleaning. I neglected to notice that one of the cam towers wasn’t seated on its metal sleeve as I was torquing down the retaining bolts. Everything looked good, and I was being gentle, until I heard a small POP. I figured the towers popped into place, I’ve experienced that before on other engines.


Nope. The cam literally broke in half. The #3 cam tower was wonkeyed on top of the bolt sleeve that fits into the head.


I never thought that a camshaft would break like that. If not for that oversight I would have had the engine together about right now. LoL


So now, searching for a cam so I can get this damn truck driving again. I can’t wait to drive it without all the awful exhaust and coolant leaks from which it was suffering. 


Its my DD, not looking for anything other than getting it running smoothly. Been looking for a used cam all day for L16/18/20B motors, it’s all I need, and I figured Ratsun is the place to ask.

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Ah... I thought perhaps the lobes were worn and would suggest a diesel oil with the proper ZDDP level, unlike today's oils which have about half what it did when the L20B was new.


I will advise to avoid removing any cam tower at any cost. The bolts will strip easily in the soft aluminum and as for alignment.... better just left alone.

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I will, and thanks guys. I sourced a cylinder head last weekend from a local Datsun guru named Rick living nearby in Washougal. We met for a simple transaction and ended up talking about our rigs for a good half an hour. He has a slick 510 he is working on and has been in the Datsun world for years, his place is like a salvage yard for parts. And he has front grille emblems, score!


Needless to say he saved me. I got a complete head for a hundy, and was able to reassemble mine with his drivetrain parts (his valves didn’t look so great, and my head looked beautiful in comparison, only 150k original miles).  I just got the head back on the block this afternoon, and Pikachu should be running by Sunday. 


I want to start throwing up some pics but haven’t gotten familiar with the forum yet. All my pics are on my phone, and it looks like I have to upload them to a site first?

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For now I’ll just tease y’all by changing up my profile pics until the weekend, when I can sit down and sort out my project pics.


And I totally agree Mike, about the cam tower bolts. They are sketchy. I meticulously cleaned all the bolts and holes before reassembly. The head bolts still looked great, I reconditioned them and reused them, no issues. My Lady got me a Chilton’s, FSM, and owners manual for the ‘78 King Cab for my birthday this year. She knows me so well.

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I hope these photos show up. Thanks all for the warm greetings. I got my 620 completely refreshed, all new gaskets on the engine, and she purrs. 


Ive had her since January. Since then, I’ve done the following:


2” drop spindles, discs, calipers, hubs, from a Hardbody. 


The engine work, of course, with emissions delete and routed the PCV to the exhaust 


I’m loving how smooth she runs now. I have lots of plans from here on, and will be sure to share when I tackle them.


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  • 1 month later...
On 7/18/2019 at 2:28 PM, DatNoss said:


The engine work, of course, with emissions delete and routed the PCV to the exhaust 




Please, tell me more. I'm either excited if you can do this right, or excited to laugh at some jerry-rigged bullshit.


Pics now!

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  • 4 weeks later...

I haven’t signed on in awhile, sorry for the late reply. It was just a simple mod that I chose to do, because I had eliminated the whole EGR block which contains the PCV valve.


After some head scratching, I did some internet research. This is a pretty common practice, more so in high performance applications. I was just looking for an outlet for the PCV, because I feel it’s an important part of the engine and didn’t want to cut it out of the picture.


I basically made a small sleeve that I welded into the exhaust down pipe with a fitting for the PCV. The idea is to create a Venturi valve, so it has to be welded in at a 45 degree angle to the exhaust flow. I actually used the metal tube that holds the PCV valve off of the intake manifold, drilled a hole in my sleeve, and burned it in.


So far so good, no issues and no gunk in the intake. The oil particulates vaporize in the exhaust. My theory is that this should keep the intake manifold cleaner, now that oil particulates aren’t being pulled through it.



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The intent of the PCV is to recycle it through the combustion process and burn it. Dumping it in the exhaust just spews it out the back.


Here's my '79 L20B intake with the EGR/PCV manifold removed...




Here it is after some grinding, re shaping, some JB weld and tap threads. Looks like an earlier L16 intake but had the larger L20B runner ports.




 A good engine produces very little oil and 'gunk' and gas washes it off the insides of the intake anyway. This removes the EGR completely and keeps the PCV intact and in stock location.






I think there are plastic parts inside the PCV that will melt or wear out from the constant pressure/vacuum pulses. It is supposed to be a one way valve and close if there is a backfire. This would prevent a flame igniting any fumes in the hose and crankcase. In the '60s I saw a chevy six engine explode that was flooded. It blew the oil pan, tapet cover and valve cover off and bent the hood. I would move the PCV farther away from the heat.

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You’re an immense resource of info, mike. Thanks. Perhaps I was just overthinking the whole situation, and I think most of us do. 


Since I have this in place, I’ll let it run and keep an eye on it. I drive this truck 40 miles a day, 5 days a week, and more on the weekend for recreation. If it isn’t optimal, I’ll change it. 


I just love tinkering on vehicles, and I had a chance to do this when I rebuilt my L20B. If I get a chance to modify something for posterity, I’ll do it for fun. 🙂




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And, to reiterate on mike’s post, the PCV port I made is a goodly distance away from the exhaust manifold, about 36” from the collector. I’m hoping this is far enough away from extreme temps, but something more for me to think about. Good convo. It’s not a race engine hehe

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