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LivingLikeLarry99

My Grandpa's 1978 Datsun 620 pickup

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Hey Everyone, 

I'm new to the Datsun Community and am ready to learn as much here as I possibly can. My Grandpa has a 1978 Datsun 620 pickup and he's decided he wants to give it to me as he's starting to get up in years (69) and can't drive so well anymore. But before he does he wants me to help him restore it. He's loves Datsuns/Nissans and has always worked on all his cars but he's had a heart attack already then retired and hasn't done much on his own since then (2012). Anyway the truck ran and drove up till about 2 months or so ago. It needs some work I'll explain after and it definitely needs a paint job, including the original Datsun Logos and grill. I'll post pictures this Sunday when I go over there again. But I'll definitely need your guy's expertise and know how so my grandpa and I can get the old girl back on the road with some class. Thanks again.

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Welcome, sounds like a great project. Looking forward to pics. 

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Is the 1978 620 one he bought new? GGPA620 has his great grandfather's 1976 620, which his great grandfather bought new. So he has a lot of history behind him. Just wondering if you have similar history to go with the pickup.

 

Don

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4 hours ago, 620slodat said:

Is the 1978 620 one he bought new? GGPA620 has his great grandfather's 1976 620, which his great grandfather bought new. So he has a lot of history behind him. Just wondering if you have similar history to go with the pickup.

 

Don

My Grandpa bought it off an Older lady back in '80 According to him. So 1 year after she bought it so I'd say brand new. It's been in the family all those years since then. And he's had many adventures with it. I wish he could share here but he's not exactly Tech savvy. 

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Thanks for responding everyone don't worry I'll definitely get pics this weekend. The paint is pretty bad and it's got a tiny bit of rust, mostly surface rust thankfully though. Nothing I or any decent person can't fix. Has a rusted whole on the bottom of the drivers side floor panel though. Might have to weld a new piece in. He paid a guy to paint it for him 2 years ago but the guy did a real shabby job. No clear coat and the guy didn't even move my grandpa's tool chest he just painted around it.

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5 hours ago, 620slodat said:

Is the 1978 620 one he bought new? GGPA620 has his great grandfather's 1976 620, which his great grandfather bought new. So he has a lot of history behind him. Just wondering if you have similar history to go with the pickup.

 

Don

Ha... I thought this was ggpa620 s post...

Welcome larry...  

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13 hours ago, LivingLikeLarry99 said:

My Grandpa bought it off an Older lady back in '80 According to him. So 1 year after she bought it so I'd say brand new. It's been in the family all those years since then. And he's had many adventures with it. I wish he could share here but he's not exactly Tech savvy. 

Close enough, thanks for the reply.

 

Don

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Haha welcome larry. Congratulations on the awesome truck!  I am new as well and here to learn and share also! Cant wait to see pics! I'm sure your grandpa is excited to see what you do with it!

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Have pictures of the job we just did too. We removed the Transmission and clutch components including the flywheel which was insane getting off. It had a lot oil buildup in there. Apparently he's had a leak there for a while and the clutch wouldn't grab anymore because of so much oil buildup. Anyway we are gonna clean the bell housing, put new transmission fluid and a new mount because we have it out and are gonna clean the flywheel. We also got a new clutch kit to put in even though the old one was in good shape. We need to find the leak though, and it's hard to pin point exactly. Looks like from the head maybe a bit towards the back.  Also the oil pan is leaking too we are gonna replace the gasket. Doesn't appear to be the rear main because it looks clean and in good condition but debating whether to change since I have access to it. 

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Is it possible the oil is from the transmission? 

 

There is a seal behind the front cover ....

 

Even if not it wouldn't be a bad idea to put fresh seals on both the front and rear of the transmission.... you will need a new gasket for the front cover too....

Your already in there and the seals are cheap enough....

Oh if you haven't put it all back together yet replacing the pilot bushing in the end of the crank is a good idea.... not neccessary but again not a bad idea while your there....

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e8EVsAq.jpg

 

Take the 5 bolts out and strike the clutch arm pivot ball to dislodge the cover. That nose will snap it you hit it. You can clean and use a thin smear of RTV to seal it. You don't want that shit squishing inside and into the two bearings. The front and rear seals are about $5 each. Change them, they are hard to replace once the transmission is back in. Be sure to oil or grease them so they don't start up dry.

 

Definitely change the rear crankshaft seal while the flywheel is off. Oil it so it doesn't start up dry. Check the oil pan gasket. Replace the valve cover gasket... that should do it. Have a look at the pilot bushing. They are only >$5. Split the old one (very soft powdered bronze) with a screwdriver blade in 3 places. Poke the pieces inwards and remove. yes there are several ways to do it hydraulically with grease or even pack with bread or a puller but I have yet to see it done in less than a minute and no tools or mess made. Do NOT oil or grease the new one, it will only attract abrasive clutch dust, they are permanently lubricated.

 

IbSIpBR.jpg

 

9F9rL0D.jpg

 

Be sure to use some lithium grease on the ends of the clutch slave push rod, the pivot ball, the ends of the clutch arm where it clips onto the release bearing collar and a thin smear on the transmission spline. Clean the release bearing collar and fill the small cavity inside with grease. ALWAYS replace the release bearing with a new one.

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10 hours ago, Crashtd420 said:

Is it possible the oil is from the transmission? 

 

There is a seal behind the front cover ....

 

Even if not it wouldn't be a bad idea to put fresh seals on both the front and rear of the transmission.... you will need a new gasket for the front cover too....

Your already in there and the seals are cheap enough....

Oh if you haven't put it all back together yet replacing the pilot bushing in the end of the crank is a good idea.... not neccessary but again not a bad idea while your there....

I thought that too but it's all motor oil from what I can tell. We're in the process of cleaning it. Then we'll look for new gaskets. I'm not sure if they have parts at my local auto parts. The clutch kit, release bearing,  and tranny mount were all special order. 

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9 hours ago, datzenmike said:

e8EVsAq.jpg

 

Take the 5 bolts out and strike the clutch arm pivot ball to dislodge the cover. That nose will snap it you hit it. You can clean and use a thin smear of RTV to seal it. You don't want that shit squishing inside and into the two bearings. The front and rear seals are about $5 each. Change them, they are hard to replace once the transmission is back in. Be sure to oil or grease them so they don't start up dry.

 

Definitely change the rear crankshaft seal while the flywheel is off. Oil it so it doesn't start up dry. Check the oil pan gasket. Replace the valve cover gasket... that should do it. Have a look at the pilot bushing. They are only >$5. Split the old one (very soft powdered bronze) with a screwdriver blade in 3 places. Poke the pieces inwards and remove. yes there are several ways to do it hydraulically with grease or even pack with bread or a puller but I have yet to see it done in less than a minute and no tools or mess made. Do NOT oil or grease the new one, it will only attract abrasive clutch dust, they are permanently lubricated.

 

IbSIpBR.jpg

 

9F9rL0D.jpg

 

Be sure to use some lithium grease on the ends of the clutch slave push rod, the pivot ball, the ends of the clutch arm where it clips onto the release bearing collar and a thin smear on the transmission spline. Clean the release bearing collar and fill the small cavity inside with grease. ALWAYS replace the release bearing with a new one.

Ok. I'll definitely take your advice. Gonna take a bit to get those seals and we got a new release bearing as well. The pilot looks good but might as well. And the rear main I guess as well. I wish I could post the pictures but I'm not sure how.

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You'll need to get a free picture hosting account on imgur, image shack or any of the many that are out there EXCEPT Photobucket. Download your pictures and store them there and when needed copy the picture information, bring it here and paste in your post. This is very a very abbreviated explanation.

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Hey guys, I'm back. Sorry for the long delay and happy new year. So I got the transmission mostly cleaned up, in the process of putting on getting more parts (the pilot bearing, oil pan gasket, valve cover gasket, and the transmission seals. I did the rear main seal already. Lubed it with fresh oil as I had to change the oil anyway ( I'm gonna use 10w 30 high mileage with a quart of Lucas oil additive). Hope I did it right, looks flush and everything. Also degreased the whole rear of the engine and the oil pan, definitely was leaking there. I have some pictures of where it looks to be leaking oil elsewhere. Can't exactly tell but might be the head. My grandpa says it can't be because it never lost coolant or drew white smoke only leaked oil. So I'm kind of at a loss here. Should I get the head redone and the gasket replaced because it might be that or just replace the valve cover gasket  and see? Or should I get the whole engine rebuilt? And should I get it done now with the transmission out? Thanks again and I appreciate everyone's feedback

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Most likely the oil leak from around the head is from the valve cover gasket, not the head. My experience with motors older than these (the 50's) is that the valve cover is the most likely culprit. Replace the valve cover gasket and put the motor back in the pickup.  You have already done a lot of cleaning of the motor (and replacing gaskets and fixing known leaks), make sure the head and valve cover area is very clean, drive it, and watch very carefully for oil leaks. I would guess that with replacing the valve cover gasket you will not see any leaks.

 

The valve cover gasket is usually tightened too much, creating a leak. The gasket is thinned down too much, close to cutting it in half, or even cutting it in half in several places around the valve cover.  It needs to be snugged down good, but not too tight.

 

Don

Edited by 620slodat

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Just get a good oil with lots of ZDDP in it.... like 10w30 Shell Rotella T4 or Chevron Delo 400. Any oil marked racing also. These are the same ZDDP levels as the regular oils used to be 30 years ago. Don't use additives they are just snake oil. All oils are made to a minimum standard even the $1.99  WallMart shit so just get a brand quality band name one. I wouldn't use a synthetic, they tend top leak past old seals and gaskets.

 

 

Sources for oil leaks...

 

1/ Valve cover gasket

2/ Oil sender failing

3/ Fuel pump gaskets (2 ) One on either side of the plastic spacer.... or the fulcrum pin on the pump arm. 

4/ oil pan gasket

5/ Timing chain cover crankshaft seal.

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Hey guys, I'm back. Sorry for the long delay and happy new year. So I got the transmission mostly cleaned up, in the process of putting on getting more parts (the pilot bearing, oil pan gasket, valve cover gasket, and the transmission seals. I did the rear main seal already. Lubed it with fresh oil as I had to change the oil anyway ( I'm gonna use 10w 30 high mileage with a quart of Lucas oil additive). Hope I did it right, looks flush and everything. Also degreased the whole rear of the engine and the oil pan, definitely was leaking there. I have some pictures of where it looks to be leaking oil elsewhere. Can't exactly tell but might be the head. My grandpa says it can't be because it never lost coolant or drew white smoke only leaked oil. So I'm kind of at a loss here. Should I get the head redone and the gasket replaced because it might be that or just replace the valve cover gasket  and see? Or should I get the whole engine rebuilt? And should I get it done now with the transmission out? Thanks again and I appreciate everyone's feedback

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Sorry, double posted that. Anyway that's for the replys. I'll take your advice on the Valve cover gasket. And 

On 1/16/2020 at 7:42 AM, datzenmike said:

Just get a good oil with lots of ZDDP in it.... like 10w30 Shell Rotella T4 or Chevron Delo 400. Any oil marked racing also. These are the same ZDDP levels as the regular oils used to be 30 years ago. Don't use additives they are just snake oil. All oils are made to a minimum standard even the $1.99  WallMart shit so just get a brand quality band name one. I wouldn't use a synthetic, they tend top leak past old seals and gaskets.

 

 

Sources for oil leaks...

 

1/ Valve cover gasket

2/ Oil sender failing

3/ Fuel pump gaskets (2 ) One on either side of the plastic spacer.... or the fulcrum pin on the pump arm. 

4/ oil pan gasket

5/ Timing chain cover crankshaft seal.

I'll use the Shell one I think. I'll have to check out pricing.I only bought a quart of castrol GTX 10w30 high mileage so it ain't much of a loss.  Waiting on that Tax money to come so I can finish gathering the rest of the parts and then work on the interior. Anyway can you clarify what the fulcrum pin is and the oil pump is on the inside right? I apologize I do general mechanic work but anything inside engines are not my specialty. My grandpa said that it only loses a quart a oil, but that was years ago. Now he hadn't really kept track he only added as needed and we haven't started it in about a couple months since we took out the transmission. So I don't know if that info helps. I'll update again with more pictures when I get those new gaskets on. And I'll try and get a better pic of where that upper leak is. 

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