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mainer311

Just bought a 521

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Dang whats all over your plug wires?  Oil? Block looks wet too.  

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That was a long time ago, that block went thru 3 quarts of oil in one tank on a trip, it burned so much oil and had so much blow-by I could not keep a gasket in it for long, you should have seen the cloud it made after I put a quart of oil in it every other day just driving around town.

I beat the shit out of that truck everyday using it as my business truck, I put a new modified head on a low mile L20b block and got 10 plus years out of it and put somewhere between 100,000 and 200,000 miles on it, I put 4 dogleg 5spds in it and one hybrid 5 speed in it before building my LZ23 which has been in there over 5/6 years now.

33 minutes ago, d.p said:

Dang whats all over your plug wires?  Oil? Block looks wet too.  

 

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1 hour ago, mainer311 said:

Yeah Mike, that’s not what we’re talking about. I just need the hose that sits below the fuel pump. I’m not bypassing anything.

I am the one that didn't read your thread properly and thought you were talking about the bypass hose and Mike read my post and continued my mistake.

If you have an L16 in your truck then it didn't have a bypass, it had the jiggle valve, but Nissan moved to the bypass hose fairly quickly, if you ever have to put a new thermostat in, it has to have the jiggle valve or a hole drilled in it(both are bypasses), if you don't have a bypass of some sort, you will and are overheating the head and will have to do a headgasket eventually, a clue is when you are driving down the freeway and your temp gauge is all over the place, it should be rock steady all the time once up to running temperature.

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Yeah, I had that problem after first buying the truck. What I ended up doing in the end was just cutting the jiggle valve out and calling it a day. Everything was fine after that.

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When you removed/cut the jiggle thing out it made that hole bigger which allowed more water to get thru which is good, I always say drill an eighth inch hole, the bypass hose Nissan went to is likely a quarter inch bypass hole/hose, that lets a lot of coolant bypass the thermostat.

 

 

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The correct by-pass returns the coolant directly to the engine again, uncooled. A 'giggle valve' sends partly warmed coolant to the rad which circulates cold rad water back into the engine to replace it, slowing the warm up.

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Well, I got some prep work done on the truck today. Pulled the dizzy and starter motor off. Drained the transmission. Then I started pulling the original oil pump, which was an absolute nightmare. Two of the bolt heads snapped off, and luckily the other two came out with a lot of heat. They were all seized in the aluminum pump casting. I have a D21 pump coming tomorrow, but now I’ll need to find new bolts.

 

I pulled the inspection plate off and didn’t see any coolant on the flywheel, but I decided to pull the trans anyway. There are too many seals leaking and things to spruce up. 

Edited by mainer311
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Got my little coolant hose from Nissan today. Perfect fit. No adapters. No bullshit.

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Anyone know the difference between an output shaft seal and an extension seal on the 4 speed? If oil flows from the main case into the tail shaft extension, why would there be an output shaft seal? Both are listed on RockAuto. I bought both just for the hell of it.

 

My 4 speed is leaking like crazy from behind the companion flange, so it's one of the things I'm rebuilding while it's out. 

Edited by mainer311

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I think they are the same.... I'm bored at lunch.... I was able to cross both the parts as the same.....

 

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There's also an input seal under the front cover, might be worth grabbing that too.... if your gonna pull the transmission.... I think you said your doing the clutch too....

Edited by Crashtd420

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What do they look like? Are they the same and just using two different words?

 

The output seal is what the drive shaft fits into and generally the Nissan one fits all their drive shafts and transmissions. Hell they may be still using it today.

 

32136-E0100 (changes to U0100 later) is for the 1.6 liter 4 speed in the Roadster and 521 plus most other Datsuns.

32136-20100 is for the 2.0 liter exclusively, or at the time of the Roadster but I bet it fits all other Datsuns.

 

 

Ah, I was out shoveling snow and didn't check for replies. Yes my guess is they are the same.

 

 

Critical you grease the seal lips so they don't start turning dry.

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2 hours ago, mainer311 said:

 

 

My 4 speed is leaking like crazy from behind the companion flange, so it's one of the things I'm rebuilding while it's out. 

Companion flange? Is the flange held on by a nut on the tailshaft? Or is it a slip yoke?

 

If it's a flange with a nut, then it could be leaking past the splines. Remove the nut and flange, clean splines and threads with some kind of spray cleaner, install flange, but before you replace the nut, apply a bead of the right stuff inside the flange around the splines at the base of the threads, then install the washer and nut.

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True for the 2 liter 5 speed in the Roadster. My info does not show a bolt on spline on the 1.6 transmission which visually is a longer edition of the 510 four speed and would be sealed at the U joint end.

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Definitely has companion flanges on both ends. Would be weird to have a slip yoke with a flange on the end, but you never know. I crawled under there the other night, and it looks like the flange bolts are really fun to get to. Everything is above the torsion bar cross member.

 

So, this image doesn't show the slip yoke, but definitely flanged on both ends shown here:

https://www.carpartsmanual.com/datsun/pickup-1965-1972/power-train/propeller-shaft/l16

 

And here is the splined flange, lower right:

https://www.carpartsmanual.com/datsun/pickup-1965-1972/power-train/transmission-gear/from-oct-65

Edited by mainer311

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I assumed this was for a Roadster.

 

Indeed the 521 spline is bolt in and does not slide. It might leak but unlikely as the nut and washer would seal it up.

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Not always, especially if the nut had come loose at some point and galled the washer or flange. Most OEMs now days use some sort of sealer on the threads or an o-ring or even a small lip seal.

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Was there a FSM for the 521? Never seen one but it may mention sealer.

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The splines leaked on the x-fer case of my 2012 Xterra, so definitely possible. It's definitely a blown seal on the 521 though. Probably never been changed.

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Transmission and propeller shaft don't mention any sealer.

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You get to the front drive shaft bolts at the transmission flange from the top. Remove the bench seat, then the plate on the top of the transmission tunnel, inside the cab.

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11 hours ago, datzenmike said:

Transmission and propeller shaft don't mention any sealer.

Yeah, but guess what? It's leaking. So in this case, years of use have shown that the designers were wrong.

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Ever driven a 620 at night?  😄 Ever turned the dimmer to the right to turn up the brightness and wished you had Nigel's dimmer switch? Another thing designers got wrong. I'm merely saying I didn't see anything on a quick read through. Sealer is a good idea.

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