My 1971 521

[thisismatt]

Mike, you just aren't looking hard often enough.  I check ebay multiple times per day just out of habit.  All my hoard is NOS, save for maybe one windshield weatherstrip.  It's out there, just few & far between.  Ebay has been really dry lately, though.

Edited April 16, 2021 by thisismatt

[Charlie69]

By the way d.p I am just joking with you about the money wasted on parts for your 521.  This is an unavoidable rabbit hole that any one doing modding on any car or truck experiences, myself included.  Years ago when there was a good rotating stock of various Datsun/Nissan cars and trucks in the wrecking yards I would spend days in various yards pulling parts and trying them on on trucks like I owned and was modding.

 

When my brother and I put my first Z20 5 speed in a 69 521 J13, this truck was  AZ titled and registered as a 1970 because even though it was a 69 it was first sold in AZ as in 1970 so the 70 title and registration.  Any way, there was a 71 521 in the wrecking yard when I pulled the Z20 5 speed out of the Datsun car.  I took it to the 521 and set it in to see if it would fit.  The oil pan and pickup tube did not fit because of the center link and the cross member.  I ended up buying about a half a dozen oil pans and pickup tubes before i found out the stock 521 L16 oil pan and pick up tube was the one I needed.  Remember the 69 521 had the J13 engine.

Edited April 16, 2021 by Charlie69

[Charlie69]

7 hours ago, MikeRL411 said:

Roeberk makes a replacement mirror that almost duplicates the factory Datsun ones.  It even fits the factory installed door mount plate.  I said "almost" bercause it improves on the original by having the tensioning screw for mirror adjust fixing on the back of the mirror arm, not under the whole mount [you have to remove the factory mirror to access the internal locking screw].  Externally except for the visible locking screw it duplicates the fit and function of the original door mounted mirror.  Just go to an auto parts store and look for the round replaacement Roeberk.

 

Alternately there are several replacement mirrors [only] that might be the correct diameter.

Glass shops here will cut mirrors to fit and silicone them in.   Last one I had done was under $20.

[d.p]

9 hours ago, Charlie69 said:

Glass shops here will cut mirrors to fit and silicone them in.   Last one I had done was under $20.

 

I know man, I have 3 cut and glued in on the mirror I already have.  First one glue leaked through the glass and fouled it all up, had to pay them to cut a new one.  So thats 2, 3rd time mirror went limp and the only way to get to the screw is by breaking the glass (glued in) and that was a bitch in and of itself.  So I tightened the screw, got new glass put it in and then the mirror went completely limp so I have no interest in trying to save it.  I think its just done.  

 

And I know about the money wasted, it is what it is and I am willing to pay but not really willing to pay $250 for a single side view mirror.  

[d.p]

9 hours ago, Charlie69 said:

I am told the 720 Z24 block mounted alternator bracket moves the alternator up toward the water neck making more room for a larger alternator.  I think that is the style bracket on my L20B in my 66 520.   The block alternator bracket mounting holes are the same on the L20B,the Z20, Z22, and the Z24.  I do not remember if the L16 and L18 blocks are the same but I believe they are.  I am also running the 280zx water inlet neck that has a threaded hole instead of a cast in hose nipple.

 

 

This combination I was able to get a 100 amp Saturn alternator in my 66 520 with the 66 chassis still under it.  I did not have much movement for tightening the belt is why I chose to go with a 60amp 280Z alternator.

 

I will look for a Z24 block alternator bracket.  It is tight down there and a bitch getting alternators in and out due to the lower radiator hose and the fact that you can't take them out from below.  

[d.p]

9 hours ago, thisismatt said:

Mike, you just aren't looking hard often enough.  I check ebay multiple times per day just out of habit.  All my hoard is NOS, save for maybe one windshield weatherstrip.  It's out there, just few & far between.  Ebay has been really dry lately, though.

 

I check ebay every couple days but only really looking for replacement parts, like my mirror.  No interest in hoarding anything so even if I do see something NOS and I don't bother.  

[datzenmike]

I don't remember my 521 but the 620 has a grease fitting on the top of the idler arm directly in the way when tensioning the belt. I didn't but should have replaced it with a plug. In the '90s I got a 720 mount as it positions the alternator 1/4"? higher and a 280zx? lower water inlet because it's more swept back than the L20B one. I think it was the zx one but although they all have the heater hose connection they don't all have the much smaller bypass hose as well because the EFI didn't need this. I don't remember getting if from a carburetor 240/260z. Maybe. The larger 50/60 amp alternator was still a shitty fit and the belt had to go on the pulley first then the mounting bolts.

[d.p]

Mine does as well, anyone know the thread/pitch on that zerk fitting?  And yeah belt has to go on before the bolts or its never getting over the pulley.  I think I am a master at installing and uninstalling alternators on a 521 now and can do it in no time whatsoever.  

[thisismatt]

40 minutes ago, d.p said:

 

I check ebay every couple days but only really looking for replacement parts, like my mirror.  No interest in hoarding anything so even if I do see something NOS and I don't bother.  

Same. I only have multiples of a couple things 🤷‍♂️

[mainer311]

I used a 720 alternator mount and the same belt from my L16 went right on the L20b no problem. I don’t know why Mike always make the alternator fitment a big deal. There’s nothing to it.

Edited April 16, 2021 by mainer311

[d.p]

Where did you get the mount from?  I could have probably sued my original belt but I didn’t mark it so I just bought a new one.  
 

also is it normal for jets to always back out of Mikunis?  Another one backed out today this time on #1.  Truck got progressively worse while driving and when I stopped to check the plugs #1 was fouled.  
 

 

[datzenmike]

3 hours ago, mainer311 said:

I used a 720 alternator mount and the same belt from my L16 went right on the L20b no problem. I don’t know why Mike always make the alternator fitment a big deal. There’s nothing to it.

 

Just my experience with a 620. (my 521 snapped the mount bolts off in the block, I transferred the alternator to the driver's side) Drove around fine for a few weeks but the belt slipped and when tightened it banged on the idler arm and the fins nicked the radiator hose. It's just not a good fit with larger diameter alternators and why (or one of the reasons why) the 720 has the idler on the outside of the frame. 

[banzai510(hainz)]

1 hour ago, d.p said:

also is it normal for jets to always back out of Mikunis?  

 

Mine back out all the time.  I carry a screw driver with me all the time in glove box.

This is usually it above idle it will start cutting out. I dont know why it does this. My 44s never did this.  I dont want to overtighten it as the pop metal on the carbs are a casting and not overly strong.

Maybe Stoffregen Motorsports on here will know how to lock it down w/o pluggiing up the jet

Edited April 16, 2021 by banzai510(hainz)

[datzenmike]

Put some Blue on the threads.

[banzai510(hainz)]

Mike wont the gas desolve that Blue permantex???

[datzenmike]

Thread locker, whatever it is. Blue/Red, Don't know. Would be a poor product if oil and gas dissolved it and main caps flew off.

 

I've even scored the threads so a nut  won't back off. (not on anything important)

[mainer311]

Loctite 243 is an improved version of blue that is less impervious to oil contamination.

[d.p]

10 minutes ago, mainer311 said:

Loctite 243 is an improved version of blue that is less impervious to oil contamination.

I have that but will it hold up against fuel? 

[mainer311]

7 minutes ago, d.p said:

I have that but will it hold up against fuel? 

I’ve never used it in an application with direct contact. My guess is that the bowls would need to be drained, the loctite applied to the threads only, installed, and wait 24 hours for it to cure. I’m fairly certain that after curing it would be okay.

[john510]

5 hours ago, d.p said:

Where did you get the mount from?  I could have probably sued my original belt but I didn’t mark it so I just bought a new one.  
 

also is it normal for jets to always back out of Mikunis?  Another one backed out today this time on #1.  Truck got progressively worse while driving and when I stopped to check the plugs #1 was fouled.  
 

 

Don't know if it's normal but mine do the same thing.I've tried just a dab of gasket maker type stuff and Loctite.It doesn't work.What did seem to help was tightening the jet pretty firm which is somewhat scary.I didn't want to strip anything.I'm just used to it and now have wingnuts on top of the covers so i can check it quickly when i do all the normal checks.It will run like shit when they loosen up.You definitely know a jet came loose.

Edited April 16, 2021 by john510

[Crashtd420]

Does mikuni sell a special tool to tighten them.... there are 2 flats on the side of the tube.... 

 

Are you tightening the tube with the top jet installed?

I would remove that top jet and see if you can tighten the tube first, then install the top jet.. 

[thisismatt]

Put some springs on top of them? 😅

[d.p]

1 hour ago, john510 said:

Don't know if it's normal but mine do the same thing.I've tried just a dab of gasket maker type stuff and Loctite.It doesn't work.What did seem to help was tightening the jet pretty firm which is somewhat scary.I didn't want to strip anything.I'm just used to it and now have wingnuts on top of the covers so i can check it quickly when i do all the normal checks.It will run like shit when they loosen up.You definitely know a jet came loose.

yeah one bolt on top of the carb stripped today when I was trying to get it off. Maybe I’ll get some wing nuts for them and have a tool kit in my truck for stuff like this.
 

One top plate screw was soft as shit and I stripped it today trying to back it out.  And yeah you can definitely tell when they come loose. Truck misses like crazy.  I guess all that I read about constantly fucking with dual side drafts was true.  

I don’t know if they sell a tool if so probably NLA now anyways.  I just tighten them with the jets in them as they are slotted. Taka said just tighten them down as they’re brass and need to be tight. 

[d.p]

I was thinking there’s got to be a way to lock them down somehow. Like one of those locking wires that flip over the top like a mouse trap.  
 

oh got my trans cover painted install. Made a world of difference in sound vs heat deterrence.  

[banzai510(hainz)]

On 4/16/2021 at 5:41 PM, d.p said:

have a tool kit in my truck for stuff like this.

Dude that is a no brainer on that one.  better have a tool kit!!!!

 

Maybe squeze the jet block threads with vise grips and flatter the threads and maybe it will hold  better( OK Im guessing on this one). Maybe Stoff on here would know more on these..

Ask the MIkunis guys you bought all your stuff from what does he do. and tell us

 

Yes Mine back out and its no very reliable and I dont know how they did it back in the day in the Africa Safari Ralley and won for years w/o the jets backing out