Nice info here: http://www.alfabb.com/bb/forums/carburetors-fuel-injection-air-intake/101677-replacing-throttle-plates.html

Okay, after reading the post that Philip provided you guys have convinced me to take the carb off and take a closer look at the throttle plate.  I do not want to risk any damage the bores in the carb body.  Tonight I will attempt to fill the hole and smooth out the outer edge.  Seems do-able with some rosin flux and solder.

4 hours ago, Hardway said:

Okay, after reading the post that Philip provided you guys have convinced me to take the carb off and take a closer look at the throttle plate.  I do not want to risk any damage the bores in the carb body.  Tonight I will attempt to fill the hole and smooth out the outer edge.  Seems do-able with some rosin flux and solder.

i think that is a good idea. brass solders fairly easy

Well I wouldn't necessarily give up on the replacement and go back to trying to fix the old drilled one. My biggest issue with the replacement is the burrs. I'm worried that they will gouge the aluminum casting inside the carb throat. But it's not hard to fix. You should be able to dress the burrs off easily with a piece of sandpaper on a hard surface. Couple swipes and they should be cleaned off. Just make sure you don't get too aggressive and remove good material. Keep the corners sharp, but not burred.

The rest of the workmanship stuff is annoying, but won't affect performance. Except......

Have you verified that the edges are bevel cut and not straight cut? Can you see the bevel on the original plate?

Edited November 30, 20177 yr by Captain Obvious
Attached pic highlighting burrs

Per everyone's input and suggestion I took a stab at filling the hole in the old throttle plate.  Using my soldering iron and some rosin flux paste I let it really cook in the crevice the hole.  With it still hot I added solder to it.  Once everything cooled I started sanding the solder down with some 600 grit sand paper.  I followed the up some 1000 grit and then some super fine 0000 steel wool to clean up the plate.  The surface is super smooth despite the visible scratches.  I paid attention to maintain the taper of the edge of the throttle plate so that I only flattened the solder and did not disrupt the angle of the taper.  All in all it came out better than expected.  I really kick myself for not doing this first as it would have saved me $15 and 2 weeks of time.  Oh well, need to take more changes in life!

I swapped out the throttle plates and after studying the new one some more I could see the taper on the edge was not as steep as the taper on the original.  I checked the bore for any grooves and could not see or feel any.  With everything re-installed and buttoned up I fired the engine back up and at idle I am getting a solid 5 on my sync-meter across all six bores.  Throttle response all seemed the same as before but I rest easier knowing the right part is in the carb.

Way to go!  You da man!

2 minutes ago, 240260280 said:

Way to go!  You da man!

Thank you Philip!  Unfortunately the hits keep coming with the Red Rocket.  I decided to do a valve adjustment since they were tapping pretty good on the last test drive.  Some of the locking nuts were so tight I had to use a cheater bar to break them loose.  Thankfully they all saw things my way and everything went in to spec.  It is a stock cam so I set it stock specs. 

As I was turning the motor over by hand I kept hearing this tap but couldn't figure it out at first.  Then out of the corner of my eye I saw the timing chain tap the inside of the head.  I almost thought I was seeing things but my fear was realized when I moved it with my hand.  It is stretched for sure and warrants a replacement sooner than later.  Luckily I have a new chain kit in the box and all the gaskets already from the lime green Z when I thought about doing it on that one.  I will pull the engine to do it as I would like to clean everything up, possibly paint the engine bay, and inspect the clutch.  For now, here is a video.  Feel free to weep with me.

 

With the valve adjustment done I turned my attention to the driver side door.  With the rebuilt hinges the action of the door was much more solid but in order to close it required slamming it hard as I could.  Knowing the new weather stripping was a bit big I removed it to ensure the door was aligned properly.  With the weatherstripping off the door closed like butter, effortlessly latched, and opened with almost elegant satisfying sound you expect and want in any vehicle.  Since the door was spot on I took a risk and cut the bottom third of the weatherstrip off along the lower half of the door opening.  This helped a lot as now the door only required a good push to close all the way.  However this is not what I want to have to do to close the door every time so I am looking at the Kia Sportege seals and taking a long look at the McMaster-Carr weatherstripping.  There is already another recent thread on this topic and I will be following it as well.

  

Would some or all of that slack not be taken up by the oil pressure moving the chain adjuster????

As previously mentioned one of my horns was not working properly and I have purchased a restoration kit for them.  I want to get the car on the road as soon as possible so I decided to run some after market horns for now.  After some research and YouTube comparison videos I settled on some Hella Sharp Tone horns for $27.99 shipped off eBay.  Don't let the name fool you, they sound like modern loud vehicle horns.  They come with yellow cages on the front which would make them stick out from the rest of the car so a color change was in order.  After a once over with some steel wool to knock the shine off the paint I put two light coats of satin black on them.  Painting conditions were not ideal this weekend and but they look much better and on the car you don't really notice them, which is the point.  With the horn button pressed everyone in the immediate area will take notice!   

I worked on other stuff too but it was not really picture worthy.  This included installing some used door panels that did not have any speaker holes cut in them.  With the door panels off the doors were vacuumed out, lock and latch mechanisms lubed, and the window tracks were greased.  I installed some new side mirrors and adjusted the rear brakes shoes as they were a little too tight.  I did get to drive the car on a short shake down run and it performed very well.  I love the sound of the triple Dellortos, the transmission shifted very nicely with the new fluid, and everything seemed to be humming along quite well.  I did notice the car tracking to the right a little and as I drove it some more it only got worse and I could smell brake material.  Once I was home and the Z back on the lift I confirmed the right caliper was sticking.  I am picking up a new/rebuilt caliper and hose tomorrow so that should be resolved tomorrow night.  With the carbs running so good I put the air filters back on them which is 30 minute job due to their design and limited space.  All in all, a very productive weekend!  The final Cars and Coffee at the Oasis is next weekend and I plan to be there even if I have to tow the Z up there.  Hopefully it won't come to that as I am really looking forward to making some runs down the toll way in it.  Stay tuned! 

There is always a lot of Datsun "spirit" in your posts.  Motivating like watching car restoration TV programs.

 

For the chain slop, are you turning CW at the crank (ref. standing in front of car)?  Usually the left side (ref. driver) has tension all the time when turning and when stopped so it will not flap that much until lifting pedal at high revs. The tensioner on the other side usually takes up the slop after the oil pressure is up so the slop will be less on the road... but as you say it does look like a lot of slop regardless. 

You can have a look for stretch by using the triangle cam sprocket markers at TDC.

Check the inside of the valve cover above the chain to see if it left you any gifts.

 

Maybe do a compression test too while you have the engine in the car before pulling it.  You may want to do more when it is out

Edited December 4, 20177 yr by 240260280