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MARTS-PL310 61 Datsun Bluebird Sedan


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A tale of two Bluebird transmissions. Had to take the trans out to continue and detail the tunnel weld work.

I suppose I couldn't wait months to post something else.

The all synchro side loader coming out. It was wedged against the firewall and momentarily stuck until I tilted the engine some more.

The all synchro 312, 311 Bluebird side loader trans. It's a beast. Longer, wider and heavier than original 310 top loader trans.

Side-by-side trans compare. 310 Bluebird top loader on left and 312 & 311 Bluebird side loader on right.

The 310 trans uses a carbon hockey puck release bearing whereas the 312, 311 trans uses a  rolling element bearing type. 
Sure wish I could find a verified source for otherwise unobtainable replacement parts for these two trans. Top loader needs a new 2-3 shift fork (completely worn out), input shaft for 2-3 (sheared off) and external lever arm for 2-3 (lost). Otherwise, as a last resort, I could get them made with expensive machine shop fabrication.

I believe the side loader is is going to need a 2-3 shift fork soon as well since it does not always stay fully engaged in 3rd (high) gear on rare occasions.

I actually prefer to use the top loader with its non synchro first gear as it is the much slicker shifting and shorter lever throw trans. Without repair parts though, it's not going back in anytime soon.

As the situation stands, I'll reinstall the side loader after completing the tunnel underside details including epoxy primer.

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Building the 1961 Datsun 310 Bluebird Floorpan - Details.

I have a large number of photos and so I'll split this update into several posts to minimize any load delay.

Picking up the story from mid-August 2019, beginning with making underfloor bracket replacements.


The first of two bracket replacements, all the others were salvaged from the existing floor. This first bracket is simple, but I had destroyed the original by cutting off the flange that attaches it to the inner sill. I just sketched up the right side bracket while laying under the car. Left floor bracket has the flanges bent in the opposite direction from the sketch.




The second bracket that needed replacing. The underfloor support, inner attach for the lift jack pipe and parking brake lever attachment. It appears to have been destroyed by road debris that was run over by a previous owner. My guess is piece of rebar hit at 60 mph by the front tire that was kicked up and pierced the underside. The damage included a hole in the floor and a severely bent  steel shaft for the parking brake.


I split it in half for measurements since that's that way I'll make a replacement and then weld it into one. It includes minor complications to be duplicated such as the gusset bumps and welded on 5/16 - 24 fine thread square nuts (which are hard to find in 24 pitch thread btw).




Made the halves out of 1.5 mil. Initial checks against the inner sill.





Making parts and finishing up the welds. Then I welded on the square nuts, fuel line clip and forged the four gussets into the corners with 3/8 inch rod, some heat from a MAP torch, and backed up with angle iron.







The hole in the middle is where it will get pinned to the lift jack pipe. Nissan had brazed the original attachment to the pipe sides but that's not practical for me since I'm welding this to the floor first and attaching to the pipe last. The heavy oxidation was later cleaned off with a soaking in muriatic (hydrochloric) acid.

Additional posts soon...




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Building the 1961 Datsun 310 Bluebird Floorpan - Trimming the perimeter.


Started off by taping together a big piece of cardboard.


Then carefully trimmed it to fit between the inner sill, toe board, tunnel and rear seat box.



Added extra margin with heavy paper to the edge. This was laid into the floorpan.



Then I pie cut and panel beat the mating trans/drive tunnel edges to merge in accordance with the cardboard/paper template. The other edges were bent similar but with less beating since no blend radii were required. 



The result.




First of dozens of fit checks in car. It looks not too bad for a start. It's a lot better than the rusted out floor that was there. Visible progress finally!

I left it this way for a long while since the excess material made it a bit easier to grasp the floorpan by the edges and pull it out after each fit check. Much later, after doing several other feature additions, bend/panel beat tweaks, and satisfied the trim edge plans were stable and would work, I taped and trimmed all the finalized edges, then applied an angle grinder cut-off wheel and tin snips.



Next up is duplicating factory body mount indentations and other stiffening features.

Still lots more to catch up on. Might take me the rest of the day to upload it all.


More posts soon…




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