Datsun B310 turbo coupe, A15 project

[Atomic]

ARP suggested a kit 204-5402 with following specs to suit the 10 mm girdle:

 

85mm overall length with 25mm of block thread and 20mm for the nut.

The nuts have a height of .404” and a flange o/d of .625”. The washers have a .750” o/d and are .120” thick

 

[Atomic]

Oops, It seems like that kit will be 5 mm too short for the application with the girdle. I'll try to find another kit. The above kit will work with standard main caps tho.

[Atomic]

Alright got another kit 209-5401 with 102 mm length and 25.5 mm of thread on both ends. So that would leave around 7 mm extra thread on top of the nut when washers are also used.

Edited April 2, 2020 by Atomic

[slowlearner]

Is this gonna be the toughest A15 in the world? Love it. 🙂 

I've never encountered an A15 with a girdle. Remind me what rods you're putting in it?

[Atomic]

7 hours ago, slowlearner said:

Is this gonna be the toughest A15 in the world? Love it. 🙂 

I've never encountered an A15 with a girdle. Remind me what rods you're putting in it?

These H profile rods:

(new and old ones compared in the photo) 

Edited April 2, 2020 by Atomic

[Atomic]

To make my prototype life easier, I went and bought a big printer:

it had good reviews and was on sale: https://www.anycubic.com/products/anycubic-chiron-3d-printer

 

Soon I'll be be having dozens of B310 prototype parts 😄 

 

[Atomic]

I'm also planning to make a DIY forge for lost PLA casting

 

[Atomic]

The ARP bolts arrived yesterday, they look perfect for the application with the girdle. The bearings should be here next week according to the tracking. The 3D printer should be here too pretty soon. I'll be printing the girdle first so I can test fit it. I'll look how it fits with the counterbalances on the crankshaft, and how the oil pickup works with it.

[Atomic]

Bearings and the 3D printer arrived, I'm currently printing the main cap girdle for tomorrow mockup:

 

Took me one day to get it calibrated to a level which i was satisfied, but now its rocking well!

[Atomic]

This would be my very first print, and I count it as a success! Couldn't ask much more from FDM printer really:

 

Very little layering visible with default settings (0.2 mm layer height)

 

Surface texture on the heated bed side:

 

Surface texture on last layer:

 

I should tweak the skirt overlap percentage, infill overlap percentage and skin layer count. I mainly had few problems with the cylinderical holes attaching to the filler material, but I think it is easily tweakable. The print feels rigid even with 20% infill, so it's mostly hollow, only 144 grams were used to print this. I think I'll be ordering a resin printer too for really high detail models. All in all, I'm really impressed about the results! Glad I took the time and set up the printer bed properly.

 

Also all the dimensions held accurately. Spot on 10 mm height and the distance between girdle openings 67 mm. Seems like I didn't get any shrinkage with the heated bed.

Edited April 19, 2020 by Atomic

[Atomic]

block is now o-ringed, I think I did pretty good job. I used a a punching tool made out of POM and a small hammer to knock the wire into its snug hole. And then I cut the wire to length when approaching the end and used a file to get the last 0.1 mm off.

 

Small adjustments have to be made for the girdle. The crankshaft and conrods are able to spin freely, but the oilpan wont fit anymore. Also the main cap bolt holes were a bit off from my first sketch. So I'll be shrinking the girdle 20 mm from width and relocating the holes. I'm putting another version to print for next night. Currently printing an electronics box. Also bought a resin MSLA printer for really fine detail works, should be here in a week.

[datzenmike]

I've been following sporadically and thought I knew what you were doing but now I'm lost. The answers are much farther back in your posts. This is a crank girdle? To tie all the main caps together? This is plastic? so a metal one will be based on this design when finished?

[Atomic]

Just now, datzenmike said:

I've been following sporadically and thought I knew what you were doing but now I'm lost. The answers are much farther back in your posts. This is a crank girdle? To tie all the main caps together? This is plastic? so a metal one will be based on this design when finished?

Correct!

[Mattndew76]

I have been considering machining a girdle for the A12 build. just never thought I would be spinning 10K to need it. 

[Atomic]

24 minutes ago, Mattndew76 said:

I have been considering machining a girdle for the A12 build. just never thought I would be spinning 10K to need it. 

Me neither, but it costs 68 euros to make one, so why not 😛 

[Mattndew76]

Better safe than left wanting.

[datzenmike]

Seems the thinnest points where the rod caps pass by will be the first place to flex. It's most rigid in it's own plane... lengthwise and side to side but much less if twisted or vertical forces.  The dashed line in the bottom left... is this going to be thinned?

 

 

 

 

Below is a crank girdle from my KA engine. The main caps are integral but just imagine they were not there and it was as yours is. This is strong in 3 dimensions rather than a single plane and thicker as you like where the rod caps pass under the arches. It also clears the pan and the oil pickup without any compromises.

 

 

Have you thought about a combination windage tray and crank scraper????

[Atomic]

13 hours ago, datzenmike said:

Seems the thinnest points where the rod caps pass by will be the first place to flex. It's most rigid in it's own plane... lengthwise and side to side but much less if twisted or vertical forces.  The dashed line in the bottom left... is this going to be thinned?

 

Below is a crank girdle from my KA engine. The main caps are integral but just imagine they were not there and it was as yours is. This is strong in 3 dimensions rather than a single plane and thicker as you like where the rod caps pass under the arches. It also clears the pan and the oil pickup without any compromises.

 

Have you thought about a combination windage tray and crank scraper????

 

There the material thicknes will come into a play. I would not be too worried about flexing that much as the main caps hold the structure together by themselves. The added laddersupport is then to minimize what is then left and I think those forces do not affect that much so that I would have to worry about it with this 10 mm thick plate.

 

making a girdle with main caps is more expensive, so I'll be staying out of it for now.

 

If you mean a combination like this:

I haven't until now. The crank scrapers will be relatively easy to make, but the windage tray design requires experimentation if I would want to make one.

 

If I would make all of these, I wonder if people would be interested to buy schematics or direct parts. I already have a lot of custom components drawn in CAD that are bolt on to A15 motor

[datzenmike]

I did say..."The main caps are integral but just imagine they were not there" so not at all suggesting like the KA. If it was like shown it would be more rigid.

[Atomic]

Got the second version to the block, the hole alignment is now spot on and I used the Opel ARP studs to test out:

 

The size difference is quite noticeable from previous version:

 

The oil pan didn't clear the corners of the version two, and there is still plenty of room to work with on conrod side:

 

So I made more adjustments and reduced the size another 20 mm and gave the wall thickness another 2.5 mm to make it more rigid. I'll have the new print ready in 11 hours, so I'll be testing it after I get out of work tomorrow. This printer is seriously a prototype king, makes everything so much easier. I'm also starting to design the scraper tomorrow when I scan some sketches to the computer.

[Atomic]

Third time is the charm? I got the print ready and tested before going to work, seems like a good fit and I'm able to rotate the assembly and close the oil pan with this. Next step would be to flatten out the main caps to get even surface to mount the girdle on. 

 

 

Last check will be after I get those caps done and then I need to fit the oil pickup tube as it is not fitting yet. I have considered making my own too.

[Atomic]

Started printing the crank scrapers:

 

Super happy that I got the large print bed, almost wasn't going to fit the model there

[datzenmike]

Only need right side scraper. The left will hold the oil above the oil pan. Would you combine with a windage tray to keep oil splash from hard handling from splashing the rotating assembly?.

 

I made this combined scraper/windage tray for an LZ24 I'm making.

[Atomic]

Got the first prototype:

 

Some 2-3 mm clearance from the balancers:

 

and rod clearances need some tweaking:

 

The first and third cylinder are located eccentric from rest so I need to adjust their rod holes a bit towards the block face. 

 

And as for combining windage tray and crank scrapers, I think I first have to get the girdle to its proper level and verified before making an integration between all of these three components and see that they're properly sized. Then make some mounting holes for the windage tray afterwards. 

 

[datzenmike]

You only need a scraper on the right side. The left side throws are coming down bringing oil and spray with it into the pan anyway.  A scraper will catch and trap oil above it. How will it get around it and down into the pan? It's not needed.