Fisch's '71 510 LZ22 - "Chapman" Fogs and Bre Spook+art

[fisch]

I know crazy right! But knowing me I will hit a lull soon enough when the holiday weekend is over and won't update as often. Also paint won't stick so well in the cold so some of the custom things I am thinking of may have to wait for warm weather!

 

Chris just wrote and mentioned he didn't think the choke was pushed all the way back in in the vid (Cable is a bit sticky.). So the idle will pop up a bit form there! But I still love the way it rumbled!

[Zombro]

Yeah, Finally Caught up and saw the videos. Very nice. Great job on both projects.

[datsunz]

Looks great so far. If you need anything powder coated or ceramic coated, let me know, I will take care of you. If you Ski93 i'm right off it. I have a set of 14x7 5 slot mags at the shop if you want wider tires. Have fun.

Chris

[fisch]

DatzenMike had a trans question about the tight spacing between 3rd and fourth on the Mongrel 5 speed (200 RPM difference) in Chapman, I was curious too and Chris was happy to answer. Trans gearing talk is a bit over my head, but I thought I'd share to keep it all in one place:

 

 

Mike's question: "200 RPM? drop on the 3-4th shift? Most 4 and 5 speeds have a 24% change in RPMs into 4th. This would require a 3rd RPM of 840 to get a 200 RPM drop into 4th. Some competition boxes have a 12% drop so this would work out to about 1,700RPMs in third. Maybe he meant 2,000 RPM drop???"

 

 

Chris's reply:

When I was selling Chapman, my ad copy mentioned that the mongrel transmission had a very close 3-4 gear split.  IIRC I think I said the RPM difference between the two was only 200 RPM.  I'd like to explain.

 

I combined two transmissions to get this mongrel tranny.  I had a truck box with a .833 overdrive, and a 280ZX box with the .745 overdrive.  I figured I'd put the .745OD fifth gear into the truck box.  When I took the trannys apart, much to my surprise, both 5th gear sets were identical.  Nissan manipulated some of their OD ratios by changing the input/layshaft ratios.  I swapped input/layshaft gears fron the 280ZX box into the truck box, because I really wanted the .745OD for a long trip.

 

The net result of this was to move gears 1, 2, & 3 closer to 4th.  Looking at the truck & mongrel box numbers, the splits for 1, 2, 3 are the same, but the 3-4 split is 24% in the stock truck box, but only 15% in the mongrel box.  See the linked images to see the numbers.  I hope this explains things a little...

 

Inside an actual gearbox:

 

 

The gear count charts of the various boxes:

 

 

 

 

I think I grasp teh concept, but the nice thing is that Chris supplied a fresh built 720 5-speed in case I want to swap it.

[Pacific coast Datsun]

"wow this thing has an attitude"......Yess kool video's Scott !

[datzenmike]

Scott, thank-you for that. This elegant idea allowed a lot of other items to fall into place. Instead of different 1, 2, 3 gears for every tranny they can be made wider or closer by varying the main/counter ratio first. I'm going to start pulling gear part numbers and matching them to known trannys. Maybe put in chart form. A bit esoteric for most but I would love to build one with a .745 over drive. Maybe there is one higher that can be built???

[M.Creer]

Sick 4 door. I'm likin that exhaust setup.

[goes2fast]

Thanks for posting the trany info, that will be helpful to more than one member I'm sure. Are those Z carbs or SSS carbs? That is a nasty sounding cam, you should turn the idle up a little, so It doesn't shake itself apart though, I used to have a 2.0 Pinto with a nasty setup, 11 to 1 pistons, ported head, headers, and a 310 degree duration Crane cam. It was very fast, but unless you turned the idle up to 1200 rpm, it would shake so much that bolts and screws would loosen, and I was afraid that sheet metal might start cracking. Even at 1200, the front fenders would rock at traffic lights, and people would ask what was wrong with my car. LOL When the light turned green they would find out it ran fine, especially from 4500 to 8000, it was like a rocket! :P

[Skib]

Are those Z carbs or SSS carbs?

 

 

Z car carbs

[fisch]

Yup, Z-therapy carbs! "46mm Z-Therapy ball bearing shafted SU's custom profiled needles on port matched SU manifold. Custom modified 240Z airbox (with OEM airhorns) that takes OEM 240Z filter."

 

I believe Chris custom blended the spacers so that they would taper from the 46mm to the size of the manifold. Pretty neat! And in true Ratsun form he used a license plate as the heat shield!

 

I think the choke is stuck on in that video. (Cable slipped so I thought it was off when I pushed it in.) Indeed, when I test drove it the idle was up quite a bit more. I thought it was just the cold of the day when I filmed. :P

[WAGON JON]

Ooh! nice diagram. Gotta save that in tah memory.

[Jester]

Hey Fisch..........remember this one?

 

 

Updates???????????

[The Dat-side]

[fisch]

Thanks for the interest guys! Alas this puppy is tucked away hibernating until this snow is all gone! (Worst winter going back to 1911 I've heard.) Since I wasn't gonna drive it this winter, I haven't even registered it yet! Kinda crazy that I have this bitchin 510 here and have literally only drivin it once around the block and that was the day I bought it!

 

I can not wait for spring though!!!

[Farmer Joe]

man i cant believe you have THREE datsuns tucked away... i dont know what your gonna do come spring... lol

[The Dat-side]

And three awesome Datsuns! I can't wait for spring.

[fisch]

No progress, but things are starting to melt so I am getting excited! Little pic from a few months ago. Daughter built a tiny snowman on the hood!

 

I've scrubbed the cammo paint off the hood, grill and bumper, so I guess I made a little progress since this shot. I am feeling the itch!

 

[bonvo]

so which are you gonna work on this spring the 510 or the 59

[fisch]

Good question B! The wife REALLY wants me to get on that '59 so she can drive it. She said the other day, "Do I have to start turning the wrenches myself?" (Gotta love her!)

 

But the plan is simple in my head:

 

1. Get the cammo paint off the dime and daily that brute! The good news is the car needs nothing but a driver.

 

2. Work on the '59 while dailying the Dime!

 

3. Engine swap for the 'ol 521 at some point (New engine is on the stand.)!

[Jester]

Paint removal and engine swap can happen INSIDE the shop. Shit or get off the pot man.

[fisch]

Question guys. I was thinking about pulling the air cleaner on my SUs so I could get the paint off and repaint it. Chris (the po) drove this thing all over creation, so I think it will work great as it, but this is a Z air box and is so long it is almost almost touching the radiator hose. So I imagine it is sucking hot radiator hose air pointing right there.

 

Would a shorter box make any difference in the breathing? Or is the air under the hood so hot it wouldn't matter? This thing looks just fine to me so I don't mind painting it up and running it so if it is matter of splitting hairs, I don't know if I'd bother. What do y'all think?

 

[exit64]

I would use a roadster style filter on there if you can make it fit the carb spacing. They are open all the way around the outside and you can modify a K&N round filter to work in place of the stock element.

[exit64]

What # intake is that. I have a 220 for an L series that I can throw some carbs on and check the spacing of the roadster backplate if you want.

[goes2fast]

I would shorten it enough to get a duct hose on it, and run it to behind the head lights, then find a K&N element to fit. That would give cool air and low restriction. :)

[fisch]

What # intake is that. I have a 220 for an L series that I can throw some carbs on and check the spacing of the roadster backplate if you want.

 

Thanks for the offer! The intake is a K-14? I am so new to two carbs it isn't funny, but Dislexic mentioned the K-14 "-is the later intake with the balance tube that gets rid of the piston flutter at cruising speed." in another thread.

 

 

They are big ass 46mm Z-Therapy carbs (from a Z naturally!) if that matters for spacing?