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620 Land Speed Record


distributorguy

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I don't remember if meth injection is allowed in production classes.  I think it is, but we won't have time to test it before we go.  Here's a glimpse under the back of the truck.  A discerning eye will catch a few of the changes, of which there aren't many.  Shocks will be installed as soon as I pick up the correct locking hardware.  

 

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It took over 3 hours to make 3 relatively simple tubes last night - the helmet halo.  One more down bar on the right side of the driver and a few small gussets and I'll be painting the interior (rattle can white.)  

I can't wait to work on brakes just for a change.  I just need to run lines and mount the master cylinder.  I can't recall if the front or rear of the master cylinder feeds the front brakes - can anyone help me here?  

 

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After a LOT  of phone calls, I found a set of custom domes pistons on the shelf that will work with a set of custom rods, also on the shelf, not far off of our original build design and capable of making the 250 hp we need.  Plus the cam showed up today, and short of mapping it out, it appears to be exactly what I wanted.  Monday the custom header flanges arrive ( I made extra if anyone needs them) and Tuesday I should have all the reciprocating assembly minus small end connecting rod bushings and main bearings for the custom rods.  

 

What a roller coaster this week has been!!! :frantics:

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The cage is steel.  Weight is important - but for the opposite reason than in any other racing.  To a large extent, heavier is better.  Traction isn't a guarantee via blacktop or concrete, rather its like driving on wet sand or snow.  Weight not only aids traction, but it keeps the truck acting like a flywheel and helps maintain momentum.  We have 2 miles to get up to speed and another mile to hold that speed for the average of 2 separate mile markers to attain a record.  Speeds are recorded at 1 mile, 1.25, 2, 2.25 and 3 mile marks.  The average of any two that are 1 mile apart can earn a record.  

 

Last night the team truly rallied and a large amount of loose ends were tied up.  Seat belt mounts, fire suppression system mounts, hood pins, rear window, doors assembled, and wiring strung.  We also got the rear tires and had them mounted.  Right now I'm off to have all 4 wheels road force balanced!!!

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A question. Anyone every use a carbon fiber drive shaft in one of these land speed attempts?

I forgot to mention the wheel change idea - that it will gain 10 mph.  Barry actually tried 3 different tire sizes and gained something like 1/2 mph.   I'm impressed that they got over 120 in the first mile, but that will equate to 115 on the salt at best due to altitude.  We have 4:36 and  4:11  rear axles to chose from.  The lower (higher numerically) is probably better for top speed when wind resistance is a factor, but more dangerous due to driveline speeds.  I speculate with the 4:11 that our driveshaft will be rotating around 6200-6300 rpm, which will require a solid carrier bearing as opposed to the rubber diaphragm mount.  Barry runs a one-piece shaft, but that will have a tendency to "jump rope" in the center due to length, especially considering he's got a 'lil Hustler long box.  

 

You may note that I'm sharing a lot of design info, while others will not.  Our goal is to earn the record against the best possible competition, no tricks, no surprises.  This photo is only one of the obstacles we had to overcome early in the build:  a sandblasting outfit ruined the entire front clip and box. 

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Yes of course, but at 250 hp that would be serious overkill.  A close friend of mine used one in his drag car, and the harmonics made it explode while dyno tuning - right around the 1100 hp mark.  The driveline shop who rebuilt and balanced my driveshaft liked the idea of a solid carrier bearing mount and a 2-piece shaft.  

There is also serious conversation about lightening flywheels versus keeping them heavy/stock, and the general consensus is that it doesn't make any difference in land speed racing, other than flywheels that are even mildly marginal having a greater tendency to explode.  

Yesterday's progress included continuing to assemble the doors, finishing the fire system bottle mount, as well as building the dash panel and installing it with the dash. I also splashed 6 rattle cans of white paint in the interior.  Today I will mount the fuse panel, rollover fuel cutoff switch, and possibly the master cylinder, which will be complicated in that I can't use power brakes with a 15:1 engine that produces no vacuum, and problematic in that the Weber carbs may simply not fit with the booster in place.  

 

 

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After I thought we'd never get pistons in time, the miracle has happened!  They're already here, but from a different source.  Its all good - they're better than I expected and will do just what we need.  

 

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The header flanges should be cut tomorrow.  Apparently the laser operator had a case of the Monday flu from the long weekend.  

 

Sunday my bud Chuck got one door completely assembled with a Lexan window installed, one waiting for another chunk of Lexan.  We even have a set of NOS blue door cards to install after they are mounted in the truck!!!  Please ignore where some previous owner hacked in speaker holes with a jackhammer!

 

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And 100% new brake lines have been run throughout.  They're ready to bleed!!!  I'm torn between Castrol GTLMA and Dot5 fluid.  The system is all brand new, so either will work.  Castrol leaves a better pedal feel, DOT5 boils sooner.  

 

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And least importantly, the interior received its 2nd coat of white paint, and some "grip" spray on the driver's floor to make it easier to climb in and out with a helmet and Hans device on.  

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Yes we are allowed a flush tonneau cover, or without it we can be tailgate up/down, or off.  Everyone generally runs a cover, open in the front area???  Ours will likely be a fast Home Depot built platform.  That way we can experiment with it, as I think we may be allowed to lower part of it, to help create more rear downforce.  I am also contemplating a "partially down" tailgate in a fixed wing position.  

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Last night I built most of the header.  You won't find this one in any catalog.  Huge primaries, stepped tubes for top end power, designed on a proprietary flow software specifically for designing headers.  

Sorry for the terrible photo - it was another late night in the shop.  They were as close to an equal length header as I could fit in place while using pre-bent mandrel tubing.  Its cool that the primary (smallest) tube size is larger than most Datsun tailpipes!

 

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And more good news - the connecting rods arrived and while they will require a fair amount of work to install, they will offer a few significant advantages.   :thumbup:

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3 more hours of work and the collector is 99% done (trim to fit) and the tubes are TIG'd.  That's a 4" collector, for size reference.  

The rest of the exhaust system will likely be composed of another 8" of pipe, 2 90's, and one 45 degree mandrel bend.  No restriction, to allow for us to reach redline in 4th gear quickly.  Yet, even blowing a small amount of air into the pipe creates a vacuum in the header and helps to extract air from the cylinders!  

 

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Last night started out slow but ended with a HUGE amount of work being done.  The brakes work!  The wiring harness is more than half completed.  The passenger side door is mounted & aligned (mostly), and the rear window is installed.  Supposedly today my engine builder will get the cylinder head either done, or almost done.  The block is also back from machining, just waiting on the crank now!!!

 

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I didn't check to see if the NOS arm rests that go with the NOS door panels fit around the door bars?  

 

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Yes, we're actually required to have a horn!  As silly as that sounds, its part of being in the Production class.  

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I didn't check to see if the NOS arm rests that go with the NOS door panels fit around the door bars?  

 

 

 

 

Just 'glue' them on where ever they will fit. I imagine the doors are welded shut?

 

 

 

This should be interesting and will answer many questions from members. How easy people think going fast is.... just throw a 5 speed in it, throw a 3.364 rear end in it, lower it, add 50 more hp.

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