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Member Since 24 Apr 2015
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#1511535 620 Land Speed Record

Posted by distributorguy on 20 August 2017 - 11:08 AM

Sorry Rat - we spent as much time as we could over on the rookie course or the short course.  We got in 11 runs overall, if I'm counting correctly.  

#1511524 620 Land Speed Record

Posted by distributorguy on 20 August 2017 - 10:19 AM

I don't think I'm allowed to use a quick change in production class - plus they sap a lot of hp that we can't spare.  Only 230 hp or so, and no traction so I'm not too worried which axle we can fit.  If they are cheap, we can bring an entire assembly and swap the works.  


Mike, is that ZX ratio with the 1.858 or 2.077 2nd gear?  

I only have a 4WD trans, so I'm not sure how I'll get this set up.  Its a nice progressive ratio trans however, and would be ideal for land speed racing.  Can you build us one???  I'm about to go out and check what exactly we have.  


So our 720 trans (with 1200 miles on it) is a wide ratio with a 3.59 first gear.  

Then we have the odd duck that came out of the truck.  The case number is 7Z31794, if I read it correctly.  Not sure what it is but the front upper gear is 21 tooth, the lower it engages is 32 tooth.  Its still partially assembled and I have no idea how to remove the rear case.  

#1511388 620 Land Speed Record

Posted by distributorguy on 19 August 2017 - 05:25 PM

Mike, I think I have both of those transmissions - if the 1980 is a wide ratio?  COOL!!!   I have a new Chevy 3500, so we can push until the truck is ready to take over!  


If you watch this video, the AFR was in a good range the evening before, when it was 88 degrees and 14% humidity.  The morning this was filmed it was 72 degrees and 35% humidity and the top-end mixture went crazy rich, yet it was still our best time because the salt is drier in the morning, and traction  is better.  Yet we were still clocking 151 mph by the tach, 110.7 by the GPS.  




Yes, this year was WET.  A lot of the old timers who have been racing for decades walked away on Monday, yet plenty of folks still set records throughout the week.  It just shows that if you plan for the worst, you can still succeed.  


That Wagoneer diff may work great, or it may leave us sorely disappointed at 127-8 mph?  I'm willing to do some research and figure out if it will pan out.  I'll also go measure the Cutlass 12 bolt diff I have with a 2.55 ratio and see if I can get shorter axles for a reasonable price.  


I can't wait to do some serious dyno tuning to figure out what we were missing.  

#1511331 620 Land Speed Record

Posted by distributorguy on 19 August 2017 - 01:41 PM

Yes Beebani!    I'm required to make a larger flange to mount outside the heim, so if they come apart, the flange will hold the heim in place.  That flange later bound up when the alignment was done (unknown problem to me) and that allowed the heim movement to loosen the bolt.  I'll make new spacers to allow full heim movement without making contact and red loctite at that time. Problem solved - and thanks for your offer to repair the issues I had, but they were my fault and I have them mostly corrected already.  


I think the biggest thing we learned from this trip to the salt is just how much wheel slip we can expect, so that we can set the truck up properly for next year to reach the speeds to set a record.  If we were really turning 8100 rpm in 4th, on pavement that's 152 mph.  152/110 = 1.38 = 38% wheel slippage.  We need roughly a 40% taller rear gear ratio, and more hp!  Anyone have a good idea there???   What options do we have around a 2.50 ratio with a 6-lug pattern without building custom?  


We also learned that:

ERC fuel sucks.  Their 100 octane unleaded may be required to burn at the rpm we run (break 9000 in 1, 2, 3.)

We shouldn't have any front brakes mounted.

We should use rear disc brakes.

We can run a little hotter spark plug.

We can probably advance the timing a bit - to make up for crap fuel.  

A close ratio trans with a push start is the only way to go!!!  

The ignition needs its own dash switch.

We need more suspension travel, AND more rear ballast.   

Probably 20 more items on the checklist for next year, but those are the big ones.  


I'm not so sure the carbs were having an issue with the track - its greasier than it is rough.  Jetting was the largest carb issue - caused by the fuel and radically changing air density.  The 5 mile tow to/from the paddock was brutal, and caused most of the other problems we experienced.  Once we started leaving our truck by the start line overnight, less things rattled loose.  I'll need to recheck the float heights, as I suspect they changed from the beating they took, but no spacer or isolator will eliminate the 9" deep holes in the road we have to drive.  Imagine orange traffic cones sticking only half way out of several holes along that road!


Time to start doing more homework and clean up the mess in the shop fro Monday...

#1511081 620 Land Speed Record

Posted by distributorguy on 18 August 2017 - 02:03 PM

5/8 bolts. 3/4 wrench. The rotation of the heims may have grabbed the lock washer and loosened the bolt. I'll reconfigure the assembly maybe with a thrust bearing?

I'm now on a search for a close ratio gearbox and a low3s gear set. I still need to do some calcs after reviewing all the GoPro videos to document gauge readings.

The carbs were working great - we simply ran out of gears and rpms. We weren't lacking power. The truck pulled hard to 110 where we were going 8100 rpm. Across the 3 mile mark. We were able to pull 9k easily in 3rd. It's a matter of traction loss and not enough gear to get where we wanted to be. We will make appropriate changes and revisit the salt next year.

#1510606 620 Land Speed Record

Posted by distributorguy on 17 August 2017 - 04:38 AM

Well we started out yesterday morning with a DNF.  Disappointing, but not surprising.  I tried a pretty drastic jetting change to learn something.  I learned not to do that.  


Then we got another member of our crew behind the wheel to get his rookie license, at 107 mph.  Our main driver pulled a 105 after that.  He lost some speed trying to use 5th gear - because at this point we're throwing in the kitchen sink to see what works and what doesn't.  We are currently sitting on the short course grid ready for the track to open for the day.  

#1510403 620 Land Speed Record

Posted by distributorguy on 16 August 2017 - 05:02 AM

Iiternet and cell reception out here is awful!!  Just grabbed onto the hotel wifi, took 4 minutes to load this page.  


According to everyone who has been here for years, this is the worst salt they have ever seen.  Most of the big teams left Sunday or Monday.  


Here are the runs we've made so far:






Seems slow, right?  

Jump on an online wheel speed calculator and plug in our data:

3.89 diff

1;1 gearing in 4th

24.5" tall tire

8100 rpm

The salt is BRUTAL!!!


Potential speed is 151.8   Wheel slippage and traction loss here is amazing bad.  We're trying for 110 today, but first we have a big problem to fix:  One of the 5/8" upper control arms bolts from Beebani vibrated loose on our last run, and bent.  We'll have breakfast and be at the hardware store when the door opens at 9 am.   We also need to change jetting again - carb jetting is roughly 25% off from where we started.  I've been soldering and drilling all our jets until the AFRs look good and we get as close as we can.  Right now I just need to go WAY smaller on air correctors and see how it plays out.  


Error on my part:  the distributor needs to be on a separate switch from the main power, as the driver uses the Cool Shirt for quite a while, feeding power to the ignition for a along time with the truck not running.  


So far we have only been running the 2 mile rookie course, trying to work out all the bugs.  Hopefully we get a chance to hit the 3 mile short course to see what the extra mile will deliver.  It should get us up in speed significantly.  I'd be thrilled to break 110, given the conditions.  For now we're still faster than the 240Z team here from Japan.  

#1509510 620 Land Speed Record

Posted by distributorguy on 11 August 2017 - 04:15 PM

Made it to the salt. Injured one pronghorn, flattened one tire as we arrived, but our pit is set up and we're ready to mount the new tire in the morning. Fingers crossed.

#1509175 620 Land Speed Record

Posted by distributorguy on 10 August 2017 - 02:21 AM

Fingers crossed - we hit the road within an hour.  

Bonneville or bust!   Bonneville and bust?  Bonneville either way.  I can't wait!  


If anyone wants to join us, you can just show up and wander through the pits until you see our blue/orange 620 or text me (I won't be answering many calls) if you're in the area.  It may be very difficult to find us among the 450 other vehicles spread over a mile's worth of pit lanes.  


#1508962 V6 swap

Posted by distributorguy on 09 August 2017 - 05:34 AM

as for 2.  Mike, Because there are literally millions of them, they do break down more often, because everyone and their brother thinks that he/she can "rebuild" one professionally, often doing things on the cheap and skipping steps that enhance reliability.  What other motor can you buy brand new for $1500 from the company who designed it?  GM Goodwrench crate 350s are $1500 for a decent performer that will fall from 96-99% leakdown rate fresh out of the box.  You can barely buy a good set of rebuild parts for the Datsun for that kind of cash, by the time you uprate the oil pump, raise the compression with decent pistons, rework the connecting rods, etc...


Then again a $500 fully rebuilt head may be Phantom's best answer since he already has an L20b.  Throw in a better cam and it'll be fun.  

#1508957 620 Land Speed Record

Posted by distributorguy on 09 August 2017 - 03:39 AM

The local VW shop had everything I needed!  I switched to F11 emulsion tubes which were still a touch rich, so I soldered a couple of the lower holes closed and they work pretty well.  The richer I set the jets the better it runs.  I have a full precision pin set from .011" to .250", so I can drill and file jets to any size, including modifying crappy original Weber jets to a more consistent size.  

Duax - not only are the sizes not linear, they're not consistent either!  I buy 160's and drill them to fit since my new 160's were actually 160, 160, 161, and 163.  Probably because they were so inexpensive.   :poop:


I have another issue, and I haven't pinned it down yet.  Once in a while the acceleration goes completely to hell and it just spits and sputters, like its running out of fuel - usually right off a start.  The fuel pressure gauge stays consistent.  I think the crappy spring loaded balance bar between the two carbs is compressing, allowing the carbs to get out of balance.  Today I'll cut that out and install a solid adjustable stop.  Crossing my fingers.  


And last night we blew a tire making the last run up the driveway.  I'm not sure if it took a rock or what happened.  Now I need to get a new tire express shipped to the hotel, unless Ratpatrol66 comes through for me with the right size?  At this point I just need to go pick up the trailer and load it so we can leave VERY early tomorrow morning.  Today is one of those days that I have to remind myself this is fun...

#1508533 Bonneville Speed Week

Posted by distributorguy on 07 August 2017 - 10:33 AM

T-minus 4 days and counting...

#1508390 Copper Gaskets

Posted by distributorguy on 06 August 2017 - 01:15 PM

A phone call to these guys and send them a gasket.  I bet they'd make any thickness copper gasket you want.  I'm contemplating using them next year, with a thinner gasket to up my compression a bit.  This could be a decent solution for big overbores as well.  And they may also be able to supply custom stainless O-rings for your block?  


#1507639 79 620 Drum Problem

Posted by distributorguy on 03 August 2017 - 07:21 AM

How did it break?


I hand torqued the wheel to 55 ft lbs.  It felt odd as I did it, like when you feel a bolt stretching to its breaking point.  I spun the wheel and the brakes were dragging hard.  If it wasn't for the Photofuckit site being so douchey, I'd be happy to post a pic.  It cracked all the way around the edge of the axle flange.  There's also a sharply machined edge that's a stress point and promotes cracks on these crappy designed drums.  Centric is usually good, but these are terrible.  Get rid of them ASAP.  RockAuto pulled them from inventory.  

#1507627 Opinions on fender mirrors?

Posted by distributorguy on 03 August 2017 - 06:45 AM

I like mirrors that are functional.  They look cool, but mostly useless.