620 Land Speed Record

[sebpv]

Mike arent you Canadian? how could you mess this one up

[datzenmike]

I'm Canadian not Canadienne.

 

 

Porting pictures please.

[distributorguy]

TJ was my sales guy in Kalamazoo.  Cool dude.  Then he went to work for another company I know well in Arvada, which is where my diff is hidden.  Pretty sure he'll join us on the salt too.

TC is the driver.  He'd appreciate the lumberjack comment.  That's pretty much the life he lives.  A true woodsman, avid cyclist, phenomenal photographer.  Hopefully as good a good a driver as he is at everything else in his life!  Our whole team is like this - a bit eccentric, stand-outs in their field, and solid, quality people.  Except for me.  I'm just nuts.  

[datzenmike]

Ha ha! We've never met but have corresponded with him for, got to be 10 years, maybe more if it was on The Realm. Say hi for me? 

[yenpit]

Whut?  Huh??  My ears were burning!!  :confused:    Stop, you guys are embarrassing me.......... :rofl:

 

Paul's 4.11 diff........nope, it's a 3.89 (??), which I think was an auto or shortbed or something! :sneaky:  However, my offer to pull the diff out of my truck still stands!!  I'll grab Paul's 3.89, you get mine IF it actually a 4.11.  You & Paul put yer deal together, BUT let's make sure mine is a 4.11 before you guys trade out parts!!  I'll get to pulling it in next few weeks............still a l'il cold outside!!

[distributorguy]

3.89?  Well that'll work too with a tire change, if it still fits on the carrier???  How can it be SO hard to find a 4.11?????????

[datzenmike]

The later Z24 powered 720 used 3.889 and lower. Earlier ones had smaller engines and needed the gearing. The '80 2wd were 4.11 also, just like the last year '79 620.

[yenpit]

HAPPY TO DO THE SWAP, so you get yer 4.11, but if the 3.89 will work, we can skip the labor, and you & Paul can make yer deal right away!  Think on it, let me know VIA PM MESSAGE OR EMAIL, cuz I do not get notifications from Ratsun when somebody responds to a post I'm involved with!!!!! :w00t:  

[wayno]

3.89?  Well that'll work too with a tire change, if it still fits on the carrier???  How can it be SO hard to find a 4.11?????????

Because not that many Datsun 720s in the yards anymore, and the 620s are getting to be a rare find like the 521s used to be, now it seems like only one 521/520 a year shows up between the 3 pick and pull yards around here.

Also it is a dirty job to pull one, so no one that actually has one wants to pull it unless you pay them a fortune to do it.

Can you change tires to get where you need to be with the 437 gears?

[distributorguy]

By going to the next larger rear tire, we actually lose a significant amount of tread on the ground.  Odd, but the specific brand and model of tire we have has a more square profile than any other tire in its class.  I'd really like to use that tire for its specific characteristics, which means we will need gear options for testing.  It may end up that the 4.375 is the right rear end for the job, but at great expense given the rpm needed to make it viable.  

[distributorguy]

Just had an alignment done.  Managed to get a little over 7 degrees of caster out of this thing.  Woot!!!

 

The icing on the cake is that we're within 300 lbs of perfect balance after having it scaled.  A driver will significantly help that, as will some simple ballast over the rear axle.  

 

 

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[distributorguy]

Saturday was a boring, horrible day of doing body work on the hood.  The hood scoop is blended into the hood now, and hopefully will see paint in the next couple weeks.  One accident happened.  I sprayed high build primer on the hood when I was tired of doing repair work.  I accidentally grabbed the wrong can of thinner to mix in with the primer.  The attached pic is what happens if you use paint thinner instead of lacquer thinner to reduce your primer.  I was able to brush most of it off as it did not adhere at all once dry.  What a stupid mistake!!!

[/url]">http://http://s1148.photobucket.com/user/distributorguy/media/Datsun%20project/A2D8FFA2-5605-4BB8-847D-16AC3F5895FC_zpsan6bh3do.jpg.html'>

[datzenmike]

That's a 130 paint job. Looks good at 130MPH from 130 feet away.

[distributorguy]

At that speed there would have just been chunks of primer flying in the air like snowflakes.   :blush:

It literally brushed off with my hands for the most part, a scotchbrite pad for the remnants.  Stupid.  I knew when I poured in the thinner what I did, but since it did blend ok in the cup,  I thought I'd try it and see what happens.  Essentially it sprayed out fine but since it dried very slow, it did not adhere.  I just hope it doesn't create a bonding issue when I try to respray it.  Someone should revoke my man card.  

[petercscherer]

Someone should revoke my man card.  

Considering the other impressive work in this thread, I'll simply suspend it temporarily.  :angel:

[distributorguy]

Last night the team gathered to iron out more details, and drink beer and eat white chicken chili!  

The seat belt mounts are welded in place, to suit the new seat and the proper location of the door net (inside the cage).  We also installed new brake drums since the old ones had a mild warp.  I had to true one of the new drums as it was machined improperly - no surprise - but at least now the brakes don't drag.  I also test fit a spare set of rear wheels/tires and a 1" drop in the back looks ideal from where we currently stand.  I have the lowering blocks, but need a new set of U-bolts.  Ordered up a couple new radiator caps too, as I'm having a hard time finding one that actually lives up to its pressure rating.  I'm hoping to get close to 16 psi.  And a new coolant overflow tank is on its way.  

 

And a pan in the neck got solved - replacing the clutch pivot pin at the clutch pedal with a hardened bolt and lock nut.  The list is getting short!  Saturday we buy material to make the box cover!

[Stoffregen Motorsports]

Imagine stabbing the brakes at 130 mph and having that warped drum. You could get wheel hop from that. Brake hop at that speed would not be fun.

[distributorguy]

Exactly!  Everything will be sorted through, about 100 times over.  

 

Today's fun:  back to porting.  Finally!   This is long overdue.  I hope to have the head ready to assemble some time Sunday.   Its impossible to photograph porting due to reflection and crappy lighting, but here's the basic look of it:

[/url]">http://http://s1148.photobucket.com/user/distributorguy/media/Datsun%20project/FEDC8E17-2D9A-49AD-9CD5-77DC7580BD3F_zpsrwvjmqje.jpg.html'>

[G-Duax]

Suggestion:

When you are done porting, ceramic coat the exhaust ports (and valves, and combustion chambers, and piston domes).

 

It keeps a lot of heat out of the head.

 

 

[Stoffregen Motorsports]

Are you going to install new guides, or leave them short like that?

[distributorguy]

Those are new guides.   They will stay short.  Dangerous I know, but worth the risk.  It improved flow by 12 cfm, bringing the intake ports to 236 cfm at .550.  Valves are Manley extreme duty.  The head has to survive a couple dozen 3 miles runs at .550" lift measured at the valves.  By the time we finish each run, the engine will be at full operating temps.   Is there a DIY ceramic coating available?  MN isn't a hotbed for these surface treatments, although our crank is Teflon coated to prevent oil wicking. 

[G-Duax]

Yes, Tech-Line coatings, and Cerakote both make make high grade heat barriers, and moly coat.

Parts need to be abrasive blasted (not glass beaded), degreased, de-gassed (pre heating in oven).

Then are sprayed with a cheap hobby air brushed, let set up, and then baked.

I've been using the Cerakote gold cote on my piston domes, and ports, valves, and combustion chambers I've been doing with Tech-Line CBX.

 

http://www.techlinecoatings.com/index.html

 

http://www.techlinecoatings.com/index.html

 

I once did a set of valves with CBX, and upon assembly, fumble-fingered one, and bounced it off the garage floor.

Though 'oh s#it', thinking it would have chipped, but nope, valve was just fine.

 

It's important to use clean blast media, because the stuff will pick up oil from dirty parts, and transfer it to the part.

But I follow the 'better safe, than have flaking coatings', and have plenty of clean acetone to give last minute rinses.

 

Here is the gold-cote on my pistons, and moly skirts:

 

 

 

Valves that went into my Cressida:

 

 

I did just the face of the intakes to help keep them, and incoming charge cool,

but the exhaust got both sides done.

[datzenmike]

Would a kitchen stove work for this????

[distributorguy]

Cool but I just went to their website and their store is NOT secure.  I'll have to call in an order tomorrow.  

 

I'd suspect a standard oven would work great, especially since it only needs 300 degrees.  Easy peasy, as long as you get it done before the wife gets home.  Harbor Freight sells an airbrush for $15 that'll do a nice job.  

 

This is great timing, since I need to order all new grinding stones to finish off the final "tune" of my valve job.  

[G-Duax]

Easy peasy, as long as you get it done before the wife gets home.

 

I can't describe the look on my late wife's face, when she come home, opened our dish washer, and found it full of 2-stroke engine parts.

 

But they were clean :)