Bruiser! 78 620 KC project

[carterb]

Time to get this *new* head on there.  I say new but it does have 4 hours of racing at The Ridge on it before Jeff blew up the bottom end.

 

In an effort to preserve timing, I added a mark at the bottom of the main pulley

 

 

And measured the current position of the pistons.

 

 

 

I also did this because I was concerned that there was a possibility that I bent a rod while trying to start it when the cylinders were full of oil.  Not shown but I used a travel indicator and found TDC of each piston and measured to the block deck.  They were all 0.005-0.010 from the top.  Difficult to measure with the caliper but good enough to make me (mostly) confident that I could proceed with head installation.

 

Also not shown is my wife holding the cam gear and timing chain up in the air while I'm turning the crank - again in an effort to hold timing.

 

 

[carterb]

Much to my relief, I found the carbs we were running on the race car too.  Many new parts in there so I'm happy to be putting them to good use.  And happy to unlock some power in this old truck.  It had the most anemic L20b I've ever driven.

 

 

L power let's go!!!

 

 

Found some other racecar bits too.

 

 

First I had to finish stripping away the old stock carb and single downpipe exhaust manifold.

 

 

So much room in there without all that plumbing

 

 

Anyone need this?  Functioned perfectly up to the head gasket failure.

 

 

 

Test fit head gasket

 

 

Half the people say use a sealer, half the people say put it on dry.  The L16 in my coupe is constantly drenched in oil.  I chose sealer.

 

 

Looking over head making sure there is no obvious damage from previous engine explosion

 

 

So much more compression!

 

 

I cleaned it up nice and I spun the cam a few times to make sure all the valves did their valve thing and all looked okay.  Then I set the cam position in the same place as the old head - again in an effort to hold the timing.  (notice a common theme here)

 

 

When I raised up the cam gear though, it would not reach the cam.

 

 

 

I had to rotate the bottom end a bit and the chain freed up.  Not sure if this was from being loose (and potentially off one tooth) on the lower end or if the timing chain tensioner just wasn't giving me the slack I needed but either way, I got it on.

 

 

Found a nice NISSAN intake/exhaust manifold gasket in my pile.

 

 

Perfectly matches the ported head!

 

 

 

[carterb]

Now for more fun.

 

I test fitted the exhaust manifold and found that the old exhaust was blocking that move.  Out comes the saw-zall.

 

 

Test fit #2, to this time the exhaust goes on but the intake and carbs clash with the sump breather (hits the rear SU fuel bowl).  I was able to rotate the breather and later cut off 90 degree bend.  (will worry about plumbing later)

 

 

Success!

 

 

This time for real.

 

 

When tightening the bolts, I find that one of the lower bolt holes is stripped.  : (

 

 

Of course...  This whole project has been 2 steps forward - 1 step back.

[carterb]

Heli-coil installed

 

 

We'll clean this back up and try again.

 

 

 

Found a NISSAN rocker gasket as well.

 

 

 

Now we're getting somewhere!

 

 

Cherry on top!

 

 

Just (... just...  right....) need to do some basic plumbing now and I can fire this thing up and make sure it runs before worrying about how the heck I'm going to convert the SU linkage to cable pull.  I called Z Therapy and they have made kits in the past but don't have anything at the moment.

[wayno]

That breather tube was supposed to be pointed towards the back and then stick out the side back by the firewall like in the photo below.

 

Try bottoming a stud out in that hole that is stripped out, the threads don't usually get stripped out all the way to the bottom.

[carterb]

Got a little distracted by a hail storm the likes of which I had never seen before.

 

http://datsun510.com/uploads/monthly_2020_03/02292020_bruiser_(1).MOV.365a911a7909a9f6601c7fcfdee02ccf.MOV

 

[carterb]

Just now, wayno said:

That breather tube was supposed to be pointed towards the back and then stick out the side back by the firewall like in the photo below.

 

Try bottoming a stud out in that hole that is stripped out, the threads don't usually get stripped out all the way to the bottom.

 

I know, but it hit the rear carb fuel bowl.

 

I think that's what we did on the racecar - used a longer bolt - but I repaired the thread so I'm good to go now.

[datzenmike]

Nice gasket match on the intake ports, why not do the exhausts too??? Did you match the intake to the gasket and if you do do the exhausts the exhaust manifold???

 

Nice flattop SUs I have a set on a K 14 intake but they are not de-smogged like yours. Mine still have the cut choke cables from the wrecking yard in Japan.

 

How come you didn't set the engine to TDC before removing the head? Not that there's anything wrong with this.

 

The SU's use coolant warmed/cooled intake runners, you can see the pipe over near the thermostat housing. All you need do is drill 2 3/8" holes in the head to make functional. I've done this on a U67 head.

[carterb]

You may not be able to tell by everything described here - but I'm trying to take the path of least resistance - while not making too many compromises along the way.

 

--carter

[datzenmike]

I'm hearing ya.

[carterb]

I installed the minimum amount of hardware/connections/plumbing to attempt a start up with the new head and carbs.

 

 

 

After a little priming, cranking, and application of the choke - we have a wonderful sound.  Click below and Turn it up!!!!

 

http://datsun510.com/uploads/monthly_2020_03/03082020_bruiser_(1).MOV.8f7d7e8366aa9c99bf1a8f23951dc4c2.MOV

[carterb]

Slow movement here.  Corey is home from school (C19 virus shutdown) so no rush to get him back on the road.

 

Besides finishing all the plumbing, I needed to figure out how to convert/adapt the SU carb linkage to accept the 620 throttle cable.

 

 

Hmmm....  What to do here?

 

I remembered seeing a bag of parts in one of my bins that I thought might help.  At first glance, it looked similar to above.

 

 

but on closer inspection, although it has the arc for a pull type throttle cable, the end links are backwards from what I need, and it also only has one throttle actuation tab.  Okay, so scratch that idea.

 

Maybe I can fit it somewhere on the intake linkage instead.

 

 

More thinking...

 

 

The OD of the tube is the same as the ID of the bushing on the intake linkage ears.

 

 

 

Trouble is, the location would make it incredibly difficult to actuate.  It is right behind the rear SU dome.

 

Maybe I can use 510 linkage back to the firewall and do something back there?

 

 

I found that the 510 actuator rod is the same OD as the ID of the throttle cable linkage I have so I shaved the 510 throttle linkage ears off the back of the rod with the idea of slipping it into the new linkage and fastening it in place.

 

 

Then I looked at the firewall to make sure I could mount the 510 bracket and bushing where it needs to live.

 

 

Okay, a plan is formulating. 

 

 

[carterb]

Next I found that the tubular throttle cable link has a stepped down ID and also the 510 actuator rod is made out of something harder than my drill bits so a welder is going to be involved at some point. 

 

While I mulled that over, I had a think about the other issues, like exhaust.  I rounded up some likely suspects.

 

 

and I also mounted the choke cable.

 

 

That came out really nice.  And who ever uses the dash light dimmer anyway?  Dim to nothing?  I'll take dim please.

 

Then I found this for the crank case ventilation to the intake.

 

 

 

Next I began thinking, well, if I get the cable actuation figured out, how am I going to mount the cable?

 

The stock carb has a very complicated multi-purpose bracket.

 

 

 

I can't use it but I can emulate it I s'pose.

 

Then, let's see, more plumbing.  I have this 2nd fuel line (return?) that I can plumb to the SU overflow line.

 

 

 

And I need to figure out how to tie in the coolant bypass line from the thermostat housing to the line running to the intake from the lower radiator hose connector.

 

 

Also need a vacuum line from the front carb body to the distributor.  Maybe I can use one of these?

 

 

Oh yeah, more plumbing, the vacuum line for the brake booster.

 

 

No wonder there was so much spaghetti under the hood before!

 

 

[carterb]

More distractions...  The previously installed battery hold down broke (I think I mentioned that before) almost immediately (cursed cheap consumer rubber) and I had to resort to a giant zip tie.  Time to do something better there.

 

 

Also realized my battery tray has nearly been removed by tin worms.  : (

The rear hold-down tab is coming loose from its moorings!

 

 

Oh yeah, don't forget to change the oil!

 

 

 

 

 

 

[carterb]

Okay, time to get back to business...  I know I need to modify the throttle linkage and get it mounted:

 

 

 

(Also need a bushing for the choke cables)

 

 

I didn't like my options for drilling the 620 firewall so I made an adapter plate that used the throttle cable guide mounting holes and cut up the linkage in preparation for assembly.

 

 

I quickly found that the adapter plate would not slip past the rear carb once fit over the throttle cable so I had to slot the end of the plate to assemble.

 

 

But with everything in place, it actually looks do-able.

 

 

 

Now to figure out throttle cable mounting.  I guess I will need to make something like this:

 

 

That will allow me again to use existing mounting holes.

 

 

Edited March 24, 2020 by carterb

[carterb]

Next step was to assemble the new throttle link.  I clocked the parts to the best of my ability and tack welded them in place:

 

 

The tack weld was a good choice because test fitment said I was about 10 degrees off so I filed the weld, rotated the shaft, and then welded complete - maybe a little too generous on the wire feed speed.

 

 

We have a working throttle set up!!!!

 

 

 

The material I had (2x2 angle) was a little short for perfect throttle cable alignment so I will need to go back and put some spacers behind it to get better cable to actuator alignment.  Otherwise I'm pleased.

 

[carterb]

Okay, now to the exhaust.

 

I did some test fitting of the short 2-1 collector and a stock 510 Y-pipe.  Neither will work without modification.  Also, I noticed that the short 2-1 collector has a slightly smaller tube diameter compared to the 510 Y-pipe.  In fact, it actually slips inside the 510 pipe.  Seems like that could work against me in terms of possible leaking?  (exhaust wanting to go around the tube and putting pressure on the gasket)

 

 

 

 

 

Who's idea was it to put a torsion bar where the exhaust needs to go?!

 

 

First the short 2-1 collector.  As-is, it is aimed about dead center on the torsion bar.

 

 

Lots of frame rail clearance though.

 

 

But it hits the transmission.

 

 

I think it may have a larger than stock outlet pipe and so the pipe and associated weld create this interference.

 

It was all I could do to get the 510 pipe near enough to the exhaust manifold to even be able to determine if it would fit.  (it would not)

 

 

So I thought maybe sectioning the Y-pipe and jogging it over at an angle could fix my issue.  Transmission flange is about 5" away from the exhaust manifold.  The torsion bar is about 8" away.

 

 

Then I remembered I had the old blown out Y pipe from Cooper so I cut off the collector about 5" away from the flange and gave that a test fit just to see where the tubes end up.

 

 

They are actually almost perfectly pointed at the gap between the frame rail and the torsion bar.  But the complete unit won't fit because the collector is at a twist in that area.  If it were not twisted, it would work.  Hmmm....  What to do? 

 

I know, I'll query the greater Ratsun knowledge...

 

 

[carterb]

But before that, I want to get this thing moving under its own power!

 

All connections made, all fasteners tight, all fluid in the appropriate place, battery connected, battery tray treated and reinforced, and new hold down crafted... 

 

Turn the key!

 

Wait for it, wait for it, nothing.  What the?!

 

I primed the carbs and tried again.

 

Started up and sputtered out.

 

I primed the carbs again.

 

Started up and sputtered out.

 

Okay, no fuel.  Got it...  Why? 

 

Checked to make sure I didn't plumb the fuel pump backwards.  Nope.

 

Then I removed the overflow line from the front carb so I could get a look down in the bowl and tried to start again. 

 

Fired right up and ran like crap - like on one carb.

 

Okay, that's interesting.  I reinstalled the overflow line and then disconnected the pair from the mystery fuel line which I thought was a return.

 

Fired right up and ran okay. 

 

I'll have to figure out that one later.

 

Did I mention this thing is louder than bombs with no exhaust hooked up?

 

Now that I have the neighbor's attention, time to get this thing out of the garage for the first time since this all started and go for a little drive:

 

http://datsun510.com/uploads/monthly_2020_03/03222020_bruiser_(1).MOV.b065e6a5ab05c0459ddcca88b54c9dc2.MOV

 

Everything seems to work anyway... 

 

I need to get the exhaust finished now.  I wonder if exhaust shops are "essential businesses"?

[slepe67]

Great progress!

I've been using your build as a Datsun Refresher.  😂

 

I'm in the same boat as you regarding the battery hold down.  Mine was identical and only 2 yrs old.  I opened the hood after a year long hiatus and yup...the hold down was snapped.  I only put it on in 2017, never touched it since, and the battety was brand new (not leaking).  Guess I wont buy that style again.  Thinking of going this route (but on The Cheap):

 

 

On 3/23/2020 at 8:56 PM, carterb said:

More distractions...  The previously installed battery hold down broke (I think I mentioned that before) almost immediately (cursed cheap consumer rubber) and I had to resort to a giant zip tie.  Time to do something better...

 

Edited March 28, 2020 by slepe67
typos

[banzai510(hainz)]

Carter

i hate helicoils I think a Keensert would be better if this pull outs again 

[carterb]

On 3/28/2020 at 4:39 PM, slepe67 said:

Great progress!

I've been using your build as a Datsun Refresher.  😂

 

I'm in the same boat as you regarding the battery hold down.  Mine was identical and only 2 yrs old.  I opened the hood after a year long hiatus and yup...the hold down was snapped.  I only put it on in 2017, never touched it since, and the battety was brand new (not leaking).  Guess I wont buy that style again.  Thinking of going this route (but on The Cheap):

 

 

 

 

As long as there are lines at Walmart, they will keep making cheap crappy throw-away products.  Apparently we can't get enough of them.  Makes me very sad...

[Ooph!]

On 3/23/2020 at 8:07 PM, carterb said:

We have a working throttle set up!!!!

 

 

 

 

 

Okay this might be a dumb question but do the cars that came with side drafts like roadsters have the throttle linkage connected to both the intake and firewall?  I'm thinking that the engine moves and the firewall doesn't 

[wayno]

That is a seriously modified 510 setup, maybe other cars had that also.

The trucks had a cable setup with a center pull, much easier to deal with in my opinion.

 

[carterb]

19 hours ago, Ooph! said:

 

Okay this might be a dumb question but do the cars that came with side drafts like roadsters have the throttle linkage connected to both the intake and firewall?  I'm thinking that the engine moves and the firewall doesn't 

 

Here is a picture of a stock SSS Bluebird set-up.

 

 

Yes the engine rotates on its mounts as the motor torques but the arm from the firewall pivot to the manifold linkage is long enough that it moves up and down without really changing the throttle position.

 

The only difference between this and what I ended up with in the truck is that the truck is cable actuated where the bluebird and 510 are mechanical linkage actuated.

[carterb]

Finally made it to the exhaust shop today.

A-1 Muffler in Everett, WA.

Wayne is your man!  He's been doing exhaust since '76!

 

I brought the short 521 (?) collector as well as the 510 Y-pipe and let him choose which way to go.  He chose the collector which suited me just fine as I assumed that solution would be quite a bit quicker to execute.

 

Q: 

 

How can a Datsun be lowered and lifted at the same time?

 

A:

 

 

30 minutes later and we're done!

 

 

 

I suspected the 520 collector would fit with a little love from a grinder and sure enough that's what it took.  Wayne is pretty handy with the bender and was able to curve around the torsion rod without making a single measurement.

 

Tested for leaks, paid the bill ($49!) and away I went.  Happy to have our little truck back on the road.

 

Everything seems to work well but the nozzles stick down when you apply the choke so I need to look into that - otherwise, no leaks and all the power seems to be there.

 

Oh yeah, while I had the hood open, here is my budget aluminum battery hold down:

 

 

If I drilled some holes in it I could call it a "racing" battery hold down.

Edited April 29, 2020 by carterb