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ANOTHER Datsun Z/LS3/T56 Swap Thread


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Finished the stitch welding....nice to have that chore done....and moving forward at my normal glacial pace.   Started building the supports for the main hoop of the roll cage.  I included c

Thanks for the kind words Vanilla.   I spent most of the day today getting the passenger side door hoop bent.  It really fought me.  To make it fit decently, bends in multiple planes are nec

Calling the cage done, at least from the dash back.  Also hit the tubes and welds with Scotchbrite so they are ready for primer.          

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5 hours ago, 280Z-LS3 said:

What's the advantage of going with a Jeep wiper motor and what car was it sourced?

 

Looking forward to the reports of getting your car fired up and suspension sorted!

 

 

 

The main advantage over the stock motor is just that they are available...

 

But I used the Jeep motor (from a '90s Cherokee IIRC) because the common Honda wiper motor swap was a bad fit for my particular car.  I am using a PDM for electrics, which can only switch +12V and the Honda motor is designed to work by switching to ground.  The PDM cannot send a ground signal.  Yes this could be overcome by using relays and such, but I figured this motor would be easier, simpler, and cleaner.

 

All I did was look at photos of various wiper motors for sale, and chose this one because it used a similar mounting arrangement to the stock motor.

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Humm, I plan on using the new AiM PDM32 and 10" screen.  It's slated to be released in Feb 2021.  Not sure if the 280Z OEM motor is ground signal reliant for operation or if the AiM can handle ground signal but assuming it won't.  The Jeep wiper motor, or similar, maybe a good way to go for me as well. 

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  • 2 weeks later...

I am using the "new and improved" front diff mount from T3.  Their original one was a flimsy joke, so I had fabbed up a .25" steel plate monstrosity to try to keep my diff from moving around.  Well, I am quite happy with these T3 parts and the one I constructed is getting scrapped.  I am probably saving at least 15 pounds in the process.

 

Basically this uses billet aluminum pieces to bridge together the front and rear control arm pivot points, and then a third piece of 1" thick billet bolts to these to support the front of the diff.  I have read opinions from some that they believed even these new T3 parts are not adequately substantial and rigid to keep the diff from moving around.  I am no engineer, but I am quite confident that these new pieces will either rigidly hold the diff in place, or they will break.  The fact is 1" thick billet aluminum is not going to flex much.  And I seriously doubt they are going to break.  The design also eliminates the cantilever effect when using a short nose diff that puts so much stress on many front mount designs.

 

Another plus is that this design is claimed to be compatible with the Ford 8.8" diff, which I probably should have used from the beginning and will be switching to should my R200 prove not up to the task.

 

The only downside to these parts I can see:  It significantly encroaches into available space to run exhaust beneath the control arms.  I am about 75% certain it is going to interfere with my already constructed exhaust, but I like the design well enough that I am willing to modify the center section of my exhaust to make it fit.  I do think I am going to replace the four visible Allen bolts with lower profile button head bolts, and use larger hardened washers under them.  This will allow a bit more exhaust clearance and better spread the load on the aluminum parts.

 

Thanks for looking.

 

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Edited by Ironhead
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The tiny bit of lip that those socket head screws hold on to in that T slot always bothered me about their design.  It just seems like they needed to give you two plates with two holes in it for the bottom side.  I would be tempted to put an 1/8" plate with a couple of holes there.  Or some thick oversize washers for each of those screws.

 

I always thought the T slot should at the very least be just two unconnected slots.  I know they're trying to do a T and all but it would have been better/stronger if T was tow unconnected lines.  Can you imagine if the placement of that front screw in the longitudinal hole landed at the intersection..

Edited by LooseRocks
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Agree about the large hardened washers, as I mentioned.  I often wonder why places like to include Allen bolts in locations like this where there is really no need or advantage to them.  These are good, grade 12.9 bolts (T3 likes to send weak and gall prone stainless hardware too, sadly), but one main issue here will be vertical clearance and in that regard Allen bolts are no better (maybe worse) than standard head six point bolts.  Like I said, I think button heads will be the best approach, although the threads in the blocks are M10/1.25 and button heads in that threading are hard to find (Belmetric has them).

 

IMHO the plates (as opposed to large washers) would be a bit overkill, and having seen the parts I am not as concerned by the connected "T" slot as you are.  Keep in mind, that part is 1" thick.  It is very rigid. 

 

I'm sure after running the car a bit, it will be quite apparent on inspection how the parts are holding up (if I ever get it running).

 

 

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Yah but socket head bolts looks so cool! 😄 I used to work for an engineering firm who did not typically allow high strength (a.k.a. brittle) socket head bolts in structural applications.  They had encounters issues with the heads twisting off during torqueing.

 

Its nice to see someone finally is mass-producing a rear end sway that has good, strong supports for the diff.  I agree with comments regarding the use of thick hardened washers.

 

Looking good!

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Just a bit more progress...

 

My initial air intake was just a 4" tube with a K&N filter on the end.  I knew it would benefit from an air horn on the end, but I couldn't find a part with the attributes I wanted, IE would fit on a 4" tube, accept a large (but not TOO large) cone filter.  Well, if you look long enough on the 'net, you can find pretty much anything.  This was from Vibrant.  The constant re-engineering of things I am unhappy with after mock-up is one of the reasons this car is not yet running...

 

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The engine bay is pretty much done.  The plug wires are off because I have to remove the plugs and spin the engine to build oil pressure....soon anyway.

 

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Rear brakes are done and seemed to bleed easily, at least based on the solid feel of the handbrake.  Even though it wasn't "time"...I just had to bolt on one of the rear fenders to see how things looked.  Now I'll probably scratch it and hate myself....

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Edited by Ironhead
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Feel you on the re-engineering of parts.  Thought I had the engine placed right where "it should be" and now not so sure.  A few specialty fittings for the oil pan return line will and a few more thoughts on allowing space for headers should get the issue sorted. 

 

As for priming oil systems on LS motors I've seen some videos of guys employing SBC oil pumps and oil 5 gal buckets.  Basically, pressurizing the system by methods other than using starter to turn motor/oil pump.

 

Excited to see your build move under it's own power!

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9 hours ago, 280Z-LS3 said:

Feel you on the re-engineering of parts.  Thought I had the engine placed right where "it should be" and now not so sure.  A few specialty fittings for the oil pan return line will and a few more thoughts on allowing space for headers should get the issue sorted. 

 

 

 

Clearance between the header tubes and the oil fittings is a problem.  I used the lowest profile fittings on the market and it's still very close to the header.  I just put reflective heat shield on both the header and the fittings.  Sure hope that is sufficient.

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  • 4 weeks later...

RE: Build oil pressure - can you pre-prime the system using a socket and strong electric drive on the front of the pump, with the belt removed from the pump gear?

That's our standard procedure on some of the vintage race engines running dry-sump setups. That way, you're pressurizing the whole system, but not rotating any engine components dry. On the 6-cylinder engines, it requires use of  1/2" electric impact driver to produce enough torque... not sure if that is viable on your v8 setup?

 

 

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53 minutes ago, UNHCLL said:

RE: Build oil pressure - can you pre-prime the system using a socket and strong electric drive on the front of the pump, with the belt removed from the pump gear?

That's our standard procedure on some of the vintage race engines running dry-sump setups. That way, you're pressurizing the whole system, but not rotating any engine components dry. On the 6-cylinder engines, it requires use of  1/2" electric impact driver to produce enough torque... not sure if that is viable on your v8 setup?

 

 

 

I have a scavenge only dry sump system, still uses the stock pump for pressure.  I did that because I would have to completely redesign my engine mount setup to use a three or four stage pump, and also because I didn't want to spend $5K on an oiling system.

 

I already primed the system.  Took out the plugs, filled the tank, the oil cooler and oil filter, attached a charger to the battery, and cranked it.  It was quickly developing 35 PSI just from cranking RPMs (which seemed like almost too much....but anyway).

 

One thing that is disconcerting...when the car sits for a couple of days....the oil tank almost completely drains into the pan.  I guess that is inevitable with a dry sump system, and the scavenge pump will quickly refill the tank on cranking....but I wish it didn't do that.

 

I thought about installing a ball valve on the oil supply line from the bottom of the tank, but that brings with it the (very real in my case) risk of forgetting to open it when I go to start the car.

 

 

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Do you have a dip stick oil level in your tank?  I am curious what is the difference in oil level/volume between running and after sitting for a few days.  I have heard that dry sumps do bleed oil into pan after sitting for some time.  It's just a matter of physics, the oil seeking level throughout the system I suppose.  As long as there is a good amount of oil left in the tank for oil pressure at startup you should have no problems because, as you said, the scavenge will empty the pan pretty quick.

 

 

 

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5 hours ago, Ironhead said:

 

One thing that is disconcerting...when the car sits for a couple of days....the oil tank almost completely drains into the pan.  I guess that is inevitable with a dry sump system, and the scavenge pump will quickly refill the tank on cranking....but I wish it didn't do that.

 

I thought about installing a ball valve on the oil supply line from the bottom of the tank, but that brings with it the (very real in my case) risk of forgetting to open it when I go to start the car.

 

 

 

On an old formula car I used to have it did the same thing sitting overnight.  I found that the supply line to the pump had enough oil in it to supply the bearings on start up.  I always would spin the engine a few cycles without ignition or fuel turned on to build pressure and then start.  My system had to be ran for some time to get the oil temp up and allow the pressure to come down to a reasonable level.  Cold my system would make close to 100 pounds of pressure.  Once everything was hot that would drop to about 65.

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7 hours ago, Ironhead said:

One thing that is disconcerting...when the car sits for a couple of days....the oil tank almost completely drains into the pan.  I guess that is inevitable with a dry sump system, and the scavenge pump will quickly refill the tank on cranking....but I wish it didn't do that.

 

I thought about installing a ball valve on the oil supply line from the bottom of the tank, but that brings with it the (very real in my case) risk of forgetting to open it when I go to start the car.

 

 

Can't you put a one way check valve in the line between the scavenge pump and the tank?

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22 minutes ago, JMortensen said:

Can't you put a one way check valve in the line between the scavenge pump and the tank?

 

No, it drains from the supply line at the bottom of the tank....the line that goes directly to the oil pump.  

 

As I understand it, since the tank is slightly higher than the pump/pan in virtually every dry sump setup I have seen, the tank keeps a constant slightly pressurized (from gravity) supply of oil at the pump when things are sitting.  Since oil pumps have tolerances and such, gradually the oil seeps through the pump and finds its way to the pan.

 

When the car is running or just shut off...the scavenge hose attachment to the tank is above the oil level, since it is at the very top of the tank, and it is designed to maintain air space at the top. 

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6 hours ago, 280Z-LS3 said:

Do you have a dip stick oil level in your tank?  I am curious what is the difference in oil level/volume between running and after sitting for a few days.  I have heard that dry sumps do bleed oil into pan after sitting for some time.  It's just a matter of physics, the oil seeking level throughout the system I suppose.  As long as there is a good amount of oil left in the tank for oil pressure at startup you should have no problems because, as you said, the scavenge will empty the pan pretty quick.

 

 

 

 

I don't have a dipstick, I just take the cap off and shine in a light.  I can still see oil at the bottom of the tank, but it is very difficult to tell how much there is.

 

I know the scavenge pumps move several times the volume that the pressure pump does, but it concerns me that there is a gallon or so of oil sitting in the pan on startup when the pan has no real volume capacity.  On cars with really large 3+ gallon tanks, it would seem like enough oil would seep into the pan to hydro-lock the engine and blow it on startup.  I mean, I know it is possible to blow an engine if it is way overfilled after an oil change.

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Last few weeks it seems like I have been going in a dozen directions at once trying to get this build running.  

 

I made sure the rear tires clear everything at full bump.

 

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I got the exhaust fitted with heat shield and installed.  Most of the heat shield is to protect the CF driveshaft.  It is only rated for 300 degrees sustained temp, and while it is a few inches from the exhaust, I didn't want to take any chances.

 

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This photo shows beyond doubt that ground clearance is an issue.  I honestly don't have many choices, unless I want to raise the ride height or not use a dual 3" exhaust.  It really is tucked up just about as tight as it possibly can be.  I have a bit less than 3" ground clearance from the lowest points of the exhaust.  Definitely not daily driver material.  Even oval tubing, which I used under the rear suspension, wouldn't help further forward because it would make the exhaust too wide to fit in the trans tunnel.

 

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Most of the rest of the time I have been doing suspension adjustment/alignment.  I figured that since I had invested in fully adjustable suspension, that part would be a breeze.  Wrong again...  In order to get 6-7 degrees of caster, recommended by most knowledgeable "Z" people for track oriented cars, I needed longer tension rods, to move the LCA pivot 1.5" forward, to move the sway bar mounts 1.5" forward, smaller washers for the upper strut mount (the spherical bearing was binding), to cut off a portion of the aluminum "chin" undertray, and most horrifyingly, I still need to cut up my already painted front fenders to clear the further-forward front wheels.

 

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Adjusting bump steer to zero required more spacing than I would have liked for the tie rods, but it clears the wheels and I am sure it will be OK....even though it looks at bit alarming.  To cover all bases I used NAS 180K PSI "shear bolts" and lock nuts which cost stupid money but hopefully will be up to the task.

 

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Made front and rear brackets for toe strings.  I know this can be done with jack-stands or other simpler methods, but I have tried that and the constant bumping and having to reset them was brain damage for me.  These things bolt on in a couple of minutes any time I need to check or adjust toe.

 

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Final alignment settings, as of now:

 

Camber: -2.5 front, -2.0 rear.

Caster: 6.5 degrees.

Toe: Zero front, 1/16" toe in rear.

 

These settings were taken directly from JohnC's post from years ago, and are just a starting point while I am breaking in the engine and ironing out what I am sure will be a bunch of hiccups when I get the car running.  Hybridz is such a great resource.  I would have had no idea where to start without it.

 

Thanks for looking.

 

 

 

 

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Re-paint, ugh!  Such a chore when you don't have dedicated body shop facilities.  Really hard to anticipate how things will go together and build accordingly

 

When I get to dialing in alignment and suspension setting going to learn how to do alignment also.  Having to take the car to alignment shop for every little change would be too time consuming and I'm sure price of home shop alignment equipment could be paid for with just a few trips to alignment shop.

 

Is the lowest part of exhaust right underneath the rear control arms?  I have a feeling that is going to be the lowest point on my build.

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