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Joe's 1972 240Z adventure


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On 10/19/2022 at 3:43 AM, A to Z said:

10-19-2022 UPDATE. Mic'ing the stroker crank for my engine build. So, the micronometer I ordered on Amazon came in and I went ahead and masured my crank. All journals are within spec for standard bearings per the Factory manual under "EM Mechanical". I have attached a form showing my recordings which were right on for all 14 bearing surfaces and the crank snout. Because there can be the question on whether or not I didn't take it out enough decimal points, I attached another form, showing what the measurement would have had to be to step up to a thicker bearing for an udnersized ground crank. Sure, there will be some with the "but, but, but...." and I accept that, for an engine that is being built like a race engine with a redline in the stratosphere.....but mine is building build to stock specs and a 6,000 RPM redline. My cam maxxes out at 5600 RPM anyways (for horsepower, for torque around 4500 RPM). if I want more oil pressure, I just use the thicker 20W50 oil instead of 10W40.....just remember the ZDDP additive. So, here they are, think what you will.

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I've been following along for a while now, and I love the build thus far!

Might I make a few suggestions?

 

First, I would recommend to re-measure the crank journals with a micrometer instead of calipers. The cheaper plastic calipers aren't exactly known for their precision. Another thing to take into account is the taper of the journal, which the micrometer would be able to better measure.

 

Out of curiosity I tossed your measurements in a spreadsheet and calculated a 0.078mm out of factory spec condition with the main journals and a 0.177mm out of factory spec condition with the rod journals based on the info you provided. Personally, I would have the crank checked and the journals turned 0.010" along with having them check the straightness of the crank(especially if it has indeed been riding around in the back of a truck in Thailand). I would hate to have spent so much time and money building this engine for it to have issues. IMO, it would be cheap insurance!

 

I'll have to dig out my "how to modify" book to see what the max acceptable "race" clearances would be but I'm not sure I would risk it if I were in your shoes.

 

I'm looking forward to the updates and progress!

 

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What I was able to figure out, was the size they are now, and what size in diameter they would be if the crank was turned .010 under.  Because I am a LONG way from being that size, I know that I am within tolerances.  It might not be scientific, but if an engine is a hair loose, using thicker oil can and will make up for it.  20W50 can make an engine with 35-40 psi of oil pressure at idle have about 10 more!  My intention, is to plastigauge it when I put it together on the mains and rod journals, and use 20W50 if she is a little loose.  I am betting it won't be loose at all...it will be just fine and will warrant 10W40 oil.  When I start it and the oil gauge goes past the halfway mark?.....success.  This is being built as a stock motor, to be used within the power band of the early 240Z "A" grind cam and E31 head with small ports and small valves, the cam maxxes out at 5600 RPM!  4300 for torque.  Just a lot of torque.  I am going to advance it to #3 on the timing upper sprocket per Dave Rebello's suggestion.  I am doing this the opposite of what everyone else does in the Z car world. 6K would be the absolute max RPM the engine will ever see.  I just put it in drive and go!  It shifts at peak torque anyway, 4300-4500 rpm. :)

 

 

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Agreed.  If you are making a torque monster, then generally, RPM is not where you make power.   It also makes a more comfortable round the town car, which it sounds like is your aim.  Takes a few corners, let it rip for half a block etc.  Maybe you can smoke some tires, which would be something on a 240z. 

 

I have to say that lowrider's idea of using a micrometer is intriguing.  I have never used them but I would probably buy a set if I were doing what you are doing, just because.  And can never have enough tools to play with. 

 

Testing the crank for trueness seems like a good idea.  A machinist can throw it on a lathe and find this out in about 1 minute.  

Edited by YoBrother
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11-4-2022 UPDATE.  I have ordered more parts for the engine build.  I got some NOS Nissan main and rod bearings, a cleaned up and restored front cover, New Nissan NOS oil pump, New NOS Nissan water pump, and in talking to Dave Rebello, found out that these V07 Diesel cranks don't "like" stock harmonic balancers.......He sells a single pulley variant of BHJ harmonic balancers which have been designed and are successful in handling the harmonics that the extra stroke brings to the table. He also stated that for some reason, 6400 RPM is a point where the engines show a great deal of harmonic disturbance, and that it is best if guys avoid that RPM, shoot right through it or shift before it, but make all efforts from doing anything that holds the engine at that precise RPM.  Food for thought.  He also said that racing and hot street engines, have shown that the factory torque specs for various parts is not near tight enough, case in point the harmonic balancer instead of being factory spec'd at 120 ft/lbs torque, should be 150!  Flywheel botls are another he mentioned......he recently had another guy lose his harmonic balancer, just fell off!  So, Dave Rebello at Rebello Racing woud be a good call for anyone doing a lot of high RPM stuff.

Nissan Main Bearing.webp

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Nissan oil pump3.jpg

Nissan Rod Bearing.webp

Nissan water pump.webp

Oil Galley Plugs.webp

Oil psi valve.webp

Restored front cover.jpg

Edited by A to Z
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  • 2 weeks later...

Thanks.  I am trying to. :)

 

11-17-2022 UPDATE:  I found myself in the Bay Area for a few days, so I took some time and drove out to Antioch to meet Dave Rebello and his crew. Very nice guys, and the tips for building my engine were extraordinary. 50 years of doing this means a lot of good knowledge to gain. While there I picked up the Harmonic Balancer I need for the stroker crank and checked up on the pistons. Guys were so nice they took the balancer into the back and honed it.....for street applications, Dave said it needs to be honed.....when I told him I would hone it with my drill on my leg he handed it to one of his guys and they went and did it proper! 😃 Pistons almost ready. Amazing that the quality control is so good nowadays. The chief engine builder, Mark, was telling me the last 20 SETS of pistons from TRAUM, all rings were to spec, and DIDN'T even need to be filed to fit. INCRDIBLE! Also saw out front awaiting shipment a 2.5 stroker heading to europe, 13.0 to 1 compression race engine, Dave told me numbers and I don't remember but it was WAY more than 300.....almost 400. Mark said from idle to 8000 it is a beast! I also snapped a pic for a dyno chart from a 2.7 street build he did that showed torque way above 200 all the way across.....I hope, I hope! 🙂

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11-23-2022 UPDATE.  I jumped off into the deep end yet again.

 

To go with my stroker engine.......I bought a 5 speed manual trans!

 

I already have the pedal box for a manual trans.  I can buy a brand new conversion kit from Godzilla raceworks.  I was going to just get a 4 speed since they are so much cheaper, but at the last minute I decided to do this.  It is out of a 1980 280ZX NON Turbo car.  So, it is the desireable close ratio unit.

 

There is a shop in Colorado Springs, Precision Transmission, who will rebuild it for me.  Crossing fingers as some parts are NLA ( no longer available).....so hope fully the bearings and syncros are all that will be needed.

 

Also went ahead and got the engine plate for manual trans.  Dirty as heck.....needs my "golden touch". :D

 

Other than the conversion kit, I need, a shifter, a couple of shifter boots, inner and outer, and a new starter.......would be nice to get a NOS one, who knows.

 

Anyway, that's the news..... here are a few pics of the stuff.  I got it on eBay.

 

 

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On 11/23/2022 at 7:33 PM, A to Z said:

11-23-2022 UPDATE.  I jumped off into the deep end yet again.

 

To go with my stroker engine.......I bought a 5 speed manual trans!

 

I already have the pedal box for a manual trans.  I can buy a brand new conversion kit from Godzilla raceworks.  I was going to just get a 4 speed since they are so much cheaper, but at the last minute I decided to do this.  It is out of a 1980 280ZX NON Turbo car.  So, it is the desireable close ratio unit.

 

There is a shop in Colorado Springs, Precision Transmission, who will rebuild it for me.  Crossing fingers as some parts are NLA ( no longer available).....so hope fully the bearings and syncros are all that will be needed.

 

Also went ahead and got the engine plate for manual trans.  Dirty as heck.....needs my "golden touch". :D

 

Other than the conversion kit, I need, a shifter, a couple of shifter boots, inner and outer, and a new starter.......would be nice to get a NOS one, who knows.

 

Anyway, that's the news..... here are a few pics of the stuff.  I got it on eBay.

 

 

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11 hours ago, A to Z said:
On 11/23/2022 at 7:33 PM, A to Z said:

11-23-2022 UPDATE.  I jumped off into the deep end yet again.

 

To go with my stroker engine.......I bought a 5 speed manual trans!

 

I already have the pedal box for a manual trans.  I can buy a brand new conversion kit from Godzilla raceworks.  I was going to just get a 4 speed since they are so much cheaper, but at the last minute I decided to do this.  It is out of a 1980 280ZX NON Turbo car.  So, it is the desireable close ratio unit.

 

There is a shop in Colorado Springs, Precision Transmission, who will rebuild it for me.  Crossing fingers as some parts are NLA ( no longer available).....so hope fully the bearings and syncros are all that will be needed.

 

Also went ahead and got the engine plate for manual trans.  Dirty as heck.....needs my "golden touch". :D

 

Other than the conversion kit, I need, a shifter, a couple of shifter boots, inner and outer, and a new starter.......would be nice to get a NOS one, who knows.

 

Anyway, that's the news..... here are a few pics of the stuff.  I got it on eBay.

 

 

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Nice Joe... Some things come full circle... A five spd will be nice.. Can't wait to see the results... Maybe you can sell the auto stuff to offset some of it.. Guessing the rearend might need different gears too.. Keep it up.. super build...

 

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