1973 Rebuild

[Matthew Abate]

Thanks for the info.  Those are high dollar, high quality rings from what I read when I was researching mine.  I bought Hasting chrome, molly rings for mine.  My machinist said that's what Nissan used.

 

My strategy (if you can call it that) with the engine is to put the money here, because this is the thing I can't really fix myself. The rest of the car isn't really an issue for me when it comes to doing the work, but I want to make this engine as bullet proof as possible because it's way outside my wheelhouse, so I'm not skimping. The machinist we're working with has a few decades of L-series experience so I'm pretty confident we'll reach that goal. Will it be the most powerful L28 ever built? No, but I'm confident it will be more reliable that my 2009 Subaru Forester's engine.

[siteunseen]

I agree completely, it's the "heart" of the car in my opinion too. Looks great judging by the photos and the parts you guys are using.  I know you've done your homework. 

[Matthew Abate]

Thanks. I'm pretty stoked about it. The only thing I wonder (and this is a tiny, infinitessimally small little bit of hesitation) is if a 240 crank might have been more fun. I know it would be less less power and less torque, but I've read all over that people love the revvy L24 character. I know Diseazed has two engines that are near identical except the crank and I remember him saying something to this effect.

 

However, since I never drove this car I have nothing to compare it to, so it will be what it will be.

[siteunseen]

An aluminum flywheel would make up for the crank weight.  I love my 2.4's quick rev with my exhaust system.  Once you get used to the light flywheel you would really like it, I know I do.

Another thing on my 240 is the low gears in the differential, seems quicker than my 280's R200.  After I put a 5 speed in it's a blast to drive.  Almost like a motorcycle without the dieing aspect when you ride bikes.  I made it this far in life so no more motorcycles for me.

Edited February 11, 2017 by siteunseen

[Matthew Abate]

Yeah, I remember that crash you told me about when I first joined the forum.

 

I almost went with a light flywheel, but I was concerned with the lack of inertia at red lights and bogging down the engine. I suppose I could walk that decision back, but I'm not sure I want to ATM.

 

Edit: not sure if you remember, but the five speed I have is out of a 720 truck and has the same first through fourth as my stock 240z four speed. I am seriously considering going with a quaif to get the LSD rather than an r200 in order to keep the 3.54 ratio I have in the car now. I think I'm the end after modification parts the price is only a couple hundred bucks more. I don't know. We'll see how it is when I drive it for the first time.

 

[jwtaylor]

Another option would be the Subaru WRX STI R180 rear differential.  2007 and newer are 3.545 ratio Torsen LSD.  You would also need a set of output flange stub axles to match up to you current half shafts.

[Takhli]

Okay... a little more of the assembly coming up.

Piston and Ring Inspection and Preparation

Before we took the time to install all the rings on the pistions, we checked the pistions were correctly installed on the rods. The rods are in the proper order front to back and the valve relief for each pistion is where it needs to be.

With the crank in, it's the last chance to make certain the rods and pistions are assembled correctly and to measure the piston to cylinder wall clearance. It ought to be checked as soon as the block is clean, after the machinist is done, and for this build, it’ was. Here are the measurements...

First, the cylinder bore measueasurement the old fasioned way...

Here's a better view of the micrometer reading spool.

Then we measured the piston skirt about one-half inch above the bottom of the skirt, but below the pin; we measured twice or more until certain, and measured each piston and cylinder.

Here's a better view of the micrometer reading spool, for the piston skirt measurement.

We needed 0.0035" and we are okay (if you see a mistake, for goodness sake let me know!!).
 

Next it came time to gap the rings. We're showing the #2 compression ring here but they were all checked the same way. We measured the ring gap on each ring right out of the box, and to assure consistency we placed each ring into the cylinder at the same depth.

But to do so, we had to make a little tool...   Behold!   One each cat food can; wrapped with masking tape for a soft but firm fit in the cylinder, and marked at one-half inch from the rolled edge.

We place the rings in the cylinders a little bit below the deck and set the tool onto the ring...

And, with a bit of a push down to the line we drew, the rings are all the same depth for measuring the gap.

So, we had the rings in the cylinders and we took measurements; we didn't just start filing away at each ring to get the proper gap but made a note for each in our construction log, then looked for variations. We then swapped rings from cylinder to cylinder until things were as close as possible.

Later we gently used the ring gaping tool and took measurements. I count each turn of the handle when I use the gaping tool and if I apply consistent pressure against the abrasive wheel, my cuts are pretty consitent too.we had what I want. We finished by dressing the ring ends with a small fine file and inspecting each end for burrs and sharp corners. I wear a set of magnifying goggles for a good close view.

I'll have more pix of with the narative of the work coming up, but we're going to restrict the photos to ten or less, for now.

Best to all,

Takhli

 

Edited February 11, 2017 by Takhli
duplicate photos and narrative

[siteunseen]

Looks great!  I can definitely see the cross hatch now.  Keep on marching...

Here's mine after the machine shop.

Edited February 11, 2017 by siteunseen

[siteunseen]

I can't remember if y'all are using a ground down cam but if you are do you know about the shorter valve seals fro Fel-Pro?  Anything more than .460 needs these if I recall correctly.  It's discussed in this thread about OE seals squashing down. 

http://forums.hybridz.org/topic/68120-problem-with-viton-valve-seals/

[Takhli]

Hello, "Site". 

Glad to know you're moving forward with your build, as well. I read that you need shorter stem seals with the high lift cams but didn't know were to get them; now I do -- thanks!

Are you posting your build?

Do you know theie height? We have seals in our gasket set and we're using a cam with 0.458" lift, so I think we'll be okay. I'll double check the clearence when I get to that point in the build.

[siteunseen]

I'm sorry for not mentioning that was a year old picture. 

I've got over 1,000 miles on it now and it's just now "loosening up".  I believe like Matt does, get a strong reliable motor 1st and all the small stuff is actually fun doing, drinking beer makes it fun for me. 

 

Edited February 11, 2017 by siteunseen

[Takhli]

6 hours ago, siteunseen said:

I'm sorry for not mentioning that was a year old picture. 

Very nice!!!

Matt would like to finish his valve cover just as you did. Can you tell us how or where it was done?