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PostPosted: November 4, 2013, 2:17 am 
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Joined: April 17, 2009, 1:28 am
Posts: 205
Location: San Tan Valley, Arizona
Well, I guess it is time for me to start a build log and join in on the madness.

In August, I picked up a well traveled, but stalled, project.
It is a book chassis with Miata running gear and suspension.

The poor thing had been out in the weather for some time, and suffering from a severe case of oxidation. I have spent a bit of time removing a good portion of the rust, but still need to strip it down to get to the rest. In addition to the cleanup effort, I have been tightening things up a bit, replacing odd bolts with a more correct fitment.

I will be posting pics later.
In the mean time, I do have some observations:

1. The engine is soft mounted.

2. Transmission and differential appear to be hard mounted.
--Is the machined surface (with two 10mm(?) threaded holes) on the bottom of the tail housing,
just ahead of the gear selector, strong enough to use as a soft mount point?

3. Ride height with the 14" wheels currently fitted is about 4.5".
--I think 15" wheels (at least) will fix #3 & 4

4. The pan sits about 1.75" below the frame, giving 2.75" clearance. That should be OK in the
garage, but out on the street -- maybe a little low.


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PostPosted: November 4, 2013, 12:58 pm 
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Joined: August 15, 2013, 4:04 pm
Posts: 28
Location: Victoria, BC
Hi Walt. Nice to see another Miata build taking place. That's what I'm doing as well though it sounds like you have a head start now. Looking forward to pics.

Marcel

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PostPosted: November 5, 2013, 12:09 am 
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Joined: April 17, 2009, 1:28 am
Posts: 205
Location: San Tan Valley, Arizona
Well, I promised photos, so here are a couple to start out.
Attachment:
locost 005.jpg

Attachment:
locost 006.jpg

Attachment:
locost 007.jpg


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PostPosted: November 5, 2013, 12:36 am 
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Joined: April 17, 2009, 1:28 am
Posts: 205
Location: San Tan Valley, Arizona
O.K., I think that went well. Now for a few more:
Attachment:
locost 010.jpg
Attachment:
locost 012.jpg
Attachment:
locost 013.jpg


The trip to the local machine shop was a worthwhile venture. Where there had been an obstruction allowing only 1" of thread engagement of the upper ball joint, now it will thread all the way in (more than I need)

Attachment:
locost 014.jpg


Although the stock headers seem to work here, I may opt to try my hand at some fab work down the time-line a bit


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PostPosted: November 6, 2013, 10:55 am 
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Joined: August 12, 2012, 6:38 pm
Posts: 1935
Location: worcester county, Massachsetts
waltj wrote:
Well, I guess it is time for me to start a build log and join in on the madness.

In August, I picked up a well traveled, but stalled, project.
It is a book chassis with Miata running gear and suspension.


nice! And, Welcome!

Quote:
1. The engine is soft mounted.

2. Transmission and differential appear to be hard mounted.
--Is the machined surface (with two 10mm(?) threaded holes) on the bottom of the tail housing,
just ahead of the gear selector, strong enough to use as a soft mount point?


it has been noted hereabouts before that all three mounting points of the engine trannt subassy should either all be solid mount, or all be soft mount. I'm sure others will chime in, but the concensus I have read in differnt builds has been to design a soft tailshaft mount that uses the original mounts for the Miata torque arm which connects the transmission tailshaft to the differential housing.

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The B-3 build log: http://www.locostusa.com/forums/viewtopic.php?f=36&t=13941

The Jag Special Build Log: http://www.locostusa.com/forums/viewtopic.php?f=36&t=19012


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PostPosted: November 6, 2013, 1:48 pm 
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Always Moore!
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Joined: November 9, 2007, 3:40 pm
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Location: Pittsburgh, PA
To add to that, there have been several builders that have had Miata differential snout mounts fail when they are hard mounted. You'll want to either install a bushing on the front and keep the stock bushings on the ears or hard mount all three points.

The harder the mount, the more load it will carry. If you have two soft mounts and one hard mount, the hard mount will carry most of the load. Not to say there isn't significant load at the engine and transmission mounts but the torque trying to move the front of the differential will be 4.1 times what it is at the back of the transmission and this is before you start worrying about drivetrain shock loads.

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PostPosted: November 6, 2013, 10:28 pm 
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Joined: April 17, 2009, 1:28 am
Posts: 205
Location: San Tan Valley, Arizona
robbovius and a.moore, thanks for dropping by.

I know that I must at least match the mounts on the engine and trans, which I intend to do. The question I did have about the Miata trans is that in the Miata, it hangs onto the PPF at the side mounting point, and there is, what appears to be, another mount point under the tail housing (like most transmissions). This is a machined surface with 2 threaded holes (for 10 mm bolt) spaced at about 32 - 33 mm apart. I am guessing at that measurement and can't check at the moment. The question is, would the tail housing handle using that as the rear, third mount for the engine/transmission combo?

This would simplify things if it will support the task.

I would like to soft mount the diff. but I think that will require some serious rework + replacements for the missing pieces.
I think the diff needs a little nudge any way, because, as close as I can measure, the drive line is currently as straight as an arrow. That may not be real good for the drive shaft components.

Walt


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PostPosted: November 6, 2013, 10:33 pm 
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Always Moore!
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Location: Pittsburgh, PA
The NC transmission has something similar on the bottom and a beefy PPF mount on the left side. I used the lower mount for mine and after 4,000 miles it has been fine: download/file.php?id=15687

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PostPosted: December 2, 2013, 12:05 am 
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Posts: 205
Location: San Tan Valley, Arizona
Between waiting for solutions to come into view and then the parts to arrive, there has been only minor progress. It seems like one step forward is followed by two steps back and if that keeps up, I'll be looking at a bundle of steel on the garage floor.

The diff is now mounted using Energy Suspension mounts bushings at the rear, but still needs the nose to be supported in some manner. I'm still thinking on that.

The transmission hard mount is disconnected, and the parts are fabricated to support the tail of the transmission using the mount point at the rear of the transmission. There are, however, clearance issues with the “B2” frame piece and the floor in the tunnel. There appear to be two possible solutions:

1. Remove / relocate the tunnel portion of “B2” (an inch forward would work).

2. Move the engine to the left about ½” and back 1 ½”. This would help with the
transmission mount clearance issue, and would also give the throttle linkage a little
breathing room.

If the tunnel section of “B2” is moved forward 1”, how will that effect the integrity of the chassis?
Attachment:
locost 049.jpg


Option 2 is interesting for several reasons. It will resolve the two points mentioned above, and gives the opportunity to reduce the engine exposure below the frame rails and I could do a little upgrade to the motor mounts.
Attachment:
locost 009 a.JPG


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PostPosted: December 2, 2013, 9:29 am 
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Joined: September 22, 2005, 8:12 am
Posts: 1836
Location: 4AGE in S.E. Michigan
Walt
I would just add a gusset between the two vertical plates on the motor mount, which should stabilize the mount when seeing fore/aft loads. Depending on clearance you may want to put an access hole in the gusset to reach the motor mount nut if the gusset is on the outboard side of the mount. Dave W


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PostPosted: March 25, 2014, 12:15 am 
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Joined: April 17, 2009, 1:28 am
Posts: 205
Location: San Tan Valley, Arizona
Well, it has been a while since I last posted on progress. I have not been totally idle, there has been a lot of repositioning, rebuilding and removing going on since December. The front motor mounts had to come out to move the engine back a bit and I found one mount torn (in two pieces). When I set the engine back down, I noticed that there was about a 10*+ difference between the engine plate and the chassis plate, putting undue stress on the mount (Both sides about the same). So, chassis mounts got reset to proper angle. On to the trans mount; as the engine was moved back to allow for a clean location of the rear mount, the "H" verticals at the tunnel entry and the center of "Q" were too close to the trans (they got repositioned). When I set the engine back down, G1 and G2 were the only things keeping it up. Looking at the drawings, seems like they were where they should be at the nose end, but were too far apart at the firewall end. Fixed that by adding G1a and G2a. Added plates to support the reworked motor mounts. Then the trans mount was tacked together.

As soon as my camera battery comes in, I can get the pictures I have out of the camera and post them.

Walt


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PostPosted: April 21, 2014, 9:28 pm 
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Joined: October 2, 2012, 11:24 pm
Posts: 176
Location: Winter Park / Orlando
Great to see you back at it, Walt! Pictures would be nice to show your progress, so add them when you get your battery back in your camera.

Sometimes you have to ad-lib a bit! I wanted my Miata 1.6 as far back in the frame as possible, so I ad-libbed!
Attachment:
IMG_2516.jpg
Attachment:
IMG_2526.jpg
Attachment:
IMG_2799.jpg
You can see far back the engine sits:
Attachment:
IMG_2885.jpg
My advice is not to worry too much about the drawings...there are endless ways to make it work! My $.02 worth...
Good luck!
-Gar

viewtopic.php?f=35&t=14227&p=179494#p179494


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PostPosted: April 21, 2014, 9:35 pm 
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Location: Shawnee, Ks
Love your "tie" rod!!!!

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PostPosted: June 29, 2014, 11:40 pm 
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Joined: April 17, 2009, 1:28 am
Posts: 205
Location: San Tan Valley, Arizona
I've been somewhat remiss in staying current in this build log, but have not been idle.

I was held captive by the wiring harness, when it escaped from it's container. Actually it fell out of the bottom of the box it was in, and since it was on the garage floor, I decided to try and make sense of the jumbled mess. I am now in full agreement with those that say that the best time to label the harness is when it is coming out of the donor. I now have most of the connectors labeled (@ 90%). Since I only have the ECU, is getting the engine to run going to be an issue? Exploring the wiring mess took April and a little of May.

Now the photos.....
Attachment:
IMG_0004.JPG


Attachment:
IMG_0010.JPG


Attachment:
IMG_0014.JPG


Before I got trapped by the wiring mess, I worked on the engine mounts. both were a little off and putting more stress on the rubber portion of the mount.
Before:
Attachment:
IMG_0207.JPG


Attachment:
IMG_0205.JPG


After:
Attachment:
IMG_0208.JPG


Attachment:
IMG_0206.JPG


Now it is getting a wee bit on the toasty side in the garage (9PM yesterday was still >100*).


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PostPosted: June 30, 2014, 7:27 am 
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Joined: August 12, 2012, 6:38 pm
Posts: 1935
Location: worcester county, Massachsetts
Walt, good to see progress!

yeah, wiring, original harness, difficutly...I think we can all relate. ;-)

oh, and G'raj temps: I identify woth your hardship conditions. tho mine were last winter, 20s.

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The B-3 build log: http://www.locostusa.com/forums/viewtopic.php?f=36&t=13941

The Jag Special Build Log: http://www.locostusa.com/forums/viewtopic.php?f=36&t=19012


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