Blooze Own: An F355 Six Speed N* Build Thread (Page 77/126)
BlackEmrald AUG 14, 11:30 PM
Oooohhh preeetty
Will AUG 15, 08:31 AM

quote
Originally posted by Bloozberry:

That should be a really challenging project Will. You'll need to start a thread in the "Other Cars" section as I'm sure there will be a lot of interest. One of the challenges I'm sure you've already considered is how you're going to mount the longitudinal 348 engine into the 308's engine bay designed for a transverse engine. I'll subscribe if you start a thread.



I will eventually.
I have other things going on in life right now.
The 308 and Fiero have similar wheel bases, but are proportioned very differently. The 308 has a much larger engine bay and the occupants are pushed further forward than in a Fiero. People have done "358" builds using 355 drivetrains in 308 bodies. The 355 drivetrain is dimensionally the same as the 348 drivetrain, so I know there's enough room. What makes it work is the oddball layout of the 348 and 355 transaxles. They put the diff immediately behind the engine and the clutch at the very back end of the transmission.

I've occasionally had similar problems with Summit. They always make it right. I've also had some very good results with them, in terms of adding parts to their catalog that weren't previously there. As long as one of their suppliers carries it, they can get it, whether they show it or not.
katatak AUG 21, 09:15 PM
Spent the last hour catching up Blooz - as always - unbelievable work you are doing. I learn new tricks every time I come in this thread. Thanks again for taking the time to share all your hard work.

Pat
zkhennings AUG 23, 11:23 AM
How's the quality of the shocks? They look nice, are they for a street car or a track car?
Bloozberry AUG 23, 09:59 PM
Thanks for your feedback BlackEmrald, katatak, and zkhennings. It's always rewarding to see someone is interested. For zkhennings, the quality of the shocks seems pretty high given the replaceable bushings and the rebuildable nature of the shocks. They're really light weight too, and if price is any indication they should be pretty good. I'm not sure how to tell if they're for a street car or a track car... but I suspect the rebound adjustability using the 18 position knob will allow the characteristics to be changed to suit several applications. Time will tell whether they dampen my 350 lb/in springs effectively.

I'm a little behind where I'd like to be in the rear suspension construction, but then again it's summer. I also just got back from visiting the Yarmouth area for a week and checking out PFF member Yarmouth Fiero's convertible frame modifications. I brought down a bunch of the F355 fiberglass body panels for him to try out on his car... it looks stunning with the roof removed. Check his progress out here: www.fiero.nl/forum/Forum3/HTML/000137-7.html

I'm also wasted time and am a little disappointed with Summit Racing. After sending me $450 worth of wrong rod ends, they paid for the return shipping of the parts but advised me that I couldn't exchange them for the rod ends I wanted. It seems their supplier either can't or won't ship the new part numbers to Canada, and Summit won't act as an intermediate shipping destination. They only "drop ship" parts, meaning they only arrange their suppliers to ship directly to their customers. That's pretty pathetic service. They refunded my money but not the taxes nor duty, nor customs fees, nor shipping expenses I paid the first time around... all of which I now have to apply for on my own time because of a fault on their website. Anyways, Jegs was more than happy to sell me the correct part numbers for $5 more apiece adding $100 to the total cost. They should be here in 2 weeks.

Of course not having all the parts didn't stop me from progressing with the fabrication of the suspension mounts. I started with the mounts for the lower lateral links by making a template from my drawings and cutting the 8 mounting ears from 3/16" thick steel plate:



Here I just temporarily sat them on a spare length of 2"X3" tubing similar to the cradle side rail to mock them up and make sure they were identical in all respects. Once properly shaped, I carefully measured the location of the mounting hole, center-punched them, drilled a pilot hole, then finished up with the 1/2" bit in the drill press:



Next, I wanted to build a jig that would ensure the four mounting ears on each side would be at the right distance from each other and also have all the holes line up on the same axis. To build the jig, I found a cheap pair of female rod ends that measured the same width as the ones I've ordered from Jegs. Here are the parts that go into each side, just don't mistake the long bolts that I temporarily screwed into the rod ends as the lateral links... they're just there to help me mock up the installation:



Then, I slipped all the parts onto a foot long 1/2" fine threaded rod using jam nuts to locate the mounting ears at the right distances from each other and to make tack welding them to the cradle side rails easier. The threaded rod will be removed and replaced by two bolts (one for each pair of mounting ears) once welded to the cradle, but for now it serves to keep the holes concentric. From my earlier drawings, the center line of the rod ends must be 145 mm's apart.



Here's the completed jig sitting on a section of square tubing mimicking the cradle side rail:
Will AUG 24, 09:58 AM
I would add .003-.005 shim into the stack with each rod end... If you weld it like that, the rod end and spacer stacks will be extremely difficult to R&R.
Bloozberry AUG 25, 09:04 PM
Thanks for the tip Will. There's another way to make sure there's enough room between the mounting ears. By welding the mounts along the bottom outside edges, the mounting ears will spring ever so slightly apart at the tops when the weld cools and contracts. Tightening the mounting bolts when assembling the lateral links later on will close up the gaps.

Here I've tack-welded the mounting ears for the lower lateral links to the cradle side rail using the alignment jig. I'll finish welding them properly the next time I remove the cradle from the car:



As expected, when I removed the 1/2" threaded rod, the tops of each pair of mounting ears sprung apart slightly by about a 1/2 mm giving a little slack to remove and reinstall the rod ends and spacers. (You can't actually see it in the photo... but what you do see is the distortion from the macro camera lens I used to take the picture).



With the mounts tacked in place on the driver's side, I mocked up my "stand-in" rod ends along with the spacers using the 1/2" dia grade 8 bolts, nuts, and hardened washers that I intend to use in the final assembly. I threaded the bolts so they are head-to-head to give me the maximum possible clearance for the axle shaft to pass between them.



And here's the passenger side tacked in place as well (I only have two stand-in rod ends while I await delivery of the proper ones, so there aren't any in this photo).



With the lower lateral link mounts basically completed, I turned my focus to where the new upper link mounts would be installed. I started with the aft upper mount since I knew it would be the most difficult and I wanted to get it done. If you go back to my drawings earlier on, you'll notice that the upper mounts get welded directly to the top of the lower frame rail. After studying the rail in that area, I realized that the sheet metal from the strut tower was sitting in the way on top of the frame rail acting as a sort of doubler. I marked up the area with a red marker so that once removed, I would have access to the frame rail:



Apart from the surrounding sheet metal, that section of the strut tower metal was also being held to the frame rail with two big spot welds, so the first thing I did was drill them out:



Once they were gone, the zip wheel in the angle grinder made short work of removing the hashed area leaving full view of the underlying frame rail:



That then allowed me to take accurate measurements to draw up a cardboard template for one of the aft upper mount ears. I used my drawings to guide me in making the correct shape for the template and used the chart of suspension coordinates I created earlier for the Lotus Suspension Analyzer program to locate the hole in the template in exactly the right place.



Unlike for the lower mounts, the contour of the frame rail changes so the two ears for the aft upper mount will have to be slightly different shapes, making it more challenging to keep the pivot axis (the bolt passing through the ears) aligned in three dimensions. Creating the template for the second mounting ear is next.

[This message has been edited by Bloozberry (edited 08-25-2013).]

Bloozberry AUG 28, 09:48 PM
After lots of fooling around with the laser level and a pair of rulers, I finally got repeatable measurements to trace out the template for the second mounting ear. If you look carefully, there are subtle differences between them to accommodate the changes in profile of the lower frame rail:



These are the parts that go into making the upper aft lateral link mount (once again I used my female rod end as a stand-in for mock up purposes):



This is what it looks like once it's assembled... this photo also gives a better idea of the size of the mount:



And here it is mocked up onto the lower frame rail (the red thing is just a magnet to hold it in place for the photo). I'll tack weld the ears to the frame rail while it's mocked up like this to ensure the alignment stays true:



And a close up:
bubbajoexxx AUG 30, 04:18 PM
looks great but are you going to put 1/8 plate in the area for extra strength that upper metal is thin and should be reinforced
Bloozberry AUG 31, 10:43 AM
Thanks for your observation Bubbajoe. I don't believe the upper mounts will see much load considering the geometry. When you consider that in the stock configuration only a single point locates the top of the knuckle (ie the strut pushrod in a bushing), the bulk of the side loads are resisted by the lower lateral link mounts. (Accelerative and decelerative forces are transmitted through the trailing link.)

Nevertheless, a quick look at the forces applied to the suspension of the outside rear wheel in hard cornering shows that that lateral forces exerted by the road onto the tire (red arrow) transform into a moment (pink arrow) about the bearing, which is then applied to the upper and lower link mounts (blue arrows) by the links.



The leverage from the tall knuckle favors the upper link mounts and reduces the load considerably compared to the lower lateral links which take the brunt of the load. If you bear in mind the total lateral load on each of the two outside tires won't exceed half of 1G (or approximately 1500 lbs), then that means the bearing will see about a 1970 lbft moment that is countered by the upper and lower link mounts. Solving for the forces at each mount, the lower link mounts will need to absorb around 630 lbs each and the uppers will need to absorb about 260 lbs each at max lateral G's, which isn't very much. Normal driving probably won't generate half of those forces.

Even still, when you look closely at the cross section of the lower frame rail where the aft upper link mount is attached, the frame is already doubled up in thickness due to the left-over strut tower material (except for the very top surface of the rail). I'll have to weld that second layer to the frame rail properly to gain any strength though. Then, when you consider that this area of the rail is framed by two vertical structures (the remnants of the strut tower) that connect it to the upper rail, I believe there's sufficient strength to handle the anticipated loads. But I invite others to express their views as well.

(edit: error in drawing)

[This message has been edited by Bloozberry (edited 08-31-2013).]