PFF - Pennock's Fiero Forum, PDA Edition

The White Bug (Page 44/46)

pmbrunelle

SEP 20, 07:29 PM

quote

Originally posted by Will:
I have noticed the same things you have about mounting the metric bellhousing transmission "Fiero style". I was expecting that I'd grab the front mount bracket from https://thelinsellsdotcom.wordpress.com/ (or is it https://thelinsells.limitedrun.com/ ?) and add to/modify it to pick up some other bolt holes on the bellhousing.

It looks like Roger Thelin has a rear bracket that will work, but I probably have to contact him to be sure.

I don't think using a Roger Thelin front mount would be a useful starting point; not much of it would remain after adaptation to the Metric bellhousing transmission.

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FIEROFLYER uses a beam solution which would have to be built very heavy-duty:
https://www.fiero.nl/forum/Forum2/HTML/126774.html

WCF does something similar:
https://westcoastfiero.com/...unt-and-bracket-kit/

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ericjon262 uses a transmission mount near the bellhousing plane, but then the transmission mount force is applied closer to mid-span of the cradle crossmember. In this case, I think the crossmember should be reinforced/stiffened, or replaced with something more beefy (as he has done).

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I noticed this ear on the transmission case which is sort of close to the Fiero's front transmission mount.

It might be able to handle the brunt of the transmission mount force.

I need to do a strength evaluation of this ear to determine if it is feasible to make a mount bracket that transmits force mainly to this ear... I guess assuming some aluminium die-casting alloy such as A380. My car is traction-limited in 1st gear. I am not sure how to estimate the force on this mount; I need to think about it.

Those who have selected the "beam" solution perhaps thought that the ear was too flimsy, so they avoided using it.

ericjon262

SEP 20, 09:07 PM

I'm not a fan of that boss, IIRC, it's for the HTOB hydraulic line. If you look on the end of the transmission, there are 2 sets of bosses, one with two bolts going in horizontal, and one with three going in vertically, the more or less line up with the front driver's side cradle rail and would probably make for a significantly more substantial mount than the boss you pointed at, however, it doesn't line up with any existing mount location.

Edit: I seem to have forgotten the horizontal bolt bosses are not on the same plane, the planes are approximately 48mm apart.

this is the mount I had come up with for my 5 speed swap in the Gran Damn.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

[This message has been edited by ericjon262 (edited 09-21-2024).]

pmbrunelle

DEC 09, 09:42 PM

With the Muncie still in place, I installed temporary engine supports, and then I removed the Muncie.

From here, I can bolt the Getrag F23 to the engine, make/modify/fit the transmission mounts, and then finally remove the temporary supports once the transmission mounts are done.

The front temporary support was fairly easy to do. It mounts to the starter's mounting location on the engine block:

The rear temporary support was a bit more tricky to figure out; it is a long rod going to the rear engine lift hook:

ericjon262

DEC 16, 06:38 PM

I like the temp supports. when you make your mounts, you may want to add a little bit of preload to account for the weight of the engine and transmission

pmbrunelle

APR 24, 10:04 PM

It has been a little while since the last update here!

The F23 mated onto my engine, without having to change the clutch, turbo piping, or even the coolant crossover pipe.

The shift linkage was a pain to figure out, as the shifter tower is on the wrong side of the F23 and oriented the wrong way for Fiero use.

I also liked my current turbo setup, and I didn't want to redo everything to install this transmission. This is what I came up with.

The cables will arrive with a fairly direct routing from the firewall, as they did with the stock Muncie setup.

The shift cable is not quite perpendicular with the F23's shifter shaft. It is 7.5° from perpendicular, so shift cable force will have a slight axial component. I installed stiffer centering springs in the F23 to help stay in the 3-4 plane despite the presence of axial force during hard shifts.

These parts (except for the bellcrank, which is in stainless steel) need to be sandblasted and painted with POR-15.

I designed this shifter (on the transmission) to work with custom Cablecraft cables. Now I need to modify the shifter in the cabin to work with Cablecraft cables.

Will

APR 25, 05:35 AM

The parts look shiny... I was going to ask if you had them plated. I guess they're just new, since you said you'd have to POR them.

pmbrunelle

APR 25, 05:55 PM

The weldments are just freshly fabricated.

The edges of the plates needed to be deburred/sanded/wirebrushed as-delivered from sendcutsend because the laser-cutting process doesn't generate fully "nice" parts.

Then, the parts needed to be sanded/wirebrushed to prepare the weld areas for welding (remove mill scale).

After welding, welding spatter and silicon islands had to be scraped off, sanded, wirebrushed...

After all of this, the parts end up shiny!

ericjon262

MAY 03, 01:59 PM

your shift linkage looks fantastic.

I assume you're adding a bushing of some kind to the area circled in green?

is there some kind of bearing on the red circled shaft?

pmbrunelle

MAY 03, 05:15 PM

At the bellcrank pivot (green circled area) there are plastic Igus bushings.

I used the J350FM-1012-10:
https://www.igus.com/iglide...artnr=J350FM-1012-10

Igus bushings are quite easy to use. They often press in with a small amount of force (my bench vise was more than enough in this case). Inch and metric sizes are available in many different kinds of plastic. We used them regularly at my work in small electric actuators.

In this case, I made the steel tube part with an undersized centre hole, knowing that the welding could distort the hole. After welding, I used a hand reamer to enlarge the hole to the size needed by the Igus bushings.

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The pin (red circled area) is just a rod (actually, it was the shank of a Grade 5 bolt) with a hole drilled through it.

I don't think there's much friction there, so a bearing would be overkill.

This is a bit like with (properly designed) valve rocker arms, where there is not much movement between the valve tip and the rocker arm shoe, so a roller there is generally not worth having.

Additionally, my shifter has less sweep there than on a stock F23, because the bellcrank's lever arm is longer than stock F23.

ericjon262

MAY 03, 05:53 PM

the bushings are very similar to what would have been on the stock F23 shifter, when I built my mechanism, I was able to salvage the stock bushings from an F23 and reuse them, but my shifter also used the stock F23 select arm so using the stock bushings made sense.

I look forward to hearing how everything fits and feels in the car, especially with relation to the centering springs!