Turbo 3400, F23 build, 1985 GT (Page 2/26)
jelly2m8 JAN 25, 04:14 AM

quote
[B]Originally posted by 1985 Fiero GT:[/B

Cradle out





I have no idea why Cliff won't implement a LIKE function on these forums....anyway, this pic reminds me of how my Fiero evolved. Tired of the leaking valve covers.... I got those off, may as well put valve seals while I'm in it... Oh! that valve stem face has a nick in it... off with the head... Long story short.. Engine, transmission and Electronics swap / upgrade.


Fiero better than ever
1985 Fiero GT JAN 31, 12:15 AM
Well, one more evening of work on my Fiero, I got the old engine off the cradle, new engine on the cradle, the old rubber engine mount was separated, I don't know whether the 1985 is different, or maybe there are several different oil pan options for the 3400, but I had to notch the engine to rubber mount bracket to clear the oil pan, the front "shock" fit fine using 2 out of 3 of the original bolts (top hole does not exist, any thoughts/potential issues with leaving it like that?)I know the 88s have to notch the oil pan a little in some way, but if I had notched the oil pan on my bracket, I'd have had a big hole, which brings me to my second, rather disappointing part, the big hole in the oil pan. I drilled a hole for the turbo oil return, but I forgot that the starter existed, so I put it right there, so now I either have a big hole in my oil pan, or I get a new one, so that will be on the way soon.
pmbrunelle FEB 01, 11:53 AM
I’m not so sure about the shift cable being laid flat over the transaxle. With that angle, the shift cable force will not only cause rotation (which is desired) of the F23’s shift shaft, but will also push/pull the shift shaft in an axial direction (i.e. the select direction), so the shifter might hang up in the gates.

I’m tilting my shift cable a bit (but much less than yours), and I plan on installing stiffer centering springs so the shifter will remain in the 3-4 plane despite the shift cable force causing a select force as a side effect.

********************

2/3 bolts for the engine mount damper sounds sketchy.
1985 Fiero GT FEB 01, 12:25 PM

quote
Originally posted by pmbrunelle:

I’m not so sure about the shift cable being laid flat over the transaxle. With that angle, the shift cable force will not only cause rotation (which is desired) of the F23’s shift shaft, but will also push/pull the shift shaft in an axial direction (i.e. the select direction), so the shifter might hang up in the gates.

I’m tilting my shift cable a bit (but much less than yours), and I plan on installing stiffer centering springs so the shifter will remain in the 3-4 plane despite the shift cable force causing a select force as a side effect.

********************

2/3 bolts for the engine mount damper sounds sketchy.



Good point, I haven't finalized anything, I'll see how much extra cable I have once it's in the car, get as much tilt as possible, my cable mounts aren't fastened on yet, so they were sagging under the weight of the cabin end of the cables, which makes them look less angled than I intend, I will look more into that though.

One thing to remember is that the 88 Fiero (and obviously the 3400 engine) didn't even have the dampener, I don't know whether it was deemed entirely unnecessary due to the internal balancing of the newer engines or whatever, it does seem unnecessary with the dogbone, and it doesn't carry any if the weight of the engine.
pmbrunelle FEB 01, 12:37 PM
For low NVH, you want a soft rubber dogbone. However, a soft rubber dogbone alone may allow the powertrain to move around too much.

The damper is an auxiliary dogbone that becomes stiff for rapid powertrain rocking movements, such as on launch, or hard shifts. The rest of the time, it does nothing.

For 1988 they probably just stiffened up the rubber dogbone enough to no longer require the damper.
1985 Fiero GT FEB 01, 12:42 PM

quote
Originally posted by pmbrunelle:

For low NVH, you want a soft rubber dogbone. However, a soft rubber dogbone alone may allow the powertrain to move around too much.

The damper is an auxiliary dogbone that becomes stiff for rapid powertrain rocking movements, such as on launch, or hard shifts. The rest of the time, it does nothing.

For 1988 they probably just stiffened up the rubber dogbone enough to no longer require the damper.



Then I'm set, I have a poly dogbone, and couldn't care less about NVH haha
ericjon262 FEB 01, 06:05 PM
Man, I'm having flashbacks to when I started building my car 15 years ago....

are you planning to update to DIS while you're changing from OBD1 to MS? I'd recommend it. Also, be aware your 2.8 timing cover might not fit the 3400 oil pan, IIRC you have to get a 88 timing cover.

------------------
"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.

1985 Fiero GT FEB 01, 06:12 PM

quote
Originally posted by ericjon262:

Man, I'm having flashbacks to when I started building my car 15 years ago....

are you planning to update to DIS while you're changing from OBD1 to MS? I'd recommend it. Also, be aware your 2.8 timing cover might not fit the 3400 oil pan, IIRC you have to get a 88 timing cover.




Nope, I'm keeping the distributor, by choice, but using the cam and crank sensors in the block for positioning for the sequential fuel injection (all calculation is computer, distributor will basically just be there for the looks), I already purchased a new 88 timing cover, 88 flywheel, gaskets, etc.
pmbrunelle FEB 01, 06:45 PM
I’m not sure about the 3400 cam sensor being compatible with MegaSquirt.

I remember ericjon262 welding onto a camshaft to make a half-moon sensor… maybe he can say a bit more about this.
1985 Fiero GT FEB 01, 06:57 PM

quote
Originally posted by pmbrunelle:

I’m not sure about the 3400 cam sensor being compatible with MegaSquirt.

I remember ericjon262 welding onto a camshaft to make a half-moon sensor… maybe he can say a bit more about this.



Depending on how long ago or what version of megasquirt he used, maybe it wasn't supported, I'm using a version of the 3 pro, and per the manual it supports all the gm 7x types, 1 tooth, 4x, and 6x cam gears, if that doesn't work, I will figure something out with the distributor like you did.

[This message has been edited by 1985 Fiero GT (edited 02-01-2025).]