Build update - 4T80 3800 Turbo (Page 2/10)
Will FEB 02, 08:11 AM

quote
Originally posted by LFiero67:

Pontiac 6000 was available with the larger axles as well. Station wagons and HD suspension option had them. Also found on chev celebrity, and a few other cars of the era. I went transport because they were available in the wrecking yard.



Again, not so much...
I'm checking RockAuto for these applications.

The A-Bodies & U-Bodies through 1991 had 10.25" front rotors and 27 spline CV joints and hub cartridges.
For 1992+ the U-bodies went to the 11" and 33 spline combo.

The Buick Century was the only A-Body to stay in production beyond 1991. It appears to have 33 spline CV's and wheel bearings for 1992+, BUT the Century kept the 10.25" brakes.

The 27 and 33 spline hubs are bolt-in swaps for each other.

The 11" brakes do NOT bolt onto the older style knuckles.

A-Bodies were never built with 11" brakes.
Celebrity, 6000 & Ciera were never built with 33 spline hubs & CVs.


quote
Originally posted by LFiero67:
These are 95, so they have the larger brakes, with same calipers as Fbody. Unfortunately they are iron calipers, and 1.25” rotors, so it’s heavy.

Requires the ball joints and outer tie rod ends to match the knuckles, but they bolt onto the Fiero control arm and inner tie rod.



I'm not saying they don't bolt in. I've done the swap on my car. I'm saying that '90's U-Bodies have the biggest brakes and wheel bearings while the '80's A-bodies do not.

[This message has been edited by Will (edited 02-02-2022).]

LFiero67 FEB 02, 08:36 AM
Edit: incorrect information removed.

[This message has been edited by LFiero67 (edited 02-03-2022).]

LFiero67 FEB 02, 08:51 AM
Cadillac axles will require shortening to fit the Fiero Chassis. The 99 deville has the shortest ones available with the 4T80, I have not determined yet how much they need to be shortened. Others have done the longer Seville cv shafts and taken 3/4” off each end for total of 1.5” shorter.
Will FEB 02, 09:11 AM

quote
Originally posted by LFiero67:

If you look up a 1986 Pontiac 6000 with Light duty brakes, it has 5x115 bolt pattern and 33 spline outer cv joint. I owned a 1986 Celebrity years ago, and it had the larger bolt pattern and cv splines as well.

It was my mistake saying the HD brake cars have the larger splines I had it backwards.

If someone wanted the just larger splines, these cars are options, but you do not get larger brakes with the 80s cars. The LD brakes are 9.68”, similar to Fiero but vented, and lighter than the larger 10” & 11” brakes on the vans. Any of the swaps require 5x115 wheels.

This images is larger than 153600 bytes. Click to view.




FYI, the 27 spline pattern used in the A-Bodies has a larger diameter than that spline. I have the 27 spline A-body parts on my car now and the large pattern 33 spline U-body units ready to go on. I forgot that GM engineers were crack heads and used a fine pitch 33 spline on the small pattern parts.

Zooming in on that RockAuto screen cap and compare the hub end splines on that axle with this one:


quote
Originally posted by LFiero67:

Picked up a set of Pontiac Transport uprights for the rear suspension to accept the larger diameter Cadillac Axles. This change should reduce the instances of this:






Also the larger spline has larger threads, so the the larger spline is even larger than it looks compared to the small pattern spline. The small pattern hubs have small pattern splines.

The small pattern hubs and light duty brakes have 5x100 bolt pattern, just like the Fiero. This is an area in which Rock is difficult to use, as they throw all wheel bearings into the list, regardless of which engine is selected. The 5x100 bearings are universally garbage and the suppliers don't give Rock any data, so you typically can't actually look at what the dimensions of any given cheap bearing are. The light duty rotors are listed at 5x100, though.


quote
Originally posted by LFiero67:

Cadillac axles will require shortening to fit the Fiero Chassis. The 99 deville has the shortest ones available with the 4T80, I have not determined yet how much they need to be shortened. Others have done the longer Seville cv shafts and taken 3/4” off each end for total of 1.5” shorter.



Cool. Let us know how that works out. I've never looked into running a 4T80E, but it's been done with plenty of Northstar swaps.
LFiero67 FEB 03, 12:03 AM
Used my wife’s cricut machine, with her help to create a template to locate the 4 torque converter bolt holes for the 4T80 converter. The line on the template aligns with the Center of it the counterweight, and puts the holes equally on each end.


Drilled pilot holes at the locations on the template, then drilled each hole to fit the m10-1.50 bolts. I purchased bolts for a VW Caliper to Knuckle Mounting from Amazon: https://www.amazon.ca/M10-1...Grade/dp/B07PRG68MZ/
They are a bit too long and have a unthreaded portion, so I cut them down and ran a die down to the head.


Trial fit the torque converter, and it bolted up with just a little wiggle available. Reduced head socket bolts are flush with the counterweight so there will be no interference with the engine.








Relocated the rear knock sensor, cut the ear off the block and got the new engine mount installed.



Have to get a new gasket for the oil filter housing, then it is ready to attach to the transmission.

[This message has been edited by LFiero67 (edited 02-03-2022).]

Will FEB 03, 09:28 AM
I guess the converter pilot works and/or is compatible. Are you going to put an indicator on the pump drive and roll the engine over to verify concentricity?

[This message has been edited by Will (edited 02-03-2022).]

LFiero67 FEB 03, 09:37 AM
Converter pilot is same size as 4t65.
Will FEB 04, 08:40 PM
Checked offset of a 3800 flexplate relative to Caddy flexplate?
DimeMachine FEB 05, 08:34 AM
Enjoying this thread - thanks for sharing the process !!
LFiero67 FEB 05, 02:26 PM

quote
Originally posted by Will:

Checked offset of a 3800 flexplate relative to Caddy flexplate?



I don’t have the measurements for a northstar.

Converter has 0.094” of clearance to flexplate when fully seated in transmission. RWD GM stuff is supposed to be 1/8-3/16”, so I’m a little under that, but it is a number I’m comfortable with.