After great deliberations, searching, and what ever I have finally began my 3.5 v6/4T65E swap. I finally located a low mileage 2010 Chevy Impala 3.5 VVT v6 with 30,000 miles on the clock. The engine comes from New York state, hence some rust issues, but nothing major (mostly surface rust). I received the engine about 6 months ago but have not had the time to begin the swap. As you can imagine this will be a slow swap (it's summer family first)! I plan on documenting this swap as much as possible as I have really been less than successful in finding any 3.5 v6 swap information on this site (with photos of the process).
I have acquired several parts from the local Pull-a-Part. Firstly, the engine and transmission mounting brackets. I have already prepped my spare cradle for the swap.
I know the cradle is "RED", the same color as my 86GT.
Here is a couple of photos of the engine as it appeared up packed from the shipper.
I noticed the engine I purchased came with a power steering pump? I am seriously thinking about keeping the power steering pump and go ahead and add power steering to the GT. Any thoughts?
Today the front engine motor mount arrived from RockAuto so I decided to go ahead and install the 3.5 on the cradle.
The next set of parts to acquire will the 4T65E & torque converter and the AC compressor. I need those items to complete the engine mounting process. Hopefully that will happen within the next month or so.
Tell me, is that not a thing of absolute beauty?? I have been wanting to do this swap for a very long time now.
[This message has been edited by Cajun (edited 05-01-2022).]
...and here I am building a 3.400->3.5 L 6" rod, high-revving cam, lightened drivetrain old school pushrod motor with Fiero heads and 11+:1 compression running E85...
Today the front engine motor mount arrived from RockAuto so I decided to go ahead and install the 3.5 on the cradle.
Do you have a higher resolution version of this photo?
I snagged one of those brackets on spec a couple of years ago (2018? Maybe more than a couple of years) https://www.realfierotech.c...php?p=157012#p157012 I have not yet had the chance to test the bracket. Thanks!
Okay, as builds go this is my first (1st) hicup; engine placement:
As I had indicated I had mounted the 3.5 VVT v6 on my spare Fiero cradle. Thought all was good, then went on a fishing trip. When I returned, I checked out my engine placement. As it turns out the 3.5 is about 2 inches to the left from where it is supposed to be.:
The square is where the engine pulley is supposed to be. Here is my 87 GT parts car engine on it's cradle for engine placement reference.
I have lifted the 3.5 off the Fiero cradle for test fitting engine mount brackets. My plan is to utilize the Fiero 2.8 front bracket, modify it to fit the 3.5, etc. Once I get my son to fabricate the bracket I will post the results.
[This message has been edited by Cajun (edited 05-09-2022).]
Is there clearance to the trunk wall? I did a bit of rough measurement, but it seems like that from rear mounts to the forward side of the trunk wall was something like 5".
I guess that is why so many swappers cut the trunk out.
When I did my lx9 swap into a 86 we used stock fiero brackets with the 3500 front cover. I replaced the stock mounts with 2x3 steel after I ripped the new rubber mounts apart.
looks good! I figured I would reply to your build thread instead of the PM, I think it wouldn't be crazy to make a mount plate similar to the LZ4 part, but mounting the engine in the correct location.
measuring off of the front of the block is fine for the front to back placement of the engine (relative to the car), however, I wouldn't do that for the side to side placement, I would measure off of the bellhousing flange instead, or off of the end of the crank snout (not the balancer) as the balancer and timing cover have undergone many changes in the past 30 years.
------------------ "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 have stumbled upon a build thread by MaddMatt regarding the mounting of the 3.5. His approach is exactly what I wanted to do. Thanks MaddMatt!
The Fiero front motor mount bracket is with my son who will modify the bracket accordingly. He will also modify the Fiero cradle so the AC compressor clears when the engine is mounted.
Okay, as builds go this is my first (1st) hicup; engine placement:
As I had indicated I had mounted the 3.5 VVT v6 on my spare Fiero cradle. Thought all was good, then went on a fishing trip. When I returned, I checked out my engine placement. As it turns out the 3.5 is about 2 inches to the left from where it is supposed to be.:
You could just take a piece of 1/4x2 flat bar and drill three holes in it. The middle hole in the flat bar picks up the forward hole in the engine mount and the aft hole in the bracket on the engine. The other two holes pick up the other two locations.
...and here I am building a 3.400->3.5 L 6" rod, high-revving cam, lightened drivetrain old school pushrod motor with Fiero heads and 11+:1 compression running E85...
Lou, they just simply don't understand there's more ways to find cubes and power than installing a junkyard engine and calling themselves "engine builders". And when they fail, a turbo or an LS will come to the rescue. Don't spoil the man's party!! Maybe he just want a 3.5L to cruise around.
I'm not wild about mad matt's mounts, they probably work ok, but I would imagine that with the metal fab equipment you suggested you have available to you, you should be able to do something much better.
------------------ "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 was hoping to be making some, any progress on the 3.5 v6 install! Am waiting on my son to modify the Fiero cradle so the AC compressor on the 3.5 would clear the cradle. He is also making a modified front engine bracket. Now it appears it will be a while before that will happen, the family just left for 2 weeks vacation. Oh well.... that what's happens when you depend on other individuals to assist, help with your projects.
In the mean time I thought i would do a little prep work on the front engine bracket and associated mounting components. I have modified the Fiero 2.8 front engine mounting bracket to fit my 3.5 v6. Not pretty but functional.
For this to work one will have to trim down the webbing on the oil pan so you can access the bolt/nut on the right side of the front motor mount. I used a cut-off blade to get the job done then finished up with a grinder. The webbing needs to be cut back until it's flush with the bottom of the oil pan.
Photo of the modified Fiero front engine mount bracket installed on the 3.5 for fitment checks.
This next photo is a test fit of the modified Fiero front engine mount bracket with the Front engine mount installed. From this phot one can see why the oil pan webbing needs to be trimmed a bit.
In the next couple of days I plan on making a trip to the local Pull-a-Part to pick up an AC compressor for the 3.5 and get that out of the way. Once I get the Fiero front engine mounting bracket welded up I will post photos of it.
Back to waiting on my son to complete the mods to Fiero cradle..................
[This message has been edited by Cajun (edited 05-31-2022).]
Since that's a 2010 engine, it must be an LZ4. Is the upper bolt hole for the Fiero engine mount bracket still in the same place on the block? I had heard that for the LZ9 and LZ4, the same bolt holes used for the Fiero engine mount bracket were no longer present.
Only one bolt hole is available (See my install photos). That is why I utilized the front engine mount for the 2010 3.5 v6 and a fabricated plate welded to the Fiero front engine mount.
I saw that bolt was there. I can also see that the upper bolt is not present. What isn't clear from the photos is whether the upper HOLE is still in the block.
I saw that bolt was there. I can also see that the upper bolt is not present. What isn't clear from the photos is whether the upper HOLE is still in the block.
The upper hole is not present on my LZ4.
------------------ "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."
Finally received the modified front engine mount bracket from the shop a few days back. This is the first opportunity I have had to check mounting fitment. I have placed the modified Fiero 2.8 front motor mount backed and the modified Chevy 3.5 front motor mount bracket on the 3.5 for fitment purposes. Once I was happy I removed everything, waiting on locating a suitable transmission for the build. One that they don't try to extract too much blood from me.
Photos of the modified Fiero 2.8 front motor mount bracket:
Photo of the 3.5 v6 secondary front motor mount mating points:
Photos of the modified front motor mount brackets installed:
[This message has been edited by Cajun (edited 06-26-2022).]
I have taken care of the need for wiring information for the 2010 Chevy Impala 3.5 v6 engine swap!
I went ahead and purchased two (2) FSM's (Factory Service Manual) for the engine in question. The manuals are from two different sources so I am sure I have all the wiring diagrams/schematics I will require to complete the swap. I am currently in the process of printing the information I require for the wiring interface.
I have been working on building wiring harness(s) to interface the 3.5 to the 86GT wiring. One of my goals is to keep my digital instrument cluster. It took me over a year to get digital cluster to work with the Fiero wiring and data information.
I still need to make a run to the local Pull-a-Part to pick up a foot pedal assembly and wiring from a 2010 Impala.
I still have not located a reasonably priced 4T65E transmission with low miles on the clock. I am still looking. I did locate one but when I went to inspect it I noticed the oil pan was leaking. I don't want to inherit and additional issues, so I rejected that one.
I finally found some free time to pull the engine wiring harness out of my parts car, a 87GT.
What a ***** to pull especially in 100 degree heat. But it's done and complete.
I also have pulled the engine wiring harness from a 2010 Chevy Impala but from some reason I have not been successful in getting the photo to load. Will keep trying.
I am still in the process of drawing up an integrated wiring diagram to interface the Fiero wiring to the 2010 Chevy 3.5 v6 engine.
As I am building up a wiring harness to mate the 2010 Chevy 3.5 v6 engine with my 86Gt my current plans and thoughts are is not to bring any engine wiring from the new engine into the cabin!! The only wires I plan on moving into the cabin are the wires needed for the DBW (Drive by Wire) from the accelerator pedal to the throttle body motor. I plan on using a Bluetooth OBD2 scanner and a tablet as the instrument cluster for the engine. That is just to keep tabs on the engine vitals.
The original wires going from the engine bay to the cabin for instrument cluster information will remain the same ( I hope).
Still working on the wiring harness interface.......... looks like I may need to make a trip to the local Pull-a-Park for additional wiring harness material
In the mean time I have remounted the 3.5 v6 on the Fiero engine cradle. I have also mounted the A/C compressor on the engine. Now I am on the hunt for an alternator so I can begin the process of developing a lower alternator mount for the engine.
Made another trip to the local Pull-a-Part for an alternator off of 2010 Impala, 3.5 v6. While there I also pick up a mounting bracket to secure the A/C compressor, back end to the block.
I have fabricated a bracket to relocate the alternator. This is only a mockup using 14 ga plate. My plan is to use 3/16th or 1/4" plate for the final version of the bracket.
that might clear the decklid, but I doubt it will clear the trunk wall.
------------------ "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."
To me, the 3500 is the best possible engine upgrade for the Fiero- same V6 family, lighter than the 2.8 and has (Approx) 210-220 hp and 215 torque- and a very broad power band. Although the 3900 has a bit more power, I prefer the lighter 3500.
You do realize that there are only 2 or 3 parts different between a 3500 and 3900, the crank, rods, and pistons. The weight difference is probably less than 5 pounds.
------------------ "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."
ericjon262; Thanks for the comment! I had not checked the clearances; you are correct the alternator will not clear. Oh well, on to plan "B".
Plan "B" is to place the alternator in the approximate location as the alternator is located on the 2.8. Back to the drawing board........
I have a buddy with a 3900 swap, who put a LSX truck alternator in approximately the stock 2.8 position, I'll ask him to send pics, or post some here.
------------------ "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."
he sent me a few pictures. I didn't design or build this, but I would probably try and make the top idler a little bigger to increase clearance to the tensioner. a heat sheild on the manifold near the alternator is probably a really good idea too.
The boss under this pulley needs to be trimmed about 5mm.
------------------ "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."
cognita semper
[This message has been edited by ericjon262 (edited 08-23-2022).]
You do realize that there are only 2 or 3 parts different between a 3500 and 3900, the crank, rods, and pistons. The weight difference is probably less than 5 pounds.
Yes- but what about that variable intake? I own a 3900 (In my van) and have looked at and compared the two intakes- there is a lot of added weight there- and it is high up raising your CG.
