LFX 3.6/F23 option (Page 9/13)
Rickady88GT SEP 23, 09:22 AM
Any updates?
mender OCT 04, 12:14 AM
As a matter of fact, I just started the swap this weekend. Dropped the old cradle with the LX9 and 282 out and onto jack stands. Tonight I braced the engine in position and removed the 282 without moving the engine. As a matter of curiosity, I also removed the clutch that has about 35 race hours on it and was pleasantly surprised at the condition, probably less than half worn. Stock disc and pressure plate, held up well to the 186 whp but then again it's road racing, not drag racing. The front trans mount however didn't do so well, looks like that mount would be a regular replacement item if I had stayed with the 282.

I put a spare F23 with the V6 pattern on the LX9 engine as a jig to locate the new trans mounts. If you look at my first picture in this thread you can see the stock F23 mounts. The front mount is going to be very easy, it's right above part of the cradle so will be two ears welded onto the cradle. The rear mount is only slightly more involved, it has to straddle my relocated toe link but still very easy. Once those mounts are done, I'll remove the LX9 and F23 and put the LFX and F23 in on the new trans mounts, then fab the motor mounts. This should help keep everything aligned properly but I'll of course measure to make sure. I'll take pictures once I'm done. I'll be updating the F23 trans mounts by replacing the rubber with Prothane inserts as well, still deciding what motor mounts to use.

I have some updates that I'm going to do on the cradle while it's out. I'm going to replace the lateral crossmembers with 2" x 3" rectangular steel tube, my present ones have some racing related issues (cracks) and the new tubes should be more rigid. The motor mounts are on the side of the LFX engine and will rest on those pieces.

[This message has been edited by mender (edited 10-25-2017).]

mender OCT 25, 10:51 AM
Slow progress as I'm also upgrading the rear suspension and cradle. I weighed the LX9/282 combo as it came out of the car and it's 524 lbs, 26 lbs heavier than the LFX/F23 in the same configuration. I'd say a reasonable portion of that difference is the weight of the clutch package, the LFX has an aluminum flywheel with a six puck clutch disc.
mender OCT 25, 10:33 PM
Picture from page one showing the tabs and holes that the bracket attaches to:

Pictures of the lower bracket:


The pegs go into the bolt holes on the transaxle and the bolts go through the lower engine flange and hold the two together.

[This message has been edited by mender (edited 10-25-2017).]

mender OCT 28, 11:15 PM
Crossmembers are replaced, engine and transmission mounts are done, and the lower control arms with the new bushings are installed. Getting closer.
mender NOV 30, 12:11 PM
Cradle with engine and trans reinstalled, waiting for some spare time to do the wiring and plumbing.


I used poly engine mounts (Jeep application). Front mount using stock bracket to engine (note the new front and rear crossmembers to support the side engine mounts.:

Rear mount - had to make it from scratch to clear the axle:




I used the stock F23 bolt-on Cavalier brackets with poly inserts. The mounting brackets are just strap steel tabs welded to the cradle. Front:


Rear: had to straddle the present toe link bracket that may be moving so excuse the unfinished look.


Raydar NOV 30, 04:27 PM
Interesting. Didn't realize that you were replacing both crossmembers, though. We "welding impaired" are going to have to figure out something else.
But nice work!

Did you have to do anything to the shock towers or hinge boxes to make it all fit?

Edit - Got your msg. Thanks!

[This message has been edited by Raydar (edited 11-30-2017).]

mender NOV 30, 07:35 PM
There may be a way to reinforce the stock crossmembers to handle the loads. I'm putting a fair bit of stress on them with racing so figured now would be a good time to replace them. No other mods needed to the cradle or structure of the car but I removed the hinge boxes a long time ago so there may be interference in a stock Fiero.

If this particular engine swap has interest, I might see what can be done to make a kit for the WI folks. Thanks to Joseph Upson, I had a look on car-part.com, there are 64 pages of good used LFX engines with the cheapest ones around the $400 mark. Might be just in time to take over for the SC3800s!

[This message has been edited by mender (edited 01-02-2018).]

Raydar NOV 30, 10:14 PM

quote
Originally posted by mender:

There may be a way to reinforce the stock crossmembers to handle the loads. I'm putting a fair bit of stress on them with racing so figured now would be a good time to replace them.
...




There were actually some reinforcements being sold for the 88 cradles. The 88 cradles seem to be more fragile than the earlier ones. I haven't seen them in a while, however.

FWIW, My 4.9 has a 2" x 5" plate welded in where the front tranny mount bolts through. It otherwise uses the normal tranny mounts/locations, in addition to one under the crank pulley, and one on either side of the block, in the "front" corners. (i.e., 5 point mounting.)
It uses no dog bone, and I would venture to guess that you could pick up the car by the engine and shake it until the body panels fell off, and the engine would still be solidly attached. No. I didn't do the install.

[This message has been edited by Raydar (edited 11-30-2017).]

mender DEC 01, 01:10 AM
Could do a five point mounting on the LFX/F23 by adding the adding the upper front mount to right strut tower. I have the bracket on my engine at the moment, still deciding whether to use it or loose it.