Looking at 4.9 swaps there seem to be two or three configurations used: the two transmission mounts doing duty as rear engine mounts plus one front engine mount plus a torque strut (aka dogbone). This is the configuration Rockcrawl used. The Fiero Factory site says they use five mounts....that would likely be the two transmission mounts plus TWO front engine mounts PLUS a torque strut. It seems to me that five mounts is a bit excessive and the two transmission mounts plus two front engine mounts should be perfectly adequate.
Any of you swappers try that last combination....or am I wrong about what Rockcrawl and The FieroFactory are doing....or is there a better or best way? (Manual transmission, btw.)
TIA, Larry
[This message has been edited by imacflier (edited 02-16-2016).]
with my auto, I used the 5 mount setup, 2 stock type trans mounts plus 2 of the energy suspension trans mounts used as engine mounts one under oil pan and one in rear on an L bracket, then a dogbone strut from a maxima rear control arm from front head to cradle. It was simple, and easy but I suspect that 4 correctly placed mounts would work fine especially with an automatic. If I was to do it again I'd avoid the mount under the oil pan, and go with some round mounts in four corners. FWIW, my engine feels very solid to me.
Personally, I'd prefer to use a "four corners" setup. But the stock style setup is convenient, and it works. The Caddy 4.9 isn't a "monster torque" engine, so I don't think the extra mount is really necessary. But it wouldn't hurt.
I run with 4. I thought of adding the dogbone, but there is no movement from the engine at all. If I see any change after more mileage I will consider it. For now...4 seems to be enough. (Of course my car is now parked for a major body build, so it'll probably be another few years before I get it back on the street...)
I have the 4 mount setup using 3 poly trans mounts and one rubber trans that was still good and didn't need replacing. I have the engine mounts as far apart as possible for the best stability and still have a fair bit of engine rock under acceleration. I think the doggone would be a good idea as a backup in case either of the engine side mounts broke due to wear. And we've a seen engine mounts break. Check my swap thread "Let's replace my 4 cylinder with a 4.9!" For full pics of my custom made mounts. Not saying they are the best mounts... just the way I wanted to make them.
The Fiero Factory method is "4 corners" plus the usual mount under the crank pulley. There is no dog bone. You could pick up my car by the engine and shake it until the body panels fell off, and the engine wouldn't budge.
Edit - They also added a reinforcement to the front cradle rail, to stop the tranny mount from tearing out. 88 cradles have fractured, there, even with stock engines.
[This message has been edited by Raydar (edited 02-17-2016).]
The "system" I used could be called 5 point system.
Originally I used the "4-point" system: 2 tranny mounts, 1 mount going to the front of the cradle (attaches to the engine block at the a/c compressor location, and the stock 2.8 location basically front center.
This was an issue as the engine would have a lot of move still under heavy acceleration. I have pictures from some 100' drags that show the decklid actually being lifted by the alternator. A buddy that used the same system actually tore the front mount out of the cradle and that had to be welded back up. I then added the "dog bone" attached to the rear of the cradle an up to the top of the block/head. That solved all the issues with the motor "rocking".
Not the best picture, but the best I have at hand that shows the "dog bone".
First, let me thank all of you folks who have commented! I am amazed at how much stuff there is on what appears on the surface to be quite straightforward.
Now, Reallybig....could you please tell me on which page of your thread your mounts are pictured? Nice thread by the way. What I really want most is the design of the mount for the forward front corner....I picked up one of Rockcrawl's mounts for the aft front corner.
First, let me thank all of you folks who have commented! I am amazed at how much stuff there is on what appears on the surface to be quite straightforward.
Now, Reallybig....could you please tell me on which page of your thread your mounts are pictured? Nice thread by the way. What I really want most is the design of the mount for the forward front corner....I picked up one of Rockcrawl's mounts for the aft front corner.
Anyway, anybody really HATE their 4.9 manual?
TIA, Larry
mine: this is before welding it to the cradle. that bolt was just helpful setting it up.
reallybig's: https://www.fiero.nl/forum/Forum2/HTML/122389.html page 2 for mounts, he used the aluminum mount, where I used the steel one. Honestly his was done nicer than mine, but mine works too. his, mickeymoose and neils88, amongst others were all very helpful build threads when I made mine.
[This message has been edited by gen2muchwork (edited 02-17-2016).]
Sorry. I have no idea where the pics are in the thread. You would have to hunt around.... but they are there! And I have no regrets with the 4.9 manual swap. It's a blast to drive!
[This message has been edited by Reallybig (edited 02-18-2016).]
I hated the automatic Caddy tranny. Cadillacs were not designed to do anything quickly. A full throttle downshift required sending a telegraph message down to the engine room. Then it happened... eventually. Upshifts were just as leisurely.
I love my 5 speed, even though it blows through 1st gear fairly quickly. It's one of my favorite mods.
The further the mounts are from each other front/rear, the better the can withstand the drive train torque from the axle shafts. So for the 4.9 manual swaps I use simple piece of angle bolted to the engine and some box tubing welded to the cradle.
If you want to use a dogbone setup, then an 88 lateral link fits perfectly and makes the engine mount setup nearly as wide as the transmission side.
The axle shaft is pretty close, but clears:
The front mount is pretty typical, angle welded to the front crossmember and use of stock upper mount bracket:
The other reason I like this mount setup on the 88's is the stock engine mount pad doesn't leave much room for the exhaust to go between it and the oil pan. Moving the rear mount to the side of the engine and not using the stock engine mount pad allows it to be removed, freeing up a lot more room for the exhaust.
