Engine alignment during swap question (Page 1/1)
Billdavidson MAY 12, 07:46 PM
I'm putting a ls4/4t80e on a 87 cradle. I've noticed that the engine is a little cocked in the engine bay. Are there any tips on how to get the engine and trans aligned or measurements on the cradle I could use as a reference?
fieroguru MAY 12, 08:56 PM
With the cradle level, remove the rear valve cover and use the head surface for a level indicator.

Bolt a bar across the rear cradle mount bolts or run some 1/2" all thread through the front cradle mounts. Then measure from the engine block (front and back) to the bar or all thread to square it up.

Before finalizing the mounts, I like to do a couple of test fits with some mockup engine/transmission supports that allow me to slide the engine around in the engine bay to fine tune the placement, clearance, and squareness. Once you like the placements, tack weld the temp mounts to the cradle, pull it out, then build the mounts.

You likely need to clearance the cradle in a few places for the engine and transmission to be properly positioned square and level.

Here is an inspiration pic:
pmbrunelle MAY 13, 07:14 PM
Start thread hijack (well, this is kind of on-topic)


quote
Originally posted by fieroguru:
Before finalizing the mounts, I like to do a couple of test fits with some mockup engine/transmission supports that allow me to slide the engine around in the engine bay to fine tune the placement, clearance, and squareness. Once you like the placements, tack weld the temp mounts to the cradle, pull it out, then build the mounts.



Hey guru, what would you do to position a turbo in the engine bay of a Fiero? I need to position it so that the various plumbing connections are where they need to be, and so that there is clearance with everything (engine, body, and decklid). Then, I need to be able to drop the cradle, in order to weld the exhaust piping to the turbo, without losing the previously established turbo positioning.

I was thinking of building myself a really beefy "dial indicator support", like this one:


Instead of a supporting a dial indicator, I'd have the turbo supported by these adjustable rods.
The base would be somehow attached to some reference on the engine/transmission.

Opinions/ideas?

End thread hijack
fieroguru MAY 13, 10:23 PM
For my turbo mock up, I just used some blocks of wood and metal bars to rough in the general location.

Once I do a test fit in the chassis, I will make some temporary support brackets from the center sections and weld the supports to some brackets using the bolt holes in the differential housing or off the side of the head. So get everything set in place using whatever means, then once you like the placement, weld in some temp supports to keep everything in place while you remove it and finish up the plumbing and welding.

I like keeping things hidden... even turbos!

[This message has been edited by fieroguru (edited 05-13-2019).]

theogre MAY 14, 12:21 AM
May look odd to you but Engine/trans doesn't care about perfect alignment. Even many OE powertrains are off one or more ways worse when engine/trans mounts are bad.
But Axles will care about position of them, Most so if either or both inner CV's are too far in or out.
Axles won't bother much about minor up/down, front/back or twisting errors of powertrain as long as axles don't hit things and tear boots etc doing that.

Axles may look ok w/ car at curb but suspension makes wheel to move in/out as you turn or hit RR tracks, Speed Bumps, etc. as wheels move up/down.
Inner CV big reason for design is to give some slack when, not if, that happens but most only are "safe" in a "sweet spot" and that spot is small. Often only fractions of 1 inch. Maybe ~ ½ to ¾ of 1 inch total for many.

Is bad enough to get wrong axles for stock cars and axles break when driven a mile or three. I had a wrong axle in a box w/ right PN on the box years ago and didn't notice and inner CV torn itself apart just getting out of driveway because axle was short.
What if you got the opposite wrong axle?
Too long and inner CV tries to compress over the limits and axle, suspension and trans will have much worse problems including a destroyed trans and/or knuckle failure. Hopefully you have problems just to install this and won't fit but can happen when car is jack up and error is only a little longer.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 05-14-2019).]

fieroguru MAY 14, 11:54 PM
Any non-stock swap should verify axles are free of binding at full droop and full compression. Easiest way to to remove the tripod boots and the rear springs and cycle the suspension while turning the rear wheel by hand.

This is Bad (and is a result of moving the tripod position about 1" further to the driver side, the tripod being a fabricated unit, and the engine being as low as possible, and flipped upper strut bushing hat... so lots of extremes.


Fixed by trimming the end back and only leaving 1 boot groove: