pentiuman

Help (again please). As explained in my other post, I just replaced my bad 350 in my 91 GTA, auto tranny. I've installed the parts and bolts for the following: flywheel (of course), bellhousing, torque converter, motor mounts, and tranny mount. While admiring my hard work and planning the order to install everything else, I'm now concerned that the engine may be slightly crooked, but this may be an optical illusion. Since the engine hoist is rented and due back in just 6 hours, I must try to figure this out soon, or pay for another day. Facts:
1. I put wooden blocks under the tranny after raising it just slightly (probably not enough). Removed the engine by itself. Had tranny on wooden blocks, but not very high. Tranny mount was either already broke or broke during the 3 weeks my car sat. When trying to install the new engine, we had trouble getting over the motor mounts on the frame, w/out hitting the flywheel against the bellhousing. Had to install a new tranny mount, but left bottom nut off, and had to raise the tranny much higher than it was when we took the engine out. Put engine on the hoist, level in the chains, and lowered in very slowly. At the last, had to wrangle it in by hand with most of the weight off of the hoist.

After hand installing the motor mounts and the bellhousing bolts (no crossed threads) and tightened, and removing the boards suppporting the tranny, I was standing on the ground, but in the engine bay area, and the engine / tranny seemed to fall down! I was surprised, since they were bolted together, since the motor mounts were already in, and since the engine and tranny didn't come down when I removed the boards under the tranny. However, since those bolts were in and it did fall, and nothing seemed amiss, I figured it fell into its rightful place.

While planning the install of the remaining parts, and admiring my work, I noticed that the engine seems to be slightly crooked, with the front pointing right and the rear left. Also, the engine seems to be closer to the passenger side, than the drivers side. I'm trying to figure out if this is an optical illusion or not, and whether I should loosen the various bolts and try to raise / move the engine (/ tranny unit) a little? I'm stumped, because the bellhousing joint was perfectly matched when joining the engine to transmission.

Upon closer examination, all I've found amiss was that one of the tabs on the engine mount top half, is two millimeters off, and not sitting in the bottom half of the motor mount, like the other side is. How is this possible? As long as the engine and transmission are mated together properly, does it matter?

Regarding centering / straightness, I've tried to measure various points in the engine compartment, but it's not easy. Yes, there's more room on the driver side of the engine to the fender, than on the passenger side, but there's also more components unique to each side. Yes, measuring from the front of the car nose, to the front of each head is different, but (as many of you may know), on a v8, the design makes the heads staggered, so that's not a good ruler.

Guess I will loosen some bolts and try to raise the engine/tranny unit a little, to see if it can be straightened and the possible engine mount tab problem fixed.

Thanks everyone!

Damon

Many cars have the engine offset to the passenger side slightly. On my 78 Malibu it's about an inch off of centerline at the water pump-mounted engine fan. Can't recall if it is or not in a 3rd gen, but it wouldn't surprise me.

Is the engine level in the engine bay? If it's not dropping all the way onto the mount that will make it sit crookedy, but it won't affect the side-to-side offset by very much. Another reason is that the lower engine mounts themselves can be collapsed from age/abuse. Usually the passenger side one settles first becuase it's got both engine weight and engine torque pushing down on it.

Tranny's gotta be reasonably close to proper mounting position if the engine mounts are going to line up. If you replaced the mount or are dealing with a broken one I'd do the engine mounts first and then do the final tightening on the trans mount.

Not sure why one of your engine mounts isn't getting all the way mated up, other than that. The upper clam-shell is supposed to drop down onto 4 tabs on the lower part of the mount (if we're talking about a stock engine mount here). If/when it does, the through-bolt will slide right in with little or no force requried.

Supervisor42

Actually it's offset a LOT to make room for the steering sector. It's no optical illusion. Take a look at this straight down picture I took bolted in with new motor mounts. Notice the distance from the valve covers to each strut tower or frame rail (ignore the headers). Ain't that something?

AlkyIROC

Just about every GM car is like that. They move it to the passenger side to clear the steering shaft. Most people never notice it. The tranny, driveshaft and pinion yoke on the diff are all also slightly to the right. The diff sits slightly offset which you'll never notice until you put really big tires on the car.

It very noticeable on my car with the tunnel ram poking through the hood. The air filters are not inline with the peak on the hood.

If you do a lot of measuring, you'll also find the third gen body lines are not symmetrical from side to side. When I tubbed out my car last year, I found the passenger wheel opening to be a different shape and position compared to the driver side.

pentiuman

Thanks everyone for the info and the picture! Remember - there's no such thing as a dumb question (just dumb people). But seriously - I have yet to meet someone who is right 100% of the time.

Please note, I already quit working on the car for the day, and then checked this thread. However, when I looked at the front of my (presumably stock) motor mounts earlier today, it turns out that both motor mounts have 1 front tab sticking out about 3/4 cm, and 1 front tab sticking in (tab edge visible, but not protruding). Didn't think about there being a total of 4 tabs on each clamshell motor mount (2 in front, and 2 in rear), but when I put the through-bolts in, they slid in by hand very smoothly. I did install the motor mount through-bolt and nut on each side, facing different directions, as they were when I removed them. I'm gonna (try) to look at the rear of the motor mounts tomorrow, to see the position of the rear tabs. IF the motor is sitting on/in the motor mounts crooked, it is just a few millimeters. I already took back the engine hoist, but will reluctantly re-rent it, if it isn't sitting in the mounts correctly. I don't want to put a strain on my new engine, or transmission, because I was too cheap to do it absolutely right.

If anyone has the identical setup and chance to look closer at their motor mounts, specifically the positions of the tabs (my word), I'd appreciate it.

1 ISSUE SOLVED: Again, I installed the through-bolts in the motor mounts, 4 of 6 bellhousing bolts, the new transmission mount UPPER bolts, and removed the wooden blocks holding up the tranny, before the engine / transmission fell / fell into place / moved. But now that I think about it, I guess I didn't yet install the nut on the bottom of the transmission mount stud. Evidently, after bolting the engine to the tranny, and when I removed the blocks holding up the front of the transmission, the rear of the transmission (where the transmission mount is), didn't go down completely until a minute or two later, by itself. When I went to install the tranny nut, the protective plastic cap was partly torn (but the stud threads were OK).

My prior inexperienced assumption was that motor mounts hold an engine perfectly tight, but I guess this is proof that (on used engine mounts anyway), there is still quite a bit of movement (tilt - front up, back down).

-Thanks everyone for the very useful information regarding centering / offset. I never even noticed the engine, transmission, and other things were offset (side to side) until yesterday when I was most worried about my new engine install. Now that I know that a side to side offset is by design, (with the engine closer to the right than left), my concerns regarding offset are squashed.

However, regardless of left to right position in the engine bay area, I'm still wondering if the engine is suppossed to be pointing straight forward? It appears like my engine is slightly crooked, with the front pointing right and the rear left, ever so slightly. Any comments or info on this specific observation?

-I'd just like to again thank everyone who takes the time to read my long posts, and especially those who reply. Although I'm a newish member, I'm a longtime Firebird / Trans Am enthusiast and plan on contributing help to others in this community once I get my own issues solved.