Rochester

iTrader: (9)

When I picked up the car, the mechanic was telling me how these mounts are adjustable for height, meaning you can raise or lower the engine somewhat. My first thought was that's a welcome feature if you're installing an aftermarket UIM and need the clearance, but overall it didn't mean anything to me. As for where to configure the height, he just compared them to the OEM mounts and winged it.

Anyway, I woke up this morning thinking... OMG, what if this compromises clearance between my engine cover and my FSTB? I mean, it's already very, very tight. So I went out to the garage just now and checked, somewhat nervous what I was going to find. I was really hoping not to see the engine slammed up against the tower brace. To my surprise, it's the opposite, and the engine is actually lowered what looks like more than a 1/2 inch. Seriously, there's a huge gap now between the engine cover and the FSTB, relatively speaking to what it was before.



So, the engine is lowered at least a half inch from OEM position. What does all that mean?

On the one hand, moving a significant weight downward is probably a good thing for handling. But on the other hand, it changes the geometry of the drive train, which worries me.

Anyone have any insights into this?

Baadnewsburr

iTrader: (3)

Interesting...my unqualified $0.02 ....I would think that the only thing that might be slightly out of alignment b/c of a lowered engine would be the pinion flange on the differential, but b/c the sedan uses a 2 piece driveshaft that is flexed in the middle anyways it probably wont make a difference at that point...instead maybe it will wear the U joint at the center of the driveshaft a little more b/c it will be at a slightly greater angle, but that probably won't show up for sometime (if at all) and can probably be replaced pretty easily down the road...

Rochester

iTrader: (9)

That was my thought, too, about the 2-piece Sedan driveshaft being able to absorb the alignment tweak.

rotarymike

iTrader: (4)

I remember seeing a guideline for u-joints and CV joints that talked about how far out of perfectly inline they could be without getting appreciable wear. IIRC it was an odd number like 7* or so.

Personal experience says differently - when I raised my old Jeep 2" without installing motor mount shims the resulting increase in driveline angle made a heck of a lot of noise. Way more than could have been accounted for by increased wind noise under. On the other hand, I put another 120k miles on it after that without needing to replace the drive shaft - so maybe just noise, no wear. :shrug:

4DRZ

iTrader: (7)

Glad to hear you like the motor mounts. Sorry to hear about the labor. I was lucky and got mine on just before the store changed policy where I have to run everything through the shop at my "employee rate" which means it costs a lot more than paying the techs directly. Boo. As a result, I bled my brakes recently since I had always had a tech do it before. I was always afraid of getting air in my brakes and did not want to risk it. It turns out all these years that bleeding my brakes was really simple, at least until I got to a rounded bleeder screw on the front...

With a lowered engine just take a quick look to see if your oil pan sits much lower or is in the line of fire if you bottom out on anything. On my car my skid plate sits so low that I forget how low the oil pan actually is.

Rochester

iTrader: (9)

Certainly an unexpected aspect of this mod. I didn't even know this was a thing, and even though the mechanic pointed out that the mounts were adjustable, I probably never would have thought about it... except that I have a FSTB, and that gives me a clear before/after perspective.

For years now, the way I installed the FSTB was to fold a thick microfiber towel over once, lay it down on the engine cover, lay the bar down on the towel, bolt the ends into the brackets, then pull the towel away. It's a consistent technique, which insures a reasonable gap (although tight), and doesn't scratch anything. When doing this, I'd end up with a 1/8 inch gap, every time.

Right now I have a 5/8" gap that I can actually fit my fingers under. I measured it this morning. This means the engine was lowered 1/2". There's no doubt about it.

Hmmm

Rochester

iTrader: (9)

After driving around yesterday, I realized the new normal is coming on fast. Meaning it's quickly becoming something I'm less aware of, if that makes sense. And in some strange way, the car feels new again, because the H in NVH has been reduced and tightened up.

4DRZ

iTrader: (7)

It's funny how quickly mods that made a huge difference a few days ago suddenly become normal. If you ever get a chance to drive a stock G sedan it will feel very sloppy & slow compared to your car now. Sometimes you need to do that just to recalibrate normal and see how far you have come.

Rochester

iTrader: (9)

Dropped my kid's Sentra off at the shop and had a discussion with the tech who installed the mounts on the G. He agreed that poly motor mounts on the G/Z is an incremental upgrade. All good, and certainly an improvement if your goal is to lean in to sport over luxury, but the money could be better spent elsewhere (like a tune). It's all very subjective, and absolutely influenced by the other suspension mods... particularly the transmission mount, the diff bushings and the diff brace.

And we talked about how the engine is lowered 1/2 an inch. He said he matched the height of the new mounts to the OEM mounts before installing them, but that the compression on the polyurethane behaves differently than OEM, and the engine likely settled where it is. His opinion was that lowering the weight of the engine a nudge is a good thing for handling, but something I'd only be aware of if I tracked the car, and even then maybe not. In that it was just a 1/2 inch, all the hoses and wiring are (probably) uncompromised. Most important, he didn't feel there would be any issues even long-term for the drivetrain and u-joint wear. It was his opinion that the drive-train can easily handle the small change, particularly because it's a 2-piece drive shaft.

So that's that. I guess I'm done with this project.

Baadnewsburr

iTrader: (3)

thats good to hear about your mechanic's input on the matter. I think you're underselling one thing on the upgrade though, particularly in your case where you have/intend to keep the car for some time and its got low miles...the durability/longevity of poly over the rubber components that will dry and rot faster even if you don't drive the car a lot ..the poly mounts will probably be good for the life of the car given the mileage you put on it.

Rochester

iTrader: (9)

I guess so. Never really thought about that. Do the OEM mounts degrade that noticeably with age?

I'm currently 7 years into a 10 year plan for ownership. But that's just a guideline, really, and no one has a gun to my head making me move on after 10 years. Life will always intrude with other priorities, and it may go longer. Just this week I tipped over into 42,000 miles, so three years from now I'll be in the mid-50k mile range. That's pretty gently used for a DD.

Baadnewsburr

iTrader: (3)

Iol I'll never get over how low the mileage is on your car...not just the mounts but any rubber bits tend to dry out and rot over time even without use ... I'd say in a northeastern climate, ten years (or more) is enough that the mounts would likely be dried/rotted enough that very slowly over time the car would feel a little buzzier or less smooth and most would chalk it up to the age of the car and not think twice about it or not notice the transition at all, but a switch to fresh mounts would provide a noticeable difference, with the ploy you probably won't go through that degradation process...

I see what you mean about the 10 year plan, I never intend to keep my car for ten years or for any period in particular beyond paying it off which was long ago, but now I'm inclined to keep the car even if I replace it as a daily driver in the near future so you never know ...

4DRZ

iTrader: (7)

Rochester, your comment about the mounts lowering the engine got me thinking. I am almost positive the technician who installed my motor mounts used the same method to try to make sure the height was set correctly. I wonder if my engine dropped much. I installed my strut tower brace after I got the motor mounts so I didn't notice an immediate difference. (I also have the engine cover off so I have lots of room and probably would not have noticed the same way you did anyway.) I bet my engine is slightly lower too. Crazy. I would have never noticed if you didn't say anything.

Hashim, you are right about seals drying out. I have a friend in Canada with a very fast old RX-7 who replaced all the rubber bushings in his suspension and he said the change in handling was amazing. (Keep in mind his car is nearly 30 years old) However, I feel like Rochester and I have already replaced almost all of the bushings so we should be good for awhile.

Rochester

iTrader: (9)

I swear it occured to me this would stick in the back of your head, and you'd be thinking this over. If your tech lined up the mounts to OEM length off the car, odds are good your engine is also lowered a half inch. If you come across any info on this, good bad or indifferent, please share. Personally, I'm leaning towards indifferent, then again drive train geometry is what it is for a particular reason, so...



Looking back through my comments in this thread, I'm really glad I thought things through and wrote it all down in the moment, because I'm deep into the new normal already, mounts and diff brace both.

4DRZ

iTrader: (7)

My technician claims that he lined them up similarly to the OEM engine mounts so I am sure the same thing happened with my engine, but neither one of us noticed because I don't have anything to compare to that is as obvious as your strut bar. Cool to know about this though as it has to make some small bit of difference in handling.

I know what you mean about the "new normal." It took a while for the rear diff brace to feel normal to me because it was such a big difference, but it happened to me as well. At least until I did a track day at Road America a couple of weeks ago. Coming out of corners the car just hooked up instantly and put the power down so much better. I think that is a big reason why my lap times dropped so substantially compared to the last times I drove at that track. My car actually felt really fast and I caught a lot of people coming out of corners due to the newfound grip, especially heading toward turn 3 and toward the hurry downs. That is saying a lot for my car as I am at a huge power & weight disadvantage compared to almost everything in my class and the track is big with long straights.