Engine Swap Forum

Bringing up the mount issue, I've always thought this might be a good approach for us:

Pros:

1.Allows many header/turbo manifold possibilities (FWD manifolds would be an option)

2. Easy as pie to fabricate and reproduce (once designed)

3. Allows for solid mounting or could easily be built for soft mounting

4. Makes for easier motor removal/install (that's a biggie on a project like this)

Cons:

1. The front of the VQ isn't very flat so it would be a challange to make this clear all the accessories

2. Some people won't like bolting or welding the brackets to the frame rails (I don't see it as a      problem)

3. A little less "clean" looking then stock like mounts, more clutter in the engine bay, minor issue

 

I think the 3 large bolt holes on the front that the FWD RH mount bolts to would be the logical best place to bolt the plate but may not work out quite right in regards to the accessories.

 

Any thoughts on this?

 

Fred

Fred

Kurt

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Argh... guess I'll stick w/ the plan...

[Apparently I posted before the pics and the pros & cons were posted]

Fred Allen Burge:

Bringing up the mount issue, I've always thought this might be a good approach for us:

Pros:

1.Allows many header/turbo manifold possibilities (FWD manifolds would be an option)

2. Easy as pie to fabricate and reproduce (once designed)

3. Allows for solid mounting or could easily be built for soft mounting

4. Makes for easier motor removal/install (that's a biggie on a project like this)

Cons:

1. The front of the VQ isn't very flat so it would be a challange to make this clear all the accessories

2. Some people won't like bolting or welding the brackets to the frame rails (I don't see it as a problem)

3. A little less "clean" looking then stock like mounts, more clutter in the engine bay, minor issue

 

I think the 3 large bolt holes on the front that the FWD RH mount bolts to would be the logical best place to bolt the plate but may not work out quite right in regards to the accessories.

Any thoughts on this?

Fred

Fred,

If we keep coming up with good ideas, I'll never be satisfied with choosing one. That being said, I'm loving this idea. It would help me eliminate some of the chassis bracing I intended to add...

In regards to the front not being flat, the front 'motor plate' could be made as 2 pieces rather than one. It could also be made as a [logically designed] 'wireframe' (with holes/ slots to strategically avoid certain accessories) instead of just a plate with bolt holes in it. It could also be designed with mounting holes for accessories (our ProMod car has front & mid plates and it has holes & slots for mounting 'accessories'. Will take pics).

 I'm actually thinking of doing both the front plate and a 'mid' plate (which would actually mount on the back of the transmission bolt holes rather than between the eng & trans).

I could see it being a problem for street use tho... Of course, some kind of soft mount could be made to go where the plate bolts to the frame.

Great golly! I've got to go ponder about this some more so I don't keep rambling!

I'll be back later!

Kurt

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Argh... guess I'll stick w/ the plan...

Here's a quick sketch of what I have in mind so far:

 

Your right though, it may work out better as a two piece split design, I'll try to take a good look at the available bolt holes today.

This would be easy to mock up in cardboard/poster board to get the accurate dimensions then maybe someone could make a CAD file out of that....then we could get some estimates from someone who does plasma or waterjet cutting.  If a few of us wanted these we could get a decent rate I think.

 

Fred

Here's a couple more layouts (I borrowed a pic out of your gallery Kurt, hope you don't mind )

 

 

These are 1/4 scale so they're pretty accurate to actual size (in relation to the engine) and their relationship to the frame rails in space (the two black rectangles).  There would need to be 3 tubular spacers holding the plate off of the engine by about 3" or so to clear the pulleys, or one thick solid spacer would be stronger but more expensive to produce in that thickness.  It would bolt behind the 3 center bolts. 

Also necessary would be two "saddles" on the frame rails to bolt this plate to (solid mouting).  Soft mounting would require a little more engineering and time.  From what I've been reading from the 350z guys vibration is a non-issue with solid mounts on the VQ35DE.

 

I like the look of this setup.  It would be a lot smaller then I had originally thought which is good and it's a lot lower in the bay then I thought too.

 

thoughts, interest, criticism?????

Fred

I actually wrote 2 detailed replies and one got lost b/c of stupid wireless connections and I accidentally pressed the power button trying to put the comp to sleep. Sometimes I hate computers...

Long story short: I now know for a fact that I've made my decision and this is what I'll be using on my car (both front and 'mid' plate). The setup would need some refinement for a street car application but is not impossible (or too difficult)...

My main concern is where to attach it to the motor. The curvy surface on the front 'restricts' using a one piece. Some spacers would be required to make it one pc in front of the front cover. I wouldn't suggest any 'spacers' longer than maybe 3/4" and any smaller in diameter than 2" for this [engine support] application. Especially with over 600ft-lbs tq...

The other (1 pc) option is to run it behind the front cover (which is where the chain sits and is less feasible).

The 2 pc options transform the engine into a 'stressed member' (effectively a part of the chassis which now absorbs deflection) - a trait [the front of] this engine wasn't exactly designed for. That being said, we could "bridge" the 2 piece design over the engine (using a 3rd piece which could have provisions for lifting the engine or attaching chassis bracing...).

The option I'm investigating will require shaving (machining) 1/16th off the mating surface of the front cover and another 1/16" of the mating surface of the "rear section" of the front cover. I'm planning to use 1/8" thick 4130 steel sheet and have the holes machined (I'm using the scaled drawings in the fsm to generate the hole patterns). The plate will mount between the front and rear section of the front cover (sandwiched) and will also require some form of 'gasket treatment'.

From the way it looks right now, it seems the 9 perimeter bolts at the top (locate the middle, count 4 left and right respectively) are the most feasible, unfortunately, not the most comforting. I'll have to do some more 'investigating' to find suitable alternatives. I see the bolts u're 'targeting' Fred, but they're in the middle of the motor (i.e. middle of the timing chain, or obstructed by the black access covers, both setups will require spacers). I'm still open to ideas on this tho.

Another option, is to machine the entire front cover (front and rear sections) down 1/16" each all the way round, cut some 1/8" 4130 sheet to the entire shape and have it protrude outwards with provisions to attach 'frame mounting plates' (or 'legs').

Stylewise, the "spaceframe" I was referring to is Fred's 3rd rendering, which [with some careful design] could be made to have all the features we'd be looking for (including "sweet!" factor).

I plan to do some CAD files pretty soon but upcoming vacation 'requires' that I labor intensively until then (Sometimes I want to pay these customers not to place an order...).

Kurt

P.S. I thot I said "long story short"?...

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Argh... guess I'll stick w/ the plan...

Kurt,

  That's a cool idea, I never would have thought of sandwiching a plate there.  But, for me I think I'll have to stick to the bolt on type for simplicity.  I'll need it thicker than yours too since I'm not using a mid-plate. How thick do you think would suffice, 1/4" aluminum?

Also, I took a look at a factory Nissan front motor mount bracket and it looks like it could be machined down to serve as my spacer:

If it was machined flat I think it would be perfect.  Also, I don't think the spacer would need to be as thick as I previously mentioned.  Maybe 1-2" tops I think will suffice, possible less depending on how we designed the plate.

 

Fred

Don't get me wrong! I'd rather not have to do all that machining!

I never thought about it but it does make sense that there would be a mount there on the fwd engines. Duh. That throws some tequila in the mix!

The only drawback of using just those 3 bolts I can think of is that being so close to the center doesn't allow them to resist engine torque very well (relatively). This is part of the reason Nissan still uses the 'side' mounts in fwd config. If you decide to use a 'mid' plate as well (which I highly recommend as it will be a 'bolt on' solution...), the 'mid' plate could be used to resist torque while the front plate primarily resists vertical load...

1/4" thickness will more than suffice, 3/8" being the norm for domestic drag race cars (that thickness used primarily for mounting accessories to the plate rather than mounting to the engine). If u can go 3/8", do it so u'll feel comfortable when the speed bug starts to bite in a year or so...

I'd also use 7075 Al for more 'comfort'. (darn engineers and their overkill designs! )

Kurt

P.S. Can you take some [perpendicular] side shots of that engine mount on the engine please?

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Argh... guess I'll stick w/ the plan...

I'd like to avoid a mid plate, the mid plate is kind of a deal breaker for me personally.  If it's a necessity I'll stick with what I've got and focus on other areas of the car for now.  If I can avoid the mid plate I'll press on.  I'm hoping a top brace from the head or intake manifold to the strut tower would suffice for limiting torque  (similar to torque struts you see sold on ebay all the time now).  While the front plate will support the bulk of the weight of the motor, shared by the tranny mount.

Another thing that's good about a plate type mount setup is total flexibility in how high/low and how far forward/backward you mount your engine, just a thought I had.  Oh ya, it also gives you a perfect place to mount a crank trigger..

 

I'll get that pic tomorrow.

 

Fred

Wow, this IS getting intense. What are the complications for using the plate on the street?

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S13 Fastback...putting the chassis together.

Suspension before power!

Fred - if you're clever, you could incorporate a mid plate right at the firewall - reducing impact in the engine bay.

In my opinion, though, the mid plate is a good idea.  Yes, you can probably get away with just a front plate, but if you go that route, i would go steel rather than aluminum

Do you think 1/4" or 3/8" aluminum would be likely to fail?  Steel seems awfully heavy...

 

Fred

I just [purposely] deleted a 'book' on why using the front plate (3-bolt) with tq braces is a 'less than ideal' design, focused on moment couples and manufacturing perspectives. I feel I'm approaching the 'issue' incorrectly...

What is the basis of your (Fred's) opposition to using the mid plate? Anybody else opposed to using front & mid plates? Please voice ur opinions. I'm curious.

I get the feeling I'm going to convince you to stay with what u have (similar to stock type)... I'm definitely going with the plates tho...

Kurt

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Argh... guess I'll stick w/ the plan...

PoorMans180SX:

Wow, this IS getting intense. What are the complications for using the plate on the street?

Although the vibes are pretty low on the VQ, I suspect the daily driver cars will still require some insulation between the plates and the chassis (rather than just bolting them together). It will also require accomodations for the accessories (probably in their stock locations) and the intake tube (drivers side). Last but not least the 'required cosmetic factor' increases...

The mid plate would require accomodations for the steering shaft and possibly the rear coolant pipe. Avoiding exhausts doesn't seem to be an issue.

Of all the solutions, I beleive this (front & 'mid' plate) is the most DIY friendly...

Kurt 

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Argh... guess I'll stick w/ the plan...

bettonracing:

I just [purposely] deleted a 'book' on why using the front plate (3-bolt) with tq braces is a 'less than ideal' design, focused on moment couples and manufacturing perspectives. I feel I'm approaching the 'issue' incorrectly...

What is the basis of your (Fred's) opposition to using the mid plate? Anybody else opposed to using front & mid plates? Please voice ur opinions. I'm curious.

I get the feeling I'm going to convince you to stay with what u have (similar to stock type)... I'm definitely going with the plates tho...

Kurt

My personal reasons include not wanting to pull the motor/tranny again, not wanting to seperate the motor/tranny again (very hard to get them back together on my particular setup, haven't figured out why yet..), more design time and higher cost.  Some of those are very personal reasons that won't apply to most people.  Also, I'm wondering what effect the thickness of the mid plate will have on clutch engagement and pressure...

Basically though I just want to keep it as simple as possible for my street car.  If I can get away with just a front plate and top brace then I'd be happy.  I think most people would want to skip the mid plate too if it's not necessary.

 

Fred