Engine Swap Forum

Here're Fred's drawings of his engine mounts: http://www.engineswaptech.com/forums/storage/3/489/motor%20mounts.jpg

A few details are discussed here: http://www.engineswaptech.com/forums/thread/151.aspx

Also pictures #46, 47, 57, 58, 59 & 60 show the engine mount after fabrication.

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I'd like to develop these mounts into a more visually appealing version while, if possible, helping to correct some of the swap's flaws (steering clearance/ hood clearance/ etc). My first preference would be some cnc machined mounts but we'll see how our design intent develops. I have the capability to do 3D CAD and FEA testing (Solidworks 2007 & Cosmos 2007) and if things go as planned, there'll be little, if any, R&D left to do after the first prototype is made. What I'm asking you guys for is informative feedback during the design & development process. All files will be posted online so everybody can have access to them (bring to a machine shop, etc). We'll worry about 'copyright infringements' (i.e. a shop using the files for mass production) througout the process of designing them.

Initial Design Considerations:

1) Stock intake manifold hood clearance

2) Cost

3) Steering shaft/ exhaust manifold intereference

4) Oil pan clearance (using recommended oil pan configuration)

5) Engine position and orientation (only to ensure engine is level)

6) Accessory drives

7) Transmission crossmember mount

8) Starter to engine mount clearance

9) Vibration isolator option

10) Stress Analysis

I'll go ahead and post the first reply to give u an idea of what I'm expecting from this kind of thread.

Regards,

H. Kurt Betton

bettonracing:

1) Stock intake manifold hood clearance

I think the main problem we'll have with this is the steering shaft/ exhaust interference if the engine is lowered. Fred already established that there was bit of space under the oilpan to allow for lower mounting. Anybody care to elaborate?

bettonracing:

2) Cost

I'm aiming for max total cost of $75 (and that's way more than I'd like to pay).I doubt I'm gonna end up with CNC mounts within the given budget. It's still worth a shot tho. The less machining that has to take place, the cheaper the cost. If it even requires using a 2 piece mount w/ some kind of bolted assembly or something similar, there are ways to cut machining costs. I figure with good design we could also make them out of 6061 Al which would help cut machining costs and time.

And since CNC isn't req'd, other fabricated options are also acceptable. I doubt it'll get any cheaper than Fred's original (hockey puck anyone?), but as long as the price isn't outrageous (which to me $75 is outrageous...), and the quality is good, it would be a worthwhile venture.

bettonracing:

3) Steering shaft/ exhaust manifold intereference

See #1. For me this issue 'might' be non-existent. After a few quick conversations and holding me at gunpoint, Fred's convinced me to go the turbo route from the jump (as opposed to the NA then turbo). Flipping the appropriate manifolds on the block seems as if it would eliminate any steering interference problems. If anybody has any solutions for keeping NA then bring it up. If u don't ask for it, it won't be considered.

bettonracing:

4) Oil pan clearance (using recommended oil pan configuration)

See #1. This shouldn't be much of a problem. And that's even considering engine movement under load.

bettonracing:

5) Engine position and orientation

Engine must be level and straight. Not too hard to accomplish but I'll even take the extra step and put a laser level across the engine to make sure. I want these things to be right, darnit! *bangs table* :D

bettonracing:

6) Accessory drives

I'm thinking of ditching the AC, powersteering, and running an electric water pump. On the other hand, I'd still like to at least have the option of putting that stuff back in if my alternatives don't work as intended. I think the passenger side solution that Fred found, doesn't have any problems running any of the aforementioned accessories. If u know otherwise, let me know.

bettonracing:

7) Transmission crossmember mount

When the cross member is flipped around, how far back (from the original position) does it shift the bolt? Is that distance something that could be taken up by shifting the engine forward a bit? I know moving the engine forward doesn't seem like an ideal solution but it also gives a bit more clearance for those of us (of you) that plan to use the stock intake manifold. The whole CofG argument is a moot point in this case (1" or 2" fwd). If u think u can prove that wrong, challenge me :D I'm always up for an educated debate...

bettonracing:

8) Starter to engine mount clearance

Basically, the (passenger side) engine mount has to accomodate the starter. Easy fix.

bettonracing:

9) Vibration isolator option

I wouldn't mind putting a rubber 'hockey puck' under the mounts to suck up some vibration. The hardcore could use solid mounts, the sporty could use some polyurethane inserts, and the daily drivers could use rubber.

bettonracing:

10) Stress Analysis

Highly unlikely but I'd hate to see a thread "My torque tore my motor mounts". There're other factors at play that could make the mount weak (esp if made from 6061 Al). Shouldn't be much of an issue but I'm trying to cover all aspects before we build.

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Your formatting doesn't have to be the same, but it would be nice to know what particular criteria u're referring to.

 Don't be scared to disagree! And add anything I missed.

Regards,

H. Kurt Betton

bettonracing:

Initial Design Considerations:

1) Stock intake manifold hood clearance

Your talking about stock 350z intake manifold I presume, that's a good goal but to drop the motor enough to clear the hood will make the LH manifold pretty usless.  I had to make an indention in mine fairly deeply, too much lower and the shaft will basically need to run right through the manifold's collector area.

bettonracing:

2) Cost

Here's an area that I wouldn't mind spending a few bucks on, to have a nice aluminum set of brackets and nice cushy Lexus level isolators would be worth maybe 150$ or so to me (considering I already have usable mounts).  They'd be worth more if I didn't have any mounts at all like most people starting this project.

bettonracing:

5) Engine position and orientation

Honestly, there's not a lot of room to move it around from where my mounts put it, any forward and the oil pan will hit the sway bar, any rearward and it's getting close to the crossmember.

bettonracing:

9) Vibration isolator option

Here's an area that I wish I'd have put more time into.  It doesn't vibrate bad at all so far on the hockey pucks but still, fire up a Lexus and tell me the lack of vibration isn't nice!  I'll make a final opinion on this after I've driven it for a while. 

 An interesting note about this, some 350z owners have actually replaced their soft cushy isolators with solid mounts and have reported that the vibrations isn't bad at all, even their girlfriends don't seem to mind!

thanks

Fred

Fred Allen Burge:

You're talking about stock 350z intake manifold I presume, that's a good goal but to drop the motor enough to clear the hood will make the LH manifold pretty useless.  I had to make an indention in mine fairly deeply, too much lower and the shaft will basically need to run right through the manifold's collector area.

Here's an area that I wouldn't mind spending a few bucks on, to have a nice aluminum set of brackets and nice cushy Lexus level isolators would be worth maybe 150$ or so to me (considering I already have usable mounts).  They'd be worth more if I didn't have any mounts at all like most people starting this project.

Yes, I was talking about the stock intake. I figured this would be a problem but I had planned to do custom headers anyway and now I'm going the turbo route (reversed exh manifolds) so I haven't done much research into this area. Are the other rwd exhaust manifolds (FX35/ pathfinder/ etc) identical to the 350z/G35's? Is there any way to adapt a fwd exhaust manifold and run a custom downpipe? I'm also toying with the idea of a steering quickener (I'm somewhat accustomed to sudden lane changes :D), which has the added benefit of offsetting the steering shaft.Throw in a niversal joint or two and u can have whatever clearance u want. I seriously doubt that most ppl here will be willing to do that but it's another brainstorming idea to throw in the pot.

Fred Allen Burge:

Here's an area that I wouldn't mind spending a few bucks on, to have a nice aluminum set of brackets and nice cushy Lexus level isolators would be worth maybe 150$ or so to me (considering I already have usable mounts).  They'd be worth more if I didn't have any mounts at all like most people starting this project.

Here's an area that I wish I'd have put more time into.  It doesn't vibrate bad at all so far on the hockey pucks but still, fire up a Lexus and tell me the lack of vibration isn't nice!  I'll make a final opinion on this after I've driven it for a while. 

 An interesting note about this, some 350z owners have actually replaced their soft cushy isolators with solid mounts and have reported that the vibrations isn't bad at all, even their girlfriends don't seem to mind!

I was (am) intending to keep the basic design of your (Fred's) engine mounts as they seem to be pretty effective. This configuration allows relatively easy selection of vibration isolation (i.e. just change the hockey puck to whatever is preferred). It also allows ppl to try the solid design and if it's too harsh, just switch it. The only problem w/ that type of mount is that it puts the "hockey puck" in pure compression - which will fully compress rubber pucks and probably not have very much isolation after all. A viable option is finding a fluid filled puck (think shock absorber) that'll fit within the same location/ size requirements of the puck. We could also adjust the design of the mount slightly to accomodate a larger puck if necessary (and if someone finds an appropriate fluid filled mount).

Doing some kind of shear type engine mount (small block chevy style) - which is better at absorbing vibrations) is not out of the question but will not be employed on my car so somebody would have to do the legwork and communicate with me so we can make the appropriate files. I'll help with ideas on that type as needed.

As is the case when shopping for most other car parts, the more luxurious the part, the more expensive. After seeing fully functional engine mounts for <$20 (Fred's), I would have a hard time spending more than 300% of the functional cost to get engine mounts. Given the configuration discussed, I think the range of pucks will allow the range of comfort we're hoping to cover (i.e. fluid filled mounts $150+, solid mounts <$60). Pucks could be made with anything from pencil erasers to metal slabs to 'durometer specified' polyurethane mounts to fluid filled mounts - and still look good and last 'forever' while doing it.

Fred Allen Burge:

Honestly, there's not a lot of room to move it around from where my mounts put it, any forward and the oil pan will hit the sway bar, any rearward and it's getting close to the crossmember.

Are there any oilpan configurations not explored yet? Pathfinder/ FX35? There is no real need to move the engine from its current location (other than to help w/ the trans mount) but I figure I'd bring it up incase anybody (you) knew of any areas it would help. Since that isn't the case, I guess we can scratch relocation off the list. Unless somebody comes up with a valid reason to relocate, it won't be considered in the design from here on. (Note edit in first post)

I'll start CAD'ing up some mounts to start getting the ideas across.

Kurt

bettonracing:

Yes, I was talking about the stock intake. I figured this would be a problem but I had planned to do custom headers anyway and now I'm going the turbo route (reversed exh manifolds) so I haven't done much research into this area. Are the other rwd exhaust manifolds (FX35/ pathfinder/ etc) identical to the 350z/G35's? Is there any way to adapt a fwd exhaust manifold and run a custom downpipe? I'm also toying with the idea of a steering quickener (I'm somewhat accustomed to sudden lane changes :D), which has the added benefit of offsetting the steering shaft.Throw in a niversal joint or two and u can have whatever clearance u want. I seriously doubt that most ppl here will be willing to do that but it's another brainstorming idea to throw in the pot.

Ya, if your going turbo right off the bat or want to make a custom LH header you could lower the motor by about a half inch, maybe 3/4" without steering shaft problems.  Not insignificant and would make hood clearance a lot better with the 350z intake manifold.

bettonracing:

I was (am) intending to keep the basic design of your (Fred's) engine mounts as they seem to be pretty effective. This configuration allows relatively easy selection of vibration isolation (i.e. just change the hockey puck to whatever is preferred). It also allows ppl to try the solid design and if it's too harsh, just switch it. The only problem w/ that type of mount is that it puts the "hockey puck" in pure compression - which will fully compress rubber pucks and probably not have very much isolation after all. A viable option is finding a fluid filled puck (think shock absorber) that'll fit within the same location/ size requirements of the puck. We could also adjust the design of the mount slightly to accomodate a larger puck if necessary (and if someone finds an appropriate fluid filled mount).

Doing some kind of shear type engine mount (small block chevy style) - which is better at absorbing vibrations) is not out of the question but will not be employed on my car so somebody would have to do the legwork and communicate with me so we can make the appropriate files. I'll help with ideas on that type as needed.

As is the case when shopping for most other car parts, the more luxurious the part, the more expensive. After seeing fully functional engine mounts for <$20 (Fred's), I would have a hard time spending more than 300% of the functional cost to get engine mounts. Given the configuration discussed, I think the range of pucks will allow the range of comfort we're hoping to cover (i.e. fluid filled mounts $150+, solid mounts <$60). Pucks could be made with anything from pencil erasers to metal slabs to 'durometer specified' polyurethane mounts to fluid filled mounts - and still look good and last 'forever' while doing it.

 

The mount setup I'm using will probably be just fine for me in reality.  I want nicer brackets but honestly the vibration issue hasn't been noticed yet, I think the pucks work okay for now, maybe forever.  If someone has any ideas for something softer in the same size though I'd be willing to try it out.

bettonracing:

Are there any oilpan configurations not explored yet? Pathfinder/ FX35? There is no real need to move the engine from its current location (other than to help w/ the trans mount) but I figure I'd bring it up incase anybody (you) knew of any areas it would help. Since that isn't the case, I guess we can scratch relocation off the list. Unless somebody comes up with a valid reason to relocate, it won't be considered in the design from here on. (Note edit in first post)

I hate to sound like a know it all or something but I've personally looked at every RWD and FWD VQ oil pan that I know of in production.  All of the RWD ones have funky sump setups except the Z/G.  All of the FWD one's are basically the same as the Maxima's and won't clear the 240sx's crossmember.  I can't wait to get my hands on the new skyline motor though, oh baby I can't wait!

bettonracing:

I'll start CAD'ing up some mounts to start getting the ideas across.

Kurt

Great, can't wait to see your work!

BTW, I think we're the only ones who care about this at the moment, where is everybody else??

fred

Fred Allen Burge:

Ya, if your going turbo right off the bat or want to make a custom LH header you could lower the motor by about a half inch, maybe 3/4" without steering shaft problems.  Not insignificant and would make hood clearance a lot better with the 350z intake manifold.

Why only 3/4"? I figured with the reversed exh manifolds, I'd have so much clearance that the header/ steering interference would become moot. At what point does the oilpan become the limiting factor? Are you opposed to a custom oilpan?

Fred Allen Burge:

 The mount setup I'm using will probably be just fine for me in reality.  I want nicer brackets but honestly the vibration issue hasn't been noticed yet, I think the pucks work okay for now, maybe forever.  If someone has any ideas for something softer in the same size though I'd be willing to try it out.

I seriously doubt anybody will need anything drastically different from your mounts. With the right GD&T your mounts will also aid ease of installation. I feel it won't be too hard to find fluid filled mounts that can be used in your setup as well. Don't be surprised if u start hearing me talk about Magneto-Rheological fluid (MR fluid) mounts in the near future... (more details to come).

Fred Allen Burge:

I hate to sound like a know it all or something but I've personally looked at every RWD and FWD VQ oil pan that I know of in production.  All of the RWD ones have funky sump setups except the Z/G.  All of the FWD one's are basically the same as the Maxima's and won't clear the 240sx's crossmember.  I can't wait to get my hands on the new skyline motor though, oh baby I can't wait!

I'd hate it more if u knew this information and purposely withheld it even after being asked. U could have easily said "I seriously doubt any other will fit without mods" (which is also factual) which leaves the air open for ppl to waste money and/or time.

I think by the time I'll be able to afford a swap w/ the new skyline motor, I'll be waist deep into a mid-engined rwd, 2G+ lateral on slicks, 800hp+, 2200lb, purpose-built tube frame chassis... streetcar. I'll be more worried about my drysump lines getting yanked off by speedbumps...

Fred Allen Burge:

 I think we're the only ones who care about this at the moment, where is everybody else??

I get the feeling they're not convinced about this swap yet... Give 'em time. All those uninformed, inaccurate "swap detail" sites kinda created some negativity...

bettonracing:

Why only 3/4"? I figured with the reversed exh manifolds, I'd have so much clearance that the header/ steering interference would become moot. At what point does the oilpan become the limiting factor? Are you opposed to a custom oilpan?

 

Well, the 3/4" figure is an estimate based on using the stock Z/G pan.  If you want to make a custom pan then heck ya, drop that sucker down low!

bettonracing:

 Don't be surprised if u start hearing me talk about Magneto-Rheological fluid (MR fluid) mounts in the near future... (more details to come). 

Hmmm, sound high tech, can't wait for the details...

bettonracing:

I'd hate it more if u knew this information and purposely withheld it even after being asked. U could have easily said "I seriously doubt any other will fit without mods" (which is also factual) which leaves the air open for ppl to waste money and/or time.

I hate being vague on a site that's all about information.  We're here to share info so I like to bring it when I can.

bettonracing:

I think by the time I'll be able to afford a swap w/ the new skyline motor, I'll be waist deep into a mid-engined rwd, 2G+ lateral on slicks, 800hp+, 2200lb, purpose-built tube frame chassis... streetcar. I'll be more worried about my drysump lines getting yanked off by speedbumps...

Ooooohhhh, you've got something wicked in the works don't you!

Fred

Fred Allen Burge:

Well, the 3/4" figure is an estimate based on using the stock Z/G pan.  If you want to make a custom pan then heck ya, drop that sucker down low!

 

I guess I'm gonna need another post similar to this one then... U interested in a custom pan?

Fred Allen Burge:

Hmmm, sound high tech, can't wait for the details... 

It's not really as complex as it sounds but the possibilities are numerous. It's basically a hydraulic fluid with ferrous particles in it. Apply a magnetic field and u have essentially a solid. Remove magnetic field and VIOLA! u have a liquid. I'm toying w/ the idea of making some 'home grown' MR fluid... And I think it fits within my budget for engine mounts too.

Fred Allen Burge:

Ooooohhhh, you've got something wicked in the works don't you!

It's still in its design stages right now but the first prototype will be going thru an NA VQ, a VQ[t] and if I'm impressed w/ the VQ, it might stay in there for the 800hp version... (Is it making a little more sense why I'm interested in this 240sx project yet?...).

Keep the information flowing. U're saving me alotta time and money :D

bettonracing:

It's not really as complex as it sounds but the possibilities are numerous. It's basically a hydraulic fluid with ferrous particles in it. Apply a magnetic field and u have essentially a solid. Remove magnetic field and VIOLA! u have a liquid. I'm toying w/ the idea of making some 'home grown' MR fluid... And I think it fits within my budget for engine mounts too.

Sounds like the stock maxima front mount, soft on idle and stiff on acceleration, two wire plug, ecu controlled.

Fred

Fred Allen Burge:

Sounds like the stock maxima front mount, soft on idle and stiff on acceleration, two wire plug, ecu controlled.

Could very well be. What shape/size is the maxima mount?

I believe it is one of those round types with a bolt through the center, maybe 3-4 inches accross, bridgestone or firestone brand if I recall correctly.

Fred

Fred and Kurt beleive me i am in lvoe with the idea of this swap and i want to do it as much as fred did and you do but my limiting facotr is money. Fred i know u said ur too busy to help install but do u know where i can get a z/g vq35de with 6spd trans or have time to see if any local places have it by you thats what i really need im saving up money to do the swap and want to turbo it right form the getgo but its so expensive its gonna take time if u guys machione some of the parts and it stays cheap that would be awesome and help kids like me that have tons of college debt and don't make alot of money but sitll love their cars enough to skip meals to spend money on it lol

~jimmy

Here's a pic of that front Maxima mount, actually has a 3 wire plug, not 2.

Fred

Here's the basic design (based on Fred's) which we'll refer to as compression type.

Here's the upper section based on a shear type design (see maxima engine mount above).

Here's the lower section of the shear type mount. (this section could utilize an OEM replacement)

NOTE: These are the first revision to get ideas flowing and therefore all dimensions are not accurate.

Initially I was somewhat against the shear type because they're made to tear up (they're designed to be able to absorb more vibrations - the side effect being their lower durability). However, after doing the CAD files I'm starting to lean in that direction. Here's why:

1) The design of the shear type can look a little more professional than a compression mount in my opinion.

2) OEM's like shear type for their effectiveness w/ NVH. There has to be some merit to that. This also allows lots of potential for using OEM mounts from multiple cars (assuming the lower section fits the size and dimension criteria)

3) The compression type will require at minimum 2 pieces. To machine the entire mount as one piece will require a large piece of material (stock) to machine from (read: $+). Additionally the amount of material to be removed is excessive (read again: $++). An alternative would be to make the leg as a second piece. My idea would use some bolts through the main plate into the legs. Then comes the 'problem' of adding reinforcement to the leg to avoid the mount and the bolts being loaded in bending (similar to Fred's reinforcement shown in his album - pics 46 & 47). The acute angles also require special fixtures (jigs) or a more capable CNC machine (4 axis/ 5 axis) to cut.

4)  The shear type will require 3 pieces for the top section (which are VERY easy to machine). The two 'legs' will require 4 bolt holes to be drilled and tapped in the back and the main plate will have 8 corresponding holes drilled in it (see pic below). The lower section will vary depending on the OEM piece used (in my case probably  a slightly modified maxima mount).

5) The legs on the upper section can be easily remachined to allow for repositioning of the engine (If somebody wants their engine lowered or if I screw up the dimensions :D) without making complete new mounts. With the reinforcements and configuration, it seems it would require almost new complete mounts for different engine positioning.

6) The shear type can meet all the design requirements in machined form whereas I'm starting to see a few problems (the ones mentioned with a few more that I can't remember right now) w/ the compression mount in machined form. In fabricated form the compression type might be easier to manufacture but only marginally easier.

7) Quite strangely, the exact dimensions and pieces used for the shear type can be cut/ drilled identically from different materials for both machined AND fabricated versions (except that the fabricated version will not need the 8 bolt holes to mount the legs to the main piece in the upper section). My interpretation of the machined compression type will have slightly different pieces for the fabricated and the machined mounts and will thus require two different designs (i.e. two different bills of materials).

The more I think of this, the more logical the shear type seems. Anybody have any thoughts/ reservations about the shear type? (yes we can still get to that bottom bolt in the lower section of the shear type). The only other concern I can think of is header clearance with the mount itself which I think might be relatively easy to overcome (Fred: that's your area of expertise...).

Any justifiable changes you (everybody) feels could be made to any of the engine mounts proposed, feel free to request your updated CAD files (post brief details of changes here and pm me specific details if necessary so we don't take up thread space w/ the minute details).

Regards,

Kurt

*Sigh*

After reviewing the SCC article and seeing the exh manfiold setup, I've altered the shear type to give exhaust clearance:

Note the curved shape of the legs (which can be made more drastic for more clearance).

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Simultaneously, the changes to the shear type brought back some ideas for the compression type which would actually make it ALOT easier to manufacture and could look pretty nice while doing it:

This could be made from 4 pieces which could all be cut from the same material (stock). It also has the same fabricate-machine interchangability mentioned before in the arguments for the shear type mount.

After all is said and done, I prefer compression type, revision 2.

Kurt