Engine Swap Forum

I see some good things rolling here.  It's nice to see people so interested in pioneering the development of engine swaps.

 

My .02 would be stick with the compression design.  The simpler the better.

 

Question though.  The compression design in your digital sketch is a 4peice isn't it?

 

If so, are you going to have the legs welded to each other as well as bolted, or just bolted/welded?

 

You might want to consider cutting 2 slits where the legs would attach to the main peice(engine side) and slide them through.  Not an extreme amount, but enough to take the stress off of the "T" where the two meet.  Get what I'm saying?  Welds may not be up to the task of supporting the twisting of the engine for extreme durability if its just a "T".  I guess what I'm putting out there is you pass the legs through the main peice and weld it from both sides, making it stronger.

 

That was my little escapade in Paint to try to clarify what I mean.  Cut slits through the red part (duh) and pass the legs through and sit them flush with the other side, or even slightly protruding.  This will give you twice the area to make them stronger.

 

Also, if you decide to stick with the puck setup on each mount, I think the twin would be a good idea not only for the extra vibration dampening, but for the distribution of stress as well.

 

 

I may be thinking overkill here, but it might be worth the time thinking about.

Grdevs24zero:

Welcome!

As u can tell thru the excessive reading u probably had to go thru, we've concluded that the compression type is more suitable as well.

Yes, the final revision to the compression design is a 4 piece - the main plate that bolts to the block, the two 'legs' and the small plate that get's bolted to the inserts.

My intention is to bolt the entire mount together using socket head cap screws (visit Mcmaster.com and search for 'socket head cap screw') - i.e. bolt the legs from behind the main plate and bolt the 'insert plate' to the legs from the side of the lower insert (Hope u've been following along w/ the 'terminology' :D). Another advantage of the design is that it allows the mount to be welded as well as bolted. I chose bolts for the modular design as well as the lack of a TIG welder I can play w/.

In regards to the slots in the main plate:

I actually thought of putting a 'groove' into the main plate as well but a review of the pros & cons indicates that the slots would be beneficial to welded-only or glued assembly but could have negative effects on the bolted assembly (weaker main plate). I don't foresee any practical advantages on the welded & bolted assembly (I expect most ppl to go this route). Having twice the contact surface area will help with glued assemblies but will not affect the welded-only assemblies (both slotted & non slotted will still have only 2 fillet welds per leg). However, having slight protrusions on the back of the main plates should drastically improve the joints' strength of the welded-only assembly.  

I think the solution here is to have everything made w/o the slots (for the bolted assembly) and do another revision for the welded-only & glued assemblies. The revision will include 2 pieces for the main plate, modified legs (extended the thickness of the main plate + 1/4" protrusion on the back to allow for 2 more fillet beads on the backside) and possibly some kind of strengthening rib as required.

The welded & bolted assembly can retain the features of the bolted-only design.

I'll do some drawings t'row to better explain what I'm saying here.

If I understand u correctly, u're saying that using upper and lower inserts will help distribute stress. I'm not fully clear how this is acheived. Can u please explain?

Regards,

Kurt

P.S. Keep the ideas flowing! The more ideas on the table now, the less after thoughts we'll have... 

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

bettonracing:

Grdevs24zero:

I see some good things rolling here.  It's nice to see people so interested in pioneering the development of engine swaps.

My .02 would be stick with the compression design.  The simpler the better.

Question though.  The compression design in your digital sketch is a 4peice isn't it?

If so, are you going to have the legs welded to each other as well as bolted, or just bolted/welded?

You might want to consider cutting 2 slits where the legs would attach to the main peice(engine side) and slide them through.  Not an extreme amount, but enough to take the stress off of the "T" where the two meet.  Get what I'm saying?  Welds may not be up to the task of supporting the twisting of the engine for extreme durability if its just a "T".  I guess what I'm putting out there is you pass the legs through the main peice and weld it from both sides, making it stronger.

That was my little escapade in Paint to try to clarify what I mean.  Cut slits through the red part (duh) and pass the legs through and sit them flush with the other side, or even slightly protruding.  This will give you twice the area to make them stronger.

Also, if you decide to stick with the puck setup on each mount, I think the twin would be a good idea not only for the extra vibration dampening, but for the distribution of stress as well.

I may be thinking overkill here, but it might be worth the time thinking about.

Welcome!

As u can tell thru the excessive reading u probably had to go thru, we've concluded that the compression type is more suitable as well.

Yes, the final revision to the compression design is a 4 piece - the main plate that bolts to the block, the two 'legs' and the small plate that get's bolted to the inserts.

My intention is to bolt the entire mount together using socket head cap screws (visit Mcmaster.com and search for 'socket head cap screw') - i.e. bolt the legs from behind the main plate and bolt the 'insert plate' to the legs from the side of the lower insert (Hope u've been following along w/ the 'terminology' :D). Another advantage of the design is that it allows the mount to be welded as well as bolted. I chose bolts for the modular design as well as the lack of a TIG welder I can play w/.

In regards to the slots in the main plate:

I actually thought of putting a 'groove' into the main plate as well but a review of the pros & cons indicates that the slots would be beneficial to welded-only or glued assembly but could have negative effects on the bolted assembly (weaker main plate). I don't foresee any practical advantages on the welded & bolted assembly (I expect most ppl to go this route). Having twice the contact surface area will help with glued assemblies but will not affect the welded-only assemblies (both slotted & non slotted will still have only 2 fillet welds per leg). However, having slight protrusions on the back of the main plates should drastically improve the joints' strength of the welded-only assembly.  

I think the solution here is to have everything made w/o the slots (for the bolted assembly) and do another revision for the welded-only & glued assemblies. The revision will include 2 pieces for the main plate, modified legs (extended the thickness of the main plate + 1/4" protrusion on the back to allow for 2 more fillet beads on the backside) and possibly some kind of strengthening rib as required.

The welded & bolted assembly can retain the features of the bolted-only design.

I'll do some drawings t'row to better explain what I'm saying here.

If I understand u correctly, u're saying that using upper and lower inserts will help distribute stress. I'm not fully clear how this is acheived. Can u please explain?

Regards,

Kurt

P.S. Keep the ideas flowing! The more ideas on the table now, the less after thoughts we'll have... 

 

 

The bolt idea sounds good.

 

The protrusions is kinda what I was getting at in the welded-only ass.

 

As for my saying the twin puck design would distribute stress better...disregard.  I wasn't thinking straight and after pondering it for a bit, it might even weaken the structure.

 

If I think of anything I'll post up, but I think those were my main "additions".

Fred, can u verify if these '90 - '96 300zx motor mounts are fluid filled please:

It has an extra design feature I'm interested in: The "ear" shown to the left of the mount in the picture above resists the shearing motion we're concerned about...

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

I can't confirm the type of mount on that one unfortunately.  Also, do you know the dimensions of that mount? I have another possibility here.  Subaru mounts are pretty low profile but don't appear to be fluid filled, is fluid filled a must have?

 

Thanks,

Fred

I'm a member of a few Nissan boards, and I've posted up a request on the mount info....just waiting now...

 

P.S. to Kurt:  I'm getting back under my car today (Thursday) for those trans measurements.

Fred:

Sorry about the delays guys. My job just moved into a new facility so it's kinda hectic.

Fluid filled isn't a must have. Really and truly, that's your call. U're the only one currently who has any kind of useful benchmark to go from about how much this engine vibrates in the 240's chassis. I'm probably gonna try solid anyway and if that isn't acceptable then I'll switch to whatever mount we (you) decide. I get frequent comments that my current daily driver sounds and/or feels like a crotch rocket - both the vibes and the noise. Plus I'm considering fabbing a complete new suspension using rod ends...

Long story short: Make your pick. The fluid filled was more for your benefit. Unless somebody chimes in and explains why it needs to be fluid filled, I'm down for whatever.

I don't have measurements on that 300zx mount. I was hoping u'd have access to one. Oh well.*scratches 300zx off list*

 

Grdevs24zero:

What info for the mount have u requested? Can u post any links so we can keep track of it there as well? Thanks.

Regards,

Kurt

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

http://nismokc.com/forum/viewtopic.php?t=6768

 

This is the only site that has answered my question so far.

Here's my interpretation of  Grdevs24zero's 'welded-only' mount with the legs protruding all the way thru the main plate. If u need any more changes/ additions lemme know. I threw in some 1/8" welds

Those only protrude 1/4" on the back side but is open for adjustment depending on clearance, weld size requirements and strength necessity.

I should have some sketches done for dimensions over the next 2 days... hopefully...

Kurt

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

That's exactly what I was trying to emmulate with my Paint doodad.  I'm sure 1/4" would be plenty. 

 

My car is on it's way to the panhandle of Oklahoma right now, so I can't take any more measurements for a while.

Hi guys,

   I've found a possibility on the mount subject.  Toyota Tundra cab/frame mounts are about the same size as my hockey pucks but are probably made out of better rubber and have a nice steel top plate and hard plastic bottom plate.  I think these will be ideal, they aren't fluid filled but since my pucks don't vibrate much I don't think that's a necessity.  These will be softer then my pucks by a little bit and just seem more appropriate for the job.

What do you think?

 

 

 

I think I'll give them a shot and see what they feel like.  Looks like they'll drop right in in place of my pucks so it should be an easy test.

 

Fred

Truck cab mounts... Hmmm... Interesting...

 

Sorry to bring this back up but after looking at the 300zx mounts and the stock 240sx mounts, I noticed they both have the "ear" to prohibit that 'angular' shearing movement we brought up earlier. I'm becoming concerned with long term wear (on the softer mounts) again. More so when it's trying to resist rotation from 500lb-ft of torque from 3000rpms to redline...

I have a proposed solution (easy to make & cheap as well) which is basically a plate positioned below the insert (directly on the crossmember) with an ear. Apparently this thing is harder to describe than I anticipated so I'll just do a file t'row to explain. It's late. No it's early. Argh.

Kurt

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

Are you sure that the bottom plastic plate on the cab mounts would be up to the task of holding the torquing engine and survive the temperature changes?  I don't know of many plastics that can go through with that.  I'm no expert but it seems it would need to be replaced with steel?

Grdevs24zero:

Are you sure that the bottom plastic plate on the cab mounts would be up to the task of holding the torquing engine and survive the temperature changes?  I don't know of many plastics that can go through with that.  I'm no expert but it seems it would need to be replaced with steel?

I don't think the plate would resist that much torque, if any, since the mount is mostly in compression and without the 'ear' it wouldn't be in a position to resist the torque. The heat might be an issue tho, more so being right under the exhaust manifold. I say put it to the butane torch test and see how it reacts.

Kurt

---

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

Grdevs24zero:

Are you sure that the bottom plastic plate on the cab mounts would be up to the task of holding the torquing engine and survive the temperature changes?  I don't know of many plastics that can go through with that.  I'm no expert but it seems it would need to be replaced with steel?

 

I think it will do the job with no problems from a strength standpoint.  As far as heat goes I doubt it will be much of a factor on the bottom of the mount with the bracket shielding it from most of the radiant heat.

 

Fred