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Want to fabricate motor mounts


Guest FL83280ZX

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Guest FL83280ZX

I would like to fabricate the motor mounts for my LT1 swap into my 83 280ZX. I have seen some pictures of the MSA mounts and I would rather make them then to spend $280 on them from MSA. Does anyone have drawings of these mounts? I would be glad to pay someone for their trouble. I am just on a very tight budget and anywhere I can cut costs the better.

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heres a little tip, first, FIRST THINK IT THRU CAREFULLY, somtimes only an adapter plate is necessary added to stock motor mounts to move the location of the mounting hole locations on the block or frame , you can normally use either the stock frame mounts or engine mounts for half the setup, you need custom mounts for only one side of the mount on each side of the engine in most cases,

 

bolt your trans to the engine and suspend the engine exactly where you want it possitioned in the engine bay as to spaceing, angles, shifter location,water pump and accessories, etc. with your engine crane , engine tilter and jacks, making sure of distributor clearance, oil filter,fuel pump,suspension,oil pan, starter ,clearances ETC.

now the fun starts,

having built dozens of custom engine and trans mounts over the years heres what I found easyest, buy some 3" wide masking tape, use cardboard,and make the first trial set,then progress to fitting and mocking up a set from 3/16-1/4" thick plexglas and the solvent/glue necessary to stick it togeather ,cut and fit the necessary parts, first on the tape/cardboard then make your trial fit parts from the plexi-glass, a drill press and jig saw helps heres as does the ability to see thru the plexi-glass, for mounting hole locations (remember to gusset angles/joints and to leave room for bolts to slide in and bolt heads to be reached with a wrench) and use a majic marker to mark the mount holes and outter dimensions,

you should be able to all the mistakes and trial fitting for under $20, then take the plexi models to a local machine shop for duplication in 1/4" steel, if you dont have a welder and the skill to build it yourself

simple brackets rarely cost you more than $100

 

35531108G.gif

 

http://www.novak-adapt.com/knowledge/knowledge_gateway.htm

 

 

mm29.jpg

http://www.novak-adapt.com/catalog/kit_mm29.htm

 

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=964&prmenbr=361

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Here are the pics of the MSA mounts...

 

Passangersidemotormount.jpg

 

Driverssidemotormount.jpg

 

motormounttopview.jpg

 

 

All they do is mount to the original Datsun 2 bolt rubber mounts that bolt to the tower mounts. There is a slight angle on the passenger side mount. I wish I would have taken som measuerments for all you guys that need them. Those MSA mounts cost waaaaaaaaay to much for what you get!

 

I have to replace my oil pan gasket soon so maybe I will take the mounts out and take some measuremets for everyone who needs them, since I have to raise the engine to get the oil pan out! I will post some measurements as soon as I do the oil pan gasket.(should be with in a month/month and a half....

 

Guy

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For my motor mounts, I just used the Chevy truck mounts that JTR suggests for the Z and made aluminum spacers that go between the block and mount. If I remember correctly, my drivers side spacer is 2.875" thick and my passengers side spacer is 1.625" thick. If anyone is interested, I can go out and measure them to be sure.

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As a purely academic question spdsk8tr (and lease don't take my questioning the wrong way), did you make any provision for offsetting the engine to the passenger side? My reason for asking is that w/the JTR mounts, the drivers' side provides for an offset of ~3/4" to the passenger side of the car.

 

Viewing the JTR manual, the chevy mount on the driver's side is move 1" toward the bottom of the mount as compared to the datsun mount holes. Due to the angle that the plate is at when bolted to the Chevy Engine, I can see that this would move the engine over a certain amount and maintain it level side to side (or am I just assuming this also?)

 

Both Z & ZX use the same motor mounts, and by looking at the MSA system, they use the stock datsun mounts and leave the Chevy mount off - simple spacers.

 

I personally don't think that the datsun mounts were designed for the HP and (esp) torque of the SB, so I definitely think that spacers utilizing the chevy mount is the way to go, however - the offset ? bothers me.

 

JTR all said and done has a total of 1 9/16" (1.831") for spacer & setback plate thickness w/no offset on the pass. side. The driver's side has a total thickness of 2 9/16" (2.831") with the aforementioned 3/4" offset to the passenger side. The amount the engine is moved down on the drivers side in relation to the motor mount position seems to 'even out' the difference in spacer height, therefor the engine is level side to side.

 

Assuming your memory of your measurements is accurate (driver's side so close that it doesn't bear mentioning and passenger withing 1/4" between both systems discussed), then there appears to be a distance gap involved (heightwise and between where the chevy mounting bolts line up in relation to the engine mount towers.

 

With straight spacers the specified (and seemingly correct height) and no offset on the driver's side, it would seem that the engine would be centered in the car, and likely the engine would not be level 'side to side'.

 

I am simply trying to visualise how just spacers would work without that offset on the driver's side...

 

Inquiring minds want to know!

 

I personally wil keep my '83 ZXT turbo'd - the '75 is for a V8 - but I'm gonna do my own crossmember for wicherver engine I choose and not go JTR (if not LS1) because I want as much room in the engine compartment as possible for accessories and turbos. Beside - it will look cleaner!

 

Once again, I personally do not think much of the MSA kit for the ZX (haven't seen for the Z) because a V* should be using motor mounts designed for IT - not another engine. There is too much engineering that the car companies go through for NVH to toally discount so flagrantly, not to mention sheer stoutness-wise in this case.

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Brad man,

Your question and comments are legitamate, and not taken wrong on my part. I had to make provision for offset as I have the recirculating type power steering box in the way.The difference in thickness of the spacers creates the offset, and , yes, just using the spacers will tilt the engine slightly. To overcome this I slotted the holes in the crossmember, mounted the motor and installed "plugs" into the gap in the slots prior to tightening the mounting bolts with large washers. The passenger side mounting bolt will be at the top of the slot and the drivers side will be at the bottom of it's corisponding slot. I hope this addresses your concerns.

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I knew you were on top of it :rockon: , but I just wanted anyone else looking to make their own mounts be aware of the engineering that went into the JTR Z system that somehow needs to be duplicated for the ZX.

 

You had the thickness angle covered by what you stated - it was the moving of the drivers side attachment to the chevy mount that wasn't covered.

 

Someone really SHOULD start to make the mounts for this other than MSA - I REALLY don't like the idea of using the Datsun engine mounts...

 

Thanks for clearing it up for everyone down the line.

 

By the way, I think the post title should be renamed Fabricating 280ZX mounts for future searches...are you with me FL83280ZX?

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Guest FL83280ZX

What a great wealth of information. Thank you for all of you help. I will definately try to do the job correctly. I like the idea of using the chevy mounts rather than the Datsun mounts. And with all this info, yes I so agree that this post should be renamed to Fabricating 280ZX mounts.

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To add to my post. The method I used to acheive the thickness of my spacers is as follows. I started by installing the truck mounts to the block. I then added threaded rod with a nut installed into the mounting hole in the chevy mounts. I then dropped the motor into the car, making sure the threaded rod fit into the mounting holes in the crossmember. Once the motor was supported in the car by the threaded rod and nuts, I adjusted the nuts up or down to position the motor as low in the engine bay as I could and still clear the steering, both at the box and at the crossmember. I then measured the distance from the Chevy motor mount and the crossmember perch and this became the thickness of my spacers. Of course, the spacers then go between the block and the Chevy mount. I hope this doesn't confuse the subject. Just the method that I used to acheive the thickness of my spacers.

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Guest greimann

Just to add another option. The picture shows a Chevy "clamshell" bracket and biscuit style rubber isolator. A block of 1/2" steel and a flat sheetmetal plate puts it all in position. The picture is looking aft at the drivers side mount.

enginemountleft.jpg

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Dave,

Your method is the one I originally intended to use. It appears there are more than one clamshell style chevy mount. The ones I had did not position the motor properly or line up with the crossmember mounting perches. So, the fabrication mode went into effect. Dave, what vehicle did your mounts come from? I still think your method is the easiest, with the correct parts.

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