Guest Anonymous Posted September 20, 2002 Share Posted September 20, 2002 I'm sure you can make them. As far as being sturdy, I'd have to disagree. They're pretty beefy. As far as the spacers I was going to just use some pieces of pipe with long bolts, but it just wasn't worth my time and the aluminum extruded spacers not only look good but work well. The crossmember is particularly beefy, its like 3/8" steel. IMHO your unlikely to see a failure of the JTR mounts, they've put Z's into the 9's and if you want to go faster, well you have bigger stones that I. You could use engine plates if you really wanted to and figure that whole thing out, it just depends on if you want to reinvent the wheel and have the time to do so IMHO. Regards, Lone Ps: If I did have the time to modify JTR's rear mount I think it would be to weld another plate that goes out further with spacers to straddle the frame rails on both sides and bolt on each side of the frame rail not unlike the MSA rear anti-sway bar if you've seen one of those. That would be a bit sturdier than just bolting to the cars floorboard IMHO. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 21, 2002 Share Posted September 21, 2002 The strength is in the GRADE 8 mounting bolts since the JTR design uses sloppy fitting tolerances which do not develope any problems. I made up about five pairs of the set back plates by copying the JTR diagrams and using the copies as templates and a transfer punch to mark the locations.. Be sure to re-check all the dimensions on the copies for accuracy and you can also use the chevy pick-up motor mounts to reference your holes. The aluminum spacers were difficult due to the scarcity of scrap aluminum and price. The last 4 set's spacers were made with a thick wall pipe that had a 3/8 inch inside diameter. I made a triangular piece in the shape of the aluminum spacer out of 1/4 inch plate to fit directly to the engine( a junk engine block). I cut the pipe in the appropriate spacer lengths with a pipe cutter for trueness and then on the bandsaw for final cut. I loose mounted the set back plate, the pipe spacers and triangle piece to the engine and spot welded in place. Removed the spot welded 3 pieces from the engine and added straps (1 wide X 1/4 inch) to the set back plate to the triangular piece that mates directly to the engine block. I welded all this together including the pipe spacers. Since the set back mount is a precision fit with close tolerances....I re-mounted the welded combination spacer/setback plate to the engine a couple more times during the welding aspect to check for heat warpage and distortion with GRADE 8 bolts. At this remounting any errors could be corrected with a hammer (Do not use the hammer persuader while the set back plate is mounted to the engine OUCH!). This set up is super strong with grade 8 bolts at very close tolerances and not much heavier than the aluminum spacers.You will need pipe cutter, bandsaw, threading tap, wire welder,drill press, transfer punch(s) etc and fabrication skills.Plus a lot of patience... Keep in mind most of the strength is in the mounting bolts (GRADE 8) I saw one JTR set up where the spacers comprised of stackled washers with no apparent problems.Lone is right.. the JTR aluminum spacer is trick!. I contemplating the JTR tranny cross member without the the exhaust allowances since my project calls for side pipes. I would have very much difficulty attempting the exhaust allowances in the trany cross member with any degree of accuracy. Need a press for this work. The JTR tranny cross member also takes the guess work out of driveline phasing and angles but one without the exhaust allowance is very easy to fabricate. Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted September 21, 2002 Share Posted September 21, 2002 i was wondering if anyone has made there own v8 chevy motormounts for there 240-280z?..i know the jtrs are good (yes i have the book!) but they dont look that strong to me..i know they have been used in hundreds of conversions, but i think i can make somthing similar with out all the different plates and spacers bolted together..has anyone done this..and if i do make my own design it will be in the jtr set back position..thanks for any info. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 21, 2002 Share Posted September 21, 2002 Ya know what would be really cool, and I don't have the space or equip to do it... But replace the datsun xmember all together with one that has risers that are triangulated back (like the one they use on the RX7 chevy V8 swap) incorporated into a new xmember that also relocates the bottom a-arm pivots at the same time. In other word, pull the xmember, bolt up the new one, no setback plates and re-worked suspension geometry all at one shot! For a re-engineered back xmember, I'd like to see one that wraps around and up into the tunnel (as one of our members has done I think I remember seeing such a deal) so that 2 bolts run sideways in the tunnel and two bolt on the bottom. Plates on the INSIDE would match this contour to give a bit more strength. Then the center would BOLT onto those pieces, meaning once you drilled the holes, they could stay bolted in forever and you'd just remove the center section. I'll try to draw up what I'm saying, as I'm sure its confusing what I'm talking about. Regards, Lone Excuse this TERRIBLY drawn picture, obviously I'm not a graphic artist.. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 22, 2002 Share Posted September 22, 2002 Lone, Good idea of the removable center section. Quote Link to comment Share on other sites More sharing options...
jeromio Posted September 22, 2002 Share Posted September 22, 2002 Hrm. This'll be me tootin my horn. On the motor crossmember, sorta sounds like you are talking about something like this: Dunno why I can't find the pic I took with the motor towers bolted on the legs there. I hope it's not permanantly lost. And for the trans crossmember, TimZ and I had the same idea (well, he had it first, so, really it's his idea): Except that I think you've taken it a bit further, adding an extra set of bolt thru mount points. That does seem interesting. You could then use poly bushings in those bolt thru's and eliminate the GM-style tranny mount. I do think that it may get too bulky in the tunnel with that design though, reducing the available space for exhaust. And the way I've done mine, it's pretty easy to get the crossmember in and out of there (this is version 2 though, the first one there was some difficulty lining up the 4 bolt holes). All of this is required for the LS1 swap (well, at least my version of the LS1 swap). But the LT1 swap could definitely benefit since it eliminates the interference betw. accessories and datsun motor towers. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 22, 2002 Share Posted September 22, 2002 Jeromio, Thanks, yours was the one I remember seeing, I couldn't recall who I'd seen do that crossmember like that. A simpler version I once was thinking about and its probably to wide, but was to use a Ford 'double hump' mount often used in Mustang swaps for one particular application. Its just the center section and you'd only need to fab just a small mount on each side and either weld it to the tunnel or bolt through as you've done. And yes your xmember looks pretty much like I'm talking about, heres a actual picture of the one they use on the RX7 swap: http://members.tripod.com/~grannys/subframesm.jpg Same deal, just fabricated complete from scratch instead of a stock datsun one modified. Just thought it'd be neat to have one that just bolted in for a swap. Doing it that way lends itself to mounts for Fords as well since they just bolt lower on the block, or mopars, it'd be the same front xmember and just a difference of the back part depending on application. I guess there isn't to much under the sun that someone hasn't thought of, just variations of the same theme. Nice xmembers you have there. Regards, Lone Quote Link to comment Share on other sites More sharing options...
Russ Posted September 22, 2002 Share Posted September 22, 2002 This is all very good stuff guys, makes for useful reading Try to figure out a solution within 12months please so I can make use of your good ideas and knowledge Sorry to lower the intelligence of the thread a little but apart from the grade of metal and such is there very much to stop me making my own mounts? I'm ok at welding and can practice lots. I also have a structural engineer friend who designed the electricity pilons you see all across the uk The reason I ask is I was considering an engine swap in my 306 (read small uk hatch), we were gonna put the 2ltr turbo in from the 406 but it would require different mounts. These are cast jobbies and the expert on it around here said he wouldn't trust anyones welding to modify the new ones and so the only option is to get my current mounts heated up and remoulded somehow or something like that. Last thing I want to do is do all this trick welding, drive her up the road and have an engine on the floor with lots of broken bits Cheers guys Quote Link to comment Share on other sites More sharing options...
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