Guest Anonymous Posted November 27, 2000 Share Posted November 27, 2000 I was reading an OLD Hot Rod mag. article on motor mount fabrication. In it they basically made triangular shaped perches and welded them to the frame. I liked the design but wish to bolt them on instead. Well upon inspection of the frame rails I do not think that the frame would hold up. There is no rust it is just so damned thin. So my plan is to saddle the frame with 1/4 inch plate. To prevent compression of the frame from the bolted on perches I will then weld in 2 bushings through each frame rail. Looks like the saddle will be roughly 6 inches long. A gut named Marc e-mailed me some pics of his mounts that utilize the Datsun perches but it had oil filter clearance issues (solved with a relocation kit) and seemed to have a severe rearward moment. If this idea works I think it will be a very sanitary installation. I have also been kicking around the idea of using a pre-fab eng crossmember welded in to the same saddle described above and then welding perches to the crossmember. Any thoughts about the integrity of this idea would be greatly appreciated. Specifically, does anyone think stress cracks will develop from this design? Thanks again, Rich Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 27, 2000 Share Posted November 27, 2000 Good plan, as I see it. I think 1/4" plate is overkill though. 1/8" or 3/16" would be plenty, IMO. However, I would probably just box the entire length, from the firewall to to just past the swaybar mounts (at least) in 1/8" steel. That way there'd be less of a hard/soft point issue where the reinforcement ends. I handled this by replacing the entire rail, but mine were rusty. I think the perches would be enough, and the added crossmember would not be needed. BTW, Marc Sayer used to sell a kit to add another one (or two?) through bolts for the OE crossmember, which included tubes that were put into the crossmember to keep from crushing it with the long bolts through the crossmember. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
alsil Posted November 27, 2000 Share Posted November 27, 2000 I was going to use a crossmember from Summit racing, that you cut down and weld-in, but this has made me think. would what I'm trying be strong enough? the bar is a tube about 2" thick, and pretty much goes under the stock oil pan, and weld on with 2 square ends (flat) about 3-4" wide. do you think I should add some reinforcement? I am going to add that 1x3 square tubing to make subframe connectors, but would this hold up? Thanks, Al ------------------ http://refuse.netdojo.com/Zcar Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 27, 2000 Share Posted November 27, 2000 The real issue is how good are the frame rails. The stock ones (without rust) where probably o.k., as long as you reinforce the area to spread the load out, like Rich suggests. But the problem is that the rails rust from the inside out and it's hard to tell how bad they are unless you cut them out or bore holes and do some spot checks with a micrometer, etc. My rails gave me a clue when the side near the sway bar mount popped clean through from rust . ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted November 28, 2000 Share Posted November 28, 2000 Umm guys, why not just mount the 302 much like the JTR mounts are done? A friend did this with his and it seemed to work well. Best part was that it put the T5 shifter right through the stock hole... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 28, 2000 Share Posted November 28, 2000 I made a new crossmember for my 5.0 conversion and built the engine mounts off of it. It's 1-5/8" tube and attaches to the inside surface of the reinforced frame "rails". I used thinner material than was originally suggested here. Time will tell if my decision was correct. But it looks plenty strong because the loads are distributed over a large area. It looks a lot cleaner than trying to come off the original mounts. Larry Cutter Quote Link to comment Share on other sites More sharing options...
alsil Posted November 28, 2000 Share Posted November 28, 2000 That's kind of the same thing as I've been thinking. I'll just reinforce the frame rails. I was going to grind off the stock motor mount perches, and clean it up, and use the crossmember from Summit. I'll post stuff about it on my site. AL ------------------ http://refuse.netdojo.com/Zcar Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 29, 2000 Share Posted November 29, 2000 Pete, thanks for the input. I will drop down to the 1/8 inch. Do you think it is necessary to re-enforce the entire fwd frame rails? I do plan on tubulat sub-frame connectors after the drivetrain installation is complete. The car appears to be a typical solid California platform. I will inspect when I bore holes though. Blkmgk, I had thought of the JTR design but I think a crossmember or frame mounted design would look like a cleaner intallation. I'd like to crow about my isolater selection though. It took me a while to find what I wanted part # wise. It is off of a 63-68 Falcon. It is a similar to a chevy design. It has a single horizontal bolt going through the isolater/mount. Eng removal/inst. should be a breeze. TRW part #82286. Only draw back is I have not found a polyurethane one. Any further input would be appreciated. Rich Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 29, 2000 Share Posted November 29, 2000 I think if the frame rails check out o.k. you'd should be o.k., unless you're putting out 500 ftlbs of torque! Sounds like a good plan to me. Quote Link to comment Share on other sites More sharing options...
Guest scca Posted December 1, 2000 Share Posted December 1, 2000 the single vertical stud with a nut engine mount is also on a 65 289 in mustangs.(or 64 260 cars) i believe that comets are the same as well. (if your looking for the steel part to modify to use with that mount. i have one in the backyard now... the 66+ cars use a single long horizontal bolt and not a stud in the rubber mount. i have at least one set here but theyre for my car...i may have another.... ------------------ Mike mike@fonebooth.com http://www.fonebooth.com/brakes.html raceparts and brake upgrades. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 2, 2000 Share Posted December 2, 2000 Thanks for the offer but I would rather fab mine up from scratch. The mount I found does not have a vertical stud, only the single horizontal bolt. I really like the design. Rich Quote Link to comment Share on other sites More sharing options...
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