Guest TAlchemist Posted December 2, 2004 Share Posted December 2, 2004 i know it has been discussed before and most of the searches i found simply say it is possible if you reinforce the frame rails but i was wondering about the real pro's and con's of using a custom mount directly to the frame rails in the 78 280Z. I dont like the way the setback plates look in the JTR version but i do like its engine placement. So i am looking in to welding some metal to the frame then making some nice looking towers to accept std chevy style mounts. any ideas, comments, or what ever? ps -- i have an idea and as soon as i can get a diagram built i will post it to show my idea. Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted December 3, 2004 Share Posted December 3, 2004 Why reinvent the wheel? The JTR mounts are proven to work even in high horse power cars. Is changing the mounts just for aesthetic reasons? !M! Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 3, 2004 Share Posted December 3, 2004 Have to agree with Mat. You will just be adding one more restriction to plumb headers through, not to mention more weight. But if you are really set on the idea, check out HybridZ user jerimo (I think I spelled it correctly) web site. He did something similar for his LS1 install. But the LS1 is a completely different animal that mount too far back to consider set back plates. Quote Link to comment Share on other sites More sharing options...
Guest TAlchemist Posted December 3, 2004 Share Posted December 3, 2004 Well i just dont like the looks of the setback plates with the stock towers still attached. and i think it will be good practice for me to try and fab the new mounts up. i wont modify the frame rails till after i can get a decent looking mount but i mainly want to try. this whole project car is about me learning more. and i want the stock mechanical fuel pump cause there is no need to install an electric for my application. i like the way it looks and how simple it is. Quote Link to comment Share on other sites More sharing options...
auxilary Posted December 3, 2004 Share Posted December 3, 2004 you can mount to the frame rails. just make sure you reinforce teh metal with 3/16" thick angled steel and sleeve the frame rails Quote Link to comment Share on other sites More sharing options...
Michael Posted December 4, 2004 Share Posted December 4, 2004 Judging from the posts so far, one would get the impression that the only reason to deviate from the JTR method of mounting the engine via setback plates from the steering crossmember is some yearning for originality or customization. I disagree. Reasons for and against mounting directly to the frame rails.... Pros: * If the engine is mounted directly to the frame rails, instead of the steering crossmember, the point of application of the engine’s weight is closer to the firewall, thus reducing the strain on the frame rails, and how much the chassis would twist upon application of full-throttle. * The engine isn’t cantilevered on setback plates from the steering crossmember, so in principle the mounting arrangement is stronger, for the same amount of metal. * With enough setback, the engine mounts get close to the mounting location of the tension/compression rods (front suspension), where the frame rails are already beefed up. This is a great place to carry a point-load like the engine’s weight. So, you can take advantage of structural synergism. * You can remove the steering cross-member and service the front suspension without worrying about having to first unbolt the engine and supporting it separately * Since the there are no setback plates to interfere with the fuel pump area, using a stock mechanical fuel pump becomes possible. Cons: * Once you decide on the engine’s location, you can’t vary it as easily as you conceivably could with a setback plate system * Requires welding * Requires local reinforcement of the frame rails * More likelihood of exhaust header interference, or steering shaft interference * Engine removal and reinstallation can be more cumbersome, as the transmission bellhousing has to clear the gap between the engine mounts as the engine is lowered into place. * Requires cutting and grinding steel, whereas setback plates can be from aluminum. My car (also a 78 280Z) has a big block, with setback way beyond JTR. That much weight, with that much setback, would probably be impractical to carry as a cantilevered load, so welding mounting attachments directly to the frame rails was the only reasonable approach. The steering shaft actually passes through the driver’s-side engine mount structure. Quote Link to comment Share on other sites More sharing options...
Jolane Posted December 4, 2004 Share Posted December 4, 2004 This is very similar to what I am planning on doing as well in the upcoming few weeks (waiting for a tranny to arrive, engine is ready to go in). The different though is that I want to turn the cross member into a K member for structural reasons. I know space is tight, but I hope to mount the engine from the added legs that form the K, instead of cantilevering the engine from the stock mounts. Another advantage is that now I am not limited to using the stock cross member at all, and therefore might use a different steering rack and can easily change the front suspension geometry... I am starting with some engery suspension engine mounts, which only require a tube mounted horizontally mounted to attach to. I have the tools to cut, weld, machine, etc at my disposal... I realize this doesn't answer your question, more of a brainstorm on my part... Joshua Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 4, 2004 Share Posted December 4, 2004 * With enough setback' date=' the engine mounts get close to the mounting location of the tension/compression rods (front suspension), where the frame rails are already beefed up. This is a great place to carry a point-load like the engine’s weight. So, you can take advantage of structural synergism. [/quote'] Have to disagree with this statement. The stock cross member does a better job of off loading the engine weight onto the front wheels. The sheet metal "frame rails" at the TC mount point do a marginal job of managing the fore-aft forces from the TC rod. (That is why most racers reinforce this area with additional metal.) Can't say they would do much to handle an up-down jolt of an engine from say a speed bump or pot hole. Not without some significant gusset plates to distribute the load. Hear what you are trying to say about reducing the lever arm for the engine torque. But once again have to disagree. I think the differences would be minor, especially with the short distances involved with the JTR set back plates. I still like the idea of keeping as much of the engine weight and torque in the same plane as the front strut towers. And remember, longer shafts can handle more torque than short ones. Thus a longer chassis can sustain more deflection without failure than a short one ("all else being equal") My 2 cents anyway. TAlchemist: if you really dislike the non-stock look of set back plates, why not cut the stock engine mount towers off the stock cross member and rework/reangle those so they end up where the JTR mounts end up? Quote Link to comment Share on other sites More sharing options...
Guest TAlchemist Posted December 4, 2004 Share Posted December 4, 2004 Well i havent fully decided what to do yet. moving the stock mounts was an option as is making the crossmember into a K. Although currently i love the way Alsil makes his new crossmembers in the Ford section. Just put another crossmember behind the stock one with the engine on it so you can pull the front suspension without removing the engine. what about bolting some kind of spacer from the original crossmember to a new crossmember behind it. maybe some kind of H member that can be unbolted from either crossmember. Quote Link to comment Share on other sites More sharing options...
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