TieFighter88 Posted November 26, 2013 Share Posted November 26, 2013 (edited) Gday, I have a very low quality chassis diagram for my dimensions as I have been working on my 78 280z, I would like to confirm the measurements I have before I attach my cross member finally into my new frame rails. Can one of you blokes please fire-off to me your measurements from the firewall to the first mount as indicated in my attached photo? Edited November 26, 2013 by TieFighter88 Quote Link to comment Share on other sites More sharing options...
seattlejester Posted November 27, 2013 Share Posted November 27, 2013 (edited) 287mm is what the fsm looks like it is saying for a 240z-280z. Not 100% sure, I can take a ruler and verify it tomorrow. Edited November 27, 2013 by seattlejester Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted November 27, 2013 Share Posted November 27, 2013 (edited) EDIT: Had wrong measurement. Edited November 27, 2013 by SUNNY Z Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted November 27, 2013 Share Posted November 27, 2013 When I built my front frame rails about ten years ago, I went by the 260Z frame drawing for placement of the TC buckets and the crossmember placement. After welding everything up, I discovered that the 260Z FSM had some significant errors. I believe that these errors were corrected in the 280Z FSM but I am not sure. If it were me, I would clamp the crossmember in place and assembly the suspension to make sure everything is correct. You may even want to move the crossmember slightly forward of the stock location to gain a little caster. If you do, make sure that the wheels clear the fenders and air dam. Also if you go too far forward, the steering shaft will not reach. Quote Link to comment Share on other sites More sharing options...
morbias Posted November 27, 2013 Share Posted November 27, 2013 I made a diagram of some chassis leg measurements when I was doing repairs, it doesn't have the measurement you're looking for unfortunately but the other info might be of use: Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted November 28, 2013 Author Share Posted November 28, 2013 287mm is what the fsm looks like it is saying for a 240z-280z. Not 100% sure, I can take a ruler and verify it tomorrow. Please verify, I don't think thats it. Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted November 28, 2013 Author Share Posted November 28, 2013 I made a diagram of some chassis leg measurements when I was doing repairs, it doesn't have the measurement you're looking for unfortunately but the other info might be of use: Thanks mate, that will help me out after I decide how far to put my setup. Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted November 28, 2013 Author Share Posted November 28, 2013 When I built my front frame rails about ten years ago, I went by the 260Z frame drawing for placement of the TC buckets and the crossmember placement. After welding everything up, I discovered that the 260Z FSM had some significant errors. I believe that these errors were corrected in the 280Z FSM but I am not sure. If it were me, I would clamp the crossmember in place and assembly the suspension to make sure everything is correct. You may even want to move the crossmember slightly forward of the stock location to gain a little caster. If you do, make sure that the wheels clear the fenders and air dam. Also if you go too far forward, the steering shaft will not reach. I have heard this story before from another bloke, thats why I wanted to make sure before I start drilling holes in my fresh rails. Yep , I think after I got my ballpark measurement, I will dummy-bolt everything and see how far the steering shaft will give me... will have to check for the header clearance to, I have the 6-to-1, knowing my luck they would get in the way... Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted November 28, 2013 Author Share Posted November 28, 2013 EDIT: Had wrong measurement. what did you get sun? Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted November 28, 2013 Share Posted November 28, 2013 (edited) TieFighter, I just noticed that you are only about 45 minutes from me. If you want, you can come over and take some measurements after the Thanksgiving holiday. Do you plan to autocross when complete? The season starts in January. Edited November 28, 2013 by 74_5.0L_Z Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted November 28, 2013 Author Share Posted November 28, 2013 TieFighter, I just noticed that you are only about 45 minutes from me. If you want, you can come over and take some measurements after the Thanksgiving holiday. Do you plan to autocross when complete? The season starts in January. I might take you up on that, my in-laws are in Melbourne and I and back and forth all the time with the missus. I definitely want to autocross, how do the inspections/waivers work? Because the whole front end of my chassis is a garage job, and not official SCCA stuff, not saying I am incompetent, worried it might scare them to let me on the track with my creation... Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted December 5, 2013 Author Share Posted December 5, 2013 No numbers anyone? Quote Link to comment Share on other sites More sharing options...
LLave Posted December 5, 2013 Share Posted December 5, 2013 I could measure mine for you, but i have to tell you, measuring back to where the frame dies into the firewall is not going to be very accurate. Kind of an arbitrary point where sheet metal meets frame rail. Quote Link to comment Share on other sites More sharing options...
NewZed Posted December 5, 2013 Share Posted December 5, 2013 The FSM doesn't even call out the dimension to the firewall, from anywhere, that I can see. Doesn't look like a good reference point. Why trust somebody's shaky tape measure hand when there are several ways to cross-check the FSM numbers, and/or back out a super-simple dimension like to the top of the front strut? Quote Link to comment Share on other sites More sharing options...
seattlejester Posted December 5, 2013 Share Posted December 5, 2013 I totally blanked, asking a friend to go check. Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted December 5, 2013 Share Posted December 5, 2013 I think the sway bar mounting holes would be the easiest and most reliable reference point. When I made my frame rails, I used the dimension of the sway bar mounting holes that were published in the FSM and had no problem. I did have issues with the published fore/aft position of the TC mount and the position of "Point B." Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted December 5, 2013 Share Posted December 5, 2013 (edited) OK, I went back and tried to reconstruct what the error was with the 260Z FSM frame drawing, and I believe that I have found the error. I am posting the 260Z FSM drawing below so that I can point out the error. Frame.bmp The dimension between the TC mount and Point B is too short on the 260Z drawing. The listed value is 11.3 inches. If you look at the frame drawing posted by NewZed, that drawing shows the dimension as 12.88. That number is correct. Unfortunately, that dimension is to the engine mount on the crossmember. You can however measure the crossmember and calculate the additional distance you will need to the frame mounting holes. I hope this helps. Edited December 5, 2013 by 74_5.0L_Z Quote Link to comment Share on other sites More sharing options...
LLave Posted December 6, 2013 Share Posted December 6, 2013 I would be happy to pull and dimensions you want from my chassis, its up on a rotisserie and easy to do. Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted December 8, 2013 Author Share Posted December 8, 2013 I would be happy to pull and dimensions you want from my chassis, its up on a rotisserie and easy to do. Yes please mate, very helpful Quote Link to comment Share on other sites More sharing options...
TieFighter88 Posted December 8, 2013 Author Share Posted December 8, 2013 OK, I went back and tried to reconstruct what the error was with the 260Z FSM frame drawing, and I believe that I have found the error. I am posting the 260Z FSM drawing below so that I can point out the error. Frame.bmp The dimension between the TC mount and Point B is too short on the 260Z drawing. The listed value is 11.3 inches. If you look at the frame drawing posted by NewZed, that drawing shows the dimension as 12.88. That number is correct. Unfortunately, that dimension is to the engine mount on the crossmember. You can however measure the crossmember and calculate the additional distance you will need to the frame mounting holes. I hope this helps. So I gather that the diagram implies, the crossmember mounts and engine mounts are along the same plane/axis, spaced equally from the middle of the strut tower? So I could rely on putting the midpoint of my cross member mounts along the line straight down from the center of the strut towers to the rails? Quote Link to comment Share on other sites More sharing options...
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