nghealy Posted October 16, 2017 Share Posted October 16, 2017 I currently have a 240z with a chevy small block installed but am planning on upgrading to an ls3. The car has upgraded suspension but when going on the freeway the car drifts side to side with no steering input and I think this may be do to the weak chassis. Would it be worth it To sell the car and upgrade to a 280z which I have heard has a stiffer chassis and do the engine swap into that car instead of the 240z? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 16, 2017 Share Posted October 16, 2017 If you are sure there are no suspension issues, I wouldn't assume the issue is one of 240Z vs. 280Z, but possibly due to rusted structural parts of the 240Z. Sounds like it could be an issue, so be sure to find it before changing chassis'. Quote Link to comment Share on other sites More sharing options...
rturbo 930 Posted October 16, 2017 Share Posted October 16, 2017 Well, the 280z is indeed a stiffer chassis (somewhat), but what you're describing sounds more like it's tramlining, which would likely have more to do with your alignment or tire choice. Quote Link to comment Share on other sites More sharing options...
NewZed Posted October 16, 2017 Share Posted October 16, 2017 Worn wheel bearings, bushings, or steering gear are all likely on these old cars. Sounds like you haven't really checked anything out. Getting way ahead of buying another car. Quote Link to comment Share on other sites More sharing options...
Miles Posted October 17, 2017 Share Posted October 17, 2017 (edited) Check the steering rack bushings. They are inside the clamps that bolt the rack to the cross member. The originals are rubber and wear/rot out which allows the rack to move. If the bushings look worn, or there is any movement of the rack while moving the steering wheel, replace the bushings with polyurethane bushings. Also, failed rubber tension/compression (T/C) rod bushings can cause the car to dart under braking and to drift left - right. Do not replace the T/C bushing with polyurethane as it is too stiff and can cause failure of the T/C rod. Replace with stock rubber bushings only. The polyurethane and T/C rod bushings are available from Motor Sports Auto (MSA). Edited October 20, 2017 by Miles Quote Link to comment Share on other sites More sharing options...
Michael Posted October 20, 2017 Share Posted October 20, 2017 "Drifting from side to side" at highway speeds is often imputed to bad aerodynamics. In my view, this is partially correct. If the consumables in the suspension are worn, but only slightly worn, then with sedate driving on surface-streets, there may be no sensation of there being anything amiss. But at highway speeds, the steering might grow light, or otherwise twitchy. In steady straight-line driving on smooth pavement, there are presumably no strong transient forces - or than those having to do with wind. So, it's not the case that the aerodynamics are inherently bad (and least, not entirely), but rather, than wind-effects at higher speeds expose problems with the (front) suspension, that would not otherwise have been noticed. That at least was my own experience, driving a worn but serviceable 240z on the highway, now so many years ago. Quote Link to comment Share on other sites More sharing options...
Sandy455 Posted October 23, 2017 Share Posted October 23, 2017 Alignment. For sure. Quote Link to comment Share on other sites More sharing options...
Marks260z Posted October 24, 2017 Share Posted October 24, 2017 Old Z's are notorious for getting light in the front end at speed. Too much air gets up under the hood at speed. The grill opening is way to big with no where for the wind to go. If frame rail strength worries you about the differences between the 240 and the 280 just add big dog fame rails. That is the biggest difference that I have noticed between all my Z's. As to the wind under the hood I have seen it mentioned a number of times in the forums. Do you have a front spoiler on your car now? Quote Link to comment Share on other sites More sharing options...
Sandy455 Posted October 24, 2017 Share Posted October 24, 2017 16 minutes ago, Marks260z said: Old Z's are notorious for getting light in the front end at speed. Too much air gets up under the hood at speed. The grill opening is way to big with no where for the wind to go. If frame rail strength worries you about the differences between the 240 and the 280 just add big dog fame rails. That is the biggest difference that I have noticed between all my Z's. As to the wind under the hood I have seen it mentioned a number of times in the forums. Do you have a front spoiler on your car now? Great call! I forgot the very first mod I put on my car was a BRE front spoiler. Definitely stabilized the car at highway speeds. Quote Link to comment Share on other sites More sharing options...
nghealy Posted October 24, 2017 Author Share Posted October 24, 2017 47 minutes ago, Marks260z said: Old Z's are notorious for getting light in the front end at speed. Too much air gets up under the hood at speed. The grill opening is way to big with no where for the wind to go. If frame rail strength worries you about the differences between the 240 and the 280 just add big dog fame rails. That is the biggest difference that I have noticed between all my Z's. As to the wind under the hood I have seen it mentioned a number of times in the forums. Do you have a front spoiler on your car now? I currently have urethane air dam and it doesn't seem to help much with the aerodynamics. I plan on painting the car soon so before that happens in a BRE style front spoiler worth it? Quote Link to comment Share on other sites More sharing options...
Sandy455 Posted October 24, 2017 Share Posted October 24, 2017 (edited) I've used both on the front end of my car on race tracks in So Cal. The BRE spoiler is great because it's rigid. I think the urethane spoiler bends at 90+mph without a splitter underneath. The other problem with the urethane spoiler is that you have to remove that thin piece of stock bodywork below the grill to mount it which makes the grill opening with the urethane spoiler even bigger which isn't good for the ride either. That being said, I have a custom lowered suspension (RIP John Coffey) so my ride height is 4+"" lower than stock. *One other thing -- I think the BRE spoiler works better than the urethane air dam because the air dam only blocks the air while the BRE spoiler set at a 45 degree angle from the body work creates downforce. Bottom line is that the BRE spoiler was on the early Z cars that won EVERYTHING. That's good enough for me. Edited October 24, 2017 by Sandy455 Quote Link to comment Share on other sites More sharing options...
Lincoln7 Posted December 15, 2017 Share Posted December 15, 2017 On 10/23/2017 at 12:17 AM, Sandy455 said: Alignment. For sure. Agreed, start here. Can be checked for free making your own toe rig using tape measures and pieces of wood. Quote Link to comment Share on other sites More sharing options...
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