Stoffregen Motorsports Posted April 2 Report Share Posted April 2 @]2eDeYe might know. He's been known to play with this stuff on trucks. 1 Quote Link to comment
Crashtd420 Posted April 2 Author Report Share Posted April 2 55 minutes ago, Stoffregen Motorsports said: I'm trying to picture the control arms in my head. If they are flat on the bottom arm, and pointing down towards the middle on the upper arm, seems like lowering the tie rod would compensate for bump steer. Well I don't think I actually have a bump steer issue... atleast I have never felt it... I came up with an easy check internet surfing.... I think.... Should be enough to tell me if I need to dig deeper.... 1 Quote Link to comment
]2eDeYe Posted April 2 Report Share Posted April 2 2 hours ago, Stoffregen Motorsports said: @]2eDeYe might know. He's been known to play with this stuff on trucks. From the service manual. I assume it is in order of operation. I do know when you lower these trucks the upper control arm get's really short in it's arc of movement and the lower gets longer. This changes the camber and amplifies it's range through the suspension travel, this is why drop spindles are desirable. The 620 has spacers between the upper arm mount that can be removed, although these days I would just move the spacer to the outside of the control arm instead of tossing them. This doesn't really help the range difference much during travel though, just gets you back close to stock 1 deg camber. 2 Quote Link to comment
datzenmike Posted April 2 Report Share Posted April 2 If the tie rod ends are on a flat plane with the pitman and idler arms you will have zero bump steer. As soon as you raise or lower the vehicle height, the tie rods either tilt up (if lowered) or down (it raised) to the wheel hub. If you were to measure between the outer steering ball joints the distance becomes less and less the farther from the level position. At first very little change but the farther from level the rate of change increases dramatically. On a truck with the steering in front of the tires, shortening the distance will toe the tires in and on Datsun cars the steering is behind the wheels so they will toe out. After resetting the toe to near zero everything seems normal but when hitting a bump or a pot hole in the road, most especially on one wheel and not both, the tie rod angle increases or decreases foreshortening it's length and pulling that wheel inwards yanking on the steering wheel and pulling to the left if the right side and the right if the left side. If the dip or bump involves both wheels the temporary toe in tends to cancel and it's not as noticeable. With the steering tie rods level, the change is so small it's negligible. After lowering my 710 I noticed driving over a dip on the edge of the pavement on my street caused the steering wheel to suddenly pull to one side. I was prepared to live with this but did some research. Below I measured the difference between a level tie rod and where it met the hub knuckle. Looked like 1/2" roughly. I made spacers in 1/4" aluminum. This 1/2" spacer lowered the tie rod back down to basically, level. Amazing! 'Bump steer' gone! 3 Quote Link to comment
Crashtd420 Posted April 3 Author Report Share Posted April 3 Well I have definitely never had the steering wheel pull to one side or the other going over any bumps.... And our roads suck ... So I'm probably ok... I'll still do a half ass bump steer verification while I'm checking the camber and toe.... Quote Link to comment
datzenmike Posted April 3 Report Share Posted April 3 It's tolerable even unnoticeable when close to correct ride height and a bump or dip swings the wheel up and down through this 'safe' zone, but if raised (or lowered) substantially, one of these swings as majorly going to shorten the tie rod and affect the steering. On a Datsun car you can space the steering knuckle down like I did to correct when lowered. On a 521 if lowering a spacer could be mad like I did and placed between the steering knuckle and the spindle, with longer knuckle bolts of course. Not much can be done if the bump steer is from raising the ride height. The idler arm and the pitman arm would have to be lowered to level the tie rods. 1 Quote Link to comment
Stoffregen Motorsports Posted April 3 Report Share Posted April 3 Cars are comparatively easy to check for bumpsteer because of the single control arm and strut arrangement. Quote Link to comment
Crashtd420 Posted April 4 Author Report Share Posted April 4 Well New England likes to throw some strange weather at us from time to time.... I thought winter was over but here we are..... Quote Link to comment
Crashtd420 Posted April 8 Author Report Share Posted April 8 Well I'm not 100 percent confident where I set my front suspension.. . I always feel like my readings are a bit off.... I'll double check when I get home but atleast it drove well going to work this morning..... 2 Quote Link to comment
Crashtd420 Posted April 10 Author Report Share Posted April 10 Little up date.... I think I'm getting close.... Seems like I need to drive the truck a little to settle the suspension completely.... Because the readings I get from letting it down off the jack vs after a drive are slightly different.... I did check k that day to day they repeat so that's good.... Hopefully one final check after work and I can leave it alone.... 1 Quote Link to comment
Crashtd420 Posted April 10 Author Report Share Posted April 10 So far I'm good..... Camber is set and numbers are the same the next day so nothing funky happening.... So I checked the toe today and it was premuch dead straight.... so I added a little toe in and reset my steering wheel... It's always been a little cocked to the left..... raining now and tomorrow so I'll have to wait till Friday to drive the truck again..... 1 Quote Link to comment
Crashtd420 Posted April 14 Author Report Share Posted April 14 I got to take the truck for a good drive today.... it was so nice with the steering wheel position correctly while driving straight.... the turn signal cancel even works better now.... can't believe I waited this long to fix that.... All in all alignment seems to be staying where I set it and drives nice down the road.... the new tires feel no different from any other tire I have bought... And Bump steer is not an issue...... Only thing I need now is a mat or something to cover the holes in the bed floor... Inspection got pissy about it last year for some reason.... 1 Quote Link to comment
demo243 Posted April 14 Report Share Posted April 14 (edited) 2 hours ago, Crashtd420 said: I got to take the truck for a good drive today.... it was so nice with the steering wheel position correctly while driving straight.... the turn signal cancel even works better now.... can't believe I waited this long to fix that.... All in all alignment seems to be staying where I set it and drives nice down the road.... the new tires feel no different from any other tire I have bought... And Bump steer is not an issue...... Only thing I need now is a mat or something to cover the holes in the bed floor... Inspection got pissy about it last year for some reason.... I used a stall mat from -edit sorry tractor supply -in my old 620- downfall is it was HEAVY… But… if you wanted to get crafty a wood floor cover would be cool. So lame that that they will give you trouble for the floor of your bed… has no effect on anything or anyone… Edited April 14 by demo243 Quote Link to comment
Crashtd420 Posted April 14 Author Report Share Posted April 14 9 hours ago, demo243 said: I used a stall mat from -edit sorry tractor supply -in my old 620- downfall is it was HEAVY… But… if you wanted to get crafty a wood floor cover would be cool. So lame that that they will give you trouble for the floor of your bed… has no effect on anything or anyone… I really wanna do a nice wood floor eventually but money won't allow it at the moment. I'm just gonna do something cheap for the now. Just not sure what.... Quote Link to comment
Slow Loris Posted April 15 Report Share Posted April 15 Thinking of doing the wood floor too. I’m hoping to pounce on someone’s cast off flooring from the free section of Craigslist as I see from time to time or we’ve got one of those second hand building materials stores around here that often has excess flooring for dirt cheap…Datsun bed all of what 27 square feet? Easily someone’s leftovers. 1 Quote Link to comment
Stoffregen Motorsports Posted April 15 Report Share Posted April 15 On 4/14/2024 at 4:44 AM, Crashtd420 said: I really wanna do a nice wood floor eventually but money won't allow it at the moment. I'm just gonna do something cheap for the now. Just not sure what.... Do a google search for synthetic teak boat decking. I just came across this stuff the other day when a friend who works on ships was here and we were discussing interior options on a current build. He said he uses it and it's very durable, but also easy to roll out and use. 1 Quote Link to comment
Crashtd420 Posted April 15 Author Report Share Posted April 15 45 minutes ago, Stoffregen Motorsports said: Do a google search for synthetic teak boat decking. I just came across this stuff the other day when a friend who works on ships was here and we were discussing interior options on a current build. He said he uses it and it's very durable, but also easy to roll out and use. I have seen a few different things like that that have peeked my interest.... I am trying to do something different.... Problem is cash flow..... Not much extra for the datsun lately..... 1 Quote Link to comment
Crashtd420 Posted Wednesday at 01:25 PM Author Report Share Posted Wednesday at 01:25 PM I caused my own problem over the winter.... leaned on my coolant recovery bottle and broke the tab it was mounted to.... Probably not the best choice.... Made a stronger bracket that mounted with the radiator bolt.... coolant bottle back in place.... 3 Quote Link to comment
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