510 rear suspension

[obrut]

I have my complete rear cross member and suspension out of my 72 510.  I'm going to use stock Nissan control arm bushings but can't seem to find the mustache bar bushings, cross member mounting bushing, spring isolators and bump stops.  The only ones that I can find are poly, how bad are these on the street?  I'm building a street car that I'll use for autox too.

 

Just pressure washed it yesterday, bushing don't look bad, there just old.

Edited September 12, 2022 by obrut
add pic

[obrut]

Just noticed that the rear springs are different, wonder why the PO would do that?

[iceman510]

I think poly are the only version available anymore.  I know Whiteline makes some too.  I don't know the relative density or performance vs. others like Energy Suspension.

[Stoffregen Motorsports]

If the poly bushing are sleeved, there shouldn't be any issues at all. And since the mustache bar and crossmember don't rotate, like a control arm, there shouldn't be any squeaking, which is common with poly bushings.

 

We used to machine solid aluminum bushings for the mustache bar and crossmember. The solid mounting of those allowed the suspension to do its job and made the handling more consistent.

[obrut]

Yep, no luck finding anything in rubber.

 

I checked and Whiteline sells crossmember and mustache bushing and they do have the sleeves.  I also looked at what ermish sells and they don't seem to have them.  I also found poly coil spring isolators on ebay.  No luck on bump stops, maybe there is a universal one that will work.

Edited September 12, 2022 by obrut

[mojojojo78]

1 hour ago, Stoffregen Motorsports said:

We used to machine solid aluminum bushings for the mustache bar and crossmember. The solid mounting of those allowed the suspension to do its job and made the handling more consistent.

Ermish Racing has solid bushings (I didn't see anything about what material it is):

https://ermish-racing.com/product/207558

https://ermish-racing.com/product/207560

And Polyurethane bushings:

https://ermish-racing.com/product/207512

https://ermish-racing.com/product/207515

[datzenmike]

If you are under 50 the ride comfort won't matter much.

[Stoffregen Motorsports]

If I recall, you can use a generic Daystar brand snubber style bumpstop inside the lower control arm. OEM Toyota pickups used something very similar, but a lot more stout. I probably have a dozen laying around.

 

The neat thing about the Daystar bumps is that you can trim them to your requirements. Well, I suppose you could trim any old stops.

 

https://www.jegs.com/i/JEGS+Performance+Products/555/61860/10002/-1

[obrut]

I was wrong on the springs, they are the same.  Part number is D1210

 

[datzenmike]

Springs are 55020-21007 and 21008.

[Dguy210]

Maybe D50 springs?

[datzenmike]

D50 are 6.5 coils and that one is 9. That sort of looks like an Hitachi symbol. Maybe Hitachi made the D50 springs? Three careful and accurate measurements on the springs and the spring constant can be worked out easily enough. The stockers would be around 370 lb/in. or near 100 at the axle. D50 are 500 lb/in or 130 felt at the axle. D50 are 6.5 coils and that one is 9 

[obrut]

8 hours ago, datzenmike said:

D50 are 6.5 coils and that one is 9. That sort of looks like an Hitachi symbol. Maybe Hitachi made the D50 springs? Three careful and accurate measurements on the springs and the spring constant can be worked out easily enough. The stockers would be around 370 lb/in. or near 100 at the axle. D50 are 500 lb/in or 130 felt at the axle. D50 are 6.5 coils and that one is 9 

I will get those measurements and post them, length, width and coil diameter?

[datzenmike]

Thickness of the wire (around 0.5") diameter of coil outside to outside is fine, number of coils not touching each other. In this case it looks to be about 8.3? coils. Accuracy is important. Ticker wire is stiffer than thinner, a larger diameter error makes the spring 'softer' and a higher number of free coils makes the rate 'softer'. Just make as careful a measurement as possible.

 

N American 510 sedans should be around 11.8" tall though this doesn't really allow for age sagging. The wire diameter is 0.56" and the coil diameter is 3.543". Probably center to center, just measure the outside and subtract one wire diameter to get center to center. Stock spring rate is around 98 pounds per inch (lb./in.) 

[Stoffregen Motorsports]

Design Products sells a bunch of bushings and solid mounts.

 

https://www.dpracing.co/datsun-510-rear-suspension-1

[obrut]

Thanks Mike, I will measure when I get home tonight.

 

Matt those look like the ones the ermish sell.  They don't seem to have the solid sleeve in the middle, unless its just not pictured.

 

[obrut]

Wire diameter 0.560"

Coils not touching  9

Overall height 11.75"

 

[datzenmike]

3 hours ago, obrut said:

Wire diameter 0.560"

Coils not touching  9

Overall height 11.75"

 

 

Need coil outside to outside diameter. Probably around 4"???

 

Starting to look like stock 510 rear springs.

[obrut]

Yes 4" outside diameter.  I was searching and found a old post that's said something about red stripe was stock rear and yellow stripe stock front?  Not sure on that and I can't find any other markings on them.

[datzenmike]

Rear coils are way stiffer than the front coils. The rear control arm acts like a cantilever. The spring is not over the axle but way in front of it. To 'feel' 100 pounds on the axle the spring has to be 380 pounds per inch spring rate, or 3.8 times

 

 

4" - 0.56" = 3.44" center to center. That works out to 377.48 lb/in. When divided by 3.8 your get 99.33 lb/in. I think I said it's about 98 so close enough. It's confirmed to be stock rear springs.

 

The formula for coil spring rate calculation is 11,250,000 (steel constant) X wire diameter⁴ / 8 X number of non touching coils X coil diameter center to center ³ 

[Tedman]

On 9/12/2022 at 6:01 AM, obrut said:

I have my complete rear cross member and suspension out of my 72 510.  I'm going to use stock Nissan control arm bushings but can't seem to find the mustache bar bushings, cross member mounting bushing, spring isolators and bump stops.  The only ones that I can find are poly, how bad are these on the street?  I'm building a street car that I'll use for autox too.

 

Just pressure washed it yesterday, bushing don't look bad, there just old.

www.RaceTEP.com sells poly rear crossmember mount bushings and upper spring insulators (in two thickness- get the thinner ones). Looks like you already have the mustache bar bushings. I am running all of these on both of my '72 2drs. Poly in the crossmember and mustache bar transmit noticeably more gear noise from the diff into the cabin, but they pretty much lock the crossmember and diff mounts firm up against the underbody which helps tame most of the squirrely behavior caused by the "floating" stock rubber insulators. This also adds some anti-squat to the geometry, also a good thing. For dual purpose street/autocross, I have always gone with poly and put up with the extra noise.  I found some bolt-in conical urethane bump stops that replace the stock rubber ones in the spring seats, but I'll have to go look up where I got them. TEP used to sell similar ones, but they were NLA last I checked. 

 

www.New-Datsun-Parts.com sells the stock rubber upper spring insulators. Your rubber crossmember bushings might still be useable if you elect to stay with rubber. They are fairly easy to press out for a better looksee. I have seen new old stock ones for sale in the not-too-distant past, perhaps on eBay. You can temporarily install the lower cup upside down to push the crossmember up solid against the underbody, and go for a drive to get an idea how much noise full poly will introduce.

 

I have solid mounts like DP Racing sells (Ermish sells DP stuff) and it used to take ~15 mins to install the crossmember and mustache bar plates before an A/X. This was back when I had all rubber bushings. This could be a good option, with all rubber for street, and solid mounted for track. If you have a slotted or adjustable crossmember, be sure to have your car aligned with the solid mount kit installed, and let it be what it is for street.  

 

Hope this helps!

 

 

[Tedman]

These guys have OE rear crossmember mount bushings, $259/pr and OE diff mount bushings for $145/pr. They also have a 20% stiffer version of x-member bushings on backorder eta spring 2023:

https://jdm-car-parts.com/

[Kaiden]

I don't suppose there are any more versions other than poly, at this point. Yes, Whiteline produces these as well. The density and efficacy in comparison to similar products, such as Energy Suspension, are unknown to me  Best DTF printer

[datzenmike]

The majority of people can't/don't drive hard enough to feel any handling or performance differences and any perceived are from the placebo effect. Racing applications do benefit from splitting these handling hairs for any gain. Street cars may find strange noise and vibrations that were damped by the original rubber ones.

[Icehouse]

I toss the rear bump stops in the trash.  On a lowered car they will hit even if you cut them shorter.  Solid mount is cool but makes the car so loud.  I daily drove my with just solid sun frame bushings.  So loud!  But did track nice. I want to try poly on the diff and Crossmember and solid on the arms and see how that does.  My buddies Z32 had aluminum bushings with a small Polly intermediate bushing. They were louder the stock.  I want some of those.  Not sure anymore makes them for our cars.  
 

Autox is mostly tires and driver.  Got both those you will do well. 
 

All those plus a bunch of plaques.  All in a 510 with stock brakes and a NA SR that made 121 to the wheels in the unlimited RWD class.