Lowering an 810

[6spd_monte]

I know this has been discussed a few times already, but I couldn't quite find the info I'm looking for in my searches.  Probably my eyes are glazed over from reading too much Internet.

 

I'm looking to lower my '79 810 coupe.

I understand that it's pretty straightforward to do the front struts using the split-collar method so that's what I'm planning to do.  

Here's where I need a bit of guidance:

1) Can I lower the rear using the same method as the front?

2) Am I correct that the collars I need are 2 inch ID for the front?

3) What size collar will I need for the rear struts?

 

I would go out and get the measurements myself but the car is 1400 miles away at the moment and I'm trying to get everything in order from a distance, so to speak.

 

Thanks in advance for the help 👍

 

-James

[Draker]

Never lowered an 810 but it is similar to a 510. Get shorter springs or cut a few coils. New shorter rear shocks. Reinstall and now your lower. 

 

also you might find this thread useful if you want to upgrade to disks.

 

https://forums.hybridz.org/topic/65097-project-datsun-810-has-begun/

[datzenmike]

  I would drive it home as it is and do the lowering and order the rims and tires there. Way less headache. Make sure your new rims don't move the new tires outwards or body will rub the tread.

[yenpit]

I did the split collar thing some years ago, worked well, would do it again!  iirc I also cut off maybe a 1/2 coil.  What WILL limit how low you go is the wheel tire combo.  I had Z 14in steelies on the 510 (originally 13in) with some slightly wider tires than a stock Z & the stock spring perch (sitting on top of the split collars) would rub the tires if placed too low........nothing to do with steering geometry or suspension travel, simply brought the spring perch down & contacted the tires.  I don't like super low cuz you WILL lose decent driveability, but the 510 still had a nice lower stance.  If you want LOW, go coilover, cuz the coilover springs & perches are very narrow, thus rarely make contact with tires!

 

I have no idea what diameter strut tubes would be on an 810!  The later Maxima's still used the L24 up into the early 1980's, long after the Z's went to the L28, so the 810 could have the smaller 240Z strut tubes OR the later larger diameter 280Z strut tubes...........if nobody can give you an exact answer, WAIT TO BUY the split collars!  Sounds like a cool project! 😎

[datzenmike]

They are all 2". Don't know of a Datsun that doesn't have 2" OD strut tubes. The 510 does, zx does, my 710 did and I have Maxima struts now and they are.

[6spd_monte]

 

16 hours ago, datzenmike said:

  I would drive it home as it is and do the lowering and order the rims and tires there. 

Normally I would agree, but it would need tires anyway before I make the trip.

 

6 hours ago, datzenmike said:

They are all 2". Don't know of a Datsun that doesn't have 2" OD strut tubes. The 510 does, zx does, my 710 did and I have Maxima struts now and they are.

 

So they're all 2", front and rear?  I could've swore I read someplace that the rears were smaller, like 1.6" or so but I can't find that info again.  

Anyway, that's why I'm here asking.

I'm pretty sure (but not 100% sure) that the 810 shares rear struts with the 280ZX, if that helps.

 

7 hours ago, yenpit said:

I did the split collar thing some years ago, worked well, would do it again!  iirc I also cut off maybe a 1/2 coil.  What WILL limit how low you go is the wheel tire combo. .... Nothing to do with steering geometry or suspension travel, simply brought the spring perch down & contacted the tires.  I don't like super low cuz you WILL lose decent driveability, but the 510 still had a nice lower stance.  If you want LOW, go coilover, cuz the coilover springs & perches are very narrow, thus rarely make contact with tires!

Sounds like a cool project! 😎 

 

I understand that the spring perch vs tire will be the limiting factor and I'm ok with that, and thanks - I think it'll be pretty cool too!

 

Maybe I'm a glutton for punishment, or too ambitious for my own good, but I'm going to do my best to make this happen.  

I'll do the measuring before I commit to anything that might derail the trip.  If something looks like it isn't going to work out right, I'll just buy some new tires for the OE wheels and drive it like that.

 

I appreciate the tips and advice, thanks!

[datzenmike]

Yenpit and I were talking about the front struts, rears weren't mentioned. Yes install new tires on old rims, buy new rims later. There are only a few ways to get the rim/tire right for a pleasing fit. This shouldn't be done in a rush.

[banzai510(hainz)]

he;s gonna do what hes gonna do with or w/o your opinion

I think ,aybe a +10 would be tter incase you want to slam it down but they have 195/4515 tires that might sqeek by if needed

yes don't rush

 

I had Panasports from a 810 that was abandon in parking lot I swear they was 0 offset but car was not lowered. I sold them for $500 with tires  think they was 205 frt/rear or 205/ frnt/225 rear . 55 series??

 

But I think 810s came with 14 so the usually up size is 2 so a 16in rim might be best to fill in the gaps and then lower

 

maybe talk to a 810 guy for more expertise

[datzenmike]

5" x14" even the optional alloy rim was 14" but 5.5" wide for wider tires.

[yenpit]

On 5/27/2020 at 6:36 PM, datzenmike said:

They are all 2". Don't know of a Datsun that doesn't have 2" OD strut tubes. The 510 does, zx does, my 710 did and I have Maxima struts now and they are.

 

The 240Z had 2in diameter strut tubes, the 260Z & 280Z had approximately 2-1/8 diameter strut tubes, thus the 2in collars don't fit................we need to know when buying coilover kits!  That's why I question what the later 810/Maxima had......??  My boss had a handfull of 2in lower coilover collars laser cut to try to save a few bucks, which bit us in the rear cuz we like to use the 280Z strut tubes on our vintage race builds, as there are more strut inserts available for the slightly larger diameter tube!  Now he listens to me more when I say "nuhhh uhhhhh, they are different!" 😆

[datzenmike]

No one uses the 280z struts because I've heard the spindle angle is differently wrong but maybe it's the strut tube diameter that's wrong. Either way they aren't much of an upgrade as the rotor isn't vented. 510/610/710/A10/S10/S110/S12 /Maxima and 280zx and 300zx are all 10 degree.

 

 

 

 

[yenpit]

Correct Mike!  For 510's, you can only use the later 280ZX front struts, NOT the earlier Z car, cuz the camber angle is not good for a street car.  I have a 510 SCCA racer in FL using 240Z front struts, cuz he actually WANTS that camber angle for track use!  We use the 280Z struts in our 240Z vintage race builds for a couple reasons........more choice of strut inserts/shocks (diameter difference) & the REAR outer stub axles are apparently a l'il stronger (the 240Z outer stub axles have been known to shear/break, so we take no chances!) 😐 We also use T3's "stepped" negative camber bump steer spacers (not the simple street car spacers) on our Z cars, for that needed excessive negative camber up front!

[datzenmike]

TJ what is that angle???

[yenpit]

.......again, I'm questioning the diameter of the early 810 strut tubes, cuz he wants to PRE-order the split collars.  To me, they could be the early 2in or the later 2-1/8in......I simply don't know enough about the 810's!

[yenpit]

 

1 minute ago, datzenmike said:

TJ what is that angle???

 

I don't have the angle figures in front of me, but you are correct that the ZX work on the 510's.........the earlier Z car do not, for street use 😁  I CAN get the Z car camber angle if you want it................

[datzenmike]

Just curious. Most are 10⁰. The odd time someone says they have 280z struts and will they fit. I say no but can't say exactly why.  

[yenpit]

MANY people mix up the 280Z vs the 280ZX applications!  It's mind boggling how often I have a 510 guy ask me if I have any 280Z front struts for sale............I simply correct them saying it is the 280ZX strut that they want!  I have even had someone go buy the 280Z struts somewhere else, after I told them to buy 280ZX!!  A VERY ROUGH strut tube vs spindle (camber angle) measurement is the 240Z/280Z is approximately 105deg vs the 280ZX is approximately 100deg, so approximately a 5deg difference.  In other words, the strut tube is straight up n down 90deg to the table, the spindle shaft angles DOWN approximately 15deg on the 240Z/280Z vs approximately 10deg on the 280ZX.  Hope that makes sense........... 🙄