720 power steering on a 620

[newguy]

I was playing around with a buddys 720 with a Z24 engine that had power steering in it. I got to lookin and got to thinking has anyone on ratsun played around with maybe setting up a 620 with power steering? They both have solid steering colums to the gear box. (my 620 wasn't there to closely compare)

Can it be possiable? :blink:

newguy

[elmerfudpucker]

Well If it is I have a complete power steering setup for ya. PM me if ya want it otherwise it goes to Canby.

[newguy]

Well If it is I have a complete power steering setup for ya. PM me if ya want it otherwise it goes to Canby.

I don't want to buy something I can't make work. Within an hour or so of my place there are alot of 620 and 720 in a few yards. One guy gives me cheap prices on this stuff. ($10 for a ka oil pump)

But thats why I'm asking fellow ratsuners to see if its possable.

[datzenmike]

Check the 620 and 720 boxes... the pitman arms are on the inside of the frame on the 620 and the outside on the 720. Also 720 don't have solid one piece columns and boxes like the 620.

 

Some things to think about....

 

How will you mount the pump on an L series motor?? The Z24 pump fits where the L fuel pump is.

 

Perhaps an electric fuel pump and the pump/mount and idler pulley off a 280z?

 

The one piece 620 column/box won't work, which leaves a 720 column with collapsible spline and small u joint.

 

You may be able to use the 720 steering linkage to solve the sector shaft being on the outside of the frame rail.

 

 

I made my own mount for the steering pump and used a 280z power steering box and a 720 column. It has the sector shaft inside the frame just like the 620. The 620 pitman arm fits the sector shaft spline as well. The 280z box looks like this: Just remove the 280 pitman and slip the 620 on. (it faces 180 to the rear)

 

[newguy]

Check the 620 and 720 boxes... the pitman arms are on the inside of the frame on the 620 and the outside on the 720. Also 720 don't have solid one piece columns and boxes like the 620.

 

Some things to think about....

 

How will you mount the pump on an L series motor?? The Z24 pump fits where the L fuel pump is.

 

Perhaps an electric fuel pump and the pump/mount and idler pulley off a 280z?

 

The one piece 620 column/box won't work, which leaves a 720 column with collapsible spline and small u joint.

 

You may be able to use the 720 steering linkage to solve the sector shaft being on the outside of the frame rail.

 

 

I made my own mount for the steering pump and used a 280z power steering box and a 720 column. It has the sector shaft inside the frame just like the 620. The 620 pitman arm fits the sector shaft spline as well. The 280z box looks like this: Just remove the 280 pitman and slip the 620 on. (it faces 180 to the rear)

 

 

 

WOW thats the info I was looking for! Sweet I knew someone out there has played with this idea!

As far as mounting of the 720 pump goes I was going to mount it down where the smog pump was sitting at. (drivers side) And then use the second groove on the crank pulley to run it. First one runs the alternator and water pump. Just fab up a bracket. pump wasn't my issue. The power steering box is where I was scratching my head. I'll go take a second look and the 720 colum I looked at. I could have sworen it was solid with no U joint or spline. Could there be a few years there where they made the colum solid??

I'm sure I'm just wrong but please humor me.

newguy

[74datsun620]

WOW!!!!!!!!!!!! Great stuff.

[datzenmike]

I used a pump from a Hardbody and made a mount down where the air pump was originally. The problem is the steering box is VERY close and there isn't much room for it, this is why the 720 box was re designed with the sector shaft on the outside of the frame rail.... to leave more room near the engine. The 280z box was close but not a perfect fit.

 

Here's a picture of how the pump used to look...

 

 

.

[newguy]

I used a pump from a Hardbody and made a mount down where the air pump was originally. The problem is the steering box is VERY close and there isn't much room for it, this is why the 720 box was re designed with the sector shaft on the outside of the frame rail.... to leave more room near the engine. The 280z box was close but not a perfect fit.

 

Here's a picture of how the pump used to look...

 

 

.

 

did you ever get it up and workin? All in all. Does this setup require you to swap the steering colum? If so did it bolt up or did you have modify it?

newguy

[datzenmike]

Had the pump on the L20B until I retired it, so for 4-5 years and never touched or added fluid once.

 

The 620 steering box and column is on piece and so any power steering system will require it to be replaced. Probably a good idea anyway as the 620 column is a hold over from the earlier 520/521 and is likely to impale you if in a front end collision. The 720 column has a telescoping spline and a small bend with a u joint making it much more safer. It also has a rag joint to reduce noise and vibration.

 

The 720 column fit more or less but the plate doesn't cover the hole in the 620 floor perfectly. I could have done a better job. I think I swapped the 620 cover and signals onto it but had to wrap some cardboard around the end so the clamp would tighten up and hold the assy in place. Shortly after I swapped the 720 signal arm on as it also contains the headlights switch and the wiper switch arm and pulse delay is on the right side. Headlight and wiper switches are poorly placed and a pain to reach on the 620 dash.

 

720 headlight signal switch with variable pulse delay wiper control on right.

 

 

Shortly after this I replaced the front suspension and was able to replace the 280z power box with one from a Hardbody, which mounts the sector and pitman arm outside the frame.

 

This is the Hardbody p/s box.

 

Since then I have swapped in a Z24 with power steering pump so I swapped in the power box as well as the old Hardbody started to leak. Just before the motor went in I plumbed the hard lines in. The rubber hose is on the low pressure return line. The input pressure line has to be able to handle 1,000 PSI!

 

 

.

[]2eDeYe]

Nicely done. You should drill and sleeve the frame for that lower rear bolt hole. :cool:

[newguy]

how come no one has done a write up on this topic? Clearly a few people have done it and even took some nice pictures. There are even a few choices when it comes to which pump and P/S box is preferred. Mike in your opinion which P/S box felt better while driving? Hardbody or 720? And do you need to match pump with box to get a good feel for the steering?

sounds like swaping the colum is required but most benifical.

Are there any other setups for the 620 that could be done without significant fabbing involved?

[datzenmike]

how come no one has done a write up on this topic? Clearly a few people have done it and even took some nice pictures. There are even a few choices when it comes to which pump and P/S box is preferred. Mike in your opinion which P/S box felt better while driving? Hardbody or 720? And do you need to match pump with box to get a good feel for the steering?

sounds like swaping the colum is required but most benifical.

Are there any other setups for the 620 that could be done without significant fabbing involved?

 

The 720 and Hardbody boxes were virtually identical. The 720 one I used with the stock 620 torsion bar front steering and suspension. The Hardbody box was with the 'Yoda SAS so can't really compare them. I would guess the same as the trucks they were from were very similar.

 

The first pump was Hardbody with the reservoir mounted on the fender. The Z24 engine came with a self contained pump and reservoir mounted on the head and an adjustment idler wheel. The Z24 pump looks easier to mount.

 

 

Another possibility is a pump off of a 280 z/zx car. It's an L series motor so all the parts should fit the 4 cylinder too. If you do get all the high pressure hard and flex lines. 720 truck ones may be a better fit as they go to the same front steering box location. The 280 box is mounted much further back behind the front wheels. You can cut and flair the hard lines to fit, I did.

 

The power steering box does not care where the pump pressure comes from... could be a GM pump... it will still work. Pumps can put out over 1,000 PSI. Once installed I found that the truck was much more 'lively' on the highway. I had occasion avoid an accident and was easily able to throw the truck into the other lane. Unbelievable! The only effort required was to jerk the steering wheel over. Parking is finger tip now and around town driving less fatiguing.... and this with a 3,600 lb 620 with 12.5 X 33 tires too.

 

.

[newguy]

mike do you think you might have the time to do a write up on" how to" with power steering on a 620? If I had the money right now I would do it but unless ratsuneers are willing to domate some parts this idea will have to go on the back burner for a month or so for me.

I think i'm going to go with a full 720 setup. I like the pump and reseivor combo idea. Sounds like I will need a 720 steering colum and steering pump.

which raises another issue....wiring. The new colum will have to be wired up. Does someone have a diagram? Or can draw one up for me?

[budsaipan]

Im in the process of doing this. I'm using a 280zx steering gearbox and a steering column from a 720 4x4. It has tilt steering. I had to cut off a plate in the steering shaft so that it will go through the firewall. Then drill near the steering wheel so I can bolt it to the stock location. As for the gearbox, I had to grind one of the bolt holes so that it will bolt on to the stock location.

 

I just pulled a electric powersteering pump and reservoir from a 2nd gen mr2 at the junkyard.

[budsaipan]

720 or hardbody steering box will NOT bolt in a 620 chassis. The box is outside of the chassis whereas the 620 are inside.

 

Datzenmike,

 

Isn't your truck using a 720 chassis with 620 body? Might want to clarify this since the post seems a bit misleading on

the gearbox parts.

[newguy]

Im in the process of doing this. I'm using a 280zx steering gearbox and a steering column from a 720 4x4. It has tilt steering. I had to cut off a plate in the steering shaft so that it will go through the firewall. Then drill near the steering wheel so I can bolt it to the stock location. As for the gearbox, I had to grind one of the bolt holes so that it will bolt on to the stock location.

 

I just pulled a electric powersteering pump and reservoir from a 2nd gen mr2 at the junkyard.

 

 

great info, could you do a write up on this? I know alot of 620 will benefit from this. So everyone will need a 720 steering colum, 280zx power steering box, pump is your prefference

[budsaipan]

Yup I'll see what I can do. I still have to work out the pump deal.

[elmerfudpucker]

720 or hardbody steering box will NOT bolt in a 620 chassis. The box is outside of the chassis whereas the 620 are inside.

 

Datzenmike,

 

Isn't your truck using a 720 chassis with 620 body? Might want to clarify this since the post seems a bit misleading on

the gearbox parts.

 

Odd, never noticed that, mine is on top mostly, but it does go down on the outside!

[datzenmike]

720 or hardbody steering box will NOT bolt in a 620 chassis. The box is outside of the chassis whereas the 620 are inside.

 

Datzenmike,

 

Isn't your truck using a 720 chassis with 620 body? Might want to clarify this since the post seems a bit misleading on

the gearbox parts.

 

Oh I'm sure that the 720/Hardbody box will fit the 620 frame, it would be on the outside and useless. For all intents the 720 frame is identical to the 620. Yes I have a 2wd 720 frame but did have the 280z box mounted on the inside at first. Later I swapped to the 720 and then the D-21 on the outside. I could do this because I had done a solid axle swap and had cross steering. When the box moved outside the frame all I had to do was lengthen the steering rod. This isn't an option with a stock 620 steering set up.

[budsaipan]

Datzenmike,

 

Wouldnt you have to cut the tabs (nuts) where the bolts go into on the frame if you put the box outside of the 620 frame? If not, I might consider changing it to outside so that I can have more room for the AC pump.

[datzenmike]

You can just swap to the outside because it will move the pitman over several inches. When connected to the steering you will have trouble turning to the left and may run out of turns. Hard to explain.

[]2eDeYe]

Because of the center link style of steering on the 620, moving the box outside the frame rail will cause steering geometry issues. You would have to lengthen the center link and shorten the drivers side tie rod. I'm sure this would induce some quirky steering at the least.

 

Something like that Mike? :D

[datzenmike]

Steve, much better said! The 280 box and 620 pitman arm worked perfectly on the inside. The 720 box had a different spline and the 620 pitman arm wouldn't work. The fix?? I took the 280 box apart and swapped the sector shaft into the 720 box... it worked!!!

 

Damn this was years ago maybe 10.

[]2eDeYe]

You are a pioneer amongst Dattoheads :lol:

[datzenmike]

This was way before ratsun, before NYDE and before my computer. I thought I was all alone with my 'sickness' for Datsuns.