Builds Hammersaurus Lex - The LX470 gets tons

nukegoat

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I get stoked when I see this build pop up on the first page. Hope you get the steering woes sorted out.
Thanks. A pump rebuild kit was $7 on amazon (hmm) and it shows up Saturday. So i'll give that a shot first. If that fails, then I'll be adapting some sort of trail gear or PSC pump or something. The mounting pattern for the pump looks the same as all the GM TC pumps, but it may require spacing out from the engine block? @cruisermatt probably knows.
 

atnolan94

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Thanks. A pump rebuild kit was $7 on amazon (hmm) and it shows up Saturday. So i'll give that a shot first. If that fails, then I'll be adapting some sort of trail gear or PSC pump or something. The mounting pattern for the pump looks the same as all the GM TC pumps, but it may require spacing out from the engine block? @cruisermatt probably knows.
Dang bro never seen a 5x locked 80 or 4x locked lexus mall crawler :shame: so cool.
 

nukegoat

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So here's my rudimentary understanding of how these power steering pumps work..,

Flow control - To ensure that the pump isn't mashing out too much flow on the freeway, there is a large biased (from an "external" spring) spool valve that opens up at higher flow rates. How? the backpressure on the spool valve is controlled by an orifice on the output. The restriction in flow from the orifice creates some additional pressure on one side of the spool valve, opening it and effectively creating a system that limits flow (probably above 2k rpm or so).

This means the orifice size and the spring-external-to-the-spool valve are in relationship. Increasing the orifice size without modifying the flow control spring means that the flow control valve doesn't really start to operate until much higher flow rates. I assume that while idling, flow control is probably sort of irrelevant since there's not enough backpressure to overcome the spring bias (why would the OEM have the pump in a mild state of bypass even at idle?)

Pressure control - At lower flow rates where the biased spool valve remains closed because the orifice isn't restricting flow, the spool valve itself has an internal pressure relief valve that dictates the "blow off" pressure. This is the noise you hear when cranking the wheel all one way.

All of this goes out the window if the pump is riddled with contaminants, of course.

Fun story, though. I was trying to tap out the orifice since it's a brass pressed-in piece, and I ended up losing it. so now my "dual 7/64" orifice is more like a single 3/16". If my theory is correct, it should perform the same at idle but should be all weird and light when the revs are up a bit. And it'll be creating more parastic loss, which is great because these engines get too good of mpg to begin with.

Anyway, nothing ventured, nothing gained. The pump is easy to remove and install, I just wish I had a way to not waste 2.5 quarts of ATF each time. But oh well.
 

MongooseGA

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I used to have an old turbo-diesel S-class with a transmission on the outs. I had to do a fluid/filter change almost weekly to keep the trans shifting. Talk about a waste of ATF...


Still got 30 mpg though.
 

cruisermatt

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I just looked at all the Land Cruiser pumps and it looks like the 100 has it's own pump... that looks like a Toyota version of the CBR/Camaro pump. The return and pressure outlets are even at the same place. What I don't know how you're going to work around is the mounting, the bolt pattern is the same but the Camaro pump doesn't have through-holes like the toyota pump.
 

nukegoat

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I just looked at all the Land Cruiser pumps and it looks like the 100 has it's own pump... that looks like a Toyota version of the CBR/Camaro pump. The return and pressure outlets are even at the same place. What I don't know how you're going to work around is the mounting, the bolt pattern is the same but the Camaro pump doesn't have through-holes like the toyota pump.
Lil Mr drill bit. Also I wonder if the LX with VGRS had even flowier steering because it was like 1.8 turns lock to lock in parking lots and 3 or so on the freeway
 

cruisermatt

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You think you can just drill trough the pump housing on the Camaro pump? Its a good idea if there's nothing internal to hit. Try it
 

cruisermatt

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I wouldn't call them tabs, I would guess you'd get very close to the spinny bits if you drilled all the way though. Only one way to find out though
 

cruisermatt

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uhhh i don't want to but for the possibly of desecrating a Toyota engine with Chevy parts I may have to

Also, whats the 100 series pulley diameter?
I know you said the 100 pulley should fit this shaft (0.66"), I just ordered 10 different Dorman pulleys from various GM/Chrysler applications that will fit this shaft size, several with smaller diameters then the stock Camaro pulley (6.22") so in addition to finding a pulley for the pump to fit my application maybe there's a smaller pulley that will work with it on the 100 which should help low-RPM performance a bit.
 

cruisermatt

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i think you're good to go to drill through it. Here's a pic of the back of the pump for a duramax application and it looks like they tap the back and use a bolt on the rear in the Sierra. Buy me a replacement pump and I'll drill mine with Mr Bridgeport so the holes are straight and I'll send it to you? I really want to see this on a 2UZ

s-l1600.jpg
 

nukegoat

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uhhh i don't want to but for the possibly of desecrating a Toyota engine with Chevy parts I may have to

Also, whats the 100 series pulley diameter?
I know you said the 100 pulley should fit this shaft (0.66"), I just ordered 10 different Dorman pulleys from various GM/Chrysler applications that will fit this shaft size, several with smaller diameters then the stock Camaro pulley (6.22") so in addition to finding a pulley for the pump to fit my application maybe there's a smaller pulley that will work with it on the 100 which should help low-RPM performance a bit.
We would need a 5" or potentially smaller pulley...

I'm gonna get iterative on this. Tomorrow I'll run the stock pulley with my 'i lost the orifice fitting' mod, which if my understanding is correct will make the pump noisy but boosty at higher rpms. It should still suck at idle.

Then maybe we drill the cbr pump. I can put it in my drill press since we are making a through-hole, but what part number gives me a 5" or smaller pulley? Since you ordered 10...
 

nukegoat

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i think you're good to go to drill through it. Here's a pic of the back of the pump for a duramax application and it looks like they tap the back and use a bolt on the rear in the Sierra. Buy me a replacement pump and I'll drill mine with Mr Bridgeport so the holes are straight and I'll send it to you? I really want to see this on a 2UZ

View attachment 2173494
You just want a Sierra pump don't you? Is this a trick to fence your eBay Camaro pump?
 
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