This is going to be a very informative thread, in post 4 you have already answered a question that I had regarding the purpose of the flat ground into the PR valve. Invaluable info on differences of pump housings too.
I truly admire and respect all of you who read and look at all of this and it just makes sense to you.
Trannys scare me like Carnies do.
Had very bad experiences back in the 80s with 700r4 in my IROC and Vette. Seems like our 200r4 is stronger???
Sub'd to try to learn.
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I compare the 2004r and 700r4 the same way I and everyone else compared the GM 4 speed manual transmissions of the 60s and 70s. There were 2 types. Wide ratio ( greater drop in RPM during a shift) and close ratio ( lesser drop in RPM during a shift). The 700r4 is the wide ratio rear wheel drive 4 speed automatic transmission and the 2004r is the close ratio trans. It also has more of an overdrive. Like the 60s and 70s,the close ratio trans is the preferred choice of drag racers. The pathway that power flows through the 2004r is more efficient as well. I agree that it is a better design.I would state the 2004r is a better design. Stronger? That depends on who puts it together and what parts are put into it. I'll always think of the 700r4/4l60e as a truck trans with that low fist gear.
Here's how I check rotor clearence in the pump. I did a write up on it on my Facebook page last week. Use shim stock, very cheap, and a piece of glass or granite block. Stack shim rotor and pump up, see if the rotor is free, has drag, or is bound up.Steve V and Richard Clark have an alternate method of checking clearance and Steve can chime in with it if he wants to share it..
Here's the dataPump assembly: If you want to deviate from this setup, Steve V graciously did some recent testing of different spring/spacer stackups and posted his findings. Do a search or maybe he will post it later in this thread. It's not my information to copy into this thread. The short version: Higher RPM needs higher spring pressure to counteract inertia/centrifugal force. Do some searching if you want to go full nerd about it.
I didn't get into the 10 vane swap mostly because of the intended audience being some guy tinkering in his garage and not getting good odds of getting the clearance right or being able to adjust the clearance. And for the DIY guy there's no reason to change it from 7 vane IMO.
If you look at the 10 vane rotor you'll see the vanes aren't evenly spaced apart. This was done to make the pressure pulses happen at irregular intervals and reduce resonant frequency aka PR valve buzz. But I've personally not seen it be a problem.
Yes, very good info. I would like to add something. On the drain back holes, as was stated, drill the longer one on pump body in steps (starting with a bit slightly larger than current hole and stepping up until 1/4 as last bit) I have an extended 1/4 bit which makes it somewhat easier. I once drilled with 1/4 (not steeping) and the bit did not stay centered in hole, come through on the outside of body. Also I drill the cover hole to 5/16.Great thread and thanks for taking the time to put it together.