How to: Freshen your used 200-4r pump

[Mike T]

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.

 

[SS/GN]

Great thread and thanks for taking the time to put it together.

 

[jimski]

NICE!

 

[SpeedRacerX]

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.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[TexasT]

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.

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.

Sent from my SAMSUNG-SM-G900A using Tapatalk[/QUOTE

 

[Ttype6]

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.

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.

 

[INEEDAGN]

Better late than never! I consider it done but I will proofread this all with fresh eyes tomorrow.

As always, I welcome your feedback/constructive criticism

 

[Steve V]

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 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.

The pump I was working on was from a name brand vendor and was way too loose. Hence why I do all my own builds/work and somehow landed up doing this as a full time job...lol

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[Steve V]

Pump 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.

Here's the data

Stock BRF dual spring
@1.5 = 28.2lbs w/sonnax spacer 39.2lbs
@1.225= 54.6lbs w/sonnax 65.8lbs

NOYOYO spring 5500 rpm kit
@1.5 = 19.8lb w/sonnax 34.8lbs
@2.225 =62.6lbs w/sonnax 80.4lbs

NOYOYO w/ BRF inner spring
@1.5 = 26.8lbs w/sonnax 47.6lbs
@1.225= 77.8 w/sonnax 97.8lbs

 

[Lil Truck]

Thank you for your time and detailed procedure information! This should be in the sticky section!

Is there any negative to going to a 10 vane rotor? I am currently overhauling an 84 BQ and a TAF.

 

[TexasT]

costs more. Could lessen pump volume.
the slide is more robust and can smooth out the pressure out put.

 

[Lil Truck]

costs more. Could lessen pump volume.
the slide is more robust and can smooth out the pressure out put.

Thanks Rich, I had already purchased a 10 vane kit before reading this thread thinking it was the the best way to go with a worn 100k mile pump.

 

[TexasT]

Not a bad way to go. But I am not sure it is needed. Lots of people still running the seven vane setup. Be sure and check the clearance on it and the slide.
much more important is to upgrade to the hard rings and upgrade the slide spring. I used a sonnax. I was told after I.got it together to put the original small spring into the new sonnax and install like that.

 

[Ttype6]

The 10 vane rotor will produce less pulsation at lower RPM as compared to the 7. This is when it will outshine the 7 vane. The 10 vane rotor was first used in the 700R4 transmission which was used in alot of trucks. I think it was implemented because of its low speed pressure improvement for all of the trucks that used them,which would be good for plowing snow.

 

[INEEDAGN]

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.

 

[Lil Truck]

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.

Is there any other clearance to check than the side clearance of the rotor and slide? I am using the machinist 9x11x2 granite block for surfacing and plastigage for clearances.

 

[INEEDAGN]

Nope. I mean, besides checking the fit of the bushing when you install it etc.

If the pump vanes have flat spots worn in them where the rings contact and/or the slide has all the parkerizing worn off, there will be too much clearance between vane and slide but that's more of a common sense visual check than an actual measurement.

 

[INEEDAGN]

The b grade 9x12 granite blocks from Shars are like $20 plus shipping and are light enough for regular shipping and easy storage and let you use regular sized sandpaper. It might be a bitch to sand something the size of a pump housing on it but you can pull it off especially if you're just verifying flatness and not trying to sand out moderate imperfections. I didn't check if 12x18 is standard shipping or not but 12x18 paper can be had off the internet without too much hassle. The 18x24 paper has to be custom ordered/cut from places that make custom sanding belts for large industrial belt sanders. If you plan to glue it to the stone you should use resin bond paper as it will peel off cleanly and not leave you cleaning it off with a razor blade.

And the accuracy of "b" grade is considered sloppy by machinist standards but at +/- .001 it's probably more accurate than the sandpaper you're using on it. My 18x24s came with a cert letter (that I don't blindly trust) but these 2 particular stones were supposedly about half as far out of flat than the advertised tolerance and it's a gradual .001 high spot in the dead center of the stone in all cases. It's not as good a method as milling them in a Bridgeport but it's a damn leap ahead of assembling it without checking and it's the method many independent trans shops use all over the country for regular passenger use. Way more cost effective both in investment and refurb time.

 

[Lee O. Thompson]

Great thread and thanks for taking the time to put it together.

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.
Concerning the number of vanes--I am now a firm believer in nothing but a stock 7 vane GM rotor. I have had 2 10 vane rotors break--destroying both pump halves. This past summer I had 2 friends trans with GM (not aftermarket) rotors in them. Drove me and them crazy. Dave Huseck was kind enough to talk to me many times about my problem of pressure fluctuation. Once I told him I had a 13 vane rotor his exact words were "get rid of the 13 vane and put a stock 7 vane in and all your problems will go away" and they did. Pressure was all over the place-even cooler line pressure would drop from 55 @ min. TV to near 0 @ full TV. Most of the bushings were worn from lack of lube. I did NOTHING but change the rotor. Hope this helps someone. BTW, INDEEDGN what max. line pressure do you LIKE?

 

[INEEDAGN]

Max line pressure will be whatever pressure the blowoff spring opens at. Usually 260-275ish. You can get a higher pressure spring that allows over 300 psi from the trans vendors (and it's a better quality spring) but it's overkill for "guy in his garage".

Now, how soon the pressure gets to max (if at all) is a function of the PR valve system and the many, many factors that influence it. Starting with whether the valve itself is modified, you also have PR spring and boost valves there, then you have the TV valvetrain's influence on it, which in itself can be altered in many ways, good or bad. Don't forget the line bias valvetrain's influence if it's not blocked (usually is for performance use).

The tv system has enough factors to almost be its own thread or at least a well thought out post. Proper setup and geometry will make or break the whole trans.