200r4 pump modifications?

[Pelle]

Hi!

Got a 7 van pump that has seen som converter parts flying by so I bought a another used body that had minimal wear and though to move the high performance parts and a new 10 van pump but saw a difference in the housings that I'd like to know more about.

The pump that came with the tranny has 088 on the pump housing while the pump I bought as an replacement is made 1984.

The above is the image from the used one I bought that has good pump surfaces.

The above pump was the pump that came with the tranny and is a high performance version.

The holes goes into the pressure side on the van pump so my question is, is this a normal mod to do to get more fluid out or is this because the pump has the 088 stamping on it?

Is this mod necessary?

The pump that came with the tranny has a hole that is 11.5mm in diameter and the used pump housing has a hole that has around 7.5mm

Any hints and suggestions is highly appreciated.

Best regards
Pelle

 

[Steve V]

Pellie,

Not sure about that maybe someone who knows will chime in.

There's a nice sticky up top,read it has info on pumps. Good Luck!

 

[Pelle]

Hi Steve!

Well nothing that hints anything about this passage as far as I can understand.

Googled some as well and can't find any information about this.

 

[bison]

Buy a known good assembly from one of the vendors. You can't just slam a pump and rotor in these. If you do you will have problems

 

[Steve V]

I disagree,trash the pump with the unknown mod get an unmodded one. Do your research and mod it the correct way(plenty of info on this site..search) by a CK book or ATSG and have at it. Or give someone who knows what they are doing you money and learn nothing It's up to you.

You have to measure the pump silde and get a rotor the same(or damn close) when going fron 7 vane to 10 or 13. If you just slap it in then you are probably gonna have issues.

 

[Pelle]

Steve.

The new 10 vane pump I bought came with a new slide so I hope they have it correctly made, I'm more worried about the clearance between the slide/rotor and the housing. Will measure it today and hope it's within specs. (other wise I'll buy a new one from TCI or from GM... Hope not since I'm not made of money )

Btw got the ATSG book and another thicker one so should have enough info there, the problem is that the trans was bought from a very reputable builder that has made a lot of mods to the tranny so I'm more concerned with what happens if I do not make the pump the exact way he did it.

Btw for anybody out there..... if a tranny builder tells you to hock up your lockup function as soon as 4th gear goes in with no throttle or vacuum control and when asked "Is this really OK???? at FULL THROTTLE????" and you get the answer that the tranny will take it no worries you should walk away.......... (The tranny can take it BUT...... the converter will not and what happens when the converter pukes out metal?)

 

[SSedan64]

ASTG manual shows a Cup Plug in that hole #241 Pg. 62
I have an 088 Cover, it has the Plug installed.
Not sure what kind of Mod that would be. Looks like Line Pr. would shot.

 

[Steve V]

You really shouldn't be getting into 4th at WOT. Sounds like he has it setup to lock as soon as the 4th pressure switch trips at the shift. I had a car setup like that and it was annoying around town.

If you need to talk to a reputable board builder/vender call David Husek he will walk you thought the pump and anything else over the phone whether or not you buy his parts.

Pump...get that pump rotor clearence issue 1st,then if its ok use at a min .500,.531,.555 boost valve,teflon bushing,drill the drain back holes for the seal,billet rings and strong slide spring,pink/purple PR spring ( summit 200/700R4 search) and have at it. 200's like pressure.

 

[Pelle]

ASTG manual shows a Cup Plug in that hole #241 Pg. 62
I have an 088 Cover, it has the Plug installed.
Not sure what kind of Mod that would be. Looks like Line Pr. would shot.

Hi!

There was a plug there but I removed it to show the differences in hole size from the line pressure. (It's from the pressure side of the pump)

 

[Pelle]

You really shouldn't be getting into 4th at WOT. Sounds like he has it setup to lock as soon as the 4th pressure switch trips at the shift. I had a car setup like that and it was annoying around town.

If you need to talk to a reputable board builder/vender call David Husek he will walk you thought the pump and anything else over the phone whether or not you buy his parts.

Pump...get that pump rotor clearence issue 1st,then if its ok use at a min .500,.531,.555 boost valve,teflon bushing,drill the drain back holes for the seal,billet rings and strong slide spring,pink/purple PR spring ( summit 200/700R4 search) and have at it. 200's like pressure.

Hi Steve!

I've done the drain back mod on the pump since I read up on it on several places, I think my bost valve is larger than normal BUT it got a few nicks on it :/. Had a Teflon busing witch I ruined today when I saw that the merging places was positioned wrong and tried to take it out so I need to buy a new one on Monday. (Got it for free so not too mad at myself). Billet rings or steel rings purchased with the pump.

Will look into the spring and boost valve to make sure.

Would the larger pressure line in the pump be for some kind of shift kit?

 

[bnewsom]

You really shouldn't be getting into 4th at WOT. Sounds like he has it setup to lock as soon as the 4th pressure switch trips at the shift. I had a car setup like that and it was annoying around town.

If you need to talk to a reputable board builder/vender call David Husek he will walk you thought the pump and anything else over the phone whether or not you buy his parts.

Pump...get that pump rotor clearence issue 1st,then if its ok use at a min .500,.531,.555 boost valve,teflon bushing,drill the drain back holes for the seal,billet rings and strong slide spring,pink/purple PR spring ( summit 200/700R4 search) and have at it. 200's like pressure.

I used the 4th gear only lock-up set-up on a previous application. I just wired a rocker switch inline so that I could turn off the lock-up in situations where it was not wanted. I used a lighted switch with a green LED wired where it would light when the converter was locked. It was dim enough to not be a distraction. Some folks use a vacuum switch to make it an automatic event.