Cracking 904 converter pump drives

-
mo-cars

mo-cars

Well-Known Member
Joined
Oct 31, 2011
Messages
159
Reaction score
16
Location
Australia
Cracking at the pump drive slots on 904 converters is common . What have people done to help eliminate this.
 
My race convertor cracked at the snout.
Sent it to Turbo Action.
They gave me an option to replace it with a thicker gauge snout, but the pump has to be machined for it.
I opted out, since it was in the middle of the season.

That being said, I have only broken two 904 convertors in 30 years.
One from the result of a failed ring & pinion in low gear.
The other from a used convertor with a million passes on it.
 
TrailBeast said:
They make hardened parts to replace them with.
Click to expand...

X2 Compared to what is used now, the OE hubs were made of for lack of a better word, softer material. Also, if my memory serves me correct, the hubs at one time were machined square at the bottom of the slot for the pump lugs. Now all hubs are radiused slightly in that area.

There is nothing you can do, except replace the converter. Ask your converter supplier if they replace the hub when rebuilding converters (not all do), and if they do, do they use the hardened hub.
 
Thanks for replys . I've had a few performance converters built here in Australia and although they say the hubs are hardened and the slots have a slight radius , they still end up cracking .
I've asked them about using turbo actions solution and or reducing slot size but there just not interested .
So I am considering sourcing a hub from the US my self .

Any one heard of using the later gears and hub with machined flats .
 
Turbo Action will install the late model style hub with flats and they also sell the gears to match. I currently have 2 converters and 2 sets of gears with this option. ATI uses a hardened hub on their converters and they claim that they have never had any cracking problems.
 
Thanks for that info , do you know if the gear set with flats is a direct fit to an older model pump housing ( mine is 76-77 ) I looked through Turbo Actions site but see no email contact ! .

ATI do some nice gear , so might look into that also .
 
Sorry I took so long to respond. Yes, the gears drop right in to an older pump. They are not in the catalog or online. Call and talk to Paul Forte, he's the owner and these gears are something he does as a "Special" option. I actually have 3 sets and I am only using 1 right now. I have been experimenting with converters in my other cars recently and everyone else uses the standard hub. It would be nice if everyone would offer this option because it absolutely eliminates the problem with cracking.

Eddie
 
I rang and spoke to Paul at Turbo Action , Helpful guy , he explaned how using the flats and a thicker material is the ultimate cure , the thicker or smaller ID pump drive requires a small modification to the reaction shaft ( explaned in Turbo Actions Tech section ) .

I would love to go this way but for me it's a hassle , the speacial pump gears are expensive and getting the convertor made this way would be difficult in Australia .

If my car was more a daily driver I would more likely do it , but being a Street / race car I will be removing trans and convertor for inspection on a more regular basis.

At least now those that didint already know : there is a permanent cure for this problem available
.
 
You must log in or register to reply here.
-

Back
Top