No More Cast Water Pumps?!
 

I am unbelieveably frustrated. My friend and I have bought 2 water pumps now and spent over $100 looking for the correct water pump with the cast impeller since the stamped one isn’t the correct shape, causes cavitation, and doesn’t pump water as efficiently. 5x racing and Fab9 both advertised their pumps as being cast, and we received stamped pumps from both vendors. Turns out even though moss and other major vendors like flyin miata used to carry the correct pump and many of these vendors have put information out there verifying the stamped pump is incorrect and the cast one is better, they have all switched to the cheaper and inferior stamped pump sometime recently. This is absolutely infuriating that these supposedly reputable brands (including gates) have decided to cut corners to sell inferior products for the same price. This seriously makes me reconsider the level of quality coming from these major miata brands recently.

Question is, who sells the correct cast impeller pump? I know there might be some protege vendors out there with good pumps.

I don't think it's by choice, the cast portion is just impossible to get due to supply chain issues. The cheap sweat shop that made the castings went out of business due to covid/prices/raw material shortage etc, so manufactures had to move to the stamp/spot weld sweat shop next door for your 30 year old water car's water pump.

In the grand scheme of things, no, I don't like it, but there's nothing the vendors can do about it. Last time it happened recently, we had to order a number of pumps before getting a cast version.

Yeah, what curly said. I truly don't believe there is any intent of deception on the part of the vendors. In the grand scheme of things think of how few miata/BP pumps still sell these days? If you're looking for the cast impeller just buy several pumps until you get an older stock unit with a cast one. I see several super off brand ones on amazon with cast impellers, maybe give one of those a try?

Also, this is probably more of an "Engine performance" category topic.

If you can find it, the one I got a long time ago that has a cast impeller was from the Japanese company Nissan Pump Co.

https://www.summitracing.com/parts/dcw-dc-8140

https://static.summitracing.com/glob...dc-8140_xl.jpg

I put this under this tab because I didn’t really see an area under general maintenance. But we actually found the correct pump at NAPA. My problem is these companies are showing the cast pump pictures and in some cases like fab9 and 5x, stating in their product descriptions that they carry the cast pump; that’s just false advertising. Flyin miata and many of these brands have also been preaching for years about how the cast pump is correct and to not use the stamped one. BP motors are still pretty common too. There’s still lots of NAs and NBs and proteges on the motor using these water pumps. The engineering schematics for these pumps are out there and it wouldn’t be difficult for a company like flyin miata to find another vendor that would produce the cast impeller pump.

Haha, yes, yes it would. Lol.

FM is going down the road of being another drop shipper who happens to sell a CARB certified turbo kit. They are not gonna invest in a bespoke water pump, when a stamped impeller gates is 30 bucks, for the 25 guys who just HAVE to have a cast impeller

I get that they’re pushing the product being a cast piece and have product images that show a cast part, but I guarantee you they found/find out from a customer that they’re no longer getting cast pumps, I’m sure their supplier likely didn’t inform them, and nobody is gonna open every single water pump box to make sure they’re all cast parts when they probably order 2-3 pallets at a time. Yes they should probably update their respective websites but probably 95%+ of people order a water pump through autozone, advanced, Amazon, or rockauto. On top of their relative market share of specifically miata/protege water pumps, the overall market share of Miata pumps to all water pumps sold is laughably tiny. I bet LS or Honda K-family water pumps outsell Miata pumps 100 to 1, at best. So naturally, costs get cut at our end of the graph first. Such is life ¯\_(ツ)_/¯

how hard is it to rebuild a cast impeller pump?

they do this all the time, no?
just get the correct seals...

Yeah but that’s my point is by shear numbers miatas far outnumber corvettes and K motors that are being worked on and modified, talking problem one of if not the best selling sports cars ever, BP motors are pretty prevalent. Maybe not more than LS motors but a huge market nonetheless.

i actually just talked to fab9 and they don’t check their boxes at all and they even casually mentioned how the stamped pump is 6% less efficient than the cast pump which is HUGE, flyin miata’s most current reroute kit makes a 8% difference in coolant flow over stock. On a car with a built motor like mine that could mean the difference between blowing a head gasket or running fine, especially on a track. I found the correct pump at NAPA but these major miata parts vendors are charging the same price for a cheaper stamped pump as they were for the cast pump they used to sell. Apparently this is all because gates decided to go with a cheaper design to save money.

My issue is that they aren’t updating the information to show the pump is not the cast pump. They’re showing the cast pump in pictures and some were advertising their pump as cast up until I made this post (someone must have seen this post and updated the fab9 website). I seriously doubt that gates would not talk about such a serious design change with vendors and when I spoke with fab9 they had already received numerous phone calls about this issue so THEY KNOW. It just seems they are trying to pass it off as the same old pump we have always been buying at the same price in hopes not enough people care or notice which feels extremely underhanded and bad business.

Even still, not opening your product boxes to verify the correct product is in the boxes and verify everything is there and hasn’t been damaged is part of quality control and good business. I used to work at a warehouse as a high schooler where all I did was unbox products being shipped out to vendors and verify the products were good and repackaged them for the vendors to receive. It’s not that difficult to pay a few employees to do that so you can ensure your customers are happy, or even do a random drawing of specific packages to verify for quality control.

Lmao, you think Gates calls up FM to tell them they are no longer sourcing cast impellers? You are vastly underestimating the size of idk, like....everything.

Fab9 is known to suck dick, don't buy or talk to them about anything. They aren't opening the boxes because there's a 99% chance they're drop-shipping them and haven't even seen them in years. The fact that anyone even contacts them anymore shows how devoid of brain cells the general car community is.

I'll agree that it sucks that people don't update their descriptions, but that's life. Just buy a normal one or if you're that worried about it, do an electric water pump or one of the other previous suggestions. There are likely bigger issues to worry about.

Gates probably doesn't know that Miatas exist.

i have heard the issues about fab9, used them as a last ditch because they seemed like the only option, won’t ever be buying from them again. My problem is all of these major miatas parts vendors, not just fab9, also seem to be going that direction and it’s incredibly frustrating. I had this issue with multiple major miata-specific vendors now. At least I have the correct pump from NAPA now.

Sir, you are drastically, enormously overestimating the amount of Miata’s out there. Also you clearly have no clue how many K and LS motors get “modified” which is also a totally irrelevant stat regarding a basic maintenance part like a water pump. I’d bet money Miata replacements are like .00001% of the market.

For example, in 2017(?) Mazda produced the millionth miata. Ever. Across all 4 generations, NA, NB, NC, and ND. Ford sells on average 3/4 of a million f150s EVERY YEAR. And has for the past 2+ decades. And that’s just f150s, not counting any other models of trucks let alone other cars, SUVs, plus every model from every other brand out there. So yes, it is far less than even a blip on their radar. They couldn’t give half a fuck about the design change on a Miata water pump, just like bill gates probably doesn’t bother picking up a nickel off the sidewalk.

I get you’re frustrated but you’re screamin into a void here man. If the stamped impeller is 6% worse and the reroute gets you 8% you’re still up 2! Be happy! Lol.

I ran into a stamped Gates in March this year from an Amazon seller. Asked around and got told it's a negligible difference (for my application). I understand the frustration, but that's just the way of the road like the others have said.

Also ran into this phenomenon recently with the (old) all metal design Stant SuperStat being phased out for a generic Motorad part.

If the cast impeller is a deal breaker just buy all of em you can get from NAPA. Heck, corner the market.

Did Mazda use the cast impeller water pump on all NA and or NBs? I don't remember back to 2018 when I replaced the one in my previous 2001. I just tore down a 56k mile MSM engine for a forged rebuild for my 28k mile MSM (2560 at 11-12 psi for last 12 years) and found a stamped impeller water pump. Looked like a higher quality unit but it doesn't make sense for the owner to have replaced it at that low mileage unless the original started leaking.

Mazda used stamped impellers. They designed a street car with poor coolant flow, not a race car.

NAPA is on my commute home, so I picked up a water pump, part 42134. It's made by Gates, and they give it the same part number.

Based on the impeller casting quality, I'm really not so sure this is a huge loss to Miatadom. The surface is very rough, I can't imagine that's conducive to flow. I'd almost rather have a normal stamped impeller if that was what was factory.

https://cimg0.ibsrv.net/gimg/www.mia...2c4829dd9b.jpg

https://cimg2.ibsrv.net/gimg/www.mia...8903cd1645.jpg

https://cimg3.ibsrv.net/gimg/www.mia...3c131d453c.jpg

Am I off base here in not being particularly impressed with this pump?

Yup, that’s the one you want. I believe the thought is it’s a 3D impeller vs 2D. I haven’t done any testing myself, but I think that’s where the benefit comes from. OP might want to contact Garrett to have a billet inconel pump made.