Recently heard about shaving down the gasket surface to allow less clearance between the water pump rotor and timing cover. This supposedly will allow for more flow. i don't know exactly what the overall spacing should be between the two, but the stock pump had over .100". Do aftermarket pumps rotor depth change at all from stock? has anyone heard about or done this modification?

 

Nope and I did hear that the stock 8 blade version usually called A/C pump flows the best. There are some out there like the Milodon one that is the same eight blade with a anticavitation plate that are rated at high flow.

 

Never heard of it. It will change the alignment of your accessories.. PS,Alt,air, WP pulley would have to be shimmed

 

just shim the water pump pulley not a big deal, and yes i was planning on using the eight blade pump. can i get a pulley for my pump that will run with a serp. belt instead of a v.

 

Yep look into the March serpentine setups.

 

I'm not too sure I'm convinced this is a good idea. I would bet you money that the limitation in waterflow is not the pump, but the thermostat. Do you have any good basis for modifying the pump, or is this just something "going around the internet?"

 

i read it in a book. im using cast heads with about 10:1 sr and wanted to look into some cooling mods. im not sure if it would be overkill with the eight blade pump and the cover bieng milled, it was just a thought.

 

You really shouldn't have any trouble keeping it cool with 10 to 1. A good stock system should really be all you need. I wouldn't mess with a working system. Unless you are having trouble. Sounds like a neat trick, but why is it unheard of, if it is so great?

 

The way the impeller is pressed onto the bearing can be significantly off in some pumps. This is a manufacturing defect, IMO. If there is too much free space between the cover and pump the water flow becomes turbulent and has horrible flow. Lay a straight edge across the WP gasket surface and measure the distance to the impeller. Then go to a different vendor. I see this a lot with re manufactured pumps vs. new. But there isn't much consistency. You can splice in a Tee with a cap from Durango Dakota into your upper house and watch the flow. Pour boiled water from the upper hose to the Tstat to open up the Tstat then add water slowly and watch the flow as it hits the upper hose with car running.

 

I do a bit of "porting" of the passages that leaves the pump going into the block. I don't no if it helps lower temp but it can't hurt.