K head clearance to stock Mini water pump
Turbo Mini Forums

I did try the search engine here, but did not find the answer. Also, I can not figure out how to eliminate words from the search, I tried to keep it from finding threads about electric pumps but it won't do it.

I started my K head build/mockup on an 850 block, now getting to the point of finishing my head/cam cover, Mini block end cover, cam pulleys and whatnot. I just tried fitting an old Mini water pump and it fouls on the BMW head.

For my first build, its not going to be radical. I have a pile of 8V and 16V heads here and a pile of blocks. I was planning to assemble a normally aspirated 998 with an 8V head, stock water pump and distributor, maybe even with carbs just get it running. Then move on to crank trigger ignition and fuel injection. Sort out the bugs. Then think about turbo-ing the second engine.

Now the quiz questions for those of you who run the Mini pumps. I ran around the shop with a steel ruler and did a quickie measurement on blocks. The block height from trans flange to top of block on an 850 and a 997 block is about 0.85", on a 998 its about 0.865", on a 1071 its about 0.855" and a 1275 is about 0.89". So if I had tried this pump on the 1275 block, it probably would not have hit the BMW head. Translation, I think the BMW heads will just about clear the stock pump on a 1275 block. On the shorter blocks, do you relieve your BMW heads and cam end cover to fit the Mini water pump, or do you cut your Mini pumps?

I was trying a 1275 pump off the race car and the pump casting bulges out at the bearing by the impeller; I think the timing belt will hit the bulge part of the pump housing at this point, meaning a different pump is needed. So, what Mini pump are you using?

TIA for any help.

Edited by scooperman on 30th Jun, 2012.

You need to cut the webbing out of the pump to clear the belt.

I would just file a bit off the top of the pump, as there is plenty of metal there to trim off.

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The pump just starts to foul the head on 1275 blocks depending on final deck hight and head gasket combination. The shorter 850 block will most certainly casue the pump to foul and will need filing a bit

There are a few different type of pumps available and I think I know what you are talking about since I have a pump that has a raised section around the shaft housing. There are pumps available that are fairly narrow on the shaft housing but have the extra support ribs that Matty talks about. You really need one of those, That said, if you are using a Specialist components kit, the extra spacing on the pullies might allow the belt to clear, i don't know. John K would be your man to answere that one.

Edited by Sprocket on 1st Jul, 2012.

Matty and Sprocket, thank you. I did keep milling on the pump until it fit, quite a bit needed to be cut. Its an old pump which I don't mind sacrificing for science.

Kit? That would be far too sensible. No kits here, I am inventing as I go. I picked a common twincam automobile engine as my source for sprockets, then sat down with the Timken seal catalog and eventually picked seals which met my needs, then drew the head and block end covers. I am working on a couple of design variations now to finalize my pulley positioning (distance out from the head and block).

In the states Minis were not imported after 1967, the later engine stuff is very rare here. I was messing with Minis in the 60s, raced mine in the late 70s, brought it out of mothballs to race vintage in the 90s. But my knowledge is state-of-the-art circa 1970. In that timeframe, we used the pumps with the bigger/deeper impeller, so those are the pumps I have. I am working with ancient Mk1-era blocks, except for one later 998 with the big ribs in the block. That block does have one of those narrow-shaft pumps, like in the SC book. I will need to identify (part number) the narrow shaft pumps with the big impeller.

I will probably be asking about belt tensioners next...I would like to try one that sits on a bracket, where the bracket pivots, and I would like to try one that has no bracket but uses an eccentric bolt. Maybe another thread to ask for suggestions.

Meanwhile, back at the water pump....I whittled on the 998 (no bulge) water pump just to see how much it would take to make it fit between the 850 block and the BMK K head. Then I moved the head over to an old 1275 block. Now I have plenty of height clearance, but I hate the belt (outward from block) clearance. I would like to move the pump inward toward the block about 5mm. So my thinking now is either mod the pump, throw away the pump and go electric, or do a custom billet pump housing and put the guts of a stock pump in it. Stay tuned.