Crank-mounted water pump?
 

Guys, it’s always something.

Getting the Formula back together with closed cooling and it’s looking like it’ll be near impossible to replace the impeller without pretty much removing everything from the front of the engine.

The best way to tackle this issue is with a crank-mounted pump. The problem I’m finding is that the pumps are made to fit and center on the cast pulleys used on v-belt apps. Volvo has one that bolts to their 8.1 but hose fittings aren’t correct.


Anyone got a solution for this?

I have Volvo Pumps. They are so simplistic and simple to change. And there not plastic😎 There has to be a simple way to reduce or increase the hose size and I bet you could even get the parts at Home Depot. So simple to pull hoses off to winterize to drain.

why not make and adapter plate.

i have adapted many it is not very hard to mount the pump with 3 bolts and a bit of simple machining the hose rerouting is often tougher

as a note here there is 2 pumps a short and long impeller

I’ll probably do that. Was just wondering if anyone had a specific solution or something available to fit.

Actually, In this case the hose routing will be the easiest. I only have a short run to my trans coolers. The adapter will be the harder part.

Sounds like if someone took the time and inclination to design an adapter plate, their would be a market for it..

Mine are a total pain after my closed cooling install. I had to grind an open end wrench down to get behind the circ pump house to tighten the bolt then to get to the impeller every year I have to pull the pulley off, unbolt the clamp down and then pull it out the back and down. It's awful - just simply awful. I wish I had explored a good electric option (no idea if one exists)

At least you can sit down in front of the engines to work on them. If have about a foot of free space in front of the engines… if it’s even that much. Before closed cooling I’d remove the circulation hose, unbolt the pump from the bracket, remove the bracket, then pull everything forward. It was a ***** but I could remove it in a few minutes. That won’t be the case now.

For electric to work you would need AC to do it efficiently. I think DC would require too much current and burn up quick. For grins I did a search on this and found that while it “could” work for low rpm solutions (a guy was running his 1500 rpm Perkins diesel powered trawler with a bait well pump) others couldn’t make it work because of volume issues.

I once had a 1989 Mastercraft prostar 190 with a ford 351 with V belts , it had a crank mounted pump , maybe a Jabsco?

F6 Johnson pump

Johnson F6B-9 is the one I’m going to order. It’s supposed to be as good as if not better than the Merc pump. Ordering today and will also look into spacer plates that I can modify for the mounting.

On another forum, a solution was to machine some stand-off bushings to align the pump and also lessen them depth (the serpentine pulley too deep).

I bought these from Full Force this summer for my AT. Just sick of the Merc pumps leaking from the front seal and a pain to change the impeller.
https://cimg8.ibsrv.net/gimg/www.off...1ff5896ca.jpeg
https://cimg9.ibsrv.net/gimg/www.off...13be0f992.jpeg

those are the long impeller ones they pump a lot of water i dont use the metal bracket as thats the part that fails or always rattles the hoses stop the pump from rotating

Specs on the pump state max rpm of 5k. Any concerns running them upwards of 6k?

Another note... be on the lookout for knock-offs. Lots of junk out on Amazon, eBay, etc.

Ordered a pair this morning.

I run those pumps and have run them over 6k without incident. Do pump a bunch of water though! I switched headers that had a small hole to exhaust water and blew the freeze plugs out of one motor! Had to overboard the excess water (and install pressure gauges). Simple, efficient and if you have room, a fairly easy impeller swap. (I use 90* needle nose, but they actually make a little tool to reach in and slide the impeller out)

That's nuts!

I'd imagine this is especially important on a Gen VI block where the water jacket to side of the block surface is thin. My 502s seeped at the head/block joint due to high water pressure. It'll no longer be an issue with closed cooling but it was a big problem when raw water cooled and at speed.

Found this on the Formula Boats forum... good list of parts.

How-to: convert your Merc raw water pump to crank-driven Johnson (take 3))

use cometic headgaskets and you won't have any weeping

I hear you. The problem started before I owned it and two top-end refreshes past.

question… Isn’t it the rule to not use Cometic gaskets unless the surface can be machined per their specs? I would think that would preclude their use during a top-end refresh. Not trying to derail my own thread, it what’s the consensus?

Any thoughts on what to do about the removal of the Merc pump and serpentine belt routing? The way it works in stock form, the belt goes from the circ pump then down to the raw water pump then up to the alternator. Removing the raw water pump… can I just go to the alternator or should I get an idler? I thought about leaving the pump assembly (sans impeller) on the engine, but honestly, I'd like to sell them to recoup some of the cost.

Looks like this is acceptable...

https://cimg8.ibsrv.net/gimg/www.off...8629cf2ad4.jpg
This is a 5.7L but the routing is basically spot-on for the 454/502 MPI accessory drive. They go straight across to the alternator and then back to the tensioner. The tensioner is much larger on this setup.

I used the Felpro MLS when I added the Whipples, no machining done

I got a pair of 3/8 billet spacer plates in from Speedway Motors today. They’re needed to make up some of the depth needed to keep the pump housing for hitting the pulley. I took everything up to Lowes to get some spacer/bushings. 3/8 inside, 1/2 outside. I’ll need to cut them down but they center the bolts perfectly. This should be easy to put together. I’ll get some pics as I’m putting it together along with part numbers used to put it all together.

Uh oh, he said “easy.” :poopoo: :angry-smiley-038: :lolhit:

Famous last words!

the only "easy" way to go boating is to give someone a $100 for gas and ride with them. at the end of the day you go home while they deal with the boat and you rode around on the same boat they are spending all their time fixing. but seriously, I work on several boats that have a crank driven pump and they are so much easier to deal with in cramped compartments. as for water flow, never seen an issue, heck, my jet boat only had a 3/4 hose from the pump cooling the engine and as hard as it got run the temp never climbed with a crossover and no thermostat.

So much for easy… but not the way you’d think.

I landed bad when I jumped off the back of the boat last weekend. I knew I did something wrong because I felt the front of my left foot stretch much more than it should. Started out limping Saturday night and now it’s all jacked up… I can barely walk on it. I went out to dinner with my girl last night and couldn’t even get a flip-flip on it let alone a shoe. Guess I’ll be off of it for a while. Shoot.

I feel for you. I did the same last year, slid off the back of a platform and dropped the last foot or so and the next day my knee was swollen up and I could not put any weight on it for a week. sucks getting old and falling apart.

Boredom got the best of me so I went out to the garage to work on piecing these things together.

Parts needed….


https://cimg3.ibsrv.net/gimg/www.off...4a4090ace.jpeg
Johnson F6B-9 raw water pump.

https://cimg4.ibsrv.net/gimg/www.off...2b781ec98.jpeg
Pump unboxed. Contains basic setup instructions and specs.

https://cimg2.ibsrv.net/gimg/www.off...8a2fc672c.jpeg
Speedway Motors 3/8 Pulley Spacer - Used to take up some of the depth of the pulley giving extra clearance for hoses.

https://cimg3.ibsrv.net/gimg/www.off...3f8d23ca5.jpeg
1/2 outside, 3/8 inside bushings. These will be cut-down to the pump’s flange depth and used to center the bolt in the flange. Smallest holes in the flange are 1/2-inch diameter.

https://cimg0.ibsrv.net/gimg/www.off...48e9fa3e4.jpeg
3/8-16 x 2-inch grade 8 socket head cap screws. Important - must have a shoulder to positively center the bushing (it’s almost an interference fit). Socket head screws are needed because a hex head interferes with the flange body.

https://cimg7.ibsrv.net/gimg/www.off...98bd9af9d.jpeg
3/8 grade 8 flat washers. Probably not needed but I always place a washer under bolt heads at assembly. I may remove these at final assembly.

https://cimg0.ibsrv.net/gimg/www.off...b171c180e.jpeg
Cut-down bushings and washers (the washers interfered with the flange body - again - I’ll probably remove at final assembly).

https://cimg1.ibsrv.net/gimg/www.off...049191d9b.jpeg
Showing bushing and bolt-to-flange relationship.

https://cimg3.ibsrv.net/gimg/www.off...cf7b94b97.jpeg
Flush with flange.

https://cimg4.ibsrv.net/gimg/www.off...cc8e8f5eb.jpeg
Assembled. The spacer plate required opening up the bolt holes a little. The spacer was spec’d for a small block. I figured it was okay since this pulley is used on V6 and V8 (sb and bb) Chevy engines. The bolt circle on all of them is the same. The bolts splayed inward so I opened them up to just under 7/16. It only acts as a spacer. Alignment is correct and it appears the spacer is equally spaced.

As soon as I’m able, I’ll get these mounted. The hardest part will be making and attaching the cooling hose to the starboard trans cooler with the header on. Port does not have exhaust yet so it should be a cakewalk. Hoses will be steel reinforced so no need to brace the pumps.

I had wanted to do this prior to the engines being installed but thought rerouting the accessory drive would be a pain. I’m glad I’m finally going in this direction. Impeller changes should be a breeze going forward.

I hope this helps others with similar installs. -Tom

I have a Baja 272 with a 496mag HO and I can't even see the pully on my pump. I removed my backrest and still could barely see it. After getting my balls broke replacing the impeller I decided next time I'm just gonna pay someone to do it. I hope that doesn't mean I have to hand in my man card.

While researching this, I saw on another forum where a guy with a very tightly installed pair of 496s has to lift the starboard engine out to change the impeller. That's just unacceptable and would really make me consider outboards.

i attended the funeral of a cousin this morning who retired a month ago was sleeping on his boat in a marina getting it ready to winterize got up in the night slipped hit his head and fell in in clayton ny son found him the next morning..... be careful guys boats are very slippery this time of year

That's awful! Sorry for your loss.

The bushings gave me a little trouble requiring a more methodical approach to running in the bolts until the seated properly. That was the hardest part. The hoses came off the trans coolers easy, too.


https://cimg3.ibsrv.net/gimg/www.off...fed6aa387.jpeg

Now to measure/test-fit for hoses and then measure for belts.

I have blown a few hoses especially the j tube on the recirc pump see if it swells when you rev it up

I did the same with a lot of water pressure when it was raw-water cooled. It swelled enough to cut the hose from touching the belt. I’ll keep an eye on the raw water side. Thanks for the heads up!

Kinda personal