Sherwood seawater pump

[Steps Ahead]

I would greatly appreciate if anyone would be willing to share their experiences regarding removing-rebuilding-reinstalling a Sherwood 1730 on a Cummins 6CTA 8.3(M3) (am I correct that these are alternatively referred to as a "Diamond" or "450C" engines?).

Also, does anyone have any experience converting the Sherwood pump to the Seamax SMX 1730 pump?

Thanks in advance.

- Scott

 

[Asureyez]

Scott, glad to help:

The 17000 pump on Cummins is in fact a Sherwood pump. If your engines are in warranty, stop and just get a Cummins pump new, if they are out of warranty, then consider rebuilding.

The economies are not all that strong. You can buy a new pump for about $750 bucks and the rebuild kit is about $250 and does not include a new shaft.

Sherwood has had so much trouble with the rebuild kits that they now sell the shaft with the bearings factory pressed.

I bought two new pumps and had my take offs rebuilt at a pump house that works on marine pumps. Rebuild kits and labor ran $450 per pump, thats painted and ready to install. Because I do not have the ability to Press the new bearings, I had to have it done out and that added the labor runs $200 a pump.

I keep these as on-board spares. The starboard pump, I do not replace impellers, I replace the pump. its faster and more reliable. On the port pump, I'll begin replacing the pump now as well. The impeller change is just easier on the bench on the 460.

Keeping a spare pump on board makes sense in my book especially on that starboard engine change out.

Most guys will just buy new pumps, but I'm a Scotchman:smt101

As for the Seamax, the replacement pump is bolt for bolt I'm told. I know of no one that has made the change. Tony Adtkins has beefed up the oil gear side of the pump and added a second bearing and oil seal, plus a new impellar design that will work on the 17000 pump.




.

 

[osd9]

I can't offer any advise on changing out the impellers on your Cummins but I will add that my CATs use the same pump and impeller. I just bought two of Tony Athens' designed "super 17" impellers. The pair were delivered to my door for $120. Included with each impeller are O-rings and new SS keys.

 

[Four Suns]

Geez... if I changed out the pumps everytime I changed the impellers, I would have to carry around like 800 pounds of pumps for spares.

How many hours are on your pumps and why are you rebuilding them?

 

[Skip]

Scott,
I am about 10 miles south of you at Quantico and I run 6CTA 8.3M3s in my 420. Mine are '03 vintage, but I doubt the design has changed much if at all. I have 400 hours on mine and no problems as of yet. I change impellers annually. Will be interested to read your additions to Chad's post. Did you just buy your boat from PWM? I saw they were carrying a 450EB in used stock for a while. Nice boat.
The pumps in the 420 are easy to get to. I will probably buy new ones when the time comes, and rebuild as Chad did for spares.

regards
Skip

 

[Steps Ahead]

Dear Chad, Dominic, Gary and Skip –

Thanks for the replies. To explain my interest in the Sherwood pumps, let me provide a bit of history about our 450EB. I do not believe that there are any warranties remaining on the boat.

She was originally named Victory and put into service by her first owner on 21 Apr 00 (I believe in the Annapolis/Baltimore area). She was transferred on 03 Sep 03 to her second owner, who apparently died shortly thereafter and whose estate sold her on 02 Dec 03. She was renamed Msfitz and had her home port in Skip’s neck of the woods until being traded on 02 Aug 07 (for, I believe, a 290AJ) to Prince William Marina (a.k.a. PWM, as Skip correctly surmised).

We commissioned both structural and mechanical surveys to determine her status before we took possession on 27 Sep 07 and renamed her Steps Ahead – Everything else is just a sedan bridge (no offense intended to all the owners of beautiful DB’s – I certainly do not wish to become the focus of Gary’s wrath due to this weekend’s weather). She has subsequently undergone re-rigging including new Raymarine navigation electronics (E-120, S5 open array, DSM30, SR100, etc.), new canvas (changed from blue to black), a new genset, and some gelcoat repairs.

Now, here is my plug for PWM. They promised us that our boat would look like new, and they have done that and much, much more. They completely detailed the entire hull, deck, cockpit, cabin, and bridge. They also addressed each item identified by the surveys. In contrast to the many accounts about owner’s frustration with other dealers, we are thrilled with everything that Carlton, Bob, Michele, Ron, Brandi, Doug, Michael, Jay and all the PWM guys have done for us.

Based on the advice of our engine surveyor (from Cummins Atlantic in Richmond, VA with more than 30 years experience), we were satisfied that the engines are sound. Of course, I also want to ensure many years of future service so I asked about any “Achilles’ heel” of which we should be aware. The surveyor indicated that overheating presents the biggest potential for major trouble, and suggested regular maintenance of the seawater pump. As I do not have any records indicating the history of pump maintenance (there are approximately 880 hours on each engine), I feel that fitting new/rebuilt pumps would be prudent to establish a baseline. As Chad suggests, I would then rebuild the better of the two pumps being removed to keep as a spare.

Thus, how to proceed? Obtain two Sherwood units (I have been quoted approximately $1,000) or two Seamax units (approximately $1,400, which includes another set of replacement impellers)? And then there is the cost of rebuilding the spare unit (approximately $450-650 as mentioned by Chad). Dominic, have you completed the installation of your replacement impellers that you obtained from Tony?

So endth my encyclopedia posting …

I appreciate any thoughts that you may wish to share.

- Scott

 

[Pirate]

Take the time to call Tony Athens @ Sea Board Marine regarding the water pumps. Tony has a lot of experience with these pumps and his advice is well worth following IMO.

 

[osd9]

I haven't replaced the impellers yet and I really don't have it on my list of immediate things to do...the earliest will be next spring. The impellers I have now only have a little over 80 Hours and were replaced before the start of this season.

I'll mimic Matt's advise to call and speak with Tony...I did, and that's how I came to buy his impellers.

good luck...

 

[Four Suns]

Wrath? WHAT WRATH?! I'm always very polite...

On topic, I replaced my water pumps at 600 hours with new ones and had the old ones rebuilt as spares just like you are doing. Keeping the raw water circuit clean on the bay is a full time job with all the friggin' wildlife that thinks it is a new place to breed or live. I can see how clogged raw water circuits can be a problem around these parts. I've lived it... snakes and all...

 

[Asureyez]

At one point the in the 98 to 2002 time frame the 17000 pump had a high incident of failure in less than 100 hours causing brand new engines to burn up. Sherwood never took the issue very seriously nor did Cummins as Cummins was too concerned with engineering the block issues. The pump internals were finally beefed up in 2005 with a higher quality shaft, factory pressed bearing and the pump was renumbered to 1930/1931a, but the pump was replaced with the 18000 pump which seems to be a good product by lack of complaints we hard about.

You'll find the pump designation stamped into the cover. Good techs will have re stamped the cover if they pump has received the newer shaft during a rebuild.

If you rebuild an old casting, make sure you go for new shafts with pressed bearings. The shafts are NOT included in the rebuild kit and have to be purchased separately.

If you go with Tony's new SeaMax pump you may just want to pitch your Sherwood carcases and sell them as a lot on eBay, you'll get maybe 200 each as is.

 

[Robski97]

Guys,
For what its worth When cummins was down replacing my after cooler and fuel injector they replaced both seawater pumps. The old ones were sherwood and were replaced with another brand . Ill find out the brand. They said they have had nothing but problems with the sherwoods. I have QSC 8.3's

Rob

 

[Steps Ahead]

Thanks to all for their input. At this time I am inclined to replace the 17000 Sherwoods with either the Seamax 1730 from Seaboard Marine (I spoke with Brad and have read Tony's explanation of developing the Seamax) or another brand (Rob- did you recall the units that you obtained?).

- Scott

 

[Petep]

Great Post Guys, I also just replace the impellers-after this thread I will think about a pump rebuild- I keep impellers in my spare box-maybe pumps should be in there too! Keep us "in the loop" on this one Scott.

 

[Robski97]

Scott,
I left messages with the office to find out the brand. The pumps have no info at all. I'm hoping they mailed me reciepts that will have the info as well....


Rob

 

[Asureyez]

Hey Rob: If the pump has no stampings in the end cover and the body casting has no part number cast in raised numbners, its not a Cummins pump. Even the Sherwood swill have a cast part number.

If you have a Seamax or other ... it is a good idea to stamp in the end cover the pump Serial # and the impeller part number. This will make life better when you are a 1000 miles away and have to rely upon a yard ape to repair that pump.

 

[Asureyez]

A note to Gary:

On the pump spares .. carry two spare pumps, rebuilt. When I need to change impelelrs We just drop the elbow cap bolts and houseing boles and pop in a new pump. ON the Starboard engine the pump is occluded by the cablemaster drum on the 460. Trying to change the impeller is 10X harded than swapping the pump. The pump can be changed by one person but is damn hard still. A two person swap is a much easiler as some one can hold up the pump by strap when the other stands on their head laying over the exhaust pipe behind the cable master tub. It can take 20 minutes to get back in there and more time to get out. SR could not have done a worse job in design than they did on the 460 ER when it comes to mainenance, only to be excelled in dumbness in the job they did on the 370 dancer. So swapping pumps just makes sense especially being able to change a impeller on the bench instead of in a contorted position in a cramped ER.

 

[Four Suns]

I actually have to remove an 8" x 36" stainless exhaust pipe to get to the water pump/impeller on my port engine. But that's probably because I'm so fat and can't slide over the top. I have the bigger 1800 series pumps and they are monsters and I don't think there have been any shaft breaking problems, etc. with these things. It's about a 5 minute job to change the starboard impeller and about a 45 minute job to change the port impeller. It's still easier than changing those pumps out on the 480 DB.

 

[Robski97]

Whats up with not getting any paperwork for warrty work ? My cummins guy wont give me any paper work. They wont even tell me if my after cooler is new , rebuilt or my own rebuilt. WTF ???? Same with the water pumps ... They will only tell me they were changed....

Rob

 

[Carpedmman]

This is a great write-up about the seawater pump failures on the Cummins 6CTA engines. Having just 400 hrs on my 460 Dancer I figured now was the time to replace the impellers. I pulled the Port impeller and switched it out in about 15-20minutes. Unfortunately, the simple job of impeller replacement on the Starboard side is NOT possible due to the engine room design. As a note, I am 6'3" and built like a tight end. I backed myself into the ER and squirmed past the ISO-BOOST, mounted in front of the Generator, and sat on the gennie battery. I laid on my right side and looked at the Seawater pump. The pump had been leaking and was obviously very close to a catastrophic failure-the motor mount nut was thoroughly rusted from being dripped on by raw water and brown goo was covering the motor mount and stringer. Through the research on CSR and Seaboard Marine's website I chose to go with the upgraded Seaboard 1730 pump. It just makes sense to go with a new pump that has had the revisions made, instead of rebuilding an obviously poor design. The new 1730 Seaboard Marine pump is $750 delivered and includes a new impeller and puller bolt. One note, I made a call to Seaboard Marine to confirm if the pump comes with a set of gaskets to the elbows and engine and was told yes, unfortunately, this new pump DOES NOT come with a new set of gaskets, you need to get a gasket for the engine mount and 2 O-rings for the elbows.

Since my boat is 8 years old I am also replacing my cracked raw water lines from the sea cock all the way to the new pump. I will sleep more soundly knowing these lines are new and not a potential leak-gush waiting to occur!

This post is just a reminder to those with 6CTAs to watch that PUMP! Especially fellow 460 DA owners who can't easily see the SB pump!

 

[Jaws]

Carpedmman,

I had similar difficulty changing the starboard impeller until I followed Chad's advice and just removed the pump. Much easier.

Last winter I replaced the original Sherwoods with the Seamax pumps and have been very pleased after the initial season. They do not chew up my impellers and appear to pump more water. Besides, the impellers are splined in the Seamax and you won't drop that key down the intake hose.

You will like them.

James