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Crank mounted raw water pump wobble

bobct

Advanced Contributor
I got my second 8.1 back from the machine shop and was hoping to do break in run today but my (new) fuel pump is dead. I’ll swap over my other and run it hopefully tomorrow.

One item on my punch list was one of the crank mounted pumps which has a wobble. They’re Sherwood P110’s. Since i was rebuilding two engines, I put that on the punch list for later. In the meantime, I ordered a brand new one and rebuilt one of the others to use on the second engine or as a spare. The brand new one is installed and just in the process of cranking it over today, I could see the same wobble as the old (now rebuilt one). While the engine was at the machine shop I mentioned this so he checked the crank/pulley and said they were ok. I haven’t grabbed my dial indicator to check his work and will do that next.

On the 8.1’s, I don’t believe there is a wrong way to install these pumps, meaning there is no indexing. The pump mounts flush inside the balancer and installs with three bolts. I can feel it bottom out by hand before I install the bolts. The other engine runs true.

If the balancer is really running true and the issue is some defect in the mounting points, can I shim that out so it runs true? Probably a lot of trial and error to get it right. Or, am I missing some indexing and just got lucky on the other engine? There are only three holes in the pump and crank.

My nightmare scenario is that the crank snout is slightly bent followed by a bad crank pulley which wouldn’t be nearly as bad. And the million dollar question, does it really matter? If the shaft is running true inside the pump but the whole pump is wobbling within the balancer, do I care?

thanks
Bob
 
I think you plan to use the dial indicator is a good start. pretty sure you are correct about the lack of indexing. I thought the pump mounted to the PULLEY flange vs directly against the damper?

I would try to find the source of the wobble as it shouldn't be there...if the pulley and damper run true, I would pull the pulley and check its interface with the pump flange and machined shoulder....sometimes a paint run is enough to keep the flange from sitting true on the pulley....
 
Whether Johnson, Jabsco or Sherwood, the crankshaft pump's mounting flange requires the two raised alignment dowels that are part of the harmonic balancer pulley.

The flange uses a three bolt pattern mounting system, and a two dowel alignment system.
This means that out of 3 possible mounting positions, only 1 position aligns the pump correctly (without a wobble).

Also make sure that the center relief (on the mounting flange) is large enough to encompass the center crankshaft bolt's "washer".


Shown here I use a Johnson F5B-9 pump for demonstration.
It mounts the same as a Sherwood, but this one offers 2 more receptacles for the dowels.
Even at that, there is only 1 correct indexing when mounting.

Red = the mounting bolt pattern.
Green = the receptacles for the raised dowels.

SBC Johnson-F6B-9 for Doug Cook 2.jpg

SBC crankshaft pulley.jpg



This one offers 3 receptacles for the dowels, only 2 of which are used.
The 3 mounting bolt bores are the same as with the Sherwood or the old Jabsco.

SBC Johnson-F6B-9 for Doug Cook.jpg


If you are not able to get rid of the wobble, you could remove the raised dowels, and then resort to bushings that will align the flange.
SBC crankshaft pump pulley  alternative.jpg



.
 
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Rick,

Take a look at this pic, here's what the back of the P110 looks like... just three mounting holes which bolt inside the pulley (Mark you were correct above).

No indexing from what I can see and the pump can mate up and mount in any of three positions. I did clean up the pulley side surfaces so they were bare metal.

What do you think?

Bob
 

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Bob, my mistake and apologies.
Apparently I was thinking of the P-105, which mounts the same as the Jabsco and Johnson pumps.

shopping



As for the P-110......

attachment.php


..... is that a direct replacement for the same model Sherwood seawater pump that you had prior?
If so, do the flanges look identical?





Lastly, are you seeing an "out-of-round" wobble, as in the flange is running-out eccentrically..............
..... or are you seeing a wobble that suggests that the center axis is un-true?

As per Mark's suggestion (dial indicator on face of harmonic balancer), if you did that, were you able to see any run-out?


.
 
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i watched & listened and thanks for the correction in the post.....

I guess the first question is what are you using for a reference to determine that the pump is wobbling?

The next is did you use the balancer removal and install tools?

I'm sure none of us knows what the engines were subjected to before you got them so probably best not to assume anything.

I'd suggest the next step is to try either pump on the other engine to see if the pumps are running true. if both run of then I'd suspect the balancer in the suspect engine. it may be the pumps are fine and the issue is the 'reference' your eye is using due to the runout you measured (the 0.018" figure from the video)...
 
Mark,

I should have posted this first, here's what it looks like running. So my reference has just been me eyeballing it compared to the other engine. I did swap pumps so I'm positive it's not the pumps themselves:

Pump running:

https://youtu.be/FGer8LCDxww


On this engine, the machine shop removed/installed the balancer. I did the one the other engine and used a pulley puller for the removal and the GM tool for the install. I specifically asked them to check this one since I knew it was likely an issue going in and they said it was ok. I have a feeling the checked the crank and balancer and not the pulley if what I see is correct.

So yeah, I'm just eyeballing and wonder if I'm chasing something that's not really an issue. If the other one didn't "look" so true maybe I wouldn't have given this a thought. And maybe an optical illusion but it seems to run a lot truer off idle....
 
I wouldn't be real happy with that and agree with your concern.....

So, regarding the root cause, the only thing I see remaining is the balancer itself (assuming you eliminate interference with the pamp and the retainer bolt).....I can't believe the three radial mounting webs are out of alignment unless there was some previous action that induced it....you could probe the face of the pump flange (parallel to the crankshaft's axis)....and see what variation exists as the pump is rotated....
 
Bob, a few suggestions:

First.... use your dial indicator and check other areas on the balancer for run-out.
..... check the inner ring area.
..... check the outer ring area.
..... check the serpentine belt area.
This will let you know if the balancer itself is tweaked or if it's OK.

See if the relief cuts (within the center area of the balancer) allow for the seawater pump's flange to fit properly.
Look for any interference at these areas (see image below).
Check not only the diameter, but also the depth of these reliefs and at the bolt head area.


If those areas are good, remove the balancer.
Take it to a machinist so that he can turn it in a lathe.
He can then check the 3 mounting flats for run-out.
If need be, he will make a cut on the 3 flats to remove the run-out.
A few thousands cut may do the trick.






Bob seawater pump interferance wobble.jpg
 
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Ricardo, thanks for these pics! Yeah, I’m going to dig into this over the weekend. I don’t want to install this engine as is in case I wind up replacing the whole thing. I think the pulley might be very slightly tweaked relative to the balancer. If I didn’t have a crank mounted pump, I would never have noticed.

I can get new one for about $150 which might not be a bad option either.






View attachment 22694[/QUOTE]
 
Why not get the kit to replace the crank mounted one with a block mounted pump and pulley system. I believe this is what Crusader recommended years ago, unless they changed their minds. Part #CRU-RF057026/35
 
Why not get the kit to replace the crank mounted one with a block mounted pump and pulley system. I believe this is what Crusader recommended years ago, unless they changed their minds. Part #CRU-RF057026/35

The crankshaft style seawater pump is far superior to that of a belt driven seawater pump.
No belt dependency, no bearing side load (from belt tension), simple and easy impeller access!


.
 
Pump running update video:

https://www.youtube.com/watch?v=SG--axhRUWQ&feature=youtu.be

What do you guys think of this now? I cleaned up the mounting surfaces but more importantly noticed that the torque arm was putting some pressure on the pump. In this video, I have it removed. If I enlarge the block mounting holes on the arm, I think it will "fall" into a more neutral spot.

It's a lot better than it was, do you think this acceptable amount of movement now?
 
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Good, maybe I'll call this one done. Yes, those are the mounting bolts for the torque arm for the pump. I selectively swapped out some steel bolts for SS in low torque/mounting locations.

What do you think of the pump mounting cap/hex head bolts? (just realized you can't seem them because the engine is running). I did the same here and after I cleaned one up noticed the original was stamped 10.9. I can't imagine there is that much torsional stress on those bolts unless the pump complete locked up.

At that point, wouldn't I want the bolts to shear? I think SS is more around grade 5. I just know these will rust at some point but don't want to go looking for trouble either.


Much better!

Do I see 2 stainless steel bolts threaded into the front side of the engine, Stbd side?
 
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Good, maybe I'll call this one done. Yes, those are the mounting bolts for the torque arm for the pump. I selectively swapped out some steel bolts for SS in low torque/mounting locations.

What do you think of the pump mounting cap/hex head bolts? (just realized you can't seem them because the engine is running). I did the same here and after I cleaned one up noticed the original was stamped 10.9. I can't imagine there is that much torsional stress on those bolts unless the pump complete locked up.

At that point, wouldn't I want the bolts to shear? I think SS is more around grade 5. I just know these will rust at some point but don't want to go looking for trouble either.


edit: forgot that I have a mix (mostly metric) bolts on the 8.1 engine. 10.9 is a metric designation.
 
I think that will work....the arm may have been bent - not much but you can see what a non-neutral force does....

On the bolts, I did a little math and the 10.9 bolts are more like a grade 8. I don't see any issue with the stainless bolts....and I agree with you on the shear but I'd suspect the hose would part long before the bolts would....
 
Bob, I asked about the SS bolts because in certain applications, they can become brittle, can fatigue and snap off.
For what you are using them for, you are most likely OK.

Carbon steel bolts are typically best for any application where shear and torque strength is required.


By the way, I know of no SS machine bolts that will test out at a carbon steel grade #8 equivalent.
 
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