Wobbling pump

Hi all, I'm a newb to this forum, so please be gentle.

I've converted a Mercruiser IO to "direct" pickup cooling, using typical inboard arrangement with crank-mounted pump and through-hull pickup. Finally got everything installed, ran motor for the first time and the pump wobbles a bit. I've seen these pumps on other engines and noted that they do tend to move a little, but I'm wondering how much is too much. There's enough slop in the bolt holes to allow the pump to be slightly misaligned. Is that designed in on purpose and taken into account in the setup, or do I need to do something to try and center the pump? If so, how would I go about this? I have video of the pump in operation but not sure if I can post video to this forum.
Thanks much.

There are three possible ways to Index this pump to the harmonic balancer and pulley.
Remove the pump and look for the two raised sections (in the pulley) that serve as alignment “dowels“.
Now look for the corresponding pump flange “bores” that receive the dowels.
Install the pump accordingly!

Ah, that would be the larger holes in the pump flange? Well, I have a couple flies in the ointment. First, my pulley doesn't seem to have the raised dowels you mentioned. Maybe this is because it is an automotive engine? This is an old boat and it's on its fourth motor, and it's not a marine engine. The other fly in the ointment is that I've got the pump mounted on a spacer. Due to the "depth" of the pulley, the hoses had zero clearance at the edge of the pulley, so I added a spacer. Again, I imagine this is because it's an automotive pulley, and is not the right depth for this kind of pump.
Other than finding the correct marine pulley, do I have any options?
Thanks for your help.

I have read a little bit on the interwebs that another option would be to use bushings on the bolts to center them in the pump holes. I guess that might be my most direct solution.

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Soundside said:

Ah, that would be the larger holes in the pump flange?
Yes.... the two off-set large bores within the mounting flange! (we may occasionally find four bores for alignment dowels)
(see my images below)

Well, I have a couple flies in the ointment. First, my pulley doesn't seem to have the raised dowels you mentioned.
I would find a pulley that does!

Maybe this is because it is an automotive engine? This is an old boat and it's on its fourth motor, and it's not a marine engine.
If this is an automotive engine, you may have trouble in other areas. Camshaft profile, for example!

The other fly in the ointment is that I've got the pump mounted on a spacer. Due to the "depth" of the pulley, the hoses had zero clearance at the edge of the pulley, so I added a spacer.
The spacer may add to the wobble..... not sure! (the Chrysler guys do something similar, and apparently it works)

Again, I imagine this is because it's an automotive pulley, and is not the right depth for this kind of pump.
If the lower pulley is a deep one, then it's likely that also you have:
..... the wrong alternator mounting.
..... the wrong Power Assist steering pump mounting (if equipped with PA steering).
..... the long body GM engine circulating pump (instead of the short body used in the Marine applications).

although we will often see this called a "water pump", this is an engine coolant circulating pump (aka Circ Pump)!




Other than finding the correct marine pulley, do I have any options?
In terms of keeping things "Marine", no!

Thanks for your help.

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Soundside said:

I have read a little bit on the interwebs that another option would be to use bushings on the bolts to center them in the pump holes. I guess that might be my most direct solution.
If memory serves me, the three harmonic balancer bolts are 7/16" NF.
The corresponding seawater pump "flange" bores (for these three bolts) are a tad bit larger.
Bushings of the correct size may help...... however, the correct "fix" will be to find and install the correct Marine parts.... I.E., crank pulley, short body Circ Pump, short body Circ Pump pulley, alternator mount, PA Steering pump mount, etc.

Would you mind posting several good photos of the front area of your engine for us?

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Custom inserts can be made. You still need a impeller in the outdrive to cool the drive so why are you going to a crank or engine mounted pump? Tried that pump on a Volvo v8 .Too much wobble , ended up using a Bravo style pump adapted to the Volvo v8

Thanks for all the info guys. I should have provided more information to start with. This engine has a number of modifications. You are correct that it has the "wrong" setup on the front. The alternator has automotive mounting to line up with the deep pulley. In addition, it has a modified cooling system, with parts from Stainless Marine. Firstly, it has no circulating pump, which was replaced by a bypass crossover pipe, it has SM aluminum exhaust manifolds on it, and the SM thermostat housing. I wouldn't know where to start to attempt to make this a standard MC setup, I'd be better off taking the money and putting it toward a new engine. This motor is an automotive crate motor (350 Chevy long block), installed maybe ten years or more ago (it replaced another automotive 350 engine from which the accessories came). Did I mention this was an old boat? Original engine was 150 hp Chevy 6 (1965) Mercruiser, later upgraded (late-1970s I think) to a 165, including entire stern drive system (early Alpha or R stern drive). Some time in the mid 80's, the six was removed and the first 350 was installed, along same time added a newer Alpha outdrive. Originally it had aftermarket cast iron exh manifolds and a hodgepodge of other components in the cooling system.
The Alpha has never cooled the engine well. This is one reason the Stainless Marine stuff was added - attempt to improve cooling. Mistake? Maybe. It is what it is. First tests with the new crank pump indicate it's cooling like mad.
Bt Doctur, the stern drive cooling will be done with a drive shower. I also once had an old Volvo, which is where my experience comes from with this type of pump setup. The Volvo wobbled a little, but I assumed since it was a stock setup, it was within spec. Clearly, I need to figure out how to align this system. One option is definitely the new pulley and alternator setup. But I think I may try the bolt sleeves and see if does the trick before spending lots of time and money trying to retrofit the MC stuff. I don't have any pics of the front of the motor, but I'll try to get some in the coming days.

Just another thing to think about, you did put a marine starter and altenator on the engine? If not do so now as the marine versions are not spark proof. I also own an older boat and the micky mouse stuff that the previous owner had done, well lets just say I still come across some of it from time to time 21 years after buying her. Good luck with your boat and solving your wobble.

We all have our opinions regarding certain components, etc. I much prefer the Johnson or Jabsco or Sherwood crankshaft pump. Any wobble is likely a result of improper installation, and it can be corrected.

With the crankshaft seawater pump:
there is no bearing side load from belt tension..... they offer easy cover removal for impeller access.... etc.

With the belt driven seawater pumps:
they will undergo bearing side load from belt tension ...... they offer more difficulty accessing impeller in which it often causes deferred impeller maintenance.

Soundside said:

Thanks for all the info guys. I should have provided more information to start with. This engine has a number of modifications. You are correct that it has the "wrong" setup on the front.
Yes..... and I hope that you are able to find the right parts for it. You won't regret it.

The alternator has automotive mounting to line up with the deep pulley.
Please note that the automotive alternator will NOT be ignition source protected.
If you were to be inspected, that could land you a nice fat citation $$$$$$.

In addition, it has a modified cooling system, with parts from Stainless Marine.
Pictures would be very helpful.

Firstly, it has no circulating pump,
You should have a Circ Pump installed and working.
If equipped with a closed cooling system, you can use the automotive Circ Pump (early Chevy V-8 circ pump).
If raw water cooled, you will need the Marine version (bronze impeller and special ceramic seal).

which was replaced by a bypass crossover pipe,
And again, pictures would be very helpful.

it has SM aluminum exhaust manifolds on it, and the SM thermostat housing. I wouldn't know where to start to attempt to make this a standard MC setup, I'd be better off taking the money and putting it toward a new engine.
We can help you source the parts.

By the way...... the aluminum exhaust will be ok if running in Lake or River Water...... but will not fair well in ocean water.

This motor is an automotive crate motor (350 Chevy long block), installed maybe ten years or more ago (it replaced another automotive 350 engine from which the accessories came). Did I mention this was an old boat? Original engine was 150 hp Chevy 6 (1965) Mercruiser, later upgraded (late-1970s I think) to a 165, including entire stern drive system (early Alpha or R stern drive).


Some time in the mid 80's, the six was removed and the first 350 was installed, along same time added a newer Alpha outdrive.
This is good.
The 250 cu in GM 6 cylinder engine uses an entirely different gear reduction and would have been incorrect for a GM V-8 engine.

Originally it had aftermarket cast iron exh manifolds and a hodgepodge of other components in the cooling system.
The Alpha has never cooled the engine well. This is one reason the Stainless Marine stuff was added - attempt to improve cooling. Mistake?
Yes.... in my opinion!

First tests with the new crank pump indicate it's cooling like mad.

Bt Doctur, the stern drive cooling will be done with a drive shower. I also once had an old Volvo, which is where my experience comes from with this type of pump setup. The Volvo wobbled a little, but I assumed since it was a stock setup, it was within spec. Clearly, I need to figure out how to align this system. One option is definitely the new pulley and alternator setup. But I think I may try the bolt sleeves and see if does the trick before spending lots of time and money trying to retrofit the MC stuff.
Suggestion:
Remove the pulley from the harmonic balancer face.
Place a dial indicator against the face of the harmonic balancer spokes.
Rotate engine and check for run-out.

I don't have any pics of the front of the motor, but I'll try to get some in the coming days.
That would be extremely helpful.




NOTE:
All Marine SBC engines use the Short Body Circ Pump............. Merc, Volvo Penta, PCM, Crusader, Marine Power, and so on.
All Marine SBC alternators are to be Ignition Source Protected.
All Marine SBC starter motors are to be Ignition Source Protected.
Any electrical devices (battery charger, inverter, transfer relays, solenoids, etc. ) that are mounted within a gasoline engine bay are to be Ignition Source Protected.

Click to expand...

Rick, the easiest way to show the setup is to give links to the products. Here is the crossover and T-stat housing (slightly different than mine, but they've tweaked the design over the years. It's essentially identical. Main water inlet comes into the crossover and into the block where the circ pump would usually mount. There's a bypass that allows water to go straight to the stat housing above the stat, allowing manifold cooling when T-stat is closed.

http://www.stainlessmarine.com/shop/bb-bandm-174-thermostat-housing-with-bypass-ea/

The manifolds are here at the link below.

http://www.stainlessmarine.com/shop/set-of-sb-manifolds-with-3-taller-stainless-risers/

I should give a little more history here. This was my dad's boat for many years. He did the research on these products and decided to take the plunge (I don't believe they were quite as pricey back then, but I do remember him talking about how expensive they were). The boat is used in brackish/salty water. But my dad was a fanatic about engine flushing, winterizing, etc. He took the manifolds off each season and soaked them in a mild caustic solution of some kind (recommended by SM). To this day, they show no signs of corrosion in any area that can be inspected. My dad passed away in 2010, and I have barely used it since. This engine probably has 50 hours on it (and it's been in the boat around 12 years, and the exhaust system is even older). It has not seen the river at all in two years.

With all the money my dad dumped into this cooling system, I'm going to give it my best shot to get it working well. I have to believe that the folks at Stainless Marine know something about what they are doing (i.e. the crossover and manifolds are designed to work on this engine, and presumably they are getting something right if they are still selling them after all these years). The notes you mentioned about maintenance on the crank mounted pump are part of why I decided to change the pump system. I'm using a Johnson pump by the way. The fact that impeller changes can be done without tearing the stern drive off the boat is a big plus for me.

I have managed to locate some nylon sleeves that are exactly the right thickness to try on the bolts. I don't think I have a damper out-of-round issue. The pulley doesn't wobble. It's clearly the way the pump is installed, with the slop in the holes and no indexing pins to keep it aligned. The pulley itself is centered by means of a "dish" around the center hole that locates it properly on the damper (maybe has dishes on the bolt holes too, can't remember).

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Soundside said:

Rick, the easiest way to show the setup is to give links to the products. Here is the crossover and T-stat housing (slightly different than mine, but they've tweaked the design over the years. It's essentially identical. Main water inlet comes into the crossover and into the block where the circ pump would usually mount. There's a bypass that allows water to go straight to the stat housing above the stat, allowing manifold cooling when T-stat is closed.

http://www.stainlessmarine.com/shop/bb-bandm-174-thermostat-housing-with-bypass-ea/

This system (or similar) was used in boats with Jet Drives..... not stern drives!
Without a Circ Pump, this makes it a complete RWC system.

The manifolds are here at the link below.

http://www.stainlessmarine.com/shop/set-of-sb-manifolds-with-3-taller-stainless-risers/

This site shows Stainless Steel manifolds.

I should give a little more history here. This was my dad's boat for many years. He did the research on these products and decided to take the plunge (I don't believe they were quite as pricey back then, but I do remember him talking about how expensive they were). The boat is used in brackish/salty water. But my dad was a fanatic about engine flushing, winterizing, etc. He took the manifolds off each season and soaked them in a mild caustic solution of some kind (recommended by SM). To this day, they show no signs of corrosion in any area that can be inspected. My dad passed away in 2010, and I have barely used it since. This engine probably has 50 hours on it (and it's been in the boat around 12 years, and the exhaust system is even older). It has not seen the river at all in two years.

With all the money my dad dumped into this cooling system, I'm going to give it my best shot to get it working well. I have to believe that the folks at Stainless Marine know something about what they are doing (i.e. the crossover and manifolds are designed to work on this engine, and presumably they are getting something right if they are still selling them after all these years).
Yes.... they certainly do know about Jet Pump cooling systems....... but apparently NOT about stern drive cooling systems!

I've been doing this for a long time. I would NEVER use that set-up on this engine.
I would install the correct Circ Pump and the correct T-stat housing, and would plumb it accordingly.

I say this with respect....... I would consider the possibility that your father was just simply not up to speed re; the correct cooling system configuration.... in particular for a stern drive.

The notes you mentioned about maintenance on the crank mounted pump are part of why I decided to change the pump system. I'm using a Johnson pump by the way. The fact that impeller changes can be done without tearing the stern drive off the boat is a big plus for me.
Yes.
However, you must run the A drive pump in order to remove heat from the A drive upper gear unit.
In my opinion, a drive shower will be inadequate.

I have managed to locate some nylon sleeves that are exactly the right thickness to try on the bolts. I don't think I have a damper out-of-round issue.
I was not referring to the Harmonic Balancer as being out-of-round..... I was suggesting the dial indicator so that you could check for run-out!
If there is run-out, it may explain the wobble.


The pulley doesn't wobble. It's clearly the way the pump is installed, with the slop in the holes and no indexing pins to keep it aligned.
I would not use nylon..... I would find steel bushings, or have some steel bushings machined.

The pulley itself is centered by means of a "dish" around the center hole that locates it properly on the damper (maybe has dishes on the bolt holes too, can't remember).
Yes.... I fully understand that...... I've been involved with these engines since the mid 60s.

Click to expand...

The manifolds themselves are aluminum. The risers are SS.

This has always been a "complete RWC" system.

As far as differences between jet drives and stern drives, besides the drive, what is the difference? The engine cooling is functionally the same. I've read in other forums different opinions about whether the circulating pump is needed, and of course, there's a thousand opinions on that. But the only difference I can see in a SD and jet is that the sterndrive needs to be cooled. I understand you don't care for drive showers. But given the sketchy historical performance I've had from the stern drive pump in this boat, I'm actually suspecting my drive will be happier overall with the shower. I wish I had measured the drive temp on the old setup. But just placing a hand on the gearcase, I had more heat than I thought was acceptable. Looking at the internal water flow of the unit, I see no reason that the shower won't provide as good or better heat removal for the gear housing.

I think there might be more than one way to skin a cat. Attempting to reproduce a bone-stock power train would cost more than the boat is worth. I am going forward on the basis that the functional aspects of a crank pump with drive shower (and the StainlessMarine components) should be adequate. Issues regarding the safety of the components are my biggest concerns at this point. I want to bring the boat up to speed regarding ignition safety in particular. I believe the alternator has a spark control retrofit, but I've heard these might not pass safety inspections. I know the starter needs replacement. Don't want anything going boom on me. I always go through a ritual of running the blower, opening the engine box and sniffing in the bilge before cranking, but, I don't want to take any chances.

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Soundside said:

The manifolds themselves are aluminum. The risers are SS.

This has always been a "complete RWC" system.

As far as differences between jet drives and stern drives, besides the drive, what is the difference? The engine cooling is functionally the same.
The jet pump provides pressurized seawater (taken from the jet stream) to the engine and pushes it through the engine.
These Jet Pump companies eliminated the Circ Pump on these engines.
Cooling was somewhat erratic and unstable.

I've read in other forums different opinions about whether the circulating pump is needed, and of course, there's a thousand opinions on that.
Regarding stern drives and engine cooling, there should be only one accurate opinion. But of course, that is my opinion.

But the only difference I can see in a SD and jet is that the sterndrive needs to be cooled.
Hey.... all due respect to you..... it's your call, I'm simply sharing my years of experience at performing Marine Work.


I understand you don't care for drive showers. But given the sketchy historical performance I've had from the stern drive pump in this boat, I'm actually suspecting my drive will be happier overall with the shower.
Why would you NOT keep the A drive seawater pump active, and simply dump the seawater over-board?

I wish I had measured the drive temp on the old setup. But just placing a hand on the gearcase, I had more heat than I thought was acceptable. Looking at the internal water flow of the unit, I see no reason that the shower won't provide as good or better heat removal for the gear housing.
The A drive seawater path pushes seawater through the gear case porting. While it may not be ideal, it has worked for Merc for years.

I think there might be more than one way to skin a cat.
Yes.....there is always more than one way to skin the cat...... but the furrier dealers will tell you that some cat skinners will offer a better pelt!

Attempting to reproduce a bone-stock power train would cost more than the boat is worth. I am going forward on the basis that the functional aspects of a crank pump with drive shower (and the StainlessMarine components) should be adequate. Issues regarding the safety of the components are my biggest concerns at this point. I want to bring the boat up to speed regarding ignition safety in particular.
That would be "ignition source protection", and yes..... very important!

I believe the alternator has a spark control retrofit, but I've heard these might not pass safety inspections.
If by chance it is a Delco 10si with the marine screening, it will be OK.

I know the starter needs replacement.
Do yourself a favor and install a Marine version HTGR/PMGR starter motor.
With the gear reduction, the armature spins approx 3 xs faster (more torque to the flywheel) and consumes less AH during cranking.

Don't want anything going boom on me. I always go through a ritual of running the blower, opening the engine box and sniffing in the bilge before cranking,

That is a good practice.
You can go one better and use a continuous duty blower motor and let it run while the engine is running.
And say NO to the turbo or in-line blower motors. They are JUNK!



Good luck with the project.... and be safe!

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The water comes from the jet pump in a jet drive, so it just replaces the seawater pump. The ones I've seen didn't have bypass flow on them, so there was almost zero flow when engine is not up to temp (which I suppose is okay, but doesn't seem ideal to me). Erratic yes, since jet pump flow is highly dependent on engine RPM, and from what I've seen, stops almost altogether at idle - you have to keep the engine above 1000 RPM to get much of anything. Fine for a hot rod speed boat, but not in this case. I understand that many jet boaters have resorted to crank mounted pumps anyway because of this very problem. This behavior is actually very similar to what I've experienced with my cooling. Slowing to idle after sustained running has always been an issue (if I remember, this used to even occur on the old bone stock 6-banger).

Perhaps a better comparison of this setup would be a straight inboard configuration - which is essentially what I've now got (in terms of the engine cooling). I don't have any data from the direct drive community, but it looks like the recirc pump is often eliminated in V-drive systems. I've also heard of folks doing something like this with Bravo systems (which I understand uses a belt driven pump?). Maybe that's just a different style recirc pump, I'm not up to speed on Bravos.

I suppose the lack of recirc pump might somehow exacerbate some cooling problems. But I also can't get past the fact that the recirc pump merely "manages" flow - it does not produce the flow. In fact, I've read that in some sense, the recirc pump actually restricts flow that would otherwise occur in its absence (but that probably falls under the "everybody's got an opinion" category). In my case, the situation has gotten a little worse and the engine wants to heat even at speed. So, in troubleshooting, I found that my lower unit seawater pump is not putting much out even at higher RPM. I had the option of just replacing the pump (again) and hoping for the best. But after considering the major maintenance improvement of a crank pump (actually gives you incentive to inspect and replace the impeller) and the potential of solving the longer-standing issue of marginal cooling under some conditions, I opted for this modification.

Rick, I appreciate your time and experience. I realize what I have is way non-standard. I'm admittedly creating a "work-around" to solve a long-standing issue on a 50+ year old boat, in an attempt to continue to get some use out of it in its (and my) golden years. What I'm after is something that works and is safe. I "think" the setup I'm working on will meet this goal. If it doesn't, I will have to go back to the drawing board (which may involve tossing in the towel on this boat altogether and starting with something a little more modern).

Best regards,
Keith