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johnson pump

8

805HD

Regular Contributor
Hey guys recently installed a new Johnson pump on this 350,
and feel like it’s got a lot of movement going on while running. I could be wrong.

Take a look please
https://youtu.be/V4XAyEHMuPI

Flange side of the pump mounted down perfect over the alignment dowels on the face of the crank pulley. She’s sitting flush and tight.

The harmonic balancer looks okay, no odd noises and seems to spin true while running. The pump just looks like it’s got some “wobble” to it. The old one did too.

thanks
 
The Johnson Crankshaft Pump can be indexed in one of three positions, of which only one is correct!
Do you have it indexed correctly?


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RicardoMarine said:
The Johnson Crankshaft Pump can be indexed in one of three positions, of which only one is correct!
Do you have it indexed correctly?


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Click to expand...

I believe so, I see the three indexing holes on the flange. Seemed to me the other way around the bolt holes wouldn’t line up with the pulley.

i have seen your post on this exact issue in the forums but don’t believe it is mounted wrong.

Do you consider that exsessive movement?
 
Yes, that is an excessive wobble!

Your V belt pulley should have three mounting holes, equally placed, and two raised portions that serve as alignment dowels.
The Alignment Dowels create the need for one correct indexing only!




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Last edited:
RicardoMarine said:
Yes, that is an excessive wobble!

Your V belt pulley should have three mounting holes, equally placed, and two raise portions that serve as alignment dowels.
The Alignment Dowells create the need for one correct indexing only!




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Click to expand...

Figured it was... yes there are three equally spaced threaded holes on the pully and 2 raised “dowel” areas for indexing the flange. The flange itself fits perfectly over the alignment dowels, three bolt holes line up right. Then I EVENLY tightened down in a circular pattern.

Unless im missing something big here I don’t think the problem is mounting. Maybe the face of the pully is warped or bowed?

I would imagine if that was so I would see it in the pulley off the crank.. wobble wobble!
 
RicardoMarine said:
Yes, that is an excessive wobble!

Your V belt pulley should have three mounting holes, equally placed, and two raise portions that serve as alignment dowels.
The Alignment Dowells create the need for one correct indexing only!




.
Click to expand...

Figured it was... yes there are three equally spaced threaded holes on the pully and 2 raised “dowel” areas for indexing the flange. The flange itself fits perfectly over the alignment dowels, three bolt holes line up right. Then I EVENLY tightened down in a circular pattern.

Unless im missing something big here I don’t think the problem is mounting. Maybe the face of the pully is warped or bowed?

I would imagine if that was so I would see it in the pulley off the crank.. wobble wobble!
 
Make sure that center bolt’s large washer fits properly into the pump’s mounting flange bore...... and make sure that it’s the correct washer for the bolt’s OD.

If the large washer is off-center, the mounting flange can be off-center as well (the 3 mounting bolts are not intended to do the centering).
If the dowels are damaged, the flange may not be centered.
If the washer is too large for the flange bore...... the flange may ride high on one side of the washer.


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RicardoMarine said:
Make sure that center bolt’s large washer fits properly into the pump’s mounting flange bore...... and make sure that it’s the correct washer for the bolt’s OD.

If the large washer is off-center, the mounting flange can be off-center as well (the 3 mounting bolts are not intended to do the centering).
If the dowels are damaged, the flange may not be centered.
If the washer is too large for the flange bore...... the flange may ride high on one side of the washer.


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Click to expand...

I will do some more investigating..

I considered the washer and bolt head height off the crank, there were no signs of marring or anything on the back side of the flange when I pulled the pump the second time around.

The dowels and the whole pulley for that matter matter have seen better days but don’t show any obvious signs of defect. Both mating surfaces are flat to the eye.

When I installed the pump the second time around I played around with it and the different configurations for the holes. From what I remember there was only one way that thing was going to line up with the alignment dowels and the bolt holes on the pulley.

There is is a positive bottom out after slipping it over the alignment dowels. With slight pressure it almost “clicks” into place. Keeping that pressure against the crank I hand tightened the bolts to snug and then wrenched it down. Again, in sequence.

With all that wobble I worry about the internals of his brand new water pump. This things kicking my butt!
 
805HD said:
The harmonic balancer looks okay, no odd noises and seems to spin true while running. The pump just looks like it’s got some “wobble” to it. The old one did too.

thanks
Click to expand...

OK..... I just re-read your post #1. You suggest that the old pump also wobbled.

I would now suggest that you remove the new pump, pull the center bolt and the 3 pulley mounting bolts and remove the pulley.
Look for any substantial rust scale and/or debris that could be between the balancer face and the inner face of the pulley.
Using a dial-indicator, check for run-out at the harmonic balancer surface!


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RicardoMarine said:
OK..... I just re-read your post #1. You suggest that the old pump also wobbled.

I would now suggest that you remove the new pump, pull the center bolt and the 3 pulley mounting bolts and remove the pulley.
Look for any substantial rust scale and/or debris that could be between the balancer face and the inner face of the pulley.
Using a dial-indicator, check for run-out at the harmonic balancer surface!


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Click to expand...

okay so I checked the face of the crank pulley with a dial indicator. Where the flange of the pump bolts to the face of the pulley. Hardly any fluctuation.

Busted out the impact, pulled the pulley and this is what we got.
Ignore the green arrows and numbers, was trying to explain it to my friend via text.



outter ring of the balancer has walked off the inner ring a bit I’d say..
think I found the issue?
 
The outer hub/ring can and will occasionally slip from its original position on the inner hub.
However, if so that would not affect the inner hub’s face and/or any run-out to the face...... meaning that (baring no other issues) the crankshaft pump should run true!

An outer harmonic balancer hub/ring that has slipped may cause an inaccuracy with your TDC marking, which means that you will not be able to set the Ignition Advance correctly!
This is extremely important, and should be addressed!
(your GM Engine is fitted with full Dished pistons. Excessive ignition advance will lead to engine damage.)

In order to verify the TDC marking, you will need to perform a PPS procedure.



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It appears from the photo, that the displacement of the balancer from the hub is "even" all around. I would expect that in order for this slip to be at the heart of your problem, that it would have to be an uneven displacement. Check the runout of the hub to be sure.
 
Just a little update, looks like the pulley is the culprit. Laying it face up on a flat surface I was able to see it was bent. Definite high side and low side..

ordered him him a new pulley, balancer and I’m fixing his timing cover leak while I’m there. Should be good to go!

Ill post back results, waiting on parts.
Thanks again gentlemen ��
 
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