Harmonic Balancer VS. Water Pump Conflict

[dibbons]

After installing the timing cover, water pump, and harmonic balancer on this rebuild 340 project, the engine now rotates with extreme difficulty over 90 degrees of rotation. At first, i squirted VD-40 in the spark plug holes believing maybe one cylinder was a little dry, put that attempt provided no benefit/improvement.

Then I noticed that during a portion of rotation, the bottom of the water pump has no clearance with the harmonic balancer (photo #1). I don't know yet if the problem is with the pump, the balancer, or both. This problem really took me by surprise.

The smallest feeler gauge I have is .004" which I can fit it during partial rotation. Then at a different point it won't go in the space between the water pump and balancer. Then I placed some blue masking tape all around the balancer and found during rotation the tape starting to fold up on itself (photo #3). I have no idea what the normal clearance in this area should be. I do have another spare (old) harmonic balancer on hand (photo #2). The water pump and timing cover are new.

If I install an new balancer and still have the problem, I will really be perplexed. Standing by for input from my Mopar brothers. (also posted on FBBO) Thank you.

 

[jeff alder]

Is that the correct water pump / harmonic balancer / timing cover for what year the 340 block you have?
Chrysler Mechanical Water Pump, High Volume Aluminum 318 340 360 - CVF Racing | eBay

 

[dibbons]

Is that the correct water pump / harmonic balancer / timing cover for what year the 340 block you have?

I no longer have the box for the water pump, but I don't see anything but one choice for small block water pump with outlet on the passenger side. I almost feel like taking the water pump and balancer off the 318 that the 340 will be replacing and see how that works out.

 

[Desoto291hemi]

I suspect the pump or cover
If the cover is machined wrong it can locate the pump lower
Or the pump might be machined wrong

I have read a few times lately if this happening

 

[Desoto291hemi]

Shiny new stuff machined off shore is always suspect to me

Tommy

 

[dibbons]

I suspect the pump or cover
If the cover is machined wrong it can locate the pump lower
Or the pump might be machined wrong

I understand what you are saying but the bolt holes and gaskets seemed to match up perfectly.

I thought I was doing the right thing when I installed the balancer before final tightening the cover and pump so that the oil seal would be centered on the balancer. I don't see how that could cause a problem.

 

[dano]

Whats the part number on the damper?

 

[jeff alder]

I no longer have the box for the water pump, but I don't see anything but one choice for small block water pump with outlet on the passenger side. I almost feel like taking the water pump and balancer off the 318 that the 340 will be replacing and see how that works out.

It could be any combination of the parts conflicting. If you look at the casting in the picture you posted and the example I pulled from ebay they are from entirely different casts. Yours has that big web interfering with the balancer. The example posted has no web at all. I truly think you just have a wrong part for the year of engine you have. Either the pump, timing cover, or balancer. 1, 2 or all 3 of them. There are several different designs out there.
Mopar Chrysler SB 318 340 360 High Volume Aluminum Slimline Water Pump | eBay

 

[Professor Fate]

Check and see what you have for clearance between the balancer and the boss with the timing marks on it, too. I have heard more than once that it is also a common point of interference.
If the balancer clears the timing mark boss, then I'd be taking a die grinder to that water pump web. It won't take much.

 

[Oldmanmopar]

The rubber on the damper looks thicker on the one side then the other. Ditch the damper if it hits on one side only its junk.

 

[jeff alder]

the second one pictured looks more symmetrical.

 

[middleagecrisis]

Is the timing cover aftermarket? I remember someone having an issue not too long ago with the balancer rubbing on the timing tab of an aftermarket cover (Dorman?) . I'd look at the 318 cover you have and see how it looks compared to what you have on the engine. The fact that the balancer only rubs in one spot is a concern, as well. Stock replacement dampers are cheap enough to replace for peace of mind.

 

[dibbons]

Is the timing cover aftermarket?

Yes it is, just purchased at AutoZone.

 

[Oldmanmopar]

The issue here is the damper is rubbing only on one side, So there is definitely a problem with the damper . If it was hitting all the way around then it would be the stationary part , Due to one side of the moving part only hitting it is the moving part.

You can see the damper is junk just in the partial picture. Take a picture of it head on so the whole face is visible. That Damper will self destruct in very little time. It will also throw the engine out of balance.

 

[Kendog 170]

What diameter damper? If my memory is correct, it should be 7 1/4" diameter.

 

[jeff alder]

The issue here is the damper is rubbing only on one side, So there is definitely a problem with the damper . If it was hitting all the way around then it would be the stationary part , Due to one side of the moving part only hitting it is the moving part.

You can see the damper is junk just in the partial picture. Take a picture of it head on so the whole face is visible. That Damper will self destruct in very little time. It will also throw the engine out of balance.

Good Catch! That looks like almost 1/4 inch difference between where it's blowing out compared to the opposite side.

 

[Ant]

Get a new balancer anyway, the rubber is old.

Also, the buttress getting in the way may be an issue with that autozone special. And yes, it's called a buttress.

 

[Dartswinger70]

Agree on the balancer. try that first it just doesn't look right. Check the part number should be some sort of number on it . Maybe on back side youll have to pull it.

 

[4spdragtop]

Fyi, I bought a new TF balancer and a 68/9 used timing cover with timing marks on pass side for our 70 340. Works perfect. The TF balancer is 4 lbs heavier then OEM.

 

[dibbons]

Update: I removed, cleaned, and painted the water pump from the 318. I cleaned up and painted the circumference of the other spare harmonic balancer. Now need to substitute these other parts and see what happens.

 

[dibbons]

Update: Test fit the used 318 water pump to find all kind of clearance with the currently installed harmonic balancer, which will be swapped for another one regardless (photo #1). Found the installed new water pump had clearance issues! (photo #2) Very frustrating trying to restore a vehicle in this day in age.

 

[4spdragtop]

What mfg is the problem w/p?
Glad ya figured out the issue.

 

[CRUZE 418]

All of these same questions and answered up on FBBO. 24 up there and now 22 down here. You can stop now.

 

[dibbons]

Final Update: Installed the other spare harmonic balancer I had on hand. Now the clearance between the timing tab on the timing chain cover is zero: see photo #! (but the crank still spins freely). The water pump clears the balancer by a mile compared to the previous pump: see photo #2. The timing tape I had in storage turned out to be too short (see photos #3, #4) so I made my own with blue masking tape. The timing tape arrived all crinkled like it had been re-packaged or something.

 

[jeff alder]

Standardizing these parts to make it simple among the LA engines would have been an engineering marvel for guys like us. Some of us make a living making "some" not all engineers look good.