Harmonic Balancer VS. Water Pump Conflict

[str12-340]

complicated by a wholesale redesign of everything in front of the block between 1969 and 1970...

 

[YY1]

Pretty ballsy painting an engine white.

 

[dibbons]

Pretty ballsy painting an engine white.

Not to worry, It's only a "mule' engine that will be sold and replaced by a Mopar 305 (de-stroked 340) shortly.

Introducing "Project Odyssey" a 1972 "Super Satellite"

 

[dibbons]

Found a plastic bag blowing around the back yard. Turned out to be the bag (with part number) from the water pump I purchased what now must be at least several years ago.

 

[str12-340]

A 1970 and up aluminum pump with a passenger side lower hose should all be the same as I believe there were no housing casting versions from 1970 to the end of LA engine production (someone fact check this if I am wrong!). There are impeller differences but that wouldn't change the balancer clearance.

By the way the water pump and timing cover are located by the threaded holes in the block not the pump body or timing cover.

 

[CRUZE 418]

There are no dowl pins, so, timing cover is located or centered by the balancer.

 

[trapster]

What year is the 340? is that Harmonic neutrally balanced ? I thought 340's were internally balanced.

 

[dibbons]

What year is the 340?

The partial VIN on the block is "3G212185". The "3" indicates it was originally a 1973 model year production. But i'm using a forged crankshaft with a neutral-balanced harmonic balancer. Factory 1972-73 340's mostly had cast cranks and external balancing as far as I know.

 

[str12-340]

There are no dowl pins, so, timing cover is located or centered by the balancer.

The timing cover is located by the bolts through the lower cover that hold it directly to the block and then by the bolts that go through the water pump and the timing cover into the block. The balancer goes on after the timing cover is bolted on. Should the lower hole in the timing cover be centered on the crank when you install the balancer? Sure. But the balancer has no effect on the location of the timing cover.

 

[dibbons]

But the balancer has no effect on the location of the timing cover.

True, except for a tiny bit of "play" thanks to factory tolerances and a tiny bit of wiggle room in the bolt holes of the pump and cover. May or may not make any difference installing balancer before final torque on all the other bolts.

 

[CRUZE 418]

You do it your way sir. I'm sure that you haven't ever had a problem, but respectfully, I disagree.

 

[Woody500]

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.

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One laying on cardboard looks like rubber is delaminating. Check rubber closely