Main Crankshaft Pulley

[RobotMan 264]

I went to install the main crankshaft pulley and noticed there is no centering feature with the balancer. All other pulleys have a centering feature whether it is a shaft or boss. Is this correct? I would think the clearance in the bolt holes would allow the pulley to be pulled off center. I am missing something? Thanks

 

Rick

[Brian Conway 264]

The crank shaft pulley is just that a pulley. So match up the bolt holes and install. The crank shaft balancer is ' keyed ' for installation in a particular orientation. Brian

[RobotMan 264]

I just thought the weight being off center would make it off balance like a tire out of balance.

[1969_Mach1 333]

Some harmonic balancers have a shoulder to locate the pulley and the pulley fits snug over the shoulder.  Some harmonic balancers have a counter bore and the pulley has a shoulder that fits snug into the counter bore.  Make certain you have the correct combination.  The pulley bolts plus the clearance in the bolt holes are not intended to locate the pulley on the crank centerline. 

[Rsmach1 71]

+1 with 1969_Mach1, what balancer and pulley are you using.

[RPM 1,190]

I certainly wouldn't use use any pulley without the centering ring. Even your water pump pulley is centered by the shaft.

[RobotMan 264]

Thanks guys I will check for those features.

[RobotMan 264]

I have a balancer with P/n FRM015644 PB1009N. It has an internal counterbore inside the pulley bolt pattern. It was provided and installed by shop that built engine. I do not know the brand but know it is a 28 oz balancer. My pulley is a C9ZE-6312-B for a 351W with P/S and A/C. It does not have a feature to fit the counterbore of the balancer. Any suggestions of where to go from here?

 

[Rsmach1 71]

That is by Dayco, and appears to be the wrong balancer. The correct part # for a 69 is PB1082N according to there website. As for what to do next, 1 more question, did you have the engine balanced?

 

If you thumb through the images you'll see this one has the centering ring on the balancer.http://www.daycoproducts.com/part?category_id%3D1084%26year%3D%26make%3D%26modeltype%3D%26model%3D%26description%3D760%26part_number%3DPB1082N for a 351w or #pb1203n for a 302.

 

Edit, if you didn't have the engine balanced the fix is to simply swap for the correct balancer, if you did have the assembly balanced I would contact the shop as a swap may require a re-balance of the assembly.

[RobotMan 264]

Thanks for the info. Will do.

[RobotMan 264]

I looked at the P/N on the Dayco website. You are correct it calls for the PB1082N. However that is a for a 4 bolt pulley. I need a 3 bolt. I will continue to look. Maybe there is a 3 bolt version.

[Rsmach1 71]

My bad, look at the pb1203n, although listed for a 302 it should be fine for a 351w.

[Rsmach1 71]

OK after looking through Dayco's catalog they list different balancers for the 351w 2v,and 4v,wich is incorrect as they used the same one.

[RobotMan 264]

Yes I agree. My assy manual does not call out any diff between 2v or 4v. It's interesting they call out the P/N I already have for the 351w 2V. No doubt this is why the engine builder picked this one. But it has no centering feature for pulley.

[RobotMan 264]

Rsmach1 do you think it's worth switching to the one with the centering ring. I called the engine builder and he did not know if it was a problem but indicated he had engines in shop with pulleys bolted on without centering ring. Not sure how much it matters.

[Rsmach1 71]

Go with the PB1203N 302'S and 351w use the same crank snout, and if you look at hp aftermarket balancers they all list 289,302,351w for the same part.

[RobotMan 264]

Forgive my ignorance but how do you ascertain if the PB1203n is a 28 oz balancer?

[RobotMan 264]

That is also about a .16" thicker. Will this affect any kind of alignment?

[1969_Mach1 333]

Here is another balancer option by Pioneer that is correct for your pulley setup.  http://www.summitracing.com/parts/pio-872008/overview/year/1969/make/ford/model/mustang  Ideally if the rotating assembly was balanced it should be rechecked with the new balancer.  Sometimes that's not feasible.  I have replaced a balancer before on an externally balanced motor that was balanced and had no issues I could notice.

 

On my 1969 351W the crank pulley looks just like yours and my balancer has s shoulder and looks like the Pioneer I listed.  I am not certain what your balancer is for.  But I am not surprised if an engine builder installed the wrong balancer.  Most machine shops are not familiar enough with Fords to know these subtle differences.

[Rsmach1 71]

I don't believe so as the overall width they list is .16 different, that .16 looks to be how far the centering sticks out from the damper.

[Rsmach1 71]

The one 1969_Mach1 listed is another choice, but as I stated earlier, it is listed for a 302/351w also. Pioneer is a reputable brand, and although I'm sure the 1203 will work fine, I have to question Dayco because of there application mistakes.

 

Edit, but for all we know they may be the exact same part manufactured by one company.

[RobotMan 264]

Thanks for all the info and advice guys. Much appreciated.

[Rsmach1 71]

You're welcome, let us know what you end up with and how it works out, it makes it easier to help the next guy.