1969 383 magnum water pump questions

[nickm]

Hey Guys,

 I have a 1969 Dodge Charger SE 383 magnum with TF727 and AC.

 Question 1)  Can anyone tell me what this (see photo) sensor is?  It's mounted to the top of the water pump housing with no wires hooked up.  Is it the temp control switch, or something related to the AC?  I had to rebuild my cluster gauges, so I have not been able to test if I have any working temp sensors...

 Question 2)  I purchased a Milodon 16260 high flow water pump http://www.milodon.com/water-pumps/water-pumps.asp but after reading my manual, there are pumps specific for AC cars?  Does anyone know if this pump is compat with AC cars?

 Thanks!

[John_Kunkel]

1) That sensor is more common on cars with a temperature idiot light, I don't think it's correct for a '69 B-body.

2) Factory A/C water pumps have 6 vanes on the impeller, non-A/C pump has 8 vanes.

[nickm]

Thanks for the reply John.

I talked to Milodon Technical Support, they don't specify AC vs non-AC, the impeller's are 8 vaned for the higher flow rates. 

Will this damage any of the AC components? 

Any one on the forums running this pump with an AC car?

[A383Wing]

you need the correct AC water pump...otherwise the water will cavitate and you will over heat if you use the 8 vane pump

[71 SE3834V]

nick, to better help you understand why you need a 6 vane here's what I have learned researching this.
The AC car use a smaller belt pulley so the fan and pump spin faster at idle to pull more air through the radiator and circulate the coolant better. However at higher rpm's the higher coolant flow can lead to cavitation as stated above therefore the reduction in vanes from 8 to 6.
My AC '71 383 has a 6 vane in it. I tried to find a new pump through the local vendors when my engine was rebuilt and could not find a 6 vane so the old one went back in. I did not do an internet search so I can't tell you where to get one.

[A383Wing]

didn't someone to an extensive write up about all the different water pumps out there and which ones worked and which ones didn't? I can't find it

[Mopar Nut]

didn't someone to an extensive write up about all the different water pumps out there and which ones worked and which ones didn't? I can't find it

Is this the one? reply #191

http://www.dodgecharger.com/forum/index.php?topic=60599.175

[Pete in NH]

For some reason 6 blade pumps don't seem to be available anymore. I don't know if this is a case of vendors trying to simplify their inventory or at some point it was discovered the 8 blade pump would really work on both A/C and Non A/C cars and the original set up was a case of over engineering. Any way, I have two 6 blade pump cores and was wondering if any one has found a way to rebuild them and where parts might be available ?

[nickm]

I pulled my water pump last night and found an 8 vane.

For those of you in the same boat as me, this post has some great info: http://www.dodgecharger.com/forum/index.php?topic=81260.0

I found this http://www.theymightberacing.com/Literature/BookArticle.aspx?ArticleID=11 looking for part number #3683834, which says Chrysler replaced the 6 vane with an 8 vane.  This may explain why finding a remanufactured 6 vane pump may not be possible?  

[John_Kunkel]

The article in the link above states " Note at this point that Chrysler's reason for two pumps was simply to slow down the water flow in the a/c equipped vehicles." but they fail to mention that the reason for slowing down the flow was because of the A/C pulley ratios. A/C pulleys overdrive the pump 40% (140% of crankshaft speed).

This is the critical factor when selecting pumps, the factory sped up the water pump in order to get more airflow from the fan.

[nickm]

This looked promising https://www.jimsautoparts.com/water_pumps.htm Part #FC-5481.  But they were unable to tell me how many vanes are on the AC pump, they just said it's a direct replacement for what came on the car stock.  Has anyone here ordered one before?  I may order it and report back on the findings... I'm not having much luck finding a non-8 vaned pump.

[PlainfieldCharger]

Here is a link for a 6 vane on ebay.

http://www.ebay.com/itm/Rebuilt-3671083-Chrysler-Water-Pump-Mopar-400-440-Big-Block-Hemi-1972-1973-C/371333332396?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D31729%26meid%3D2c6d9c074c0a4ccc84fdd1f00628546a%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D391152352908&rt=nc

[BLK 68 R/T]

I have a new aluminum pump and housing from 440 source (hope they have the flow issue figured out by now that I have read nightmare stories on!) anyways, pulled the pump out to look and it is a 6 vane pump. The impellers are part of the backing plate which is supposed to help with flow. I will know how well it works here in a few months hopefully.

[John_Kunkel]

This looked promising https://www.jimsautoparts.com/water_pumps.htm Part #FC-5481.  But they were unable to tell me how many vanes are on the AC pump, they just said it's a direct replacement for what came on the car stock.  Has anyone here ordered one before?  I may order it and report back on the findings... I'm not having much luck finding a non-8 vaned pump.

Order from Jim's?