Pressure radiator caps and ??

[Lou Earle]

Someone wrote:

"I have been running a 4# cap on my stock P-15 radiator since the first time I boiled it dry at an elevation where water melts at 192 F, and my system has never had any problem with it. It is the same system used when Plymouth went to a pressurized radiator cap and there is nothing mysterious about it. I use a Stant cap with a seal that extends below the overflow tube and I bought it from NAPA so long ago that I'll probably replace it with a new one just like it when I fire the beast this coming Spring. There are other members of this forum who have done the same thing. I admit it was an experiment when I first tried it but had a spare radiator and was willing to take the gamble; that spare radiator still hangs in my garage."

That is fine and you will have pressure if the radiator has been modified like the one in the first pic. Notice the vent tube now originates from the fill neck NOT the center of the radiator.

You can put a 50 pound test cap on the radiator in mu 47 plym (pic 2) and you will still have no pressure because you r overflow tube originates in the center- it is simply a hole in the radiator top - So how can it hold pressure - it cannot.

So if your overflow tube originates on the fill neck you can pressurize the system- Mine is 7 pound cap I think. But u will get no pressure from a radiator that the overflow tube originates somewhere else.

Lou

48 Dodge radiator modified to take pressure:

Stock 47 Plymouth non modified that will not create pressure even with pressure cap:

The problem is these statements- becuause they are not consistent:

1-""I have been running a 4# cap on my stock P-15 radiator "

2-"I use a Stant cap with a seal that extends below the overflow tube "

The stock radiator - pic 2 DOES NOT have the overflow tube orginating in the water neck. So I conclude he either has a modified p-15 radiator or some other pressurised radiaton in his p-15

Hope I have helped cleer things up rather than muddy the water.

Now if I can just get the Gas to flow into my distributor so it can get to the pistons mine will run fine.

Lou

[Plymouthy Adams]

Lou..change your distributor filter..it may be clogged...

[Lou Earle]

and what is the part # And where can I get a a fan thet pushes the air out - mine for some unknown reason pulls perfectly good air thru the radiator and heats it up thereby causing the engine (the thing that rusn the car-or is that the clutch) to heat up I think i ned one to pusththe air out. Also I have noticed that my battery only had 3 holes not 6 should I drillsme more holes in it to give it better thrust?

Lou

[Plymouthy Adams]

On the battery..don't mess with it..also be careful maintaining it..I have seen idiots put so much water in their batteries that it runs through the wire and into the tail light housings and collects there...you'd think people would learn better...and oh yeah...be sure to vent the reservoir when adding turn signal fluid by flipping the lever left and right..it can blow the cap off if you don't purge all the air. What's the preload on the choke..think mine is slipping.

[Merle Coggins]

My truck radiator has the overflow tube coming out of the fill neck like in the first picture, and as far as I know it's original.

Tim, your choke preload is 2.176 newtons. Also, be sure you have the Dingle Arm in the correct position when setting the preload, otherwise the Girdle Spring may damage your Muffler Bearings. Also, after my engine rebuild I noticed one left over Piston Return Spring. Do you thing that will creat a bad Rod Knock?

Merle

[Plymouthy Adams]

Man, that is the third muffler bearing this year...I'm spending an extra 3.50 this time for the whirly-grommet to protect it..

my engine developed a leak that may have been contributed to a missing return spring and it piston my foot

[Brad Lustig]

You can always go to Kale Co Auto and buy them in bulk.

http://kalecoauto.com/index.php?main_page=product_info&cPath=3&products_id=10&zenid=f81b56533190f5d38b48b0415b566e15

[randroid]

Gents,

Okay, now I get it and feel I may owe somebody an appology. I started playing with my P-15 in the late 80's and have had three radiators, all of which had the overflow tube right under the cap. I've been wondering why some of you have been so adamant that a pressure cap wouldn't make any difference, and now I understand.

Oops.

-Randy

[Merle Coggins]

You can always go to Kale Co Auto and buy them in bulk.

http://kalecoauto.com/index.php?main_page=product_info&cPath=3&products_id=10&zenid=f81b56533190f5d38b48b0415b566e15

WOW!!! They got all the good stuff. Now I know where to get that Kneutson Valve I needed. And I think I'll order that left handed metric screwdriver too. http://kalecoauto.com/index.php?main_page=product_info&cPath=5&products_id=21&zenid=f81b56533190f5d38b48b0415b566e15

[greg g]

One thing missing from their catalog is a speedometer gear calibrated to the new speed postings in Kentucky. the new speed measuring goes int effect the first Saturday in May. So you need to get your speedometers changed over to furlongs per fortnight.