What size radiator ?

[Priesty]

Wondering what original size radiator should be in my 340 4spd (no air) Cuda ? Currently have 22" & just not doing the job, if I want to fit a 26" do I have to cut the radiator support area, or is there a removable panel to open up the extra area ?

cheers......

[burdar]

I think the 340 cars got the 26" rad.  Measure the opening in the rad support.

22" rads came on some BB cars from the factory.  The 22" should be fine on the 340.  What problems are you having?  Does it get hot while at a stop light or while driving down the road?  Have you checked the timing?(what's it set at?)  Do you have a fan shroud?  Are you using a clutch fan or a fixed fan? 

[Moparal]

so many issues and not enough info.

Fan shroud
degree therm if it even works
new block/old block  over bore
sludge in block
direct drive fan?
timing
fuel lean
calibrated gauge
lower hose colasp
plugged flutes in radiator

22 inch 2 row non air with fan shroud and direct drive , 182 thermo was efficient and would run at right temp all day, idling and cruising

[Priesty]

So I take it from your responses that either size radiator could be factory fitted for my application ? Rad support opening is for 22".
Haven't had any boiling issues as such, but definitely running warmer than I'd like. I've had it out a few times recently where ambient temps were only around 25*c
(85*F app.), & the temp worked it's way up to around 210-215f. probably ok at that temp, but given that temps here can reach 35-43*c in summer (*96-120*f) I'm concerned that engine temp would rise accordingly. I already added a home fabbed fan shroud & swapped out the 13lb rad cap for a 16lb, but seems to have made little difference. Did seem to run slightly higher temp at highway speed (around 3200rpm) & backed down about 5*f when I exited highway, but still a little too warm for me.
OK, Q&A time:
Unsure of t/stat, will check out shortly.
40,000 fresh motor, stock bore & pistons, Direct 6 blade flexible fan (no clutch) approx. 1 1/2" from rad. face.
Yet to check timing. Around 12-16 btdc initial advance sound right ?
Aftermarket gauge used, might seek a second opinion from my trusty BBQ meat thermometer. Don't laugh, it's the most reliable temp gauge I've ever used.
Radiator is supposed to be freshly re-cored before I bought the car & does appear to be in reasonable condition with a recently date stamped tag. (2 row 22").
cheers....appreciate your input.

[burdar]

Stock thermostats are 192 degrees.  The thermostat sets the "lowest" temp the engine will run at.  210-215 is probably completely normal for slow speed driving.

In order to be most effective, the fan blades should be sticking into the shroud HALF of their thickness. (half of the blades into the shroud/half of the blades out of the shroud)  You can adjust the depth with spacers between the fan and the water pump pulley.  My car came from the factory with a 2" spacer and no shroud.  If your radiator support has a 22" opening, then that's the size of radiator the car would have come with.

A lot of people don't like "flex" fans.  I would look for a factory fixed fan or a clutch fan.  Both of those should pull more air through the radiator.  If you are getting hot at low speeds, that is an airflow problem.  If you are getting hot on the highway, that is a capacity problem.  Another possibility for getting hot on the highway is that at higher RPMs, the lower rad hose is being sucked shut.  Some hoses are more flexible then others.  Some require a spring inside the hose to keep it from collapsing.

I would check the depth of the fan in the shroud, and look into a factory fixed or factory clutch fan.  You can buy a cheap infrared temp gun at Harbor Freight. Scan multiple places across the radiator core and see if there are any hot spots.  This would be an indication of a plugged core.

[crash340]

Did the new higher pressure radiator cap stop it pushing water out Steve?
my lower hose does have a spring in it FYI, my 22" radiator was cleaned out before I got my car apparently, while I had the K frame out I knocked out the anti freeze plugs and made sure all of the block's water jacket was not only rust and sludge free but sand free, it still had sand from the casting in some spots. So my car runs perfect according to the factory gauge, I have no reason to doubt it as it climbs a little in slow traffic, it does not boil or blow water, no shroud, has flexifan, dont know what the thermostate is. all I know is, radiator is clean, lower hose has spring, block is clean. good to go. Im about to advance the timing a little so I will see how that goes with temp. My A/F gauge tells me I'm running a good mix.

[Priesty]

Thanks all.
That gives me a few things to look at. Will give the bottom hose a squeeze to see if it has a spring. Also noticed my fan is nearly completely covered by the shroud, might see if I can tweak that a little as well. Also buying a high flow 180* t/stat today as well.
In the event that I do end up replacing the radiator, what's the pros/cons of Aluminium v Copper, the car is fairly original so I'm leaning towards copper replacement, perhaps 3 core version.
Crash, 16lb cap didn't stop the overflow after shut down, although I'm sure it should raise boiling point some.

cheers...

[burdar]

Stock radiators have a plate about an inch under the rad cap.  This plate is the "full" line.  If you fill the rad up to the top, it will puke out when you shut the car off.  Eventually, this should stop as the level goes down but it's embarrassing.  Check to see if you have it too full.  Definitely move the fan back towards the engine a little bit.  The fan could be churning the air inside the shroud but not pulling much air through it.  If you want to keep the stock look, you can have a new core installed onto your original brackets and tanks.  A few years ago, it cost me $400 to recore my original radiator.  Two or three row cores were available.

[Priesty]

Checked lower hose, no spring fitted, still to check t/stat & timing. Have not topped up since last spurt from radiator so will leave it & see.
Attached pic below of shtoud, it's 2 piece so I can remove & shorten the snout by about an inch to expose more of the fan.
cheers...

[crash340]

Nice shroud Steve!, have you any trans cooler in front of the radiator???, is it all stock in front

[Priesty]

Thanks Greg, no other coolers or anything in front or back of Radiator.

[DocMel]

You dont have cooling prob at 215

[Chryco Psycho]

The shroud is fine , with the fan inside the tunnel it will pull air .
 If it si running hotter at speed the fixed fan may be blocking airflow as it should cool just fine without the fan if you are moving more than 30-40 MPH , I would try a clutch fan .
 ALum rads need to be rubber mounted as they will crack with any flexing , brass is a bolt in .

[Priesty]

The shroud is fine , with the fan inside the tunnel it will pull air .
 If it si running hotter at speed the fixed fan may be blocking airflow as it should cool just fine without the fan if you are moving more than 30-40 MPH , I would try a clutch fan .
 ALum rads need to be rubber mounted as they will crack with any flexing , brass is a bolt in .

Glad to hear that, as I was hoping to avoid removing the shroud again for now, PITA job.
Timing is set at about 12* initial advance, not sure how to check at full advance as scale on block only goes to 10*.
Checked actual temp v aftermarket gauge & seems to be pretty correct.

[Chryco Psycho]

put a mark on the damper 2 3/8" clockwise from the TDC mark & that is 36*