Radiator Flow

[Rex_A_Lott]

I've seen several threads here where the condition of a radiator's flow has been mentioned.
I remember years ago the good shops had a flow checker, but I dont know if they have a clue what I should actually expect.
Does anybody have accurate numbers of what a good radiator will flow?
Are the 28/29 different from the 30/31?
I've got some old ones I want to get checked/repaired and lay them up in a safe place for spares.
I also have a 30 that's going to need some attention pretty soon.
I'm aware that it used to be common practice for the shops to block off a few tubes and solder them shut...yeah it looks like crap on the front, but how much does it really reduce the cooling ability of the radiator?

[Tom Wesenberg]

If you have 100 tubes, then each blocked off or soldered closed tube reduces the cooling by 1%. The bad thing is that blocked off tubes will slow the flow to the bottom and the water pump will fill the top tank until it flows out the overflow pipe. That's what happened to me.

I find the flow test useless. An inspection camera will let you see the tube tops and bottoms. That how I knew when mine were clean enough. Mine flows and cools great now, but I still need to get rid of some rust in the engine block so it doesn't block the tubes again.

[Mike V. Florida]

Here is the problem with radiator flow test. Let's assume the target is 3 seconds.

Which radiator is better;

1 quart drained in 3 secs
2 gallons drained in 3 secs?

Get the point, how fast is nothing compared to how much?

[Bob Johnson]

After doing tests on radiators and cores I found that the outlet on the bottom of the radiator restricts the flow rate because it can not flow as much coolant as the core. Thus you can have a partially blocked radiator and the flow rate thought the radiator will not be slower than a non blocked radiator. If the core is real bad you then will see a slower flow rate.

Bob

[Chuck Sea/Tac]

I think he's asking for the gallonage flow, plus the time. Not just the time, which, I agree is useless. I've wondered the same my self. It probably be, listed as, "blank" many gallons per minute?

[Rex_A_Lott]

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Originally Posted by Mike V. Florida

Here is the problem with radiator flow test. Let's assume the target is 3 seconds.

Which radiator is better;

1 quart drained in 3 secs
2 gallons drained in 3 secs?

Get the point, how fast is nothing compared to how much?

Originally Posted by Chuck Sea/Tac

I think he's asking for the gallonage flow, plus the time. Not just the time, which, I agree is useless. I've wondered the same my self. It probably be, listed as, "blank" many gallons per minute?

I agree, the time test isnt worth much. The machine I am referring to has a pump and puts the radiator in series with a flow meter and reads in GPM , (gallons per minute). I was hoping someone would know what an acceptable range is. Fifty years ago the radiator shop guy probably knew it by heart, but I wouldnt expect them to know that now. Thanks for the replies.

[Chuck Sea/Tac]

It wouldn't Surprise me if Marco or Vince had that info

[jkeesey]

I thought it was block the lower outlet, fill the radiator, remove the lower outlet and count 7 seconds. I think it was 7 seconds.

[GB SISSON]

There is a youtube video of a couple of guys doing a model A radiator flow test with a 5 gallon bucket on a ladder. The bucket has a flap valve which might be from a toilet. It is plumbed into the radiator and a stop watch is involved. I saw it two weeks ago when I was first investigating my overheating problem. In the video, the two guys have a number of gpm that they feel signifies a 'good radiator'. Maybe not too scientific by today's standards, but it was certainly interesting to watch and I see no reason to doubt their results. Shouldn't be too difficult to find. Post a link if you do, as I don't know how to post a link and I'm tired and heading off to bed..... zzzzzzzzzzz