Heater core mod

[jlrii]

Anyone ever have any luck modding a heater core, I have one just the size I need exept in lenth, Its about 1/2 - 3/4 to long inlet to outlet (single pass). Just looking for some advice B4 breaking out the torch.

[Bobonit]

I'm confused about your question. Are you saying the connections to the heatercore are too long? Meaning they stick out to far?

[Butcher]

Modding a heatercore lengthwise is pretty trickey - there's a lot of stuff to solder up. So far as I know, no enthusiast has successfully managed it.

[Bobonit]

Ahhh, you are trying to make the heatercore itself narrower? Man, good luck. Like Butcher said, lots of soldering. Good luck. Post back with your results if you try it !!

[AngryAlpaca]

Butcher, I got it with expanding polyurethane glue. However, most of the holes are plugged so it is useless, although only 13cm long...

[jlrii]

Well it's a long thin core, only 8 passes. the end cap "apears" to be two pieces, one soldered to the passes and a cap with the fittings. I'm pretty good at soldering/brazing (was in the HVAC trade for a lot of years). I'll try to post some pics if I can make it work.

"I'm confused about your question. Are you saying the connections to the heatercore are too long? Meaning they stick out to far?"

Nope shortening the whole core end to end...wish me luck

[Bobonit]

Good Luck !!!

[Kobuchi]

Try the original solder's working temperature on a cut off.

[Mars]

Originally Posted by jlrii

Well it's a long thin core, only 8 passes. the end cap "apears" to be two pieces, one soldered to the passes and a cap with the fittings. I'm pretty good at soldering/brazing (was in the HVAC trade for a lot of years). I'll try to post some pics if I can make it work.

"I'm confused about your question. Are you saying the connections to the heatercore are too long? Meaning they stick out to far?"

Nope shortening the whole core end to end...wish me luck

I work at a rad shop, so we build heatercores sometimes. It is easier to shorten the width of a heatercore by de-soldering the layers one at a time (they look like thin wafers). To shorten the length of the heatercore you just cut it staight. Either way you have to de-solder the top and bottom tanks off first. That is if your heatercore is like the one I just mentioned. If you alter the width, than you also have to alter the width of the tanks.

[jlrii]

Originally Posted by Mars

I work at a rad shop, so we build heatercores sometimes. It is easier to shorten the width of a heatercore by de-soldering the layers one at a time (they look like thin wafers). To shorten the length of the heatercore you just cut it staight. Either way you have to de-solder the top and bottom tanks off first. That is if your heatercore is like the one I just mentioned. If you alter the width, than you also have to alter the width of the tanks.

Thanks, planning on removing one tank, shortening (possibly with a metal cutting blabe on my tablesaw, seens to do a noce clean cut), and then re-soldering. As for solder, planning on using "BridgeIt" from Harris. It has some nickel in it which makes it easier to fill gaps with, even though it still flows well. What I'm wondering about is the best way to "push back" the fins between the passes, I am assuming that the passes protrude into the end cap somewhat.

[Mars]

Originally Posted by jlrii

Thanks, planning on removing one tank, shortening (possibly with a metal cutting blabe on my tablesaw, seens to do a noce clean cut), and then re-soldering. As for solder, planning on using "BridgeIt" from Harris. It has some nickel in it which makes it easier to fill gaps with, even though it still flows well. What I'm wondering about is the best way to "push back" the fins between the passes, I am assuming that the passes protrude into the end cap somewhat.

????? If your radiator uses tubes with fins (single pass) then I don't reccommend you do this without good practice and knowledge. Try it on a different one before hacking up yours. If your radiator is a copper/brass heatercore from a car (wafered tubes) then it is what I explained.
I have a feeling you have the first type I mentioned. I have seen professional rad-men with 10yrs experience try this alteration before and they have a bitch of a time. Try posting pictures of the rad that you have so I can further be of assistance.
Also, I have never heard of the "BridgeIt" before. What we use is 50/50 kester solder. Lead-free. It has a small percentage of "silver content" to increase conductivity.

[Butcher]

Silver also makes for a stronger solder.

[bobkoure]

What core is it?
You may find that a different manufacturer of the same heater core ID may have built it with shorter tanks.
It may also be easier to modify your case - or find a different case.
FWIW, here's a list of the single pass cores I know about (numbers and dimensions from "cores.zip") spotting that they're single pass and which way the inlet/outlet tubes go are from my web searching - and all are oriented with header tank with the inlet at the top.
front - comes towards you
back - goes away from you
top/bottom - straight up or down
side - off to left or right

2-551	5.25	6.625	2.625	side
2-549	6.25	6.375	2.625	top+bottom
2-610	6.25	5.5	1.34	top+bottom
2-553	6.375	6.125	2	side
2-149	7.75	6.125	2	front
2-208	7.75	6.125	2	front+side
2-215	7.75	7.375	2.5	front
2-216	7.75	6.125	2	side
2-217	7.75	6.125	2	side
2-278	7.75	6.125	2	side
2-451	7.75	6.5	2	front+back
2-764	7.875	5.938	1.625	top+bottom
2-770	9.188	6.875	1.625	top+bottom
2-275	9.5	6.125	2	side
2-342	9.5	6.125	2	front
2-353	9.5	6.125	2	side
2-209	9.875	6.125	2	side
2-210	9.875	6.25	2.5	side
2-272	9.875	6.125	2.5	side
2-317	9.875	6.125	2	side
2-617	9.875	6.125	2	side
2-766	14.188	3.25	1.625	top+bottom