Original vs Omix-ADA radiator

I’m always curious about people’s understanding of the thermostat and the cooling system in general.  I grew up in the radiator business.  Between my grandfather and dad, we had 5 radiator shops in Texas and New Mexico.  I have worked on thousands of radiators from the smallest heater cores to giant oil refinery heat exchangers, so the cooling system is near and dear to me.

Ya’ll are correct about the need for a thermostat, however, the temperature function of a thermostat in and of itself is generally not necessary (cold climates being an exception) for normal driving conditions.  The main need for the thermostat is to restrict flow for the coolant, as you mentioned.  The coolant must have enough residency time to pick up heat from the block/head and then it must have enough residency time in the radiator to transfer that heat to atmosphere.  The inherent restrictive nature of the thermostat provides for this.  The temperature rating of the thermostat is more of a specific circumstance selection based upon several variables; climate, condition of the radiator, engine modifications, etc.  I certainly would never recommend running without a thermostat, especially in cold climates, but I’ve seen it work just fine in certain situations also.

Condensation in an engine is definitely a killer long term, but I suspect that its accumulation in the lower end is more a function of how that engine is operated and the climate in which it’s operated.  If you never allow you engine to get up to “operating temp” with or without a thermostat, especially in cold humid climates, then that accumulation of moisture is going to get you eventually.  A 195 degree thermostat is recommended in that situation, but even with it, you aren’t helping matters if you don’t run the engine long enough to heat up.   This situation isn’t really an issue in hot, dry climates.  

In normal driving conditions, a gutted thermostat will work just fine.  You merely need the flow restriction as mentioned previously.  If you have a marginal radiator (i.e. undersized, clogged, etc.), then a lower temperature rating on the thermostat might help, but probably not.   For hotter climates and small radiators, I always recommend a 160 degree thermostat, but that’s not really going to keep your vehicle running any cooler.  I’m having cooling issues on Gus and have put a 160 degree thermostat in and even drilled holes in it as you have suggested (see page 1 of this thread).  Thermostats typically don’t have anything to do with your vehicle running hot, unless they fail closed.  The caveat is, if you have gotten your engine too hot, you may have damaged your thermostat and it may be operating erratically.  There are tell-tale signs of these conditions, however.

Since I’ve been out of the radiator business for quite a while, I’m like everyone else, having to order a radiator off the shelf.  The one I bought for Gus several years ago fit just fine, but it is undersized due to the low fin count.  It has one more row of tubes than the original, but much less fins per inch.  The radiators that we have now (modern vehicles and Willys replacements) are “v” fin design versus the “flat” fin design of our original CJ2a’s. The original Willys radiators (up to the CJ3a’s) are a staggered 2 row/flat fin design and they worked very well because they had about 12 fins/inch.  My replacement radiator has about 7 fins per inch, and this is the main reason that Gus runs hotter than I’d like.  Being bored .060” over doesn’t help either, but the subpar radiator is the main culprit.

I still have the original radiator and a few radiator tools left.  I have started the process of rebuilding it and will install it to compare to the new one.  I will have some empirical data to share with the forum once I’m finished, repleat with videos.

Long story short, with the long list ahead of me I have decided to buy a new radiator.  Mine used to have a shroud, but someone hacked it off angrily.  So this time I was looking at the Walk's and Omix radiators.

I have purchased a ton of parts on this restoration and Carl has been, by far, my best ally. I know it's more, but have every bend in the right place, welded bottom bolts, felt inserts, et.al. (via your video) tipped the scale that direction.

Since I didn't have a shroud, I obviously didn't have the extension.  I am thinking I should do that too.

What are the thoughts on that?  It is an extra $50.

I see that it attaches with bolts, but is the shroud on the radiator threaded, or are their nuts on the back side?

Thanks again for the video.