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Thoughts on this Aluminum Radiator


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I'm considering switching to an aluminum radiator to help with cooling at the track. On the street my 4 core copper/brass is just fine, but I was seeing temps of 215 at the track last weekend with ambient temps of 95 F. I have the AC condenser up front and suspect that's part of the problem but don't want to remove it. From what I've read here and elsewhere the more modern Al radiators have less resistance to air flow and while Al is not as good of a heat conductor as copper/brass, the older designs (which is what mine is) are apparently not that efficient.

 

I've already ensured that there are no other major sources of airflow into the engine compartment except through the radiator. I did have some fin damage on the AC condenser which I've since straightened.

 

So I'm leaning towards this unit:

 

http://cgi.ebay.com/ebaymotors/All-Aluminum-1970-75-Datsun-240z-260z-Radiator-110AA_W0QQcmdZViewItemQQcategoryZ33602QQihZ012QQitemZ220259419403QQtcZphoto

 

Has anyone tried it?

 

Also, what about going with a later 75-78 unit which has a larger core? Mine is still in the car and with the AC condenser in place I can't see if going with a deeper core would expose more of it to air flow. I know it would hang down lower, but my spook already hangs low so I'm not worried.

 

Also, what about mounting it? I know I'd need to isolate it to protect against corrosion, but I'm concerned about frame flex and what it would do to the radiator. Has anyone found a simple way to soft mount this type of unit?

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One idea I have for soft mounting is to enlarge the holes on the rad brackets and fit rubber grommets with an ID that is perhaps 1/4" larger than the mounting bolt. The idea is that this would provide a nominal 1/8" play in any direction as the chassis twists. It also has the benefit of electrically isolating the rad from the chassis.

 

A large flat washer would go on the engine side followed by 2 nuts tightened against each other so that the grommet was under some compression, but not so much that it couldn't move a little.

 

Thoughts?

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Woldson, I read that thread with great interest even though I'm NA. So far I'm not sure what to do differently in my situation based on that thread. Do you have any thoughts?

 

Challenger, prior to last weekend I agreed with you. But I'm out of things to do (save remove the AC condenser which I don't want to do). My temps are fine all of the time except when running hard on the track. So I'm not too far from where I think I need to be. For example, I ran 40/60 antifreeze/water and added water whetter as well. I suppose I could go 100% water + water whetter, which should help, although I doubt it's going to drop the temp 20 degrees.

 

I've looked at ducting, but not sure how that will help me. There was only one opening into the engine compartment (3" hole to the left of the radiator on the passenger side) which I've closed up. Other than that, the only path for air to get into the engine compartment is through the radiator.

 

The good news is that I never went over 215 F, but I'd feel better with it lower when I'm running that hard for that long. The rest of the time I have no issues.

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by ducting, I think he means blocking off a portion of the front of your car. it SEEMS to be illogical, but from what I understand, By having such a large opening, at higher speeds, the pressures inside the engine compartment increase, causing the air in front of the radiator to stall and slow down, reducing the cooling efficiency. By reducing the size of the opening, you reduce the amount of air entering the area, BUT at the same time, you reduce the pressure in the engine bay, so instead of pushing air through the radiator, the air gets pulled through the radiator due to the reduced pressures, and increasing the cooling efficiency. Ever notice how small the front opening is on newer cars? In order for it to work the front of the car needs to be totally air tight except for around the radiator.

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We're about to have the same discussion covered in this thread

http://forums.hybridz.org/showthread.php?t=122197 and that wasn't my intention with this post.

 

I agree that better ducting should help some, but I'm trying to avoid changing the external appearance. The only noticeable mods I've made are the panasport wheels (necessary to fit performance tires and arguably period-correct), and the spook ( which is also period-correct). I'm fortunate that my 73's body, paint, and interior are in pretty good condition. On top of that, I don't have a welder nor welding skills (yet) to build ducting.

 

Like I said earlier, I'm only concerned with improving cooling while on the track. And it may be that what I'm trying to do (build a reasonable track car that otherwise looks stock) is just not possible. But if an aluminum radiator could help flow more air and/or dissipate heat better, then it would fit in with my approach to keeping the car externally stock.

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You could build the ducting out of some rubber molding, and pop rivets. it's not like you need to know how to weld. But I do understand your dilemma of wanting to keep a visually stock car.

you could make it LOOK stock though, by say, turning the top grill into your block off plate, and riveting some duct work to draw air in from the bottom half of the grill.

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You might want to look at that radiator again. It's only a two row ;)

The integrated trans cooler is pretty cool though.

 

I think that it would be possible to keep a relatively stock look if you painted all of your ducting work a nice flat black when you were done with it. It seems like that would make it stick out a lot less compared to having it being aluminum or having shiny rivets drawing attention.

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You might want to look at that radiator again. It's only a two row ;)

The integrated trans cooler is pretty cool though.

 

I think that it would be possible to keep a relatively stock look if you painted all of your ducting work a nice flat black when you were done with it. It seems like that would make it stick out a lot less compared to having it being aluminum or having shiny rivets drawing attention.

 

that's sort of why I mentioned integrating it into the stock grill. it won't really pop out so much.

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Derek, I think I remember seeing your pictures (it's a little hard to keep all these discussions straight right now). My issue is that I have a 240Z (73) with the bumper in place. The bumper supports are what makes it extra hard to block/channel air. If those weren't there, it would be simpler to build something behind the grill.

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215 on the track on a hot day is nothing and its not something the aluminum radiator is going to improve. L6 engines put a lot of heat into the oil when running on a track. Adding an oil cooler will do more to bring the coolant temps down then going from a 4 row brass to a two row aluminum.

 

For radiator mounting with a stock style side flange radiator, use 4 Lord mounts part number 9376K213 from McMaster-Carr.

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So is 215+ for 20 minutes at a time maybe 10 - 15 sessions per year going to make a significant difference in engine life?

 

Alternatively, if I were to add an oil cooler, what about using parts like these?

 

Adapter plate: http://store.summitracing.com/partdetail.asp?autofilter=1∂=PRM-1060&N=700+4294843279+115&autoview=sku

 

Thermostat: http://store.summitracing.com/partdetail.asp?autofilter=1∂=PRM-1060&N=700+4294843279+115&autoview=sku

 

Is 3/8" hose enough or is 1/2" required?

 

Also, could the transmission cooler of the radiator be used to cool engine oil? I'm guessing it can since it would only flow oil when it was hot and less viscous. That would be easier than trying to mount a separate cooler in front of the rad and AC condenser. But if the oil cooler on the rad takes away from capacity to cool the coolant, then that might not be a good idea.

 

Sorry for the many questions, but oil coolers are completely new to me.

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So is 215+ for 20 minutes at a time maybe 10 - 15 sessions per year going to make a significant difference in engine life?

 

No significant difference.

 

Is 3/8" hose enough or is 1/2" required?

 

1/2" - you don't want to see a significant pressure drop across the cooler. Get an Earl's thermostatic sandwich plate. If you ahve the part number Summit can get it:

 

http://www.holley.com/types/Sandwich%20Style%20Oil%20Thermostats.asp

 

Also, buy a real racing oil cooler like a Setrab or a Mocal.

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