Auxiliary radiator, or auxiliary oil cooler?

For our LeMons car, which runs a 460 Ford Big Block, we have been fighting hot-running issues for a couple of races now. We've made a lot of improvements this time around- added another trans cooler, moved the trans coolers out of the "line of sight" of the radiator, sealed off the radiator and shroud, added cooling vents in the fenders, replaced the head gaskets, flushed the cooling system, drilled some bypass holes in the thermostat, and added a phenolic carb spacer. But I'm concerned about the cooling system capacity to actually cool.

So, right now we have two options we're considering. The first is adding in an auxiliary radiator (either a heater core, or a small automobile or motorcycle radiator) in the heater hose loop. The other idea is to add a remote oil cooler, likely air cooled.

My question is, which of these ideas would help cool the engine better? I'm not too concerned about oil breakdown- we run Mobil1 15W-50- more wondering whether cooling the oil, or cooling the water more, will cool the engine better.

For the record, we currently run the largest aluminum radiator Summit Racing sells aftermarket, so going larger on the primary radiator isn't really an option on the table right now. Plus, the aux radiator would cost almost nothing, and an aux oil cooler's about $100, so either option is much cheaper than trying to find a bigger radiator.

Roadkill always removes the hood when their junk starts overheating...

What about air dams?

Oil is responsible for something like 20 or 30 percent of all engine cooling, you said you already have a massive radiator the next logical step is to cool the oil. Hell maybe you could find something in a junkyard to work.

Dusterbd13 wrote: Roadkill always removes the hood when their junk starts overheating...

That was why I suggested the fender cutouts, to let air out, from my understanding, that's why that works.

Oil is my vote. It's riskier though, you need to do a good job on it, not just a Lemons job. A real sandwich plate, real hoses, real fittings, and a real cooler.

tuna55 wrote:

Dusterbd13 wrote: Roadkill always removes the hood when their junk starts overheating...

That was why I suggested the fender cutouts, to let air out, from my understanding, that's why that works. Oil is my vote. It's riskier though, you need to do a good job on it, not just a Lemons job. A real sandwich plate, real hoses, real fittings, and a real cooler.

Yeah, unfortunately LeMons requires a hood...

I forgot, we also moved the air filter up above the hood, to draw in cooler air

Tuna it correct, the oil cooler is much more sensitive to doing right. Oil's under 50 psi or more...coolant's more like 10 psi. A leaky water system means a gradual overheat...a leaky oil line makes engines go BOOM in short order.

chiodos wrote: Oil is responsible for something like 20 or 30 percent of all engine cooling, you said you already have a massive radiator the next logical step is to cool the oil. Hell maybe you could find something in a junkyard to work.

I actually have a good used radiator from a Honda Civic I was considering. Even has its own electric fan. The inlet/ outlet tube sizes are larger than the heater hoses on the 460 (though, not by much!) so some adapter fittings would be needed.

Oil coolers are a good idea on big block engines and do help keep the oil temps down. I would go with one.

vent the hood

DaveEstey wrote: vent the hood

Yes, hood extractor would be my first step.

How much power does the 460 make? I find it hard to believe its exceeding the capacity of the largest aluminum radiator Summit sells unless there is some cooling passage issue of some sort.

ProDarwin wrote:

DaveEstey wrote: vent the hood

Yes, hood extractor would be my first step. How much power does the 460 make? I find it hard to believe its exceeding the capacity of the largest aluminum radiator Summit sells unless there is some cooling passage issue of some sort.

200 hp.

OK, maybe 300 on a good day.

The hood has a hole such that the air cleaner can protrude.

The fender vents should serve the same purpose.

tuna55 wrote:

ProDarwin wrote:

DaveEstey wrote: vent the hood

Yes, hood extractor would be my first step. How much power does the 460 make? I find it hard to believe its exceeding the capacity of the largest aluminum radiator Summit sells unless there is some cooling passage issue of some sort.

200 hp. OK, maybe 300 on a good day. The hood has a hole such that the air cleaner can protrude. The fender vents should serve the same purpose.

That's why I said extractor. SUCK the air out from under the hood, don't just vent it. If there isn't a lot of positive pressure under the hood, vents won't do much, if anything.

200-300 isn't a crazy amount, I'm surprised such a large radiator doesn't cool it just fine. Is the water pump cavitating? Clogged coolant passage of some sort?

Since you don't seem to know which fluid is getting too hot and you don't have an oil cooler, I'll say get an oil cooler. Any car that sees sustained track use should have one.

An oil-to-air cooler works much better than an oil-to-water cooler (or coolant preheater as some people like to call them). An oil-to-water cooler might be better with its own radiator, but then you just threw the packaging advantages out the window so why not cut out the middleman? With intercoolers, pressure drop is a big deal (this also restricts their size), but not so much with oil coolers.

volvoclearinghouse wrote: The first is adding in an auxiliary radiator (either a heater core, or a small automobile or motorcycle radiator) in the heater hose loop.

Been thinking of doing the exact same thing to my Samurai.

I've been flushing the cooling system, and it pumps water very well. Fill the radiator, disconnect the upper radiator hose, and it spews water at idle out of the upper hose. My garden hose can't keep up.

My S.W.A.G. on power is in the middle-upper 200Hp range. The engine was rated 230 stock (SAE Net), we fixed the retarded cam timing which adds about 30 HP (and makes the engine more efficient, and thus cooler), and added an aluminum intake, carb spacer, carb tuned to rich (~11-12:1) and dual exhausts, no smog equipment. I'd say conservatively 260-275 HP, SAE Net. yeah, not that much for the size engine it is. And we don't spin it over 4000 RPM.

I also checked the spark timing, and we're running 10 degrees base advance and a total of about 35 degrees "all-in", so I'm fairly certain we're not running into a retarded timing causing overheating issue.

My bet is on air getting crammed in the huge multiple openings in the grill and not finding an easy way out, hence the fender vents.

Oil cooler could not hurt if implemented properly, but it's $$$.

It's just a big, inefficient, terrible-quench-having pig. It's not going to run cool, but the team needs to be able to lean on it for the entire race.

As Volvoclearinghouse, you may well have a heap of Volvo redblock turbo oil coolers somewhere. The sandwich plate on the Volvo filter uses (I believe) the same thread pitch as Ford. I know for a fact that Volvo is the same as MoPar. Maybe you have everything you need.

You know, Ford put these engines in lots of medium duty trucks. I wonder if there's a factory oil cooler setup that would be a drop-in done deal?

tuna55 wrote: Oil cooler could not hurt if implemented properly, but it's $$$.

You can do them for "grassroots" prices, but staying within a LeMons budget is a whole 'nother thing. You might be able to assemble one entirely from junkyard parts if you know where to get all the bits and pieces (protip: Many manufacturers use a single oil filter port type across all their engines, like Chevy and Toyota). Non-thermostatic sandwich plates and cheapo Chinese oil coolers are cheap, but the first can cause oil overcooling and WILL cause slow warmup, and the second needs to be BIG due to low efficiency.

EvanR wrote: As Volvoclearinghouse, you may well have a heap of Volvo redblock turbo oil coolers somewhere. The sandwich plate on the Volvo filter uses (I believe) the same thread pitch as Ford. I know for a fact that Volvo is the same as MoPar. Maybe you have everything you need.

Alas, I have none. I have never owned a forced-induction volvo.

My bet is on venting too. A big ass radiator is still unable to cool unless it has lots of air flowing through it. If your engine compartment doesn't purge air well it can't really accept much new air. If the only vent the compartment has is the hole for the air cleaner the air you are sucking in to the cleaner may be hotter than the air in front of the radiator. Can you leave the hole and duct air from ahead of the core support to the engine?

volvoclearinghouse wrote:

EvanR wrote: As Volvoclearinghouse, you may well have a heap of Volvo redblock turbo oil coolers somewhere. The sandwich plate on the Volvo filter uses (I believe) the same thread pitch as Ford. I know for a fact that Volvo is the same as MoPar. Maybe you have everything you need.

Alas, I have none. I have never owned a forced-induction volvo.

Sad. But junkyards still seem to have quite a few 240/740/940 Turbo cars to pick from!

volvoclearinghouse wrote: You know, Ford put these engines in lots of medium duty trucks. I wonder if there's a factory oil cooler setup that would be a drop-in done deal?

Dude!

Winner winner chicken dinner!

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Those Hayden kits are basically the bargain-bin special I was talking about, prepackaged: They come with a non-thermostatic sandwich plate and a very inefficient cooler. They might be a good deal for keeping a LeMons car from cooking, but they're not very good systems, if you didn't know.

I went through all this when trying to put together a system for my own car. Ended up going with a basic "good" system that cost me close to $350 (all new stuff), but it's very light and efficient with a thermostat, AN fittings and lightweight fire-resistant lines.

GameboyRMH wrote: Those Hayden kits are basically the bargain-bin special I was talking about, prepackaged: They come with a non-thermostatic sandwich plate and a very inefficient cooler. They might be a good deal for keeping a LeMons car from cooking, but they're not very good systems, if you didn't know.

Nope, I thought it was a reman Ford setup - nevermind

http://www.clubcobra.com/forums/429-460-engine-talk/107698-460-oil-cooler-liquid-liquid-type-anyone-else-try.html

So it's a OEM liquid/liquid cooler. Neat!

So, it probably works great, but since it's using the coolant to cool the oil, it isn't going to lower the temperature of the coolant. We need an additional cooler, not to use additional cooling capacity of the water (which we obviously don't have) so we're back to that Summit list I sent to VCH a year ago, but it's not terribly cheap. I don't remember what it was though.