Cadillac 500 auxiliary radiators

[dn010]

This is just my .02
I did some research prior to converting over to a 16" 3000CFM electric fan on my 365. They come with a 40Amp relay and 30amp breaker. If you want to get down to how much HP loss you will have, consider you'll always have loss with a mechanical fan compared to electric since the electric fan will cycle on and off when there is a demand for it. You cannot deny that electric fans move more air at idle (mine will blow the leaves out from under the car when it comes on) compared to a belt driven fan, but electric loses its efficiency compared to belt at high engine RPM. As long as I am driving down the road and air is hitting my radiator, my electric fan never comes on until I am stopped for a few minutes.

As much as I am all for the electric fan, there are times and engines to use them on, they are not for all, and I would certainly avoid one with the 500 engine. I would absolutely stick a 7 blade belt fan on it with the proper shroud/rubber and original radiator recored. If while driving, the combined air from the fan pulling and the air hitting the radiator at speed isn't enough to keep things cool, you have bigger things going on such as the already mentioned dirty block/water jacket or an impeller that has rusted down to nothing. You already know you have a flow restriction, it's time to start taking things apart to find out why.

[wschimberg]

So with the new correct thermostat, it gets up to 230 climbing hills but is much better but still if I was to get the ac working it would definitely still get hot.  The timing could be slightly retarded still but 34 total without vacuum advance seems fine.  It doesn't get hot at a stop, just under a load at speed so I don't think it's the electric fans I have on it.  They seem to be moving air properly too.  The rad sits at 185 at idle while the gauge sits right at 195.  That could be the gauge sitting in the block compared to the in the rad.  I was under the car today and the exhaust seems to be crushed a little and could very well be a restriction.  Would the restrictions lead to normal temperatures at idle but higher temperatures under load?

[Dave Shepherd]

If the exhaust  was restricted  enough to cause increased engine temps,  pretty sure that would be accompanied  by some loss of power.  Have you checked temps at the upper and lower radiator  hoses with a laser thermometer,  should be at least 20 degrees difference.

[35-709]

"The timing could be slightly retarded still but 34 total without vacuum advance seems fine."
Maybe I am misinterpreting this, but the maximum centrifugal advance (without vacuum advance) for '73 472 engine should be 11-13 degrees.  Your 500 (depending on the year) might be a little different, the later 500s were less.

Maximum vacuum advance should be 12.75 degrees for a total of vacuum and centrifugal advance (under some conditions) of about 25 degrees.

It would seem to me you are running way too much centrifugal and then adding more with the vacuum advance.  These sound more like Chevy small block numbers and if what I am seeing/interpreting is correct, they are way too high for a 472/500 and would most certainly cause overheating.

[Dave Shepherd]

Pretty sure that may be distributor degrees, not crankshaft degrees, check it out.

[wschimberg]

"The timing could be slightly retarded still but 34 total without vacuum advance seems fine."
Maybe I am misinterpreting this, but the maximum centrifugal advance (without vacuum advance) for '73 472 engine should be 11-13 degrees.  Your 500 (depending on the year) might be a little different, the later 500s were less.

Maximum vacuum advance should be 12.75 degrees for a total of vacuum and centrifugal advance (under some conditions) of about 25 degrees.

It would seem to me you are running way too much centrifugal and then adding more with the vacuum advance.  These sound more like Chevy small block numbers and if what I am seeing/interpreting is correct, they are way too high for a 472/500 and would most certainly cause overheating.

I have a pretty aggressive cam in it so it likes the timing.  It isnt pinging so I don't think it is too much and the exhaust has always been crushed so I have no clue if it is the culprit.

[The Tassie Devil(le)]

So, what type of fuel are you running?

When I was drag racing, I was running my bored out L88, that was out to 440 Cu. in. on Alcohol, and the advance timing was set at 40 Degrees at 3,000 RPM with my "aggressive" race cam.   But, the thing wouldn't idle below 1,200 RPM, and a Red Line of 7,500 RPM.

This was on a non-vacuum advance distributor.

Try that on todays' petrol, and the thing would have been pinging its' heads off, ultimately to total destruction.

When timing a street engine, it is always about timing at the Crank Shaft.

Bruce.

[V63]

If the engine is built for performance it's going to require high octane fuel .

if it's not pinging on pump gas,  then it likely is too far retarded which increases engine running temperature.

I would suspect a restricted exhaust would create incomplete combustion and power loss but not over heating?

I had a 77 that plugged its cat and it just got slower and slower until it just died not to restart. But overheating was not an issue I remember.



   

[wschimberg]

When I say aggressive cam, I mean about as aggressive as I'm willing to run on the street.  It's a cad company can with .561 lift at valve, 274 duration, and 110 lobe separation. So in the racing world a small can but for street, a little bigger.  I run 91 non ethanol and I can through more timing at it if it didn't get hot, it loves a little more timing when it stays cool during the winter but during the summer I have to back it off cause it's getting hot, and then starts pinging.  But 34 total mechanical and 8 vacuum still seems like it isnt to far retarded.  Also what's the best was to listen to pinging, I can just tell it's happening when it start bogging a hair but I have never actually heard the ping noise people talk about.

["Cadillac Kid" Greg Surfas 15364]

William,
As we "un-pack" this more relevant facts seem to be popping up. First of all that 274 degree duration must be at .001 lift and even that sounds like a Cad Co 300T cam. I ran that cam in a most street-able car, but without a VERY free flowing exhaust and stock heads it too wanted to run a bit warm (210 degrees).
Excellent cam to base a high performance engine on and I will assume you have something like a 2000 RPM stall converter behind the motor.
A heavy duty water pump (Flow Kooler) is a must,as is making sure your exhaust is not restricted.
Getting to timing, the 34 (engine degrees) total mechanical is okay, but the vacuum, which has a lot to do with cruise operations should be something on the order of 28 degrees at 16" vacuum, starting at 0-4 degrees at 5". That would be a #VC 1833 (AS-1) vacuum advance unit.  If everything else is correct you should be getting something like 15" of vacuum at idle seed which with that cam and a good converter would be around 800 RPM.
I don't know where you are but if you can you might try some 93 octane gas.
With my mild motor using that cam the stock fan and radiator (with stock shroud) was more than adequate.
Let us know how this works out. 
Greg Surfas

[The Tassie Devil(le)]

........Also what's the best was to listen to pinging, I can just tell it's happening when it start bogging a hair but I have never actually heard the ping noise people talk about.

When you hear the "Pinging" noise, you will definitely know what it is.   And you will back off the gas pedal to stop it happening, believe me.   It even sounds abnormal.   Like someone inside the engine with a hammer, happily belting away, really fast.

What it is is pre-ignition coming from the engine wanting to destroy itself by blowing holes in the tops of the pistons, hammering the big end and main bearings, and generally shocking the internal parts of the engine as the flame in the combustion chamber is firing as the piston is still on the way up to Top Dead Centre.

Bruce.

[wschimberg]

So

When you hear the "Pinging" noise, you will definitely know what it is.   And you will back off the gas pedal to stop it happening, believe me.   It even sounds abnormal.   Like someone inside the engine with a hammer, happily belting away, really fast.

What it is is pre-ignition coming from the engine wanting to destroy itself by blowing holes in the tops of the pistons, hammering the big end and main bearings, and generally shocking the internal parts of the engine as the flame in the combustion chamber is firing as the piston is still on the way up to Top Dead Centre.

Bruce.

I guess the question I am asking is the small noise that sounds like a click that I hear when I step on it isnt it?  The engine could also not make enough cylinder pressure to hurt itself but I'm not sure.

[wschimberg]

William,
As we "un-pack" this more relevant facts seem to be popping up. First of all that 274 degree duration must be at .001 lift and even that sounds like a Cad Co 300T cam. I ran that cam in a most street-able car, but without a VERY free flowing exhaust and stock heads it too wanted to run a bit warm (210 degrees).
Excellent cam to base a high performance engine on and I will assume you have something like a 2000 RPM stall converter behind the motor.
A heavy duty water pump (Flow Kooler) is a must,as is making sure your exhaust is not restricted.
Getting to timing, the 34 (engine degrees) total mechanical is okay, but the vacuum, which has a lot to do with cruise operations should be something on the order of 28 degrees at 16" vacuum, starting at 0-4 degrees at 5". That would be a #VC 1833 (AS-1) vacuum advance unit.  If everything else is correct you should be getting something like 15" of vacuum at idle seed which with that cam and a good converter would be around 800 RPM.
I don't know where you are but if you can you might try some 93 octane gas.
With my mild motor using that cam the stock fan and radiator (with stock shroud) was more than adequate.
Let us know how this works out. 
Greg Surfas

That is literally the cam that is in it.  But when I say streetable, this car is practically my daily right now as my real daily bit the dust.  With the vacuum advance, I have the adjustable can on it and it starts running rough when turn it up and hold it at 3 grand.  That's obviously too much timing right?  Also to note, with the proper thermostat in now, it stays at 180 unless I'm climbing a hill or its hotter then 90 out.  It has a stock stall in it right now but I'm planning on switching it out when I get my other car running and I can start toying with it again.  I also cant find any 93 anywhere around me but I could get 108 low lead from the local airport but that would cost me an arm and a leg.  But once it isnt 90 out I think the correct thermostat fixed it enough that I wont have issue, until I step on it or decide to get the ac working.

[Dave Shepherd]

With a set back timing lite you can accurately  determine all your timing settings at any rpm.

[The Tassie Devil(le)]

So I guess the question I am asking is the small noise that sounds like a click that I hear when I step on it isnt it?  The engine could also not make enough cylinder pressure to hurt itself but I'm not sure.

Don't know what a click is, but if it is one single click, then it isn't Pinging.

Not a small noise either, as it really draws your attention when it starts, and makes you want to back off the gas pedal to stop it.

The only real click that I can think of is the noise when universal joints are wearing out, but that click is only when moving off, after going in the opposite direction.   This noise is the needle rollers destroying themselves.

Bruce.

[Dave Shepherd]

Lot of advice here, obviously we are all handicapped by distance, this "pinging" seems to be undetermined as preignition.

["Cadillac Kid" Greg Surfas 15364]

With that cam I would hope you have some sort of "performance" rocker arms. If so, they can be noisy, and if not what you are hearing might very well be the stock RAs rattling around. You did not say anything about the valve springs, valves sizes or rocker arms.  It sure is helpful if any and all information regarding modifications is contained in your post so all the pertinent facts can be considered.  Otherwise we are all shooing in the dark.
Greg Surfas

[wschimberg]

With today being the 1st day in Colorado back below the nineties. I took it for a drive and the overheating issue seemed to stop most of the time it ran exactly at 180 and even warmed up to 190 at some point but never got hotter than that. I think most of the issue is just the  Heat and the fact that I had the wrong thermostat without the block off it seems to be solved them out.  I'm think the click may the the start or an exhaust leak or the new rockets I got. It isnt loud enough to concern me though. Thank you for all your help, it really helps me out, I have the mechanical knowledge and know how, just fall flat on my face in the experience realm.

[The Tassie Devil(le)]

I think that you are actually running the engine too cool, as they were designed to run at around 220 F.   With the radiator pressure cap at 15 Lbs, this raises the boiling point of water to around 242 F.

For peak performance, any engine is designed to have all the parts reach the hottest they can get, before boiling, with a bit to spare.

When machining is done, all measurements are calculated to allow for expansion at operating temperature.   Running an engine too cool, does not allow the parts to attain their designed sizes.

I have found that one gets the best performance when the thing is actually boiling, but that is not adviseable in a street engine.

BUT, too much heat, and things can go wrong, like seizing, when clearances become too tight, or too loose, and lubrication suffers.

Bruce.