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Discussion Starter #1 (Edited)
This isnt for our nova. This is for my 76 camaro. I have a northern (summit brand) aluminum radiator and a custom fit shroud with 2 spal electric puller fans. The fans move a lot of air and the shroud has flow vents to vent air while driving. I am running a robert shaw 180 degree tstat with 2 small holes drilled in the outer ring. Car is running up to 220 :eek: I almost wonder if there is an air pocket? I just replaced the cheap water temp gauge because i "thought" it was acting crazy. It would sit at zero then after a few minutes would jump to like 240ish then bounce back and forth till it finally settled down.

Installed new sport comp autometer and when I took out the old probe from the intake it was dry. Thought that was rather odd? While getting the new one ready the hole filled up with antifreeze.


Now whats really blowing my mind is we run the same summit aluminum radiator in our 63 nova with no fan shroud, same thermostat, same stewart water pump and a flex fan and that car NEVER goes above 185. Much worse cooling setup yet it cools much better than my camaro.


Any ideas? I am racking my brain here. :mad:


Camaro setup. No longer has that goofy upper hose. Now has flex hose.





Nova setup.








Here is the fan shroud and dual fans I have on the camaro. Supposed to be 2400cfm total.

http://cgi.ebay.com/ebaymotors/19X3...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
 

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sounds like an air pocket . i think i have seen those vacuum pumps to get the air out if im not mistaken
 

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When I "burp" my small block, as I fill the rad I'll loosen the fitting by the stat housing on the intake manifold a small amount to let out air. Then tighten when coolant comes out. I'm sure that upper rad hose didn't help,glad you changed it. Oh by the way is that a March underdrive water pump pulley? Might be some of the problem unless the pump is a high output type. just my .02, good luck
 

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Discussion Starter #4 (Edited)
When I "burp" my small block, as I fill the rad I'll loosen the fitting by the stat housing on the intake manifold a small amount to let out air. Then tighten when coolant comes out. I'm sure that upper rad hose didn't help,glad you changed it. Oh by the way is that a March underdrive water pump pulley? Might be some of the problem unless the pump is a high output type. just my .02, good luck


It has been a few years but I think it was a standard pulley. I may still have the box laying around some place so I can get the part number and look it up. The water pump is a Stewart stage 2 pump.


Here is a pic I took today with the new upper hose. Has same type of hose on the bottom also.







Here are the specs on the 2 spal fans I have. Looks like they may be under powered for my application?


http://www.spalusa.com/pdf/30100467_SPEC.PDF#view=FitH
 

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do u have

a heater core in the system ?

if i didn't ,, i think i wouldn't just block the lines , i think i would just by pass the heater core and still route collant through the lines to keep coolant flowing through the engine ,

what psi is your rad cap ?

wonder if you would move the fans away from the radiator about 4 in,,, that might give the air flowing through the fins at speed coming through the grill an easier turn to make to get through the louvers and fan ??

you might try just mounting the fans to the radiator and leave off plate with the louvers ,, the fans IMO will help you at slow speed ,,,,, i'd try it like that anyway ,, it looks neat ,, but it may not allow enough air to come through
 

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Lower hose collapsing when the water pump starts to pull?

Just a guess...

Mark
 

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Know how many CFM's those fans put out. It give Cubic meters per hour on your sheet but that too much math for today..... LOL

Also lookes like that shroud is pretty tight to the core. That can make some dead space in the rad.....
 

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Discussion Starter #9 (Edited)
Know how many CFM's those fans put out. It give Cubic meters per hour on your sheet but that too much math for today..... LOL

Also lookes like that shroud is pretty tight to the core. That can make some dead space in the rad.....


Are you sure thats cubic meters? I think its cfm? At 0 static pressure they are rated at 1750 (we know the static pressure is obviously not 0 because it is pulling through the radiator). At 5 it flows 1350, 10 it flows 670 and 15 it flows nothing.

Anybody have any clue how much static pressure a radiator creates?


To answer other questions the lower and upper hose are both new and both the spring loaded flex fit hoses so the lower hose shouldnt be able to collapse.

There is no heater core in the system

Rad cap is older and cant read the psi rating

Haven't really gotten a chance to test it at cruising speed yet. When I took it out today I was romping it hard (shhhhh dont tell the po po on me) around the block. It was hot while driving and while sitting idling.
 

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Discussion Starter #10
Well what do we have here? Here is a higher performance spal fan with the exact same dimension so it will bolt straight up to my shroud but this sucker pulls WAY more air.


0 pressure it pulls 2460
5 = 2160
10 = 1830
15 = 1230


http://www.spalusa.com/pdf/30102029_SPEC.PDF#view=FitH


I have a sneaking feeling my fans simply don't pull enough to support 550 to 600hp but I dont want to drop $250 on new fans to find out I still have the same issue.
 

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Those sheets are all in metric... the airflow measurement is goven in M3/H which I would assume is meters cubed per hour......? Most measurements are in CFM cubic feet per minute. Huge difference. That said Spal makes good stuff.

Do you have the regular part numbers so they could be looked up at summit or whatever?
 

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Discussion Starter #12 (Edited)
Those sheets are all in metric... the airflow measurement is goven in M3/H which I would assume is meters cubed per hour......? Most measurements are in CFM cubic feet per minute. Huge difference. That said Spal makes good stuff.

Do you have the regular part numbers so they could be looked up at summit or whatever?


The Spal part number is VA10-AP10/C-61A and they are 12 volt puller fans





EDIT: Your right M3/H is cubic meter per hour. According to this website you multiply the M3/H by 1.699 to get CFM.

http://www.watlow.com/reference/equations/0104.cfm

Problem is at which static pressure are you supposed to use the figures for to get a real CFM amount? Obviously the static pressure is going to be more than zero when the fans are pulling through a radiator. Because if I used the 1750 at Zero that mine are rated for they would be 2973 CFM fans which would cool anything you could possibly put them on being I am running two of them. This stuff is to darn confusing for me!!! HAHA
 

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Okay from the spal websight you can get the more comon part numbers, the number of the fans you have are 30100467. Also the conversion you have might be backwards, it list on Spal's PDF tha 1 M3/H = .59 CFM. I'd guess that the fans are rated at 0 pressure (free flow) so that would make the ones you have now (1750*.59) 1033 CFM, not a whole lot but not too bad either since you have two.

The other ones you're looking at would convert to 1451 CFM each....

If I were you though I would try it without the shroud once just for kicks, mount the fans right to the radiator. I've done a good bit of tinkering with cars that run hot and the best setup I've had is either two electrics mounted right to the radiator of a good mechanical fan with a shroud. I think that most shrouds used with electric fans are to tight to the radiator and instead of using the whole radiator core, they can actually block airflow off in the corners creating dead spots even when going down the highway where you wouldn't even need a fan. They should really be about 2-3 inches thick or better to spread the suction across the whole core.

I have a customer with 72 Nova, a GMPP 572, becool radiator (stock size) and a mechanical fan (flex fan) with no shroud who can sit in traffic all day long in 95* heat and it never hits 200.... An efficient radiator is the most important part of a good cooling system. If you don't have that you can do a lot of tail chasing to try and get enough air through it to keep it cool.
 

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Discussion Starter #14
Okay from the spal websight you can get the more comon part numbers, the number of the fans you have are 30100467. Also the conversion you have might be backwards, it list on Spal's PDF tha 1 M3/H = .59 CFM. I'd guess that the fans are rated at 0 pressure (free flow) so that would make the ones you have now (1750*.59) 1033 CFM, not a whole lot but not too bad either since you have two.

The other ones you're looking at would convert to 1451 CFM each....

If I were you though I would try it without the shroud once just for kicks, mount the fans right to the radiator. I've done a good bit of tinkering with cars that run hot and the best setup I've had is either two electrics mounted right to the radiator of a good mechanical fan with a shroud. I think that most shrouds used with electric fans are to tight to the radiator and instead of using the whole radiator core, they can actually block airflow off in the corners creating dead spots even when going down the highway where you wouldn't even need a fan. They should really be about 2-3 inches thick or better to spread the suction across the whole core.

I have a customer with 72 Nova, a GMPP 572, becool radiator (stock size) and a mechanical fan (flex fan) with no shroud who can sit in traffic all day long in 95* heat and it never hits 200.... An efficient radiator is the most important part of a good cooling system. If you don't have that you can do a lot of tail chasing to try and get enough air through it to keep it cool.


Ok that makes much more sense with the numbers. I am thinking I need more flow through the radiator. At zero static pressure I would be pulling 2066 but I bet with the radiator and trans cooler in front of it that I am only pulling half of that which for a 13:1 big cammed engine may simply not be enough. I am going to get the stroner fans and give that a shot.

Our nova has this same radiator except the smaller version and a flex fan and no shroud and it never gets above 185 but that engine is only 11:1 with a milder cam.
 

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Radiators/fans/shrouds are not created equal.

Two words that I guarantee will fix your problem: RON DAVIS

Have chased my tail with several overheating combinations before and have tried everything. After going Ron Davis rad/fan/shroud i will never look back! Ask them about the street driven 700+ cube engines they have cooled...
 

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Discussion Starter #16
Radiators/fans/shrouds are not created equal.

Two words that I guarantee will fix your problem: RON DAVIS

Have chased my tail with several overheating combinations before and have tried everything. After going Ron Davis rad/fan/shroud i will never look back! Ask them about the street driven 700+ cube engines they have cooled...


His radiators are 2 row aluminum and he uses 13" Spal fans. Almost identical to my setup except his Spal fans are stronger and I think thats my main issue.

 

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Discussion Starter #18
not to hijack but where would i get a set of them flex radiator hoses for my nova ? are they cut to fit ?

I got mine at advanced auto and they are not cut to fit. they come in different lengths. They let me go behind the counter and pick the ones I needed myself.
 

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Ok. This shroud box, I dont like it.



I think you will be pulling hot air from the engine compartment through the louvers. Just recycling the hot engine compartment air. And the fans look a lil small for a 600hp engine. Fill up the area that the shroud box is using with fan blade. Larger fans (or fan) and a sealed shroud that cant draw from the engine bay. JR
 

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Ok. This shroud box, I dont like it.



I think you will be pulling hot air from the engine compartment through the louvers. Just recycling the hot engine compartment air. And the fans look a lil small for a 600hp engine. Fill up the area that the shroud box is using with fan blade. Larger fans (or fan) and a sealed shroud that cant draw from the engine bay. JR
I agree, the fans are going to pull air from the path of least resistance. Take the shroud off and duct tape up the louvers from the inside to see if you have any improvement. The fan openings should be able to vent all the air you need.
 
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