'67 SS-396 : Correct Cooling System ?

[1972coronet]

Been building the Revell 1967 SS-396 Chevelle , and am taking some liberties with its engine : I'm replicating an  'Aluminium' Head (think : L88 427) engine (not available from the factory in 1967) .

One item stands out to me regarding the as-provided-by-Revell engine : the fan . Is that 4-paddle , direct-drive fan correct ? 

Perhaps the engine in the car which the model is based on was equipped with the base 325hp 396 , and was sans any axle ratio outside of the standard 3.08 / peg ? 

Either way , it doesn't look right to me . Shouldn't it be a 5-7 paddle fan with a clutch  ? I'm fairly confident that the L78 , L71 , L72 , and L88 would have a 'real' fan .

Input and images welcome !

[Ace-Garageguy]

I can't give you a definitive answer as to what should be there as OEM equipment (all the big-block Chevelles I have access to have been heavily modified), but this shot of an unrestored 396 car appears to show a non-clutch fan, with 4 or 5 blades.

Edited February 13, 2018 by Ace-Garageguy

[dieseldawg142]

..........

Edited May 9, 2018 by dieseldawg142

[Ace-Garageguy]

1 minute ago, dieseldawg142 said:

I had a L78 in my '67 SD Beaumont. it had a 5 blade fan

every one I've seen had a 5 blade. I don't belive the 7 blade came out 'till '70 or '71 I think.

not to say it wouldn't have a 4 blade, never, ever say was not done (pretty much anything) when it comes to GM vehicles...

I bet you're right about 5 blades. I can't recall ever seeing a big-block car with 4.

[1972coronet]

9 hours ago, Ace-Garageguy said:

I can't give you a definitive answer as to what should be there as OEM equipment (all the big-block Chevelles I have access to have been heavily modified), but this shot of an unrestored 396 car appears to show a non-clutch fan, with 4 or 5 blades.

The all-original 325hp with 3-speed and 3.08 Chevelle ! One of my favourites ; an immaculate time capsule . Doesn't get more original than that car .

9 hours ago, dieseldawg142 said:

I had a L78 in my '67 SD Beaumont. it had a 5 blade fan

every one I've seen had a 5 blade. I don't belive the 7 blade came out 'till '70 or '71 I think.

not to say it wouldn't have a 4 blade, never, ever say was not done (pretty much anything) when it comes to GM vehicles...

I've definitely seen the 6-7 paddle fan on '70 & later models (including a former coworker's '70 Nova SS-396 / 350hp) .

9 hours ago, Ace-Garageguy said:

I bet you're right about 5 blades. I can't recall ever seeing a big-block car with 4.

Just seems like such weak sauce , especially considering the application .

[Exotics_Builder]

1967 L88 Corvette (about 20 produced) form Mecum auction

A race version showed no clutch on the fan.  Here is info from a Corvette site

When equipped with the L88 427 Corvette engine, the build also called for blank covers to replace both the AM/FM radio controls and the heating/cooling controls normally found in the center console of a ’67 Corvette’s dashboard.  In fact, ordering the big-block 427 also meant the mandatory elimination of a radio head and power windows, as well as the elimination of a convenient automatic engine choke – though Chevrolet did have a retrofit hand-choke kit available for those drivers that could not get along without it.

The L88 Engine was the closest to a pure racing engine ever produced to be installed in a production model Corvette.

In addition to the removal of some of the car’s creature comforts, other notable absences could be found under the hood.  First, the fan shroud (which aids in engine cooling) was absent, as was any semblance of an emissions controls system.

There was no PCV (Positive Crankcase Ventilation) valve, but rather an obsolete road-draft tube that vented crankcase vapors directly into the atmosphere through the driver’s side valve cover. 

The 1967 Sting Ray was the only second-generation Corvette to run in the 24 Hours of Le Mans. If ever an off-road engine option had been developed for the Corvette, this was it.

The L88’s ultra-high compression ratio left Chevrolet officials no choice but to warn owners about the car’s fuel consumption.  The paperwork that was included with each Corvette equipped with the L88 option read “This unit operates on Sunoco 260 or equivalent gas of very high octane.  Under no circumstances should regular gasoline be used.”  A second label was placed inside the Corvette as well which similarly read “Warning: Vehicle must operate on a fuel having a minimum of 103 research octane and 95 motor octane or engine damage may result.”

Ultimately, sales of the L88 equipped Corvette were limited to a mere 20 units.  While the car was immensely powerful, it was also an extremely expensive option.  At an additional $1,500 over the base price of $4,240.75, the sticker shock proved too expensive for most enthusiasts, which was okay with GM since they had always felt that the L88 Corvette belonged on the racetrack.

Edited February 13, 2018 by Exotics_Builder

[Ace-Garageguy]

23 minutes ago, Exotics_Builder said:

1967 L88 Corvette (about 20 produced) form Mecum auction

A race version showed no clutch on the fan.  Here is info from a Corvette site...

Actually, that car does appear to have a clutch on the fan. It's the finned thing forward of the blades. The fan mounts to the rear of the clutch.

 

[Exotics_Builder]

3 hours ago, Ace-Garageguy said:

Actually, that car does appear to have a clutch on the fan. It's the finned thing forward of the blades. The fan mounts to the rear of the clutch.

 

My bad, I was trying to say with clutched fan.  I can see why one wouldn't want a clutched fan on a racing version, and L88's were meant for racing.  But every photo I can find of a 67 where the fan is visible shows a clutch.  And only about 20 67 L88 Vettes were produced

 

[espo]

I had a new '67 El Camino 396/360 hp with a 4-speed and Air Conditioning that had a Clutch Fan from the factory. I don't know if the Air Conditioning or the ever popular Cal. Smog Pump was the reason Clutch Fan or not but that was the way that car was.

[1972coronet]

3 hours ago, espo said:

I had a new '67 El Camino 396/360 hp with a 4-speed and Air Conditioning that had a Clutch Fan from the factory. I don't know if the Air Conditioning or the ever popular Cal. Smog Pump was the reason Clutch Fan or not but that was the way that car was.

It would seem that any time that factory-installed air conditioning was ordered , the clutched fan was mandated . Doubtful that the (dreaded) California emissions had much -- if anything -- to do with the presence or absence of a fan clutch .

I'd imagine that any time that steep gearing was spec'ed ( 3.73 [Z-28] , 4.10 , 4.56 ) , that the clutch made an appearance as well ; same with Posi-Traction .

The lack of a fan shroud is a bit of a 'mystery' to me  (excepting , of course , the aforementioned L88 , which was a weight-saving concession) , as the point of a shroud is to direct air . A missing shroud = misdirected airflow (same with underhood seals) . Perhaps the crossflow Harrison radiator did away with the requisite shroud ? Pure speculation on my part .

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Thanks again for the input , info , and accompanying photos , everyone ! 

Looks like I'm going to retrofit the kit's 4-paddle fan for the fan / clutch from the parts box (e.g. , the Revell 'COPO' 1969 Nova) .

[espo]

The absents of a Fan Shroud seems odd to me. After looking at the picture of the original 395/325 Chevelle it seems as if it may have been removed at some point. The design of the Cross Flow Radiator was a big improvement for cooling purposes but to be effective in stop and go traffic a Fan Shroud would be needed. At say highway speeds there is enough air flow thru the Radiator to cool the Engine. This changes dramatically when the movement of the car isn't pushing air thru the Radiator. The Fan will pull a small amount of air but with the Shroud in place it becomes far more effective.   This is just my thought.