New Fan Shroud

[SMac149]

I was having over heating issues and my new “correct” fan shroud finally came in. I’m in the middle of installing it and had a question for the 409 Pro’s. Do I need these spacers in between the shroud mount and the radiator? They were on with the old shroud.

Thanks for the help.

Steve

 

[62impala409]

Need more info. What year is your car. If its a 59-63, 348/409 that is not the right shroud. That shroud looks like it barely clears the power steering pulley. Looks more like a small block shroud to me. Fan blades need to be about 1/3 to 1/2 out of the shroud. The hot air needs to spill off the blade tips in order to cool efficiently. Leo

 

[MRHP]

Yes I believe you need spacers. I think the originals were square. I am to assume that the picture is of your old shroud? I thought so.

 

[Don Jacks]

What Leo said,plus I think that the shroud needs to be against the radiator to be most effective.Perhaps Nuts will chime in as nobody had fought overheating issues more than he has in the past.

 

[SMac149]

It’s a 64 Impala with a newly rebuilt 409. What you’re looking at is the NEW 409 shroud (At least that’s what I thought I ordered). Here’s some more pics.

Steve

 

[SMac149]

I'm having trouble uploading the other pics.

 

[JimKwiatkowski]

What Leo said,plus I think that the shroud needs to be against the radiator to be most effective.Perhaps Nuts will chime in as nobody had fought overheating issues more than he has in the past.

Don is right, shroud needs to be against radiator and the fan blade needs to be 1/2 in and 1/2 of the shroud. Need better Photos and details.

 

[SMac149]

 

[62impala409]

Much better pics. That shroud appears to have the 59-63 rib style. The 64 shroud had different rib size and different mounting bolt hole spacing. You are running a flex fan which will change things a bit. The original shrouds were sized to be used with clutch fans. I believe that the fan shroud spacers were used on the 2 and 3 core radiators. the 4 core uses no spacers. The reason I believe was that all shrouds for the big motors were the same dept and need to be adapted to the radiator. Leo

 

[SMac149]

I thought the spacers looked like they’d create a big gap between the shroud and radiator.

I think I’ll need to add a fan extension to get it half in and half out of the shroud after I take the spacers out.

I specifically ordered the 64 Shroud from Hubbards… so I’m disappointed they sent the wrong one.

Steve

 

[JimKwiatkowski]

View attachment 19552 View attachment 19551

SMac, your water pulley is to big, you will drop 15 to 20 degrees cooler if you run a 6 inch or smaller pulley. I run a 5 3/4 inch pulley.

 

[64ss409]

There are no spacers on my shroud, 64, 3 core, 409/340.

 

[tripower]

I would change the water pump pulley to OEM and use a 7-blade OEM fan blade with a clutch fan...

 

[62impala409]

This a '64 with what appears to be the correct shroud seen in one of the under hood pics.http://www.rkmotorscharlotte.com/sales/inventory/sold/1964-Chevrolet-Impala-SS/132947#!/164600

 

[SMac149]

Took the spacers out and it looks better. The more I look at it I think the spacers were put in for a coolant over flow container (made it easier to bolt on).

I'm running a 6 3/4 inch pully now and I always had a feeling it wasn't pumping enough fluid. The current pully came from the High Performance Shop that put the engine in for me. I think I'm done with those guys.

I have a shopping list growing for tomorrow to finish the job...

 

[JimKwiatkowski]

Took the spacers out and it looks better. The more I look at it I think the spacers were put in for a coolant over flow container (made it easier to bolt on).

I'm running a 6 3/4 inch pully now and I always had a feeling it wasn't pumping enough fluid. The current pully came from the High Performance Shop that put the engine in for me. I think I'm done with those guys.

I have a shopping list growing for tomorrow to finish the job...

Steve, I use a March 5 1/4 inch pulley from Summit. This will take care of your cooling problem. Here's a link to Summit.
http://www.summitracing.com/parts/MCH-1618/

 

[rstreet]

Steve: Also after all of the above adjustments are made some heating issues are caused by lack of or incorrect vacuum advance but the fan tips location is probably one of the bigger issues after flow volume.
robert

 

[MRHP]

Not to muddy the waters, but...... My car always cooled o.k. but not great. I finally ditched my new extreme duty fan clutch and new fan and got a speedway motors 19 inch stock car 4 blade solid fan and it has never been better. 160-170 hiway and 175 -180 town. The fan is completely inside the shroud. I know it seems wrong, but it works on my car.

 

[BULLET WITH A BENCH SEAT]

First and foremost in cooling these engines is to open up the water pump openings in the block. If you havent taken a carbide burr and removed all the casting flash...your fighting a loosing battle. The opening will get about 50% bigger when hogged out to the proper size. I was just pointing this out to Jim on his new aluminum block last weekend. Bob's castings are perfect...GM's...not so much.
Take a small rag and spray it with WD40 or something similar.
Pull your water pump and stuff the rag as far into the opening until it almost disappears.
The rag will catch all the metal dust that the burr is going to create when your grinding.
Take a new water pump gasket and trace the opening. You will see the difference in the opening size...unless yours is done already.
Take your time and grind until you have made the opening the same size as the gasket. Trust me...there is plenty of meat and your not going to ruin it.
Now grab the rag with a piece of wire or long nose pliers and slowly pull it out. Most of the dust should be stuck to the rag.
Repeat on the other side with a new rag, and then put your pump back on.
If you really want to see how much it helps...put everything back together as it was. Your temp will be lower...should be a good 5 or more degrees lower.
Then you can adjust your shroud, or change fans or do what ever you want to try. The grinding only cost you a set of gaskets.

Let me know how you make out.
Donnie

 

[SMac149]

Thanks for the input guys.

I thought I’d have some good news but I couldn’t find a smaller pulley at any stores around town. I did get the shroud installed (without the spacers), put a new shut off valve on the radiator (it had a straight plug before), put in a 160 degree thermostat, and installed those radiator filler panels. So it wasn’t a totally lost weekend. I do like the way the filler panels look, gives it a nice clean look when you open the hood.

I ordered the Pulley today and a 2” fan spacer/extension (I’ll need that to get the fan ½ way into the shroud), should have them tomorrow… hopefully that’s the end of the heating-up issues.

I’m going to skip the pump grinding for now and keep my flex fan, at least until I see if these things work.

Thanks again for the help.

Steve