The Dodge Challenger Message Board

All,

I apologize as I know this is a Chally site but you guys are so helpful, figured I would ask. A new member of the family will be here in mid May along with my 73 Challenger. We ordered a 2010 R/T for the boy with the 5.7 hemi, he wanted the Dark Titanium Metallic and we will be striping like the pic.

I am in the process of doing some clean up and chrome replacement work on the engine (383) of my Roadrunner when I pulled the shroud, fan, water pump, I noticed that there wasn't a spacer or clutch. The fan was bolted to the pulley attached to the water pump. I assume I should have one as the restoration guide said it came with a 2.2" spacer.

So here is what I am asking, Does it need a spacer? Would I be best off buying a spacer and a flex fan or clutch and flex fan?

Any recommendations on what I should do and who should I buy from?


As always, Thank you

What year Road Runner?

What width radiator?

What rear end gear ratio?

AC or not?

What restoration guide also? A couple of them are pure crap.

The RR is a 1970 4 speed/383 with no A/C, with a 26" Radiator with and 18" fan. I misquoted my above spacer size as my Plymouth Service manual suggest a 1.06" spacer.

I assume it needs a spacer? Would I be best off buying a spacer and a flex fan or clutch and flex fan?

Any recommendations on what I should do and who should I buy from?

that is a very nice runner you have there my favorite year, if you can take some pics of what you have, the factory set works well if set up properly,

is there a fan shroud? are you still using the factory viscous fan?,i personally didnt like the flex fan ,and now i use dual electric fans, but like i said the factory stuff works well, is the car getting hot now if so how hot?

Flex fans are cheap aftermarket things that can be bloody dangerous. Avoid.

Fit a good HD factory fan. If it is not close enough to the radiator fit a spacer. Use a clutch fan if you want. Use a shroud if you want. If you have enough initial timing the engine will run cooler anyway.

There are differences in the clutch fans. The commonly available clutch fans sometimes space the fan closer to the radiator than original. Making them too tight a fit in some cars. You know the fan is too close if it hits the radiator.

Sorry can't take pic of existing setup as I have it torn down.

Here is what I have 26" Radiator with Fan shroud and original fan (18' - 7 blade) bolted to pulley/water pump. This is a non - AC car.

When the car got hot, I did notice a small climb in water temp and a Power loss as I was accelerating. Although, remember it gets pretty hot in Georgia.

So what I am hearing is to not do a flex fan but keep the original fan and put the spacer back on? Or keep original fan and install a clutch which I think Mancini racing offers, they suggest it is close to original and will gain you H/P?

Thoughts?

Yes to your question, I would use a clutch style. What is the thermostat rated at? The MoPar Perf. Viscous fan is a nice piece. A shroud is a must as well as the sealing apron on the hood. At idle or when the car is stationary it must direct the airflow thru the rad. Going down the road a fan isnt needed above 25 or so miles an hour so a fixed fan wastes power, I would consider the clutch type. I also use a surface tension reducer,(Water Wedder, Royal purple ect and green coolant, not the HOAT stuff or Hybrid acid tech stuff,,they all work well but mixing different types should be avoided ,,I have seen many newer cars cooling systems messed up by mixing green with orange)) I also use Distilled water only,,there is some types of water here in the US that has way too much Lime in it and this 'clogs' the cooling systems in a very short time. Check the rad is it plugged up with crap? if so get it boiled out. You can check the condition of the coolant by using a voltmeter set to milliamps,,if any voltage is detected it's time to change the coolant, or you can buy those test strips,,either way it's best to test it from time to time.Good Luck

What Eddie said.

The fan will work better if closer to the radiator too.

dave-r wrote:What Eddie said.

The fan will work better if closer to the radiator too.

and like you said ,you will know if your to close if it hits the radiator

I forgot to mention the radiator Cap. Get a new one or have your's tested at a parts store. It should be able to hold the rated pressure, if suspect get a new one from year One or Mancini Racing at the factory rated pressure which I think is 16 pounds.

airfuelEddie wrote:I forgot to mention the radiator Cap. Get a new one or have your's tested at a parts store. It should be able to hold the rated pressure, if suspect get a new one from year One or Mancini Racing at the factory rated pressure which I think is 16 pounds.

im running a 21 to 25 lb ,er

Do the viscous coupling fans cause less or more drain on the engine than a flexlite type fan? Or is the difference so marginal as to not show any gains?

I don't think the slight extra power drain from a stock type fan is worth the hassle of poorer cooling, sharp edges, and danger of a blade failure that you get with flexy fans.

I have everything back together and measured from the fan to the radiator, I have 4 inches available.

How close do I want the fan?

Does anyone know the size of a clutch? I seem to remember the clerk at Mancini telling me that for there setup (Clutch/Fan) I needed 5"' I will call them tomorrow an other suggestions?

Thanks again, attached a pic but a bit shaky (To early for Vodka).

As I said. The clutch set-ups have different depths. The common avalible one is the deepest. Make sure it will fit first. If not fit a spacer.

And again. You know you are too close with the fan when it hits the radiator. But the closer you can get it the better it will work. If you have a shroud it will only work with the fan inside the shroud.

Installed Spacer 21/4 inch and got fan inside shroud and had 1" left between fan and radiator.

Started no problems as I reved engine the top of te shroud let loose, should I assume that this was nothing more than the plastic shroud being old or do I have other issues.

The car runs with the whole in the top od the shroud but looks like I will be replacing.

Thoughts,


Happy Easter

1-inch from the radiator sounds good.

Did the fan hit the shroud somehow?

Thats what his description sounds like to me. Was the shroud loose in any way? There is a lot of 'force' directed onto the shroud, it must be tight and have some slight clearance between the blades and the shroud. Also make sure there are no jagged edges which could catch the blades, sometimes I see 'beat up' shrouds. The Water Pump hub wasnt rusty was it? Happy Easter

All,

I will have to look at what is going on this weekend. I assume, I have a motor mount issue, a fan/shroud clearance issue or just an old shroud.

I had installed a new water pump so no rusty hub.

I will keep you posted............

Yeah if the engine mount on the drivers side has ripped (which they often do) then that would do it.