I bought a Rolls Royce and want to build it. (Page 24 of 33)

We're also fighting cooling issues.

Get the largest oil cooler you can in there, two if you have to. It's often overlooked how much cooling the oil helps with overall engine temps. The RX7 units are great, but can be pricey. With your shop I'm sure you can find some very large, high flowing, low restriction coolers kicking around somewhere.

I forget what your fan setup is on the radiator. Best bet is buy a good electric fan, make a shroud that fits over the back side, and run the fan constantly.

Once the fan is sorted, seal up the front end and duct all openings to feed the radiator. Force the air through it without letting it spill around anywhere.

Getting air out from behind the radiator can be the hard part. Vents can help or really hurt you depending on placement. Use something like a Magnehelic gauge to measure the air pressure at various points on the hood at speed, then place your vents in a low pressure area. Belly pans like mentioned can help as well. Take a look at your wheel wells too, if you have no wheel liner, and no way for high pressure air to get out, you might be pressurizing the engine bay a little bit through there.

Looking back through the thread, I noticed this pic:

The engine is very close to the radiator.  The engine is likely restricting the airflow through the radiator.  If possible, move the radiator forward some.

I also noticed that it is heavily shrouded.  Large shrouds are needed if you spend a lot of time in traffic and need the fan to pull as much air through the radiator as possible.  At speed, the shroud actually becomes a restriction.

These SPAL fan shroud flaps are kind of a neat way around that.  Its like a check valve that opens when the shroud is restricting cooling, but closes when the fan is doing most the cooling.

They are only a couple bucks each
https://www.summitracing.com/parts/spu- … gKp_PD_BwE

Probably going to take more than that to solve your issue but not a bad idea to start.

Those fan shroud flaps look awesome. I don't think they're going to solve their problem completely, but i'm going to grab some since our radiator is also 100% enclosed.

That would also require a ton of fab work. 

I did this calculator online and it roughly says at 100mph I would be bringing in roughly 750 CFM of airflow through the radiator.  I think my fan is roughly 2-3k CFM. 

Am I understanding it right that the fan will pull ~3x more air through the radiator than the wind speed at 100mph?

https://www.engineering.com/calculators/airflow.htm

That number seems low, but I have no idea what values you used for the area. I entered a 14"x16" opening at 60mph and got 8kCFM. Our bumper opening is smaller, likely 12"x8" all combined now that I have all the ducting to bring all air to the radiator and I get about 3kCFM.

The real world is not that simple unfortunately.
Air moves when you have a high and low pressure. If you have a high pressure engine bay, or no where for the air to go after the radiator, your flow will suck even with a fan because there is just nowhere to move the air. Think of an inflatable bouncy house. The fans on those move a lot of air really quickly, right until the thing is full, then all the fan does is maintain pressure, not move a lot of air. Your tiny gap between the engine and radiator is doing something similar. If your engine bay is also getting pressurized from other sources, it's just even harder to get air through.

I haven't seen anyone else mention it, so I will.
That oil cooler could warming up the air before it gets to the radiator.
ed: and disturbing the air flow through the radiator.

Ah shoot, I must have messed it up.  I went back and recalculated and I was getting almost 20k CFM @ 100mph

So:

In a car at speed it is best to have no fan and rely on the airflow through the radiator

In a car sitting at idle with low air speed it is best to optimize cooling at high ambient temperature and low air speed with a fully shrouded radiator fan.

It sounds like in regards to cooling it is best to have the smallest (even unshrouded) electric fan possible to not overheat while idling at the highest possible expected ambient temperature.  that way we get the most surface area that works with air flow through the radiator at speed.

Right?

I would certainly not recommend this as the only indicator, but I do know that drivers don't necessarily look at gauges, but they will see water squirting in their face.  Good point though.

Temp gauges are good.  Big idiot lights for overheating or loss of cooling pressure are good too.

Keep in mind that if you lose coolant pressure (bad cap), then your coolant will boil at 212F.  This is well within the "normal" range on most gauges.  Hose in the face or coolant pressure sensor are good ideas to detect this.

Starting to get back to work on the car and kicking around ideas.

Pedal knock back was from the rear axle.  If I tighten up all the pads and rotate the right rear wheel one revolution the inside brake pad has about 1/16 clearance and is loose in the housing.

So, something is bent and with it being from 1958 I would like to put in something else.

I can either continue with the suspension I have and run a solid axle.  Kinda pricey for a new axle and have to re-do all the brackets.

OR

I can play around with building an IRS setup. I would probably build my own subframe and mount a Gen V Diff to the chassis, then build my own control arms.  Use either a Vette or Gen V camaro knuckle/brake setup.

Thoughts??

Also, debating on going with 18's and a 26" tire (Compared to the 20's and 29" tire on it now) to lower the car some. 

PRO:
more tires available
cheaper tires
less rotating mass

CON:
Not even remotely as sweet and cool looking.

Also, is there an optimal sidewall size?  35, 40, 45, etc?

I vote for getting an IRS in the car. I don't have to do the work so that doesn't bother me 8-)