Swirl Tank

[AkRev]

Looking to improve the cooling system. (not my strong suit) 

 

Information on my car;

I have a Ron Davis radiator installed from the previous owner of my car. The way it was installed, the cap is lower than the thermostat on the engine. Previous owner also removed the heater core and blocked the heater core lines at the back of the head and on the lower coolant pick up. The issue I am experiencing is high temps at idle and light speeds. In attempts to help this out I have tried a few things. The two that have helped out the most have been to retard the timing and moving the cooling fans from a puller to a pusher configuration. But the car will still heat up to over 200 degrees at idle on a 80 degree day. 

 

Correct me if I am wrong, I think a large problem I am encountering is with air in the cooling system. I have two ideas, the one I am leaning toward is a swirl tank. (similar to this design http://www.britishracecar.com/BernardBradpiece-Merlyn-11A/BernardBradpiece-Merlyn-11A-BC.jpg)

 

The other thought I had, I have a spare Volkswagen Jetta pressurized reservoir (expansion tank if I remember my terms correctly.) Could I use this? My thought process is that the radiator cap on the radiator would still function as normal. The stock atmospheric reservoir would handle most of the expansion and the pressurized reservoir would act like a swirl tank and collect air there instead of hindering the cooling process of the engine and the radiator. 

 

Like I said before, this is not my strong suit. Please let me know of any critical flaws in my ideas or any basics that I have just overlooked. In advance, I appreciate the help.

 

Thank you.  

[AkRev]

P.S. Temp readings are from a CHTS not at the thermostat housing.

[m1ghtymaxXx]

Why would you switch the fans from puller to pusher? A properly shrouded puller setup is much more effective. What was the original setup? If idle and low speeds is the issue, it sounds like airflow is the culprit. 

[AkRev]

In rereading my post, it looks like I left some notes out.

Airflow was my first idea. The radiator is really thick and was shrouded with the puller setup. From my past, I was always told that pushers work better (for daily drivers) with thick radiators. Right or wrong I tried it out. it helped.

 

After I moved to the pusher setup, I started leaning to a water flow issue.  If I drive in higher rpm's even at low speeds it does not run hot. (I forgot to mention this in the first post) I replaced the water pump, no change.  

 

Thanks for the ideas, it always is nice to have someone to help me to think through the process. I still am looking at this as air inside the cooling system causing the problem.

Edited February 6, 2014 by AkRev

[socorob]

Usually if it works at speed it is an airflow issue. Above about 25mph or so, more air is being forced in then most fans will ever be able to pull, that's why a pusher fan usually is less efficient, it blocks the natural airflow making it to the radiator when you start moving. OEMs use pullers for that reason. If it got better with the pusher, could the pusher fan be rated for much higher cfm than the original puller was? That may explain why it helped some, not the fact that it is pushing the air, but the fact that it is moving more air than before.

 

Could also be a thermostat issue.

Edited February 6, 2014 by socorob

[m1ghtymaxXx]

What was the original fan setup? Stock or electric? A shrouded puller fan draws air from the entire surface area of the rad, where an unshrouded fan will pretty much just move a column of air the size of the fan. Move that fan to the front and you're just blocking air to the rad at speed. I'm wondering if the original fan was buggered, perhaps improperly wired.

 

If you suspect a coolant flow issue, one thing to check could be use coolant stop leak. I've seen that make a huge mess of the entire cooling system. 

 

I missed the bit about the rad cap being lower than the t-stat first time around. This is very valid point as the rad cap should be the highest point in the system (not familiar with how the VW reservoirs work). I'm not even sure how you would completely fill up the system, since normally you leaving the engine running with rad cap off and keep feeling it, blip the throttle, let it bubble, top it up and repeat until it doesn't take any more. I would try and figure out a way to raise the cap to the highest point, whether it be a cap with a neck to it, or ad some bends to the rad hoses. 

 

Perhaps you can find something like this but with a neck tall enough to make it the high point: http://www.ebay.co.uk/itm/JJC-Racing-Rally-Motorsport-In-Line-Radiator-Hose-Filler-Neck-Cap-/400556386601

Edited February 6, 2014 by m1ghtymaxXx

[AkRev]

The pusher fan is the same fan as the puller, I just took the shroud off and reversed the blades. I don't think it is an airflow problem. For example, if I drive at 30 mph, in 4th, it will try and overheat. If I drive in second, no issue.

 

Has anyone used an expansion tank or a swirl tank by chance? I have tried a few ways to bleed the system and there still seems to always be a bit that I can not get out. (found this out by using clear hose on the thermostat bypass.)

 

Also note, car does have large overlap cam, AFR are 14.1 at idle. Compression is good on all cylinders.

Edited February 6, 2014 by AkRev

[AkRev]

I will ask the previous owner about the stop leak. That's a good point.

[m1ghtymaxXx]

You beat me to posting before I finished editing. Added a few more points above.

[beermanpete]

Working better at a higher engine RPM suggests insufficient water flow. What size are the pulleys? Is the water passage area in the timing cover (behind the water pump) in good condition?

[AkRev]

Beermanpete, The timing cover is in good condition. Great point about the pulley size, I will look at that when I get home.

 

Thanks for your insight.

[socorob]

On some new cars you're not supposed to remove the radiator cap. All filling is done with the reservoir. My Titan has a similar setup. On my Sunbeam the radiator cap was lower than the other end of the hose where it went into the top of the engine. I used to have to fill it by using the radiator hose. Remove the hose from the top of the radiator, fill radiator to that hole, then use the hose to fill the engine. Fill hose all the way and put it onto radiator as fast as you can to keep as much water in the system as possible.

[Tony D]

200F with a 180 thermostat is about spot on for a CHTS. It doesn't looks like anything is wrong at all.

Run proper anti-boil, water wetter, and a good radiator cap.

If you run a 160 thermostat, it will be 160 at the thermostat housing, and about 20 degrees hotter when checked at CHTS point.

 

This is why it was chosen on Emissions Vehicles, it results in closed loop operation faster, and reduced emissions.

 

BEWARE on using newer thermostats in these cars. I recently was looking at the specs for a 2002 Vehcile with a 54mm thermostat. Normally I would say 'that would work' just like the old Chevrolet thermostats. But the specs were NOT compatible like old thermostats. Previously a thermostat would crack +/-5 degrees of the thermostat rating, and be fully opened by 10 degrees above that point (Fahrenheit). So on a 160 thermostat, it would crack some place between 155 and 165, and be fully opened by 170-175. (This would translate to 175-195 CHTS Monitoring Point Temperatures.) For the standard 180 thermostat, you would expect a similar range from 175 early crack to 195 late fully open. That would be normal operating ranges.

 

For this new 2002 unit in another vehicle, the thermostat was to crack at 195, and not be fully open until 215F!!!Same tolerance was stated +/- 5 F so you are looking at early crack at 190, and late fully opened at 220F, you BETTER have at LEAST a 16# cap, and pray as that would mean 240 at the rear of the head at the CHTS if you used that thermostat.

 

If you want to drop CHTS temperature, look at the cooling thread in FAQ stickies at the top of the forum. You can take that plug that used to go to the heater core, and run a 3/8" hardline around the back of the head, connecting it to the lower thermostat housing. That should drop your indicated CHTS by at least 5 if not 10 degrees F! You start a flow path from that 'dead spot' in the cooling system and get coolant flowing through there once the thermostat opens, making for considerably better temperature stabilization even on a stock engine.

[AkRev]

Few updates, pulley sizes are stock.

I ended up hooking up the Volkswagen expansion tank to the thermostat bypass. I was amazed at how much the system bleed out, the temperature was solid but its 30 degrees out today. I am going to figure out a way to mount this and test it once the weather heats up in a few months. I will update as I go along. 

 

 

Thanks again

[AkRev]

"If you want to drop CHTS temperature, look at the cooling thread in FAQ stickies at the top of the forum. You can take that plug that used to go to the heater core, and run a 3/8" hardline around the back of the head, connecting it to the lower thermostat housing. That should drop your indicated CHTS by at least 5 if not 10 degrees F! You start a flow path from that 'dead spot' in the cooling system and get coolant flowing through there once the thermostat opens, making for considerably better temperature stabilization even on a stock engine."

 

Tony,

 

First of all, thanks for the peace of mind. Got a small follow up question. If I run a line off of the back of the head to the expansion tank (mostly so I can bleed the system) then run the return line from the expansion tank to the lower thermostat housing. Would the cap on the radiator still function as normal, or would I need to put a high pressure cap on the radiator to allow the expansion tank to handle the system at that point?

 

Worse case, I could be a guinea pig and see what happens.

 

Thanks for your time.