This is not as complex as it may seem...it is also not necessary to install a tank in the front compartment. I believe you mentioned you have a petcock on the top of the radiator, correct? Use that to bleed the majority of air out of the system up front. Install a fill/expansion tank on the low pressure (return from the radiator) side of the system and higher than the intake/heads - whichever holds coolant at the highest point. I mentioned the advantage of an electric pump originally and I still stand by that as being the most efficient method for bleeding the cooling system. The mechanical pump obviously works but presents more challenges en route to success. Good luck.

PS:The use of a thermostat will also increase the difficulty of bleeding the system. Jack the car up in the rear, if necessary, to help evacuate the air.

Tony

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Hi

The puke tank is pressurized and since being higher than the block and radiator it is also where I fill the system, the radiator is a no fill type (no cap) and has a bleed petcock. I bleed the radiator when first filling and keep my tank about half full. It
seems to self bleed. Some of the newer fords have a similar system with a plastic
pressurized puke tank.

And a pic or 2 for Chris. (sorry for the hijack)

My last v8 car had the fender wells cut-out and while it worked, I think this does a better job with no weakening from the cut-outs and no hot air on your brakes.

I cut the hole in the hood with my 4" grinder (cut-off wheel). I framed it in underneath with thin 1" flat bar tacked in and 4 studs to hold the perforated aluminum panel in.

Bob

Thank you Bob! Very clean install. Nice work!

Thats a clean install! I also found that the hood exhaust to be much more efficient than the fender exhaust. I however prefer the look of the clean hood so I went back to it a while ago.

I cut a spare hood for a 2012 ford GT 500 hood vent. This is without even bolting the vent down. It looks like a perfect match of the 914 hood contour.
I had planned to use it,but found out it wasn't needed.

When I get some extra time I may finish this up.
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Agree keep it simple drill to small holes in thermostat for bleeding purposes and make sure your fill is at the highest point of the systemClick to view attachment The two LS 914s are sweet.

Matches hood really well but opening does not seem large enough to exit air quick enough especially over 40mph

My car is a race car, more than anything else, and isn't as clean as some of your's but I've been happy with the efficiency of the "through the hood venting". I plan on opening it even more and adding a little more grill screen.

PS: I'm impressed with how clean V82GO cut his opening - talk about pressure with a cut off wheel! Great job Sir!

Tony

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More good information here:

http://www.914world.com/bbs2/index.php?sho...p;#entry1380981

Jack

What kind of temps are you running.

Cali: The coolant temp depends on the air temp and whether I'm stuck in traffic or on a race track. On a hot Summer day rolling it will get to 185-190; Hot day stopped traffic - 205; Hot full blown sustained racing - 215-225 (depending upon conditions).

LS engines make their best power HOT; 230 is where you need to really take notice that you have reached the tipping point. All the best.

PS: My chassis was a multi-owner water pumper before I ever acquired it...Bob (BigKat) and I have a good friend Larry C. (Spaceshuttle) who I purchased the roller from - Larry did the hood on my car well before I ever bought it. The inner fenders were cut before he purchased it too. I tape off about 90% of the fender venting to force the heat out the hood. JFYI for all...

T

Only thing with hood venting is you can feel the heat roll around the A-pliars and then dump into the cabin if you have the windows open. Not a big deal you can just tell it is there.

That hasn't been my experience at all...my footwells do heat up - to the touch (I do not have carpet or insulation on them) but I have never felt noticeable heated-air enter through the windows. I don't have windows either, as I have a full cage...it could be your system is simply different and draws it in.


T

Its been my experience that you can feel the heat. Only if you put your hand up there by the windshield or by the a pillar. Its particularly noticeable at the windshield.

Dang, I can't believe all of the responses... thank you very much! I will read them all and of course, I'll have more questions! ;-). Right now, I'm trying to get my daily driver back on the road. Look up BMW 545 oil leaks and you will see what I'm up against! Just replaced the oil pan gasket and now it's time for the shake down test! Ciao for now!

Tangentially-related to cooling, but hot is actually better for cylinder wall wear per some studies done by Caterpillar so assuming you don't have piston/cylinder head overheating issues (tight clearances, etc.) its better to have a higher pressure radiator cap and run hotter rather than cooler.

Hey all,

I had a chance to draw up what I think will work on my car with a minimum of adding and removing hoses/connections etc... I did not include the addition of an electric water pump (yet)... I want to see what adding a header tank does to alleviate the run hot issue. Does it look like a viable plan?

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Header tank goes inline = same hose. I'd say off the t-stat since it's already the high point. Also if you have a blown head gasket it would be easy to tell with the nonstop burping.

I believe that is what I show with what I have marked as (1)... unless I do not understand by what you say "header tank goes inline = same hose". I do not think I have a head gasket issue. No white smoke, no oil in coolant or coolant in oil. The car has never overheated... it just runs on the hot side. Can you clarify what you mean?

You got it right. #1 hose needs to be a small 1/4 to 3/8 inside diameter#2 hose needs to be larger 3/4 and as close to the intake of the water pump as you can get it.
This will self bleed the air out of the system. Fill it up and run it thru a couple of heat cycles.

I'll admit I don't have a sbc, so I don't get why anyone would do it that way. Inline, as in all the water flows thru it.

Can't upload a pic as the new Google Photos doesn't link.

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In and Out holes.

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A handy and necessary device from 100 yrs ago.


The header tanks are there only to be a place for the steam to go,the highest points.
Large flows through the header tank is not needed,merely a path for steam.
A one line header tank is also functional,as is desirable at the front.
A sight glass,or plastic tube,may be temporarily installed to determine the rate of steam accumulation.
Taking a long drive in heavy and hot conditions will stress the system,building steam in the top of the rad.
Make certain the pump and pipes system can flow the minimum LS cooling flow,~55-65+ gpm.
A decent copy of a truck's cooling system is a good start,other than the remote radiator,pump and restrictive pipes.
Build your shroud to pull air through all of the radiator,make certain the airflow at 20 mph is sufficient.
Use a manometer to check pressures fore and aft of the rad,then calculate airflow.
A checklist of changes from stock configuration will point to errors,as the design has been well flogged.
A 55 gal drum should be filled in less than 60 secs,at maximum,by the pipes and pumps used.
Running @ 2K rpm,a flow of not less than 20 gpm is necessary to cool the LS.
Reducing the diameters of the pipes will yield a smaller,and hotter flow.
Stick to the LS thermostat,setting the operating temperature,and flows.

https://www.google.ca/search?q=ls+water+pum...water+pump+flow
https://www.google.ca/search?q=manometer+cu...anometer+custom
https://www.google.ca/webhp?sourceid=chrome...=thermodynamics
https://www.google.ca/webhp?sourceid=chrome...al%20conduction
https://books.google.ca/books?id=y1XuAgAAQB...ics&f=false


http://ecomodder.com/forum/showthread.php/...sure-21680.html
/
The Python look,to cool an LS.Anything else is just skinny,not cool.
http://www.914world.com/bbs2/index.php?sho...0844&st=723
Don't agree tho,with hanging them below the floor pan,inviting torn hoses by road trash.
/

Thanks veekry9! Your expansion tank connection points look slightly different than what Bob (BIGKAT_83) recommends.

Anyway; I'm looking at expansion/header tanks but there are so many out there! Any one know of good model/part number that will work for my application? I believe I need a model that has a 0.75 inch port on the bottom, a 0.25 to 0.375 inch port on the side about half way up; a pressure cap of around 16 psi and a port just below the cap for overflow. Any suggestions?

VW Death Star, works great.

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MR2 system. MORE PICS



Other notes... heater will work sooner and hotter if it comes straight off the engine like factory.

Great pix,and a way to scale the requirements for the hp of the LS.So,double++ everything,pipes,too.
A set of insulated hard pipes through the cabin,by the console stamping,or the longs,inside or out.
/
Simply have a look at the average LS powered truck,use those numbers and sizes as minimums.
The Celica and MR2 systems are for low hp applications.
The truck rad's inlet pipe ID defines the minimum inside diameter of the pipes forward.
With a rad of suitable 'capacity'and the minimum flows,you can keep your cool.
Wouldn't want to be a hot head.
Good luck with the cooling system.
/

Double the research effort there Veek... it's nearly the same size as the Celica radiator and used 1 3/8" hose.

But the point was the design, and it's a cool pic.

You do not know of which you ask! (or you do?)

The floodgates are already open, be careful what you ask for.

Cooling?
BraveHelios was inquiring advice.None to give?

Almost ready to take things apart one more time. So how crucial is it to use wye connectors versus Tee connectors? I spotted these on amazon (see picture):

https://www.amazon.com/Water-Temp-Joint-Pip...+Sensor+Adapter

And it would be much easier (and cheaper) for me to install the correct sized NPT barbed nipple to this adapter versus getting a custom wye connector.



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I have a couple of those from ebay. Ask them what part they got the measurement from because it's been inconsistent. Sometimes its the clamp area, sometimes its the lip.

I found it much easier for me to get stainless pipe the diameter I needed, weld up the connections I needed. I welded up quite a bit more than I thought I would and actually want to do more. It was simple with stainless wire and a mig.

Slowly progressing.

Quick question; which part of expansion tank must be above the block (t-stat?)... the bottom (low pressure) hose or the upper (high pressure) hose? Does it matter much Death Star or Passat expansion tank?

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That upper hose. Either of those mounted in that position will work. I prefer the non rounded version, but they do fail occasionally. Thats what I run.

Not less than N.
The method to calculate the size of cooling system expansion tanks,and the 'why' of the radiator having a smaller return hose.
The total volume of the system is larger than a pickup or van,so,not less than the size of tanks installed in them.

http://www.engineeringtoolbox.com/volumetr...sion-d_315.html

A small 4 cylinder's expansion tank is smaller for that reason,not equal,not the same size as a pickup's V8 tank.
Placing the tank below the head is ok,in a pinch,as the level is controlled by the pressure cap,tho level is desirable.

/

Here is a picture of the completed setup. Still trying to get the air out of the system. Loosened the petcock on the top side of the rad and nothing... no air and no fluid. Pictures do not show the addition of a overflow tank placed in the trunk.

So; if I do not have a vacuum pump... what is the best way to purge the system of all air?

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Engine should be running. Hot air/water makes its way to the top thin line and feeds its way to the reservoir. Then your large line is your feed back into the cold side of the coolant line.

Basically running the engine will purge the system, aka self purging.

Yes just fill the system up and run it through a couple of heat cycles. Make sure it's all sealed up so that the system is pressurized. Put the blue cap on and make sure all the hoses are attached just like it would be if the car was 100% ready to drive. Although it may seem logical to leave a line open, it keeps the system from forcing the air out. Rev it a few times the first time to make sure your thermostat opens and feel the line going to the radiator to make sure they are hot. Watch the temp needle (at least the first time) for spikes in case you have a big air pocket. Get the engine up to temp and then shut it off. Then..(the hard part)....leave it alone and let it cool off completely. When you check the coolant the level should be down a quart or so. Maybe more. A couple more like that and you should be good. In fact once you know that you don't have any serious bubbles you can drive it around a block or two. Then very quickly you won't have to add any. BTW I never got anything out of my radiator bleeder either. Probably would now but the system is bled.

An update (pictures to follow);

I have the system all together and I thought it was going well. I took it for a drive at around dusk where the ambient temperature was 67 degrees and the car only got up to around 190 degrees. This is a marked improvement considering that in the past; even on a 40 degree day, the engine temp would go past 200. Well; last night, I let it idle in the garage to see what would happen and it overheated. I mean the temp got up to around 230 and the coolant was boiling over in the overflow tank. Also the fan never came on (it is supposed to come on at 180). I did check and the fan does work. I shut it down immediately and let it cool off. As it cooled, it sucked up the coolant out of the overflow tank and back into the expansion tank and engine.

Prior to this; I tried to bleed the system. I lifted the rear end which lowered the rad and I did end up getting fluid to come out of the rad bleed petcock (upper corner of rad). I also mended the holes I drilled in the rad shroud.
After the boiling coolant episode, I noticed that no coolant was coming out of the rad bleeder.

I do have a setup where lines are coming off the main rad hoses and going to a heater core for cabin heat, and the day I took it out; I had good heat in the car too.

How much air can be in this system? The temp sensor for the fan is located by the t-stat. Is the reason that the fan did not come on because of an air pocket located by the temp sensor? I guess I really need to understand how the vacuum/manometer etc… system works and how to set one up for my system.

Any other suggestions?

Do you have a manual over-ride switch for your fan ?

On my system I have a manual switch for the fans, I usually turn on the fans when the temp reaches 180 degrees

I would install a on/off switch to control your fan, refill the system, start and bleed the system again.

You must have a running fan when stationary.

Put one of these powering a 12ga wire and a relay to control your fans. Put the probe in the radiator fins.


https://www.amazon.com/gp/aw/d/B00K75QRZA/r...&ref=plSrch




You need to have the system purge a couple times in order for the expansion tank to functuon correctly.

I had similar overheating issues with a 2000 Sonoma with an LT4 and T56 swap. It sounds like you've tried numerous times to "purge" the system of any air, and it may not be that now that you've done it a few times. I would install a manual switch to turn the fans on remotely, independent of the t-stat. I would also replace the t-stat with a new one, to eliminate that as the source. Lastly, I would take it somewhere to get it professionally pressure flushed. How's the water pump? Is it up to the task of pulling in and pushing out coolant all that distance from the engine to the front of the car and back?

Quick question. How fast is it getting up to temp? Do you have a thermostat? Do you have holes in your thermostat? How new is your water pump?

Man with all the money and time your spending get a renegade Ron Davis radiator and call it. You are trying to reinvent the wheel. I did that ten years ago three different water pumps three different radiators hole in the hood, hole in the bottom of trunk compartment, cut open the fenders and kept having the same problem. I purchased the Ron Davis Radiator hooked up a Meizere 55gm water pump and never got above 195 on a hot day. 160 to 180 all day most days. Also if you do that you eliminate the main cooling factor from. The equation. So if your still overheating after that fix you have a better chance of isolating the problem. I'm using the same radiator with my 3.5 v6 Honda engine and its less horsepower but stays at 170- 180 all day with a 180 degree thermostatClick to view attachment Click to view attachment

One more note/

I would remove the thermostat and use my manual fan switch for warm ups.

I tried a 160 degree thermostat (with holes) on mine it would not open as it was suppose to. May have been defective, but with it removed I don't worry about it.

My engine with fans off will come to temp fairly quick except in the dead of winter .

I do have a manual switch. It is located on the center console, to the right of the temp gauge. It also has a 160 degree t-stat installed with many small holes drilled around the flat surface. I am trying to avoid going to an electric water pump, but it is heading that way, it seems. I think I will remove the t-stat and replace it with a re-stricter washer and see what happens.

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Oh what the heck... here is a picture of the interior; complete with Fiat X-19 arm rests!

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[q1uote name='v82go' date='Sep 29 2016, 09:13 AM' post='2404724']
One more note/

I would remove the thermostat and use my manual fan switch for warm ups.

I tried a 160 degree thermostat (with holes) on mine it would not open as it was suppose to. May have been defective, but with it removed I don't worry about it.

My engine with fans off will come to temp fairly quick except in the dead of winter .
[/quote]

When is the last time you replace your water pump? V8 conversions us a big block Mopar pump and they do go bad. Most of them are stamped steel impellers and I've seen these blades break off and or corrode.

hum

God, if I have to take apart the water pump one more time! I can tell you I bought a rebuilt unit from a chap on this forum a few years ago and I am quite certain it has steel impellers. There has to be a way to know the pump is working correctly without taking it all apart!

Are the high quality electric pumps good enough to remove those big block Mopar pumps?