Svivel tank CAP - what is correct rating?

Hi Matthias....

MY OPINION.....  I would suspect that if you found a problem with your clamps, that the pressure in the radiator system was not the culprit - that they would have come off no matter what the cap pressure rating is.

As I look at it - the standard rating cap at 13 PSI is NOT supposed to be venting all the time.

If you have a good cooling system (which we know you do), then the pressure in the system will typically be less than 13 psi. 

If that weren't the case (and the 13 PSI caps were constantly venting) - then Pantera overflow tanks would constantly be filling up, and owners would have to keep refilling their systems.  That is generally not the case in a well constructed cooling system like yours.

I thought you said your system was running at a reasonable temp (less than 200*F or 93*C)….

NEVERTHELESS - USA radiator caps are cheap (for us) and I am certainly not suggesting that you keep running a 20 PSI cap.

MY OPINION - I don't think the cap was the problem - it was hoses/clamps. 

Which hose came off?  Most of the hoses are can't pop off (but they can leak)because there are metal tubes on both sides.  The outlet of the water pump (or is it the inlet?) is tricky because the size changes.

Viel Gluck!

Chuck

Chuck Danke!

1) OVERFLOW tank NEVER FILLED by pressure from the hot side with my 20 lib cap on svivel tank.!  I had OVERFLOW filled by 50%  no change on all my driving, was tested  (hence my worry that I might blow my engine head gaskets..no they are good no water in oil)
.2) will try 13 libs AND ALL CLAMPS NEW!!!
   - i have a mix of clamps the old STOCK good once which I used at the
      waterpump where the diamanter changes etc... all the nasty to work on parts
  - dead was the clamp at the pipe at the bottem on the "forward pass" to radiator. Here I have all the crap clamps..guess >10 of them..all will go..
3) all water hoses are Silicon high end
4) cooling system is absolutely TOP CLASS, as we had 30 Cel/86F (Germyn ok! not AZ!!) outside when I tested it for a longer (save max 3000 rpm) ride. Temp stays on the scale max 110C/230 F when car is comming  to  stop in traffic/speed at IDLE  (still need to validate the scale of the Italian  "precision" instrument).
4) I measure at the BLOCK..

Danke!

Matthias..is a nice cat..brutal to drive ..what a fun car ..some set back I survive..

Rule of thumb every lb of increased pressure the boiling point is raised 3 deg F.  The cap is pressure relief fail safe, if you are blowing off a 20lb cap your operating temperature reached the 280 deg F range, that is way too hot IMO and puts a lot of stress on the components (as you have experienced).

However, the fact that it actually got this high indicates the cooling system is not functioning well and with a lower pressure cap it would have still happened, just sooner! There is a fundamental issue with your cooling system, wrong thermostat or fans not coming on correctly. Is the cap you have the correct one for the tank neck length? It might also be that your gauge is reading inaccurately if it wasn't ready at the high extreme (260F gauge?) temperature prior to boiling over.

Silicone hoses require specific style clamps to prevent shearing or extruding into the hose. Personally I stay with good quality (Gates) rubber.

Were you stuck in traffic and engine idling i.e. the water pump flowing at it's minimum and not efficient?

Joules,

TX .. any though helps me to improve the nice cat..

1) the cooling system is ABSOLUTELY up to speed.   The Thermo switch is designed corectly and goes on and off AT TRAFFIC LIght or garage at idle. All new wiring and relais etc.
2) the Thermosdad was checked in a cooking pot (with permission) and is correctly working ..and is the one with the special ring at the bottom of the cylinder
3) the 20 lib DID NOT blow off  - I think it never opend..as the overflow tank is still 50% full as from preload (even AFTER THE loss of all water)
4) Tank from HAll requies a short neck litt = app 19 mm, I have that set up
5) Italian instrument reading needs to be  REVALIDATED ..very good point!!!
6) Waterpump and pully are top end Edelbrok pump and SACC pully (-10%)
7) system was bleeded ..several times ref to Jack's advice

8) after fixing the camps and refull I will measure the temp per external device

Current judgement:

Must be the wrong clamps..too small width and the fixture force not good enough as they are  "bend in design - worm gear" on the band vs a full Metric/or SAE screw set up.

...MIGHT NEED OTHER THOUGHTs though..

TX for thinking this through....

Matthias

wrong clamps , silicone hoses always must be tighten a few times, and are easy came off the pipe , they are more slippery.

Rubber hoses , what I like more to use , needs one more tighting after they ar hot once.

Simon

ok got the message...new clamps are comming in..will retighten..

Matthias,

My apologies, I misunderstood what happened. I think I would still look at reducing the system pressure relief.

Joules no worry ..just the hints to think about is of tremendous value. I am an ok mechanic but as you see missed the point to get the correct stuff in place and check carefully ALL details.  The forum is my source to have my CAT run..and it DOSE!!

YES...I ordered a new lit with 14 lib..I had the dum feeling it was much too high as it does not give much more on boiling temp max. but more risk !!  

..tomorrow is a "clamp" day..would prefer to eat some (a bit different spelling but "same" sound)

TX

Matthias

Sorry for what happened to you.

Do all your tubes have a little bead that prevents the hose from coming out?

René  no all good..nothing broke I just got stuck and very angry on MYSELF

1) did not retighten the slamps..what a mistake, I did retighten everything but the clamps
2) not very solid clamps ..good for garden hoses but not for car!
2) the cap is wrong too high pressure was 20 libs resulting in too high pressure in the system enforcing the mess
3) yes all tubing has this bead..

New 20mm clamps with M5 screws, new cap with 13 libs..and an other day work and then endless air bleeding..no no issue..I am just angry on my stupidity.

I hope nothing happend to the engine, well I did drive only 500 meters after the "blowing Waale" noice came on..and then at stop/engine off still  lots of cooling liquide came out....

(Pascal was here to see me yesterday ..sending regards)

Matthias

The engines are not that fragile, once when I was driving on a ring a slamp fell on my Porsche (very bad pin slamp design)  and the engine had nothing.

René merci..my mechnical skills aquired in the 70th 80th  are recovering & improving..and therby the trust..

hope to see you soon..

Matthias

ok today i did the detailed analysis

1) forward side of the one knee hose at the engine at the main bottom tube was leaking/got loose.  I will play with the full length to optimize at both ends. I used good clamps for this..Issue might be really the silicon stuff is pretty "slippery", so  need more retighten..something to learn! Tx for this comment.
2) all engine side stuff is solid, as  I used 2 clamps in parallel everywhere..Well needs retighten as well..

..is always hard to get the car all the way up in a normal garage. Using 2 lifts for the rear to avoid hitting the exhaust tubing to hit the half shafts. I always park the car on 2" rubber mats..more leeway for the lifts...  

Matthias

ok the latest and last update..

1) the tube in the middle with an extra hose in the middle had an issue as the middle (original rubber) hose was too short hence I had a very short overlap at the engine side
..understood .. and my mistake!..will  professionally fixed!!! big smile!!!

2) my thoughts:
- we understand the svivel tank is doing its job, ok, then if it opens the pressure valve say 13 psi, releases overflow due to pressure  water goes into in the overflow tank.
- well if the cooling system looses water!! my case,, woow what then? Garage floor? Yes we do!, I did.
- ISSUE the old fashened overflow design is in my opinion crap, reason:  you do NOT SEE if cooling system is sucking OUT or IN/Stable lize OR is EMPTY as in my case. To see the level of the overflow  you need to open the svivel, well is normally full and  THEN  you NEEED to open the OVERVLOW if the is an issue on cooling or just to see if the is cooling liq. level adequate. .What an issue to do this..as you need a rope funneling in  to see how full it is...
...an al of my vintage cars I just open the hood, ake a look a the ovevlow,and close it. (for Corvette C2 I need to open the lit on the tanke and the we go). BMW39 540, BMW30 25, Polo, Smart etc..I run 6 (modern cars)..

think you understand...  overfow  Tank without level idiaction is CRAP ! ok,  i am not an originality fetishist. Best to me apppears to me is a transparent plastic tank to do the job..

cat is hopefully running Wednesdy..

P.S.: I will throw the 125 USD overflow tank  on the junk jard (very big smile). lost 5 cases of corona free beer.

Matthias

never have a problem whit this , when both tanks are filled and the cooling system is bleeded  only one time the overflow tank put out about 1/2 liter .

Than it happens never again.

you can cut out an extra hole on the engine cover for an easier handle .

there are handy funnels for sale on Ebay and Summit.

Simon

Hi, Matg. I would stay away from a transparent plastic water tank unless there have been HUGE advances in heat resistant plastics lately. Most plastic radiator end tanks used by Ford, GM etc have eventually failed in use. And they were all black. But several owners have added a sight gauge to the outside of their modified tank. All that's needed is a pair of bosses welded/brazed onto the tank for compression fittings. The only problem is durability: the transparent plastic sight tube will turn yellow, then brown with rust and age in 50:50 antifreeze, so after awhile the water level cannot be seen. Then the tube must be changed. Glass is not a good option due to vibration.

20 psi (or even 26 psi!) is a NASCAR radiator cap and usually causes some other component to fail. Sometimes it's the radiator- the small rectangular transfer tubes in the radiator swell up with pressure and block air flow. Check this visually on your radiator. NASCAR uses special expensive TIG-welded radiators that are rated for that pressure. Street radiators are tested & rated for no more than 15 psi. I have an original Euro rad cap from a GT-5 that is marked '0.9 Bar' pressure (13.1 psi).

I have an old Pantera friend- Mats Gorski- in Sweden and I thought you were him until I saw 'Germany' in one of your posts. Good luck- J DeRyke

Pressure Cap rating: Thanks Jack! The car came with 20 psi on svivel, done by the previous "smart" owner; I think he applied it because the overflow tank was "dead"/rotted away. I UNFORTUNATLY continued with this mistake. NOW I GOT 12 psi!  As cooling system is top notch think this pressure is good enough, I have a 13 psi as spare as well.

Overflow tank mods: Ok I see plastic container is also an issue, however the idea with a sight gauge has something to me. Got the difficulties of it as well now. On all my cars (6)  as all older models, I open the hood look at the water tank and know in a second I am good or need to add, I am seeking for something like that. .

TX team for all your thoughts and insight... and pacients !

Matthias

If you use a plastic tank from some other car, be sure you mount it well away from the headers! I once tried a commercial plastic tank mounted 10" away from the headers, and after one or two hard, fast runs, the water filled tank was so heat-distorted, I had to cut it off its steel frame. Hall and others sell stainless tanks but no one sells a Pantera tank with a built in sight gauge.