i think one of the high flow thermostats will help with your temp fluctuations and your oil temp will likely run 20-30f hotter then your coolant.
sounds like your making progress.
Yes, this is looking better. I did a 15 mile drive last night before I put it to bed and on the way to work this morning the results were about the same: the temp likes to rest at about 80C (thermostat rating, radiator doing its job) with occasional cycles up to 90 for about two to three minutes, (hermo closed) then back down again as the thermostat opens and the radiator kicks in again.
Would a 180* thermostat be a better choice?
I'm satisfied that this is very good forward progress.
Now that this is solved it's time to get it to the tuner for the final go - over (recall all the fuel problems that happened before this but I wanted to get all the other things fixed before I took it to him.)
Cobra Make, Engine: Contemporary Cobra, 427 side oiler
Posts: 1,850
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So what solved it, the higher pressure cap or the burp?
The 160 vs 180 argument never ends. Personally, I see little use for a 160 except for the fact that it opens quicker the first time and affords that much more delay (maybe minutes at best) before your temps climb on up to operating temp. If you run a 180 or something closer to the actual operating range of the engine, then the t-stat may have a chance to actually close from time to time, allowing time for the coolant in the radiator to cool further, thus promoting a better "cooling exchange cycle." Then there is the argument that 160 is too cool for an engine to operate. It certainly is for an FE. But in my opinion a 160 t-stat is just a gate that opens once and never closes on most engines, so it doesn't really effect the overall operating temp anyway.
Last edited by elmariachi; 06-25-2009 at 11:03 AM..
your 20 lb. cap has nothing to do with recovery of coolant, forget that idea. you can go to a 22-24# cap and you might not lose any.
personally, it's hot out, with a 160 deg. thermostat my car will idle all day at 180, with a 180 thermostat it is going to hit 180 and go over that, so you gonna watch it? at what point do you shut things down? mine gets up around 200-210 i get nervous, especially if i'm not running it hard. if it is cold out and you want more temp cover a portion of the radiator, and if anyone asks tell them it is an old nascar trick.
remember, you crack the radiator cap and you lose cooling capacity until it cools again.
put the 160 hi flow thermostat in and get a 22-24 cap and get your overflow set up and forget about it.
also, when the thermostat closes there is no flow, so cooling does not improve in the radiator, the radiator requires turbulent flow through the core tubes to cool the fluid, picked that up off the stewart website.
So what solved it, the higher pressure cap or the burp?
The 160 vs 180 argument never ends. Personally, I see little use for a 160 except for the fact that it opens quicker the first time and affords that much more delay (maybe minutes at best) before your temps climb on up to operating temp. If you run a 180 or something closer to the actual operating range of the engine, then the t-stat may have a chance to actually close from time to time, allowing time for the coolant in the radiator to cool further, thus promoting a better "cooling exchange cycle." Then there is the argument that 160 is too cool for an engine to operate. It certainly is for an FE. But in my opinion a 160 t-stat is just a gate that opens once and never closes on most engines, so it doesn't really effect the overall operating temp anyway.
Probably more burping but we'll never know since more than one thing changed. The 16lb cap I have is vented so the coke bottle recovery will not work with it. Not too interested in going back since this is so much of an improvement.
Per the previous I'll probably stick with 160 but go to the high flow.
Cobra Make, Engine: Contemporary Cobra, 427 side oiler
Posts: 1,850
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Quote:
Originally Posted by twobjshelbys
Probably more burping but we'll never know since more than one thing changed. The 16lb cap I have is vented so the coke bottle recovery will not work with it. Not too interested in going back since this is so much of an improvement.
Per the previous I'll probably stick with 160 but go to the high flow.
So you could go run it with the 160 and then another run with the 180 and compare. If it didn't draw the coke bottle contents back in then a recovery system is not the answer. If burping it was the solution you should be able to run with your current t-stat and either radiator cap and be fine. A hi-flow won't matter, IMO.
Last edited by elmariachi; 06-25-2009 at 02:21 PM..
I think this is pretty much it. I'll take the suggestion to try a high flow thermostat and then a 22 and 24lb cap before the recovery tank. I did another casual drive (up Big Thompson Canyon and back through Estes Park to Lyons) tonight. Very well behaved Even the fan switch on/off was producing expected results. Still working on it but I think we're close.
I would think that if you don't have a recovery system, you will most likely always have air pockets. When your car cools, isn't it sucking air back into the system through the cap port? If that air pocket is under your temp sender, that could be the source of erratic readings. I bought a cheap catch can from Jegs, ran a tube from the top cap expansion tank port to the bottom of the can (behind the can in the pic) with the petcock open and a tube from the top of the can to outside. Never a problem.
I think this is pretty much it. I'll take the suggestion to try a high flow thermostat and then a 22 and 24lb cap before the recovery tank. I did another casual drive (up Big Thompson Canyon and back through Estes Park to Lyons) tonight. Very well behaved Even the fan switch on/off was producing expected results. Still working on it but I think we're close.
good, good. glad to see it's working. with scenery like that i could probably charge for advise. at higher altitude your cooling capacity is less i believe, could be wrong. let us know how it goes.
I would think that if you don't have a recovery system, you will most likely always have air pockets. When your car cools, isn't it sucking air back into the system through the cap port? If that air pocket is under your temp sender, that could be the source of erratic readings. I bought a cheap catch can from Jegs, ran a tube from the top cap expansion tank port to the bottom of the can (behind the can in the pic) with the petcock open and a tube from the top of the can to outside. Never a problem.
It's a problem of physics. If there were enough room above the high point for an expansion tank with enough capacity then you would only need the expansion tank. Apparently this wants to expand about a quart total and the Kirkham has only about that capacity above the radiator hose exit (I didn't measure it before I installed it). So when the system expands and pushes out more than the Kirkham capacity it pulls air back in to the tank and into the hose, so that when it starts to flow again I'm guessing air is then pushed back into the radiator.
If the Kirkham had enough capacity above the radiator outlet it wouldn't be a problem. Since the system needs more expansion the choice is to fill the Kirkham full (which gives it enough to keep the radiator exit above water), and allow the system to expand into an auxiliary tank. My assessment is the Kirkham is made to fit in the available space and couldn't be any taller without hitting the hood. So for this engine's heat characteristics, it's just not quite enough.
This could all be accomplished with the original in-line cap/tube and a catch can with enough capacity and patience to bleed all the air out (and a very steep hill to get the fill cap above the thermostat housing). Meanwhile the Kirkham is installed, and backing it out now is more work than worth. Besides, as pointed out elsewhere, it looks cool!
I just never would have though that the system would expand so much. A quart is a lot of expansion and this misunderstanding is what led to so much churn.
If I need the overflow tank after moving to higher pressure caps the trick will be to find a place to mount it. The inside is already pretty cluttered.
Thanks to all who helped! This shows the value of the forum.
Be careful running those extremely high pressure radiator caps. If your using an old style Ford surge tank keep the cap pressure 16 lbs and under, I'm runnig a 13 lb. cap and it works just find, plus a recovery tank that contains any fluid that gets by the cap after shut down ...it then is sucked back into the radiator. My water level is always perfect.
A super h P cap can cause leaks,,,,soft plugs, gaskets, hoses etc....if that occurs just dump in a little Alumi seal...fixed.
It's all about air flow on these little cars, when it's 115 degrees in Havasu I can count on the temp. getting up to 210 at long signals..but quickly going back to 190 to 195 on the road without the fan on.
just got back from a drive in 100+ heat with pretty good himidity, highway temp was little over 180, around town temp would go to 200. 160 deg. hi flow thermostat and 22-24# cap, hi flow stewart stage 3 water pump, don't believe i lost anything. that was a pretty good test, racing in these conditions would be a better test though.
There may have been a breakthrough today. Parts are on order with overnight shipping from Summit. Even if this is not the final solution it is a major breakthrough. I didn't have my camera when I went up to the shop to see what it was but I'll bring it tomorrow (or take the bad part home and shoot it tomorrow night).
Hint: There are clues in elmariachi's thread in the root post here.
So the last two things were out of my tool kit. I tossed my timing light years ago, and since he I'd been over at the S**** bar and grill a few times this weekend I told him I'd bring it up for (1) check the timing and (2) check the flow on the radiator. I dropped it off yesterday morning. At noon he calls. Said I need a part. So I ordered it from Summit Racing (I'm not telling yet!) and stopped by on the way home. Yep, broke.
The replacement came this morning and it's now working. Temp never gets above about 85C. I'll take it for a spirited drive tomorrow morning before work (I have a one-hour course that includes about 10 miles of freeway).
The timing was OK (still have to take it to the tuner, as the whole "system" needs to be brought into line). The drained the radiator and put the vacuum on it and he could hear a hissing sound - I already knew that - the radiator is probably tested to 20# and he was pulling more than that and my 24# cap also showed a little seeping...
Oh and the shaft is worn clean and smooth. The press on ribs are worn down to nothing...
Tonight after about a 15 mile drive there was no variation off about 80-85C. Solid and smooth. Like I said, tomorrow I'll put it to a little better test.
I'm going to keep the Kirkham - it does keep the fill at the high point and looks cool.
I think I can toss my coke bottle catch can though. Tomorrow I'll put the 16# cap back on before I take it out (and keep the bottle, just to be sure).
The water pump had been mentioned in elmariachi's topic, about the impeller. I'd never considered it because (1) the car only had 500 miles on it when I got it, and it's misbehaved since then and (2) whoda thunk at 500 miles the water pump had been abused?
S**** said he'd only seen this twice in over 20 years...
My guess is this is the equivalent of a belly flop. Water in the pump, put it in second, and instantly rev it to 6000RPM and pop the clutch (on a very safe track). All that torque from the crank pulley couldn't move the water pump and the pump lost. Metal meets water, and water is harder (It's one of those f=ma deals) It popped the blade and stripped the press-on threads. Look at how every metal edge is polished. If the blade had actually broken loose the failure would have been immediate instead of latent.
Anyway, now it's off to Walt Hane for the final tune.
One more thing. This is a testament to the radiator. At the height of this, the temp at the top was hot and the bottom was cool to the touch. The engine was being totally cooled by convection. That is a testament to the over-engineering of these cars.
Also, I expect that the oil cooler was a major contributor to the cooling system at this time.
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