68 Mustang over-heating after upgrades

Discussion in 'Classic Mustang Specific Tech' started by jerthemost, Jun 12, 2011.


  1. jerthemost

    jerthemost Banned

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    problem solved (mostly)

    put in new 4 core alum rad with 2- 9" pusher eletric fans on front. made careful mix with 50/50 coolant and added water wetter. fans are on thermostat.

    went to town today stayed 175 to 180 on the highway with a/c on at 55 mph outside temp 95 and 95% humidity. moving in town got up to 185 to 190 with a/c on hi and 95 degs outside. later got stopped in trafffic for about 5 min went up to 200 and had to turn off a/c. once moving agin dropped to 190 and less with a/c back on. came home on interstate at 60 stayed at 185 with 101 outside and 98% humidity.

    new 4 core helped for sure but still not getting enough air thru the rad when in traffic. but to be honest i left shroud off for now to see what it would do. plus there is a hugh gap around the rad and around the a/c condensor. just the way the bulkhead the rad is attached to and condensor being smaller than rad creates the gaps. i am going to fill gaps somehow and put shroud back on and try it again. but i think it is mostly fixed.
  2. robbz28

    robbz28 Member

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    Got a link to the radiator you bought? If you got a 4 row aluminum you should have gotten a 4 row copper/brass....the only reason to get aluminum is because of the size of the rows you can get, a 2 row aluminum with 1" rows is what you need with aluminum....4 row is going to have small rows and that removes the benefit of having the aluminum. The copper conducts heat better so works better with the smaller rows than aluminum. Still though, 200 in traffic sitting still with a/c on in houston heat is not bad at all. I am curious to see this radiator tho if you have a link.
  3. jerthemost

    jerthemost Banned

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    link to my radiator

    here is a link to the rad i bought. i bought it without the fans then bought 2 - 9" fans seperately. http://cgi.ebay.com/ebaymotors/4-Ro...r_Truck_Parts_Accessories&hash=item23109f0f56

    it's a cheapy champion brand but overall the quality seems to be pretty good. the welds could look better and the one major flaw is that the connections to the built in trans cooler are too small. they are one size smaller than stock so i talked to my trans mechanic about it and he said not to use the built in cooler. i was installing an external tube/fin cooler anyway and he said that was plenty to cool the trans and would be better anyway.

    the rad also came with a cheesy flimsy cap which i promptly replaced with a better quality cap.

    there is one other thing that you should be aware of. the height of the rad is about 1/4" too tall. it's working but i am going to have to make a slight hood modification.

    i understand about copper being better conductor but availability and price is a consideration. i researched the whole issue before buying andd in the end this seemed wirth a try. the rad has a 100% satisfaction they pay the return shipping gurrantee. so i figured i could not lose to much.

    the rad works is doing the job and i saved a ton of money over some out there. if it holds up i will be thrilled. also 2 1" cores are not same cooling wise as 4 3/8" cores. the latter is still better, more overall cooling surface and contact with water. i just have to solve the issue of not enough airflow at low speed and i am done. the shroud and fixing the big air gaps will probably do that. i will post some pics of the install later.
  4. robbz28

    robbz28 Member

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    Dude....3/8 x 4 = 1.5" of cooling surface.. 1 x 2 = 2" of cooling surface...that is just simple math. Still, that 4 row should be miles better than that ancient 2 row POS. Anyway, My radiator was too tall too, so I slotted my bolt holes so I could slide the rad down 1/2"....might want to do that instead of modify your hood.

    I looked at those champion rads when I was radiator shopping, and I immediately fell out with them when I read in their ad "aluminum dissapates heat better than copper" thats a load of crap right there. If thats the case why dont they make home wiring out of aluminum? Its a lot cheaper. When you get a high performance distributor cap....copper terminals, not aluminum. The only way the aluminum carries the heat better is because they can make the tubes bigger, but in the case of the champion rad, they didnt make the tubes any bigger, so the benefit of the aluminum is lost.
  5. jerthemost

    jerthemost Banned

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    radiator too tall

    the radiator is sitting right on the frame with rubber in between to prevent corrosion. cannot physically go any lower. the mounting holes are not problem. i had to drill almost all new holes anyway. this sucker is just tall. it is 21-3/4" tall to top of cap.

    i understand about 1' vs 3/8" but with 4 rows vs 2 i have much more total fin area to conduct off the heat. this rad is 1" thicker than the 2 row. believe me i considered that issue. plus the only reasonably priced 2 1" row i could find had return line on wrong side. i did not want to deal with conversion. the rad also came with a 13 lb cap instead of 16 as advertised but it was junk anyway. also the drain is a magnetic bolt rather than brass petcock as advertised but bolt should be better anyway. the vendor photos also show outlet going all the way through to back side of rad but that was not the case and if it had the rad would not have fit.

    and i realize they were full of it about aluminum conducting better than copper but i just blew that off as stupidity and promotion. i find that 80% of people in the world are stupid and ignorant and dumber than a brick. that's why companies tell lies. and most people do not pay attention in science class. education is wasted on most of the kids in school and believe me i pay a fortune for them to go to school and come out stupid. oh, well that's another forum.

    no doubt this rad will do the job, if it holds up over time is the question. right now i give it an 8 out of 10. time will tell.
  6. 65ShelbyClone

    65ShelbyClone Founding Member

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    You're getting electrical conductivity mixed up with thermal conductivity.
  7. robbz28

    robbz28 Member

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    Electrical conductivity is the same as heat conductivity on an elemental level, the easier current can pass, the easier heat can pass, gold is the best conductor of electricity and heat. Break out your benjamins and get a bling bling radiator and have no cooling issues ever.....just theft issues, lol.

    Just for everyones info, copper has approximately a 1.7 times better ability to conduct heat over aluminum. I can get down to the lattice vibrations and the movement of free electrons...etc, etc...but ill save that for Bill Nye
  8. jlangholzj

    jlangholzj Well-Known Member

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    two 9" fans isn't going to do it for you. I've got two 10's on mine that are supposed to pull about 2100 CFM total and they keep the rad around 190* in 100* heat idling. It could be ALOT better for the radiator Iv'e got because it will INSTANTLY hit about 180 when I'm moving.

    keep in mind also that fans are ALOT more efficient in a puller configuration than a pusher configuration. Also remember that a stock flex fan moves about 4000 cfm (at least thats the number i hear thrown around) so if your fan isn't cuttin mustard that could screw you over.

    and yes, copper disapates heat faster than what aluminum will however it also has restrictions on the size of tubes, etc. Ideally a radiator with an aluminum/copper hybrid would be ideal for cooling.

    another reason why copper isn't used for wiring is because skin depth with aluminum is quite a bit shallower than what copper is. Granted this doesn't matter much untill you get up in the frequency spectrum.... but copper is also much more piable due to its latice structure.

    I always thought thermal and electrical conductivity are different because electrical conductivity depends on the number of free valance e- while thermal conduction is laregely in part to latice vidrations and structure disturbance. Usually e- movement will cause latice vibration but not the other way around....otherwise our radiators would be making electricity while cooling! :p fundamentally the same, yes but not actually similar.

    its been a long while since I've looked at that tho so i very could well be wrong...:rolleyes:
  9. robbz28

    robbz28 Member

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    I say we all re-enroll in chemistry for the remainder of the summer and do our thesis on copper vs. aluminum and each write a peer reviewed journal on our findings.....and then go celebrate our findings at the local college bar, or two, or three.
  10. jerthemost

    jerthemost Banned

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    heat transfer discussion

    hey guys i didn't mean to start a discussion on the physics of thermodynamics and the properties of materials. it is a known fact that copper transfers heat and electricity better than aluminum. aluminum is mostly used because it is cheaper than copper, that's it period. you can make 1" tubes out of copper, just make them a tad thicker. i once made some copper tubes 6" wide when experimenting with solar energy about 30 years ago. they worked fine until the pump failed and the pressure build up caused them to blow up like a balloon. they were originally a thin oval.

    it really doesn't matter, aluminum works almost as good as copper and is a lot cheaper for the effect and end result. i think the most important issue is to make sure you do what you can to avoid corrosion. aluminum seems to react more adversely to corrosive elements. remember the first aluminum a/c evaporators? i sure as heck do, it cost me a fortune. and people who had to throw away their refrigerators and freezers. i am using a good quality coolant and distilled water and not letting alum rad touch steel anywhere.

    and the reason we stopped using much aluminum wiring is because of extrusion. aluminum expands much more than copper so when an electrical connection would heat up a bit the wire would push (extrude) itself out from under the connector, then when it cooled you were left with a loose connetion which heated up and caused fires. and another reason was severe corrosion which can be fixed with application of an oxide inhibitor.

    now for the fans .......... i still have my mechanical fan on the car in addition to the 2 9" pusher fans. the problem is the big gap at the top of the radiator and the core mount. the rad does not fit flat against the core mt. will fix that today with some aluminum flashing. the air is taking path of least resistance which is out the gap instead of thru the rad. and i am putting the shroud back on. i will report after that.

    if i can get 185 degs with 100 degs osa and a/c on high moving 25 mph then obviously it is a matter of airflow.
  11. robbz28

    robbz28 Member

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    Its all good...just wanting to make sure that folks get good information, thats what this site is all about. I think we got all the bases covered in this thread!
    I guess now the argument now is one fan vs. two. I have always had good luck out of one large fan (16"). I have read wonderful things about those black magic fans with the built in shroud, but then again all the rage here in the hot rod world are the taurus fans, which are very good fans and cheap. You could actually discard your mechanical fan altogether from what I understand....I have not done it myself, but my 16" puller does me just fine for now.
  12. blown65

    blown65 Founding Member

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    I know many have posting checking timing, but what is your timing at

    Idle
    cruise rpm
    3000-3500 rpm
  13. jerthemost

    jerthemost Banned

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    timing and fan

    i honestly don't know what the timing is. i don't have a light but i am going to have another mechanic change out my leaf springs next week and will have him check the timing. i have read what all of you said about timing and it makes sense but i have to assume that the mech who did the upgrades set it correctly. he is supposed to be very professional even though he made a few ommisions. so i will check and repost next week.

    what do you guys think timing should be?

    as for good info i also want to make sure everyone can learn from my experience and get good correct information.

    on the issue of fans...... i will probably put a large electric on and remove the mechanical fan. i put the 2 nine pushers on because i thought them combined with the mech fan would be a good combo. i could not put a larger fan in front of rad due to space limitations so used 2 9" fans pushing.

    as soon as i can get the shroud back on mech fan and block holes around rad i will repost results. this has been very interesting and educational please keep those ideas coming. maybe it will help someone else.
  14. Loftus

    Loftus New Member

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    treating symtoms and not finding a cure

    The carb is the same. The intake is the same. The #1 way to increase the air flow and performance of an engine is cam and heads. Assuming the carb was jetted correctly the 1st time, now you have WAY more flow from the heads and cam, the motor is going to be LEAN in a big way.
    It’s good to do cooling upgrades but I think you are ****ing money away if you have not checked the timing, jetting ect.
    The fans and shroud will only temporarily fix the symptoms for now.
    You can fry the motor running it lean , and burn holes in the pistons through detonation/pre ignition issues.:shrug:
    There is no way that you can increase the air flow by 15-20% and not have to do a rod/jet change. The edebrock book is simple and explains this perfectly on how to make the correct changes.
    I have sold 1000’s of the Carter AFB’s and Edebrock carbs and 2 out of 10 were jetted correctly for 4500 feet off sea level where I live.
  15. jerthemost

    jerthemost Banned

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    the only thing left

    is timing and rejetting the carb. so what should the timing be, how should i set it and how to check it out to make sure it is optimal? and should rejetting be done first or what?

    so far no one has offered that info in here.

    and another question which should maybe be another thread but it might have some bearing on the heat issue. any ideas why my exhaust would be twice as loud as before? is it the incresed internal airflow of the engine or what? i am running dual flowmasters. it sounds like a hot rod now. not that i don't like the sound just curious.
  16. PoppyMod

    PoppyMod Member

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    Hi
    Most stock timing is in the 8-10 deg range. When you begin modifying with heads, cam, compression ratio (CR), then you start advancing. I for example, have a number of mods, with my CR being 10.6. My engine responds well @ 16 degrees. I've run as much 18 deg.
    You need to check your AFR (air fuel ratio) first before deciding on any jet changes. Your "mechanic" will know about this. This is a whole other "can of worms"
    As far as the noise goes, it could be as simple as an exhaust connection coming loose, or as bad as, a hole somewhere before, or, in the muffler. This is, if you've ruled out an exhaust header gasket failure.

    Happy Trails!
  17. 65ShelbyClone

    65ShelbyClone Founding Member

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    The damper hasn't slipped? That's an awful lot of advance to me, especially with that much compression. I can believe it if the cam is really aggressive, but I think most pump gas street SBFs shouldn't need that much.
  18. blown65

    blown65 Founding Member

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    Our 10-1 347 I ran 18 degrees initial advance and 34 total at 3000 rpm.

    34 degrees locked out on my 347 14-1 motor.
  19. jerthemost

    jerthemost Banned

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    plugs are black

    just pulled 3 plugs andd they are both black, one a little toward gray but still what i would call black.

    so that means rich i assume. so what next? i assume this would maybe mean carb does not need rejetting. right or wrong. don't know what timing is yet.

    but now i have another serious problem. it is actually another thread on here but no one has offered any meaningful suggestions so i thought i would mention it to you guys. my starter relay is sticking. it's not the start signal from the ignition switch. the contacts are actually sticking together. Replaced it with new borg-warner and immediately the same problem.

    the weird thing is they usually un-stik themselves after a bit. it was only happening after the car ran a while and got hot so i assumed starter drawing excessive current when the engine is hot. we have been having 100+ days here in houston area. but just now it stuck on a cold start. after it gets hot the starter has to wind a few times to start i think due to heat soak. i have a gasket from edel to take care of that but need longer carb studs to install it.

    but my point is this time it stuck on one turn of the starter because the car cranks immediately when cold. any ideas guys?
  20. PoppyMod

    PoppyMod Member

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    Yep, I can believe it. It has more to do with your dynamic CR anyway. If you check this you'll see your actually in the low 9s.
    I'm running 23 deg. "built-in" together with 14-16 initial, I'm "all in" at 3-3100 Rs, as well.

    Did build a short rod or long rod 347?

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