I think you get to a point in old car ownership where the car's pretty close to the way you want it, and you just tinker with little stuff (If it ain't broke, give me a minute!). Anyway, my '65 Skylark has always heated up a little at idle. I'm running a Champion radiator and a 180* thermostat, and it'll run around 185-190* on the road. When I stop at a light, it'll creep up to 210* if I give it enough time. It's nothing dangerous or really even a problem, but I noticed that my fan blades are mostly inside of the shroud. I included a picture that's about even with the edge of the shroud, just enough of an angle to show you the edge of the fan. Anything I can do about this? It might not even be the right shroud...It's been on the car for the 17 years I've owned it.
I'm not sure those cars even came with a shroud without AC, especially the way your shroud looks. Does it have a hump in the middle where it bolts to the radiator cover? That is the way I thought a factory unit looked. How is the fan clutch operating? Does it start to get tighter when it gets hot? Also, you could check the fan clutch distance from water pump face to fan mounting surface. Maybe you can find a slightly shorter one to pull it out of the shroud a bit. If you really want to do something get a severe duty fan clutch. https://www.haydenauto.com/media/5587/imperial_fan-clutch-pages.pdf
I read the article at the link below and gave their spring adjustment idea a try, and it actually helped; it now takes longer to get to 210*. My shroud does have the hump with the bolt to the radiator cover. I've tried watching the fan when I shut the engine off hot; the fan stops well within one revolution. Honestly, I wonder if it might work better with a stock fixed fan and no shroud, but it's probably not worth it to try. http://midamericachevelles.com/tech/fan_clutch_adjust.pdf The car has never been an AC car, but the previous owner put a crossflow radiator and shroud in it. I think it's always run hottish; he had a 160* thermostat in it when I bought it, but I figured out that the vacuum advance wasn't working. That helped some. Like I said, I don't think it's a problem; it just bugs me a little. I'll have to take a look at that Hayden chart and see if there's something an inch or so shorter. Thanks!
Non-AC ars may not have had a shroud, but they did not sit in traffic or drive at 70-80 mph on scrap fuel. Add scale in block and heads along with solder bloom in radiator and everything cumulative adding heat is not your friend. Let me know what spacer you need. I have a couple of short spacers, I'll send you one if I have what you need, just cover shipping. (I can do the same with a 4 blade fan) Mine ran well with a 4 blade OEM fan in a shroud at correct distance. Let me know if that helps.
I've got some different length spacers you could just have for the cost of shipping, too, if Michael doesn't have one that will work. You could always get out the chop saw on what you've got now, as well.
All 64 to 67 Special/Skylarks came with shrouds, v6 and V8, with and without A/C. My 65 Special 300/300 has a 2 core radiator and a non-clutch 4 blade fan and runs 180 in all situations. Your car should not have a problem with a big radiator, big fan with a clutch. I would check the fan clutch and thermostat (or lack of).
It is hooked to manifold vacuum; I'm running the original AFB and that's the only option on that carb. The vacuum canister is holding a vacuum as well. I'll have to decide if I want to stick to the clutch or go to a stock solid fan. Michael, you have a 4-blade fan for a 300?
Yes. I'm out of town, but I have a couple as well as spacers. I'll be home by the weekend, so let me know what you need when you know.
Mine was like that after I swapped in the 350 in my '64 Skylark with stock shroud and 7 blade fan with clutch. I bought 4 steel spacers 3/4" long from True Value along with 4 longer grade 8 bolts, lock washers and nuts. I installed the spacers between the back of the clutch and fan blade and brought the fan back towards the motor. Now it sits almost centered with the back edge of the shroud. I can't say how great of an engineering idea it is, but it did what I was trying to accomplish. I have heard of people trimming 1" off the back edge of the shroud, but I couldn't bring myself to do that as it's not reversible.
My 64 V6/3 speed manual Special had no AC but had a downflow radiator and a plastic shroud with pliable rubber flaps stapled to the core dupport. The four blade fan had no clutch, just direct belt drive. I have the OEM stuff if any of it will work for you... The new Champion 3 row aluminum radiator with a 465 inch motor and four speed with no shroud RARELY runs past 175-180F. ws
Idle speed makes a huge difference in the fan's abilty to cool the engine. I would make sure your at 750 or so.
It idles at 600 or so in gear, maybe even a little less; if I raise the idle, the transmission engages pretty harshly.
I'd try to turn it up some just as an experiment. If your idling at 550 rpm anf you increase it to 700 rpm, that's nearly a 30% increase in rpm and CFM of air the fan is moving I figured this with my car. I turned the idle down so the cam would lope more. It started overheating at an idle. It went away when I turned the idle back up.
It's tough to get things lined up in a picture, but I've attached what I'm looking at from the top down. If I use a solid fan, it looks like a 3/4" spacer would be about right, but I'd probably want to have a 1/2" on hand as well. I might try Skylark Mike's idea about spacing the fan back on the clutch. If any of you guys who kindly offered up parts have a stock clutchless fan and/or a 3/4 inch (and maybe even a 1/2 inch and an inch) spacer, please let me know. Thanks!
I just went out and did some experimenting. I got some 3/4" spacers and spaced the fan back like Skylark Mike did and took it out for a short ride on the freeway. I then brought it back and put it in my hot garage and let it idle in gear. It takes quite a while, but it still eventually gets up to 208* or so. Honestly, in the rare case that I'm caught in a freeway traffic jam for 20-30 minutes on an 85-90* day, 208* isn't going to hurt anything; all cars are a little different, and I don't think my lower end has ever been apart. It could easily have some trash in there. Like I said before, it runs cool at speed. Oh, I also put it in neutral and it may have brought the temp down a couple of degrees. I think I might still like to try a stock fixed fan to see if it helps, so please see my previous post, and if anyone has those parts, let me know! Thank you for listening and for your ideas...
3/4" spacer is about all I can fit on mine. Even at that, it was a pain getting the bolts and spacers all in place.
