# Hot hot hot



## gjones (Oct 8, 2012)

Hi all. After a lenghty hiatus (winter), finally took the Lemans out for a spin this past week. Thought I had the old hot running issues out of the way last fall, but... first 30 minutes, she ran at 190, good pick up, 190 at stoplights, etc... thought I was good to go. Came to light near the house, temp went up to 220. By the time I got home, she was at 230. Shut it off, and she dieseled hard. Never did that before. Temps continued to rise to alarming heights. Let it cool completely, then started it and pulled it in the garage for the night. Next day, she cranked right up, pulled it out, and let it idle normally to 190, which when it hit that, the temp shot up to 220 real quick! Of course, I had the air cleaner off at that point, and when I shut it down, it dieseled HARD, popped through the carb, and set the fool thing afire!!! AARRGH!!! I've had a carb fire or two in my day, but this sucker didn't want to go out! All I could see was 2500+ hours of hard labor going up in flames! Was finally able to smother it, and let it sit a couple of hours. But my nerves were, and are now shot. Pulled the plugs and all were running lean-clean as a whistle (or was that from dieseling?) and did a compression check: ALL cylinders were between 170psi and 178psi. (Whew). Upper and lower hoses were hot and tight. Next day, started it and ran it just to 180 and shut it down. NO dieseling, but top hose was HOT, and lower hose was cool as a cucumber! Plugged radiator, right? Pulled radiator (shop wants $72.50 to flush it. (All aluminum 3 core, so thats about ALL they can do?). A couple of questions if you please? 1) Could a sticking float cause it to run lean and make it run hot all of a sudden? (I believe I know the answer, but need to verify). 2) What can I dump in the radiator while it's sitting on the floor to loosen any rust scale that might be in it. Muriatic acid? or what'll kill rust? (year old radiator, but ran it with the old 326 which I thought I'd flushed out-obviously not good enough- picked alot of it out with a magnet). 3) I want to change the existing 17.5" flex fan out to fit a 20" shroud. Would a 19.5" be too tight, or should I go with a 19"? 6 blade? 7 blade? What about those 19" steel racing 4 blades? I'd like to stay away from those clutch fans, if possible. (If they don't turn the fan faster than the pulley, I don't really care about the hp. loss). 4) What kind of material could I use to seal the perimeter of the shroud to the top and bottom tanks and at least make it stick to the shroud? (has about 1/4" gap on top and bottom) Soft hi temp rubber, hard rubber, high temp butyl??? Any and all info would be a Godsend. The Pontiac deities are not smiling upon me as of late.


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## the65gto (Oct 9, 2008)

If you have not already checked, is there any water in the oil, any oil in the water, thermostat. (you said top hose hot, bottom cold) Hope it is not the case but any water in the cylinder will clean the spark plugs like new. I have a mechanical temp gauge on mine and also notice that after turn off, temp raises, that seems normal. Good Luck!


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## BearGFR (Aug 25, 2008)

Could be a partially stuck thermostat also --- as in open sufficiently to get the top hose hot, but not enough to get the flow you need to effectively cool the engine. That's one thing that's easy/cheap to examine and replace at least.

As suggested, do check for coolant/oil comingleing too. Contaminated oil will take on the appearance of a chocolate milkshake.

Now would be a good time to consider investing in a decent fire extinguisher. I know several folks who keep one in their car at all times. I think I'm going to be one of them very soon.

Bear


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## gjones (Oct 8, 2012)

*hot*

'65, oil/ antifreeze look fine. I do realize the temps rise after shut-off, but 240+ is insane. Bear, I will soon get an extingusher. What would be a good one to not hurt the carb/ engine? I believe the float stuck, in addition to the radiator being partially blocked with crumbly metal pieces from the old 326. (Spent the last 3 hours blasting that sucker out, all the while picking the crumblies out with a magnet- just big enough to block the tops of certain fins. My real question pertains to the fan: I want to change the 17.5" flex fan out to fit the 20" shroud. Can I put a 19.5" in there? Or is a 19" a better fit? Anyone use those solid 4 blade fans? I do NOT trust those clutch fans- don't want one! What is a good sealer to seal the shroud to the radiator? As far as the t'stat is concerned, I will choose another from my vast stock of t'stats. (This'll be #7 in the last 15 months). Thanks Bear & '65!


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## Instg8ter (Sep 28, 2010)

During the build i took all the precautions (overheating sticky's) that were recommended for the Pontiacs as it's always been a knock on them. Happy to say if anything my car runs too cool to be thermally efficient with a 180 Therm. i have the 19.5" shroud and the clutch fan, the shroud needs to be half on fan blades (centered), unless you go electric i think its the best fan going. Also have a champion aluminum radiator. Think it may be combo of what bear said and your radiator being fouled up, make sure you flush out the motor too. I always drill a very small relief hole in the thermostat plate so when filling after flush you fill the hole system before it gets up to temp. Other thing to check is that your lower hose has the wire coil in it or is firm enough not to collapse under load and choke the system? I Keep a small extinguisher in my toolbox in the trunk.


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## gjones (Oct 8, 2012)

*counting to ten...*

Collapsed hose, NOT. Both hoses always are tight and there is no way in the world that lower hose EVER gives any indication of collasping! (Sometimes I wish it would... at least that would indicate SOMETHING different!). Cast iron impeller water pump. Divider plate is adjusted to vanes. As far as t'stat is concerned, I've drilled most all I've had with this car. I will also flush the block (again). Fan is half in, half out of shroud. Instg8ter, you say you have a 19.5" shroud? What size is your fan and how many fins? Mine is a crappy 6 blade 17.5" flex. Want to fill that 20" shroud as much as I can. Thanks!


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## geeteeohguy (Feb 2, 2008)

If it's running hot and you have cold spots in your rad core, you have a blockage in the core. Also, how is your water pump spacing?? I am running a 7 blade flex fan off of a '69 Caddy on my '67 (18" fan) and it's dead quiet and pulls a ton of air. I am running a 19.5 clutch fan on my '65 and it is also a 7 blade unit. Whatever you choose, I recommend a 7 blade fan and a shroud. And no, a sticking float will cause flooding, not lean operation. A low float level could cause lean operation, though. Overly lean conditions will cause the temps to go up, too.


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## gjones (Oct 8, 2012)

*getting hot under the collar*

Thanks, gt. This carb is odd... when I had it apart, the float would stick SHUT- float would drop, but needle would stay put- even when blowing through it! (New needles and seats, too). Also strange is the fact that she was running down the road nicely for a good 30-40 minutes (stoplights and all) before she started to heat up. Today, I blasted the radiator out (3 hours) and got some crud out of it. Not too worried about that carb,(I can pull it apart in a New York minute), but this fan to shroud business has got me seeing double. I've got a 20" shroud. So a 19" 7 blade would be the way to go? Can I get a 19.5" in there without fear of hitting the shroud when revving it? I really don't see much advantages of a clutch fan. What little hp is robbed without one is negligible to me. I just want to drive it once and for all without looking at that stupid temp gauge! Once I get this issue resolved, I'm going to remove the analog temp gauge and throw it as far as I can throw it, and hook the light back up! Water pump to plate: you might be able to slip a piece of paper in between.


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## geeteeohguy (Feb 2, 2008)

The fan won't grown in diameter as you rev it, but the motor can raise on the motor mounts and take out a shroud if the clearance is too tight. Nothing wrong with an 18" fan. As I said, I'm running an 18" seven blade GM flex fan on my '67 that was $5 off of a junked '69 Caddy. Works GREAT. Your situation of running fine for 40 minutes and then heating up sounds like a T stat is shutting down on you. As a side note, I have run 6 blade aftermarket flex fans, and they are super noisy and don't work as well as the factory stuff. Make sure the fan blades are 'half in, half out' of the shroud.


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## the65gto (Oct 9, 2008)

You said "I'm going to remove the analog temp gauge and throw it as far as I can throw it" Is that gauge electrical or mechanical? I bought one of those IR temp meters from HF ($30.00) and verify temps on the car and a lot of stuff around the house:lol:


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## jmt455 (Mar 26, 2012)

I'm running one of those 18", 7-blade Caddy fans as well, with a Heavy Duty Hayden clutch. Works excellent.

The Hayden Heavy Duty clutch is part # 2747

There is also a Severe Duty clutch (including Police car applications). It is part # 2797


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## gjones (Oct 8, 2012)

*not too cool (temps)*

Thanks again geeteeohguy, '65 and jmt. I'm looking at a 7 blade 18.5" fan on Ebay from a '66 Cadillac. Needs a good cleaning and paint, but she's solid. $29.99 + $15 shipping. That is the absolute lowest price I've seen yet, and I've looked at literally THOUSANDS. (I've got a headache). These people are PROUD of their crap! (And the thing is, it doesn't seem anyone is bidding on ANY of it!). Oh well, I guess I'd better snag it . Some of those puppies want between $50-$599+. Gtog, yep, the fan is half in and half out of the shroud. Put a new stat in it. Drilled 2 small holes in it too. Also, that's what I meant about revving the engine-she lifts slightly when I goose it, and wasn't quite sure about the tolerances there. Put her back together today, and cranked it up briefly- ran it 15 seconds. Shut off fine. Started it back up, ran about a minute- shut it off. Dieseled! AAARRRGGGHHH!!! :willy: Time to pull the carb AGAIN. Time to check the timing AGAIN. This dieseling has me worried after the escapades of the other day! Like I say- It never did it before. What changed? I do not know! "65, the gauge is a mechanical with the tube. I believe it is accurate. Jmt- I'm trying to avoid the clutch- had a couple of bad experiences with them. I'll get one if I absolutely have to, but not until. Anyone got any ideas about the dieseling issue? Thanks all.


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## geeteeohguy (Feb 2, 2008)

Check the idle dashpot and idle stop screw. If the throttle blades are open too far at shut down, it'll diesel. The idle speed needs to be just right (not too high) and the throttle needs to close all the way at shut down.


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## Instg8ter (Sep 28, 2010)

bad gas???


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## gjones (Oct 8, 2012)

*Hot potatoe*

Gtog, 10-4 on the throttle plate screw (etc...) adjustments.(No dashpot in this carb, though). Ripped it apart last night, cleaned it, and double checked specs. The throttle plate screw adj. was definately a tad overwound. Plates were pretty far away from the body. Will recalibrate everything and try it again. Instg8- coincidentally, I had just returned from the gas station. That was the first refill in a couple of months. This station is in the throws of moving, so maybe (hopefully) that is it. Also, in the right side bowl, one black spec was floating near the primary jet-wonder if that was trying to get in the jet? TNX. (Other than that spec of dirt, it was as clean as the day I put it together a few months back).


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## gjones (Oct 8, 2012)

*Eureka, (maybe)*

Well, I cleaned and adjusted the carb (and doubled up the cheesy base gasket- rotten thin ones. Can't seem to locate a nice thick base gasket for this Carter without purchasing a whole bloomin' kit). Started it (nervously) for a few seconds and shut it off. No dieseling. Repeated until it got to temp with the radiator cap off. No dieseling. WHEW. Revved it and watched coolant circulate like it NEVER did before-Even with the old radiator and the 326 in it. Put the cap on it and ran it about 20 minutes- both top and bottom hoses were nice and squishy, and temp was right on the button! :cool Revved it a few times and could hear a very faint whistling from carb, couldn't tell exactly where though. (Perhaps that doubled base gasket?). But, she ran EXCELLENT! Will take her for a burn tomorrow, and report back. Thanks for all the swell advice!


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## Instg8ter (Sep 28, 2010)

if you got the bottom of their tanks you got water....troubleshooting 101 eliminate the obvious. When you said been a long winter, got me thinking i just started mine first time in two months for same reason, made sure to top off 3/4 tank with 106 last time i was out and i keep in heated storage but i was still worried about the old gas.


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## gjones (Oct 8, 2012)

*High octane? What's that?*

106??? I didn't think they even MADE Ethyl (or Myrtle for that matter) anymore! Antiquated and fusty things of the past! Oh, how I pine for a time machine! I think the highest octane around these parts is around 94-96%. I mix some low-test with some high test just for giggles. (An old timer once told me that would boost the ratings some, if mixed properly. Years later, I heard that had some validity to it. Back in the 80's, I would do that with my Cadillacs, and could actually notice a considerable difference in the throttle response). I think they make an additive to put in the gas to extend it's life while it's sitting dormant for awhile, but costs like the dickens (though a good investment if you've got a few gallons worthy of preserving). Regards


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## Rukee (Feb 8, 2007)

If you have a circle race track around you call them and ask where they sell the race fuel. There are 3 stations around me within 20 miles. Especially useful if you have a high compression engine, not so much or at all if you have a low compression engine. And if you store your car with a full tank of fuel no worries just storing over the winter. I've never used any additive in 17+ years with no issues.


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## gjones (Oct 8, 2012)

*Spring issue*

Well, took 'er out for a lil spin. Shoobiedoobiedowap! What an enjoyable experience! 180 degrees down the highway, 190 at stop lights on the feeder road! Ran responsive and strong. Pulled in driveway, and let her idle for 15 minutes-she was at 195 When I backed 'er into the garage. Shut off. NO DIESELING again.  Temp crept to 220 and stayed put right there,and so I cranked it back up, temp went right back to 190. If 220 is all it gets to, then I think I can live with it. Or is 220 still too high after shut down? Closed the garage doors and started going into the house when I heard a loud "BANG". My heart stopped (and my drawers suddenly became a different color!). Went in to see the garage door spring still bouncing on the cable about a foot away from the left fender! She done come loose! Cable snapped! Fender was covered with bits of the ceiling where the spring smacked it, but no scratches! ( Somebody must be trying to tell me something, I guess. :lol:


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## jmt455 (Mar 26, 2012)

That's great news! (about the car, not about the garage door...)

220F is not a problem. That post-shutdown heat soak is completely normal.


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## Instg8ter (Sep 28, 2010)

good call Rukee, we are right down from the circle track, have a choice of Turbo Blue or Torko. Usaually put 5 gallons in to top off 10 gallons of 93 as the 473 is right at 9.6:1. Good to hear you got her cool G, lucky with the spring, those things can wreck havoc when they uncoil, especially when installing them.


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## gjones (Oct 8, 2012)

*Cool daddy-o*

Yes, 220 is much better AFTER shut down, as opposed to 220 BEFORE shut down. I was just about sick of that deal! If I'm running roughly 175psi in all cylinders, how do you determine compression ratio if I've got .030 over pistons in a 455? Do you need to know the cam duration, or what? I think I'll get brave and drive 'er down to Galveston sometime this week (15 miles)- she loves the highway. I'll bet I could drive 'er straight up route 66 without a problem. Wait a minute...HHMMMM...intriguing...


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## Instg8ter (Sep 28, 2010)

RSR Static Compression Ratio Calculator

put your numbers into the calculator, if your above 9.5:1 with iron heads you might wanna run higher octane than 93


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