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08-22-2019, 04:14 PM | #1 |
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Location: London Kentucky
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40 engine temperature drop by 20 degrees
I have a 1940 85 hp engine, all stock, with a 160 degree thermostat that runs 180 to 200 in summer driving. Took the intake off to adjust the valves and noticed the paint on the intake was cracked in the area the exhaust gases enter the intake manifold. I decided to have the exhaust openings in the intake closed up to keep the hot gases out of the intake and away from the carburetor. Now the engine runs 160 to 170 even on a 92 degree day. After about a one hour drive, running at 160 degrees, I turned the engine off for about 20 minutes to get something to drink. Came back and started the car. Temperature was 190 at start up, but cooled down to 170 within one mile of open road driving. The temperature did not go above 180 at any time during the rest of the day, while driving in stop and go traffic. The engine, in the past, would run 180 to 200 on a 92 degree day. I mostly drive this car during the summer and it is stored in a warm garage. Winter time starts are not much different from summer time starts. The engine, at operating temperature, starts much better now, than it did before I closed off the intake exhaust openings. This intake modification was an improvement for me on this particular engine.
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08-22-2019, 05:35 PM | #2 |
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Re: 40 engine temperature drop by 20 degrees
Was this not the old "penny" trick??
Paul in CT |
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08-22-2019, 06:02 PM | #3 |
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Re: 40 engine temperature drop by 20 degrees
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08-22-2019, 06:11 PM | #4 |
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Re: 40 engine temperature drop by 20 degrees
It can be done with a wheat stalk penny tapped into the crossover holes in the block. Only the wheat stalk, though, as the crappy alloys of the newer pennies won't stay in place. Alternatively, a thin shim stock can be slid in place without removing the manifold. Kool Kats would never think of using anything but wheat stalks, though.
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Alan |
08-23-2019, 07:05 AM | #5 |
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Re: 40 engine temperature drop by 20 degrees
Interesting. Any idea why the coolant temp would drop??
(1) removing heat from the intake charge ?? (2) prevent the movement of exhaust gasses thru the water jacket at the intake crossover?? |
08-23-2019, 08:13 AM | #6 |
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Re: 40 engine temperature drop by 20 degrees
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08-23-2019, 08:40 AM | #7 | |
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Join Date: Jun 2016
Location: Pahrump, NV
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Re: 40 engine temperature drop by 20 degrees
Quote:
1st time I ever heard of it reducing the engine temp. I was hoping some of the wiser heads here would chime in. |
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08-23-2019, 09:17 AM | #8 |
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Re: 40 engine temperature drop by 20 degrees
I'm not a "wiser head", but simply put, if you don't drive your car in cold weather, you don't need the exhaust heat provided by the ports in the block and the manifold. Any time you can cool the intake charge in hot weather there is a benefit (think the "Cold Air Induction Systems" in some of the top line sixties muscle cars). By blocking them off, you may experience some driveabilty problems in near freezing weather, but how much of a problem is that to most of us?
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08-23-2019, 02:13 PM | #9 |
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Re: 40 engine temperature drop by 20 degrees
still trying to get some input on the engine temp drop claimed by the OP, tubman.
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08-23-2019, 05:12 PM | #10 | ||
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Re: 40 engine temperature drop by 20 degrees
Quote:
Quote:
Apparently, a lot of us here gotta be "regional", None of us here has a "wiser head", The OP's "claim" is suspect, And you Sir, might personally benefit with the reading material pictured below:
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08-23-2019, 08:51 PM | #11 |
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Re: 40 engine temperature drop by 20 degrees
Also dropped the engine temp by using cupped core plugs. Do not drive at temps below 50F.
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08-24-2019, 12:30 AM | #12 |
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Re: 40 engine temperature drop by 20 degrees
How do you slide a thin piece of metal without removing intake ?
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08-24-2019, 06:12 AM | #13 |
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Re: 40 engine temperature drop by 20 degrees
You'd loosen the bolts and slide some thin stainless steel under the gasket in the area of the heat riser ports. Think VERY THIN stainless steel - kind of like sliding a razor blade under the gasket and tightening things back down. Obviously you don't want to disrupt the intake gasket seal in the port areas.
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08-24-2019, 06:29 AM | #14 |
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Re: 40 engine temperature drop by 20 degrees
Little Story on Heat Risers and Performance Manifolds: I was chatting with Barney Navarro back about 35 years ago about performance stuff (he was pondering making his Hi-Dome heads . . . which I was pushing him to do - based on my Harley KR research). Anyway he asked me if he'd ever told me about his first manifold design??? I said no - so here goes . . . from Barney:
He had built a performance flathead using all of the stuff available from the SoCal gang - and was running an early Weiand two-pot manifold - the first one that had the high carb risers. Anyway, he had driven his hotrod somewhere out of SoCal (I can't remember where) - in Winter. It was a snowy day and he was headed back to LA and was coming up over a mountain pass and his car kept getting slower, slower and slower. Pretty soon he was barely moving and had to pull over. He couldn't imagine what the heck was happening - it was like the engine was choking to death??? So he pulled his air cleaners and the throats of his carbs were all iced up. There was just a little dime sized hole for the air to get through on both of them. Ahhhh Hahhhh! So that was it, he chipped the ice out of them and went on his way. He had to stop a few more times to clear the ice out of the carbs - but he got home. This experience made him think about the early Eddie Meyer manifold that had the hot water plenum under the carbs - so Barney decided he'd make a performance manifold with a heat riser plenum that mounted under the carbs. The plenum got its heat from the exhaust cross-over - via a squareish port on the top of the manifold (between the carbs). The exhaust cross-over was nicknamed the "Dog Bone" - as it kind of resembled one. The manifold was available with or without the dog-bone and if you ordered it without it, then a little finned cast plate was bolted to the heat riser port. He said most racers didn't want the dog-bone as everybody thought that "cold was good" - so if they bought his manifold with the dog-bone, they threw it away! This kind of annoyed Barney - as he knew there was a purpose for it and many hotrods would actually benefit from it. I had an early manifold of his - but no dog-bone (had never seen one). Barney decided to recast some of the dog-bones so guys like me who wanted one could buy just the dog-bone attachment to re-equip an early manifold. When Mike at H&H bought the rights to Navarro, he acquired a few dogbones with the deal . . . probably still has some. Luckily I bought all my Navarro stuff directly from Barney - before the H&H deal was in play. Here is a picture of just the dogbane - and a polished complete setup (not mine). What a nice looking manifold - really unique! (I may have to resurrect mine and try it out on the 32 Cab?). Navarro_Dog_Bone_4e038dd6bc987-500x500.jpg NavarroDogBoneManifold.JPG So there yah go . . . an old Barney story . . . he was quite a guy. B&S |
08-24-2019, 07:09 AM | #15 |
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Re: 40 engine temperature drop by 20 degrees
thankx guys. Wiser heads have prevailed.
I was thinking along the lines of the heated charge actually being a bit leaner in the original posters comments. |
08-24-2019, 07:56 AM | #16 |
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Re: 40 engine temperature drop by 20 degrees
Years ago I was into VWs. If the heat riser was plugged (a common problem) they would ice up even on a warm day. Along with the pressure drop from air going through the venture there is a temperature drop. And with a lot of intake manifold surface area and humid air ice forms. This is also an issue with aircraft engines.
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08-24-2019, 08:09 AM | #17 | |
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Re: 40 engine temperature drop by 20 degrees
Quote:
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08-24-2019, 07:55 PM | #18 |
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Re: 40 engine temperature drop by 20 degrees
Silly question !! Where abouts do you insert this thin metal ?
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08-24-2019, 09:10 PM | #19 |
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Re: 40 engine temperature drop by 20 degrees
Over the heat riser holes in the block. One on each side between above where the center exhaust valves dump into the center ex port.
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08-25-2019, 05:17 PM | #20 |
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Re: 40 engine temperature drop by 20 degrees
We did that to a friends 47 sedan and with duels on it, there was a what we called a back draw, in other words the exhaust popped when you let off the gas. What a wonderful sound it was, we used the copper pennies. We also drilled holes in the tail pipe on another flathead Ford and put spark plugs in them so it would shoot flames out, the local fuzz made us take them out said it was illegal, sure did look cool though. Al
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