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Thin cylinder walls = prone to overheating myth or not? #2706435
10/13/19 04:05 PM
10/13/19 04:05 PM
Joined: Jan 2003
Posts: 13,825
Eagle, Idaho
Neil Offline OP
I Live Here
Neil  Offline OP
I Live Here

Joined: Jan 2003
Posts: 13,825
Eagle, Idaho
I'm sure everyone who has been around old cars has heard the tale not to mess around with engines that have been bored over too much as that can cause them to overheat. In my mind, as small as it is grin, the amount of material removed between a .0.30 over block and say 0.60 block seems miniscule in the big picture so perhaps this may be just an old wives tale that clings to the hobby even today?

It would seem that a block with thinner walls would transfer heat into the water jackets faster and therefor run cooler? Perhaps the thin wall block actually puts heat into the water jackets too fast and the cooling system can't keep up?

The block with the thicker walls would retain heat longer as there are more metal molecules in play. To me this would be a slight negative as the heat transfer process to the water in the block would be slower vs a thin wall block.

Anyone ever have any real world experience with rebuilding an engine only to have it run hotter afterwards?

Discuss?

Re: Thin cylinder walls = prone to overheating myth or not? [Re: Neil] #2706438
10/13/19 04:22 PM
10/13/19 04:22 PM
Joined: Aug 2011
Posts: 1,935
KATY TEXAS
csk Offline
top fuel
csk  Offline
top fuel

Joined: Aug 2011
Posts: 1,935
KATY TEXAS
As thin as the BB mopars are with a standard bore, I would say it is mostly a myth. to thin just cracks

Last edited by csk; 10/13/19 04:23 PM.

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Re: Thin cylinder walls = prone to overheating myth or not? [Re: Neil] #2706451
10/13/19 05:33 PM
10/13/19 05:33 PM
Joined: Jan 2003
Posts: 1,509
PA
7
70Duster Offline
pro stock
70Duster  Offline
pro stock
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PA
From a thermodynamic perspective, it's a myth.

Re: Thin cylinder walls = prone to overheating myth or not? [Re: Neil] #2706660
10/14/19 11:15 AM
10/14/19 11:15 AM
Joined: Jun 2004
Posts: 2,804
St. Charles, MO
wingman Offline
Uncreative Title
wingman  Offline
Uncreative Title

Joined: Jun 2004
Posts: 2,804
St. Charles, MO
Originally Posted by Neil
Anyone ever have any real world experience with rebuilding an engine only to have it run hotter afterwards?

Discuss?


I have heard of a couple engines running a slightly hotter (10 deg or so) after a fresh rebuild, but their owners and I attribute it more to new bearings and tighter clearances--not thinner bore walls.

In both cases after a few hundred miles, the engine temps returned to "normal".

Re: Thin cylinder walls = prone to overheating myth or not? [Re: wingman] #2706846
10/14/19 10:12 PM
10/14/19 10:12 PM
Joined: Jan 2003
Posts: 5,752
Hamilton, Ontario Canada
Magnum Offline
master
Magnum  Offline
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Hamilton, Ontario Canada
This theory would condem all engines made in the last 35 years.


69 Super Bee, 93 Mustang LX, 04 Allure Super
Re: Thin cylinder walls = prone to overheating myth or not? [Re: wingman] #2706977
10/15/19 12:24 PM
10/15/19 12:24 PM
Joined: Aug 2003
Posts: 34,948
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 34,948
Bend,OR USA
Originally Posted by wingman
Originally Posted by Neil
Anyone ever have any real world experience with rebuilding an engine only to have it run hotter afterwards?

Discuss?


I have heard of a couple engines running a slightly hotter (10 deg or so) after a fresh rebuild, but their owners and I attribute it more to new bearings and tighter clearances--not thinner bore walls.

In both cases after a few hundred miles, the engine temps returned to "normal".

Increase heat tells me the motor has more friction due to the fresh cylinder walls being rougher than before the rebuild, especially when it goes back to normal after break in work


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Thin cylinder walls = prone to overheating myth or not? [Re: Cab_Burge] #2707389
10/16/19 08:38 PM
10/16/19 08:38 PM
Joined: Jan 2003
Posts: 5,979
North Dakota
6PakBee Offline
master
6PakBee  Offline
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Posts: 5,979
North Dakota
This is my take on this topic. Think of the cylinder wall as a layer of insulation between hot gasses and cold coolant. The thinner the insulation, the more heat transfer will occur from the hot side to the cold side. Thermodynamics says the cold side (coolant) temperature will increase. But is it significant? Who knows. I'm not going to attempt to quantify it.


Wife says too many cars, liquidation coming soon......

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