69 chevy said:It might be time for a new mouse. And since the price isn't much different I was thinking going the 400ci route, ala 4.125" bore Dart shp block and 3.75 stroke. But no bigger; no 427 or 434.
All else being equal, and I'm talking street driving here, will increasing the displacement from 350 to 400 tax my OEM stacked plate aluminum radiator? No extra heat produced by a slushbox trans, I have a manual gearbox. No A/C either.
Will switching from the OEM cast iron heads to aluminum help decrease any extra heat?
And on that note, will painting the cast aluminum parts (water pump, intake and heads) Chevy Orange help or hinder the heat dissipation?
A larger displace engine built in a similar configuration to the original engine, and operated at similar rpm and loads will always tend to build more heat simply because its larger displacement, as it allows a greater volume of fuel/air mix to be burn during the same time frame, and that engine, at least in theory be able to produce more power as the larger displacement should increase torque and its larger bore and/or stroke will generate more friction during its operation, thus generating more heat.
Nearly 70% of the heat an engine generates is coming from the valve train components like rockers and valve springs,and upper bore and cylinder head areas, its generated in the upper 2" of the cylinders due to combustion and friction, the cam, lifters and bearings while being a big contributor don,t come close to the combustion and valve train friction
yes aluminum is significantly more efficient at heat transfer , so aluminum cylinder heads will transfer heat in the combustion chambers to the coolant faster, this does not necessarily make the engine run cooler but it will tend to reduce combustion chamber temps slightly, thus reducing the tendency toward detonation, a larger and more efficient radiator with proper fans , providing adequate air flow rats,and duct work will be required,
your current radiator may or may not have the ability to effectively transfer the increase in coolant , transported or transferred (heat) to the outside airflow .
most cooling systems in good working order will require 1.5-to-1.7 square inches of fined cooling tube area with unrestricted air low per cubic inch of displacement, there are obviously other factors like the rate of air flow,thru the radiator, effectiveness of duct work, fan efficiency, outside temps, use of an additional oil cooler or larger baffled oil pan, average operational rpms and loads , type of coolant etc. yes you can deduct or reduce some percentage of the heat load on the cooling system by adding powered fan equipped oil coolers and a larger capacity baffled oil pan, and remote mounted oil filters
400 blocks with the larger bore normally have SIAMESE cylinder bore walls this reduces the coolant contact surface area and can slightly increase the coolant temps.
yes theres a huge difference in radiator capacity, quality and sizes available
if your cars got an automatic transmission and a higher stall speed converter its a damn good idea to install an auxiliary trans fluid cooler with an electric fan,
OK FIRST LOOK UP THE TRANSMISSIONS FLUID CAPACITY
HERES A LINK
http://fluidcapacity.com/
http://www.cartechbooks.com/techtips/autotransfluid
keep in mind most performance cars with an auto transmission and a higher rpm stall converter, will need an auxiliary trans fluid cooler, Id strongly suggest you find one with an electric fan and 1/2" or AN#8 line size as you'll want to allow a minimum of 2 gallons a minute trans fluid flow rate
its CRITICAL to keep the trans fluid clean and ideally changed about every 70K miles and use of a auxiliary cooler that keeps the fluid temp under about 170F is going to extend service life a good deal longer
I had a larger than original capacity aluminum aftermarket radiator most of the time , in my corvette even with the current 383 sbc, and if I ran a 180f T-stat both the coolant and trans fluid tended to run about 190f UNTIL I swapped to a 3200 stall converter , where the temps jumped noticeably by about 20f higher, if I pushed the car ,but those temps dropped rapidly if I was just cruising in O.D. but I felt I needed a better system, to cool the trans fluid, adding the additional rear mount aux cooler drops temps to 150f-160f with the fan on and about 170f=180f with it off even if Im pushing the car so I wired a switch to the fan, and a sensor that turns the fan on at 175F
http://www.summitracing.com/parts/der-16759
http://static.summitracing.com/global/i ... -16759.pdf
internal cross sectional area of the fluid transfer lines matters, anything less than 1/2" or AN#8 can be restrictive to flow
read the links
http://garage.grumpysperformance.co...-octane-for-compression-ratio.2718/#post-7057
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