Siamese Blocks

[Guest Zedintheshed]

I was having a browse through a Ford Motorsport Catalogue and noticed that many of the so called race blocks are

"siamesed" and have no cooling passages between cylinders. Would this make them unsuitable as a street engine? Would they get really hot? Wouldn't a race engine work a lot harder than a street engine and hence get hotter? - or is it the stop at traffic lights that could damage them.

[grumpyvette]

the main reason blocks use siamese cylinder walls is due to clearance issues, the cylinder walls need to be about 0.200 thick,minimum, once the bore exceeds a certain size with the bore center spacing being standard for a certain series of engines, thats not possiable with water flow BETWEEN CYLINDERS, many chevy blocks have "siamesed" cylinder walls, this is not a significant disadvantage if the blocks cooling system (coolant flow)and the rest of the block was designed to move coolant that absorbs and removes heat to the radiator where its lost to airflow thru the cooling system, and as long as the (radiator, water pump,ETC) can remove heat at rates significantly faster than the engine can potentially generate heat, keep in mind well over 70% of the heat comes from the cylinder heads and upper 1.5" in the cylinders theres very little heat generated below the upper 1.5" in a cylinder in comparison

heat is increased due to the combustion,& number of power strokes and the increased compression, so it would appear that race engines will generate greater heat, but race engines generally also have improved cooling and much higher airflow rates pulling heat from the radiators and better oil control,all of which tends to potentially allow more effective heat flow control

 

http://www.howstuffworks.com/cooling-system.htm

 

http://auto.howstuffworks.com/cooling-system2.htm

 

http://auto.howstuffworks.com/engine1.htm

 

http://auto.howstuffworks.com/horsepower.htm

 

http://auto.howstuffworks.com/question622.htm

[rudypoochris]

not sure but also for drag when you put 375635789 psi u need strong cylinder walls for a 1, 2, or 3 runs... for 9 seconds, who cares you just dont want it to fall apart. But yah what grumpy vette said too

[Guest Zedintheshed]

Thanks for that expanation - I learnt something today!

So there is no reason why you couldn't use any of the Ford Motorsport race blocks (including an aluminium 302) in a road car as long as you paid proper attention to engine cooling? - eg extra cooling capacity on the radiator, radiator shrouding and an engine oil cooler.

[TomsCoupe]

Not at all, i have a buddie running an r302 in his mustang and he has absolutly no problem with cooling issues.

[Guest kbconv]

Yup, plenty of people run the R302 in blown mustangs on the street. They still need several $$$ of machining, their not out of the box ready.

 

Popular now are the Dart blocks also. Usually come in a few hundred cheaper including machine work. Weigh about 30 lbs. more than the R blocks.

 

The A4 is one of Fords old race blocks that uses non-siamese bores FWIW.

 

Forget about the B50 block. They downrated them from 600 to 450 hp. Money is better spent elsewhere on blocks.