Can somebody tell me the difference between these two, is it the displacement or the physical size? And what are the respective vee angles?
Much appreciate any help here as the atmosphere around our lunch table is getting frostier by the day.
Cheers, Bill
|
Bill
Physical size - two different castings. Presumably one was originally conceived for cars and one for commercials - before the power race of the late sixties led to some "interesting" cars.
|
|
I seem to recall reading somewhere that big block is classed as 7.5 litres and larger!!!!
|
Small block / big block really refers to GM engines.
IIRC the smallest mainstream big block was/is the 427 which is 7.0ltrs, on the other hand the largest small block was/is, again IIRC, the 400 at 6.5ltrs.
Though there were some specialist versions of each meaning that you could get a big block of a smaller capacity than a small block etc.
|
|
|
|
What Screwloose said, plus V-8's should all be 90 degrees. V-6's, which should be 60 degrees, are sometimes 90 deg when evolved from a V-8 (like the Maserati engine in the Citroen SM) and are less well balanced.
'Small block' is a relative term - it still means about 5 litres!
|
Yes; relative to our "small" engines [948cc etc.] the Yanks "small-block Chevy" is a 5.7 litre!
[Even a 6.9ltr Hummer diesel is still the small-block casting - the "big-block" starts at 7.2 upwards...]
|
It's just the differentiation between basic engine designs as most engine capacities can be varied within the same design. V8s are normally 90 degree engine but other angles have been used, I think Ferrari/Fiat used a 65 degree V8.
At a tangent, GM Europe OHC/DOHC smallblock engines are 1.2-1.8 I4 and 2.5-3.2 V6 - OHC/DOHC bigblock engines are 1.6-2.2 I4.
The Turner-designed V8s from Daimler's pre-Jaguar days were 2.5 and 4.5 and shared their design with Turner's (Norton?) twin cylinder motorbike engine.
|
"a 65 degree V8"
Must have been for reasons of space. As with motorcycle V-twins, 90 degrees gives the best balance, which is why (45deg) Harleys rattle so much.
When Honda produced the CX-500, with its 80deg V, they managed to offend LJK Setright, who described it as "not a right-angle, but the wrong angle". I don't suppose it made a huge difference, but he did like things done correctly.
|
Visually the CX500 engine was a bit suspect and the look of the bike suffered as a consequence. Once they ironed out the cam-chain adjuster problems on the early ones it became what it arguably one of the best engines to find its way into a bike frame. Smooth(ish)
totally reliable if treated properly to oil and filter changes with a perfectly matched torque curve and decent economy.
|
|
|
|
What Screwloose said plus V-8's should all be 90 degrees. V-6's which should be 60 degrees are sometimes 90 deg when evolved from a V-8 (like the Maserati engine in the Citroen SM) and are less well balanced.
Or intended originally to be a V8 but pruned a bit - the 2.7 (later 2.85) litre PRV engine most commonly found in 260 and 760-series Volvos (and a certain DeLorean IIRC) being an example that springs to mind.
|
|
|
|
The difference between Small Block and Big Block is physical size, or more correctly as it applies to Chevy and Chrysler V8s, the distance between bore centres.
Wikipedia has a reasonable explanation:
en.wikipedia.org/wiki/Small_Block
Kevin...
|
Interestingly a modern Chevy LS-1 Smallblock has almost the same external dimensions as a Rover V8, but with 5.7 litres capacity as opposed to 3.5/3.9/5.0 litres, etc.
snipurl.com/1wry1
|
Chevy made two blocks one 3.6 v6 and the other 5.7v8 hence small block and big block and it was the same with Ford and Chrysler.
|
>Chevy made two blocks one 3.6 v6 and the other 5.7v8 hence small block and big block..
So my Small Block Chevy is actually a V6?
I've been robbed!!!
Kevin...
|
|
|
|
