Engine Block Types - How Many Variants?
#1
Posted 09 January 2020 - 01:48 PM
How many types of A-series block are there? I specifically mean block types rather than how many variants of engine capacity are there i.e. removing the crank from the equation.
For instance, are 850s, 997s and 998s bored from a small size block and 1098s and 1275s bored from a larger block? Or did each of these engine sizes have a specific block cast? I’m guessing there are only a few types and they are bored differently...?
#2
Posted 09 January 2020 - 01:55 PM
simplistic terms there are two. small bore 850-998-1098 and large bore.1275 (970-1071-1275)
thene there are a few different versions if you look at NONE UK made blocks. EG the SA 1100 which is more like the 1071 but uses a block more like the MPi.
But it really depends on the reason for your question.
IE. S blocks have different main bearing sizes.
Autos need extra work to make them usable on a Manual set up.
etc
#3
Posted 09 January 2020 - 02:53 PM
#4
Posted 09 January 2020 - 04:33 PM
Do you mean A-series and specifically not A+?
There's big bore with and without tappet chests. Also the Allegro type which is a different casting
#5
Posted 09 January 2020 - 04:48 PM
Also the Allegro type which is a different casting
well hardly.
#6
Posted 09 January 2020 - 06:14 PM
Is the Allegro not the one with the horizontal oil filter screwed directly to the block?
#7
Posted 09 January 2020 - 06:15 PM
#8
Posted 09 January 2020 - 08:29 PM
I did actually mean to include A+ in the question but was mainly wondering if all bore sizes were produced from a number of castings. Nicklouse answered the question but I was still left wondering why a 1098 would be prepared from a small block and a 970 and 1071 would be manufactured from a large block. Is there any reason for this?Do you mean A-series and specifically not A+?
There's big bore with and without tappet chests. Also the Allegro type which is a different casting
Edited by PIIIOWW, 09 January 2020 - 08:32 PM.
#9
Posted 09 January 2020 - 08:34 PM
Do you mean A-series and specifically not A+?
There's big bore with and without tappet chests. Also the Allegro type which is a different casting
I did actually mean to include A+ I'm the question but was mainly wondering if all bore sizes were produced from a number of castings. Nicklouse answered the question but I was still left wondering why a 1098 would be prepared from a small block and a 970 and 1071 would be manufactured from a large block. Is there any reason for this?
every reason. the 1098n is a long stroke version of the 998 while the 970 and 1071 are short stroke versions of the 1275 with all the inherent pros and cons of each.
note in the S engines the 970 was first. and was made to suit circuit racing and the rules and regs then present. as was the 1071 they then found themselves in Minis.
#10
Posted 09 January 2020 - 08:52 PM
Big bore means room for bigger valves, which is good for racing
I also remember reading that your road tax classes were based on the bore of the engine, which skewed passenger engines towards small bore and long stroke
#11
Posted 10 January 2020 - 12:53 AM
#12
Posted 10 January 2020 - 09:31 AM
There was water all the way round all the cylinders of the 803 block.
#13
Posted 10 January 2020 - 09:59 AM
Interesting,
I wonder how many different castings/moulds were actually produced?
Do they all fall in the 2 basic flavours of ones that'll fit all 1.75" mains bearing cranks & those for 2" mains?
#14
Posted 10 January 2020 - 10:05 AM
There would be countless variations. FWD, RWD, thick flange, thin flange, big bore, small bore, tappet covers, no tappet covers. Then there is the A+, MPI, etc
More reading here
https://www.aronline...gines-a-series/
#15
Posted 10 January 2020 - 11:30 AM
And don't forget the Nuffield 947cc diesel engine.
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