6 replies to this topic

[dgear1984]

can someone please explain to me all the differnt types of 1275 rods? There seems to be alot of differnt types you see for sale? i have searched around but could not seem to find the info i am after

i thought you had cooper s 1275 blocks pre a plus with tapppet covers and a plus without but

I have noticed pre a plus 1275 gt blocks? how do these differ to s blocks? i think it is no tappet covers and smaller bearings correct?

thanks dave

[Ethel]

The original Cooper S's were different beasts - better steel cranks and smaller bearings.

A and A+ are much the same and even interchangeable. There are some improvements that make A+'es a stronger option.

[mini_kel]

I believe a series GT blocks are very similar! but have two core plugs at the engine steady end and no tappet chest covers. The smaller bearings only relate to the big end bearings.

[Rosslin Racing]

The original Cooper S's were different beasts - better steel cranks and smaller bearings.

A and A+ are much the same and even interchangeable. There are some improvements that make A+'es a stronger option.

you are talking about the cranks?
All blocks mentioned are diffrent in casting and some even the main bearing size.

[Guess-Works.com]

There are 4 basic types of 1275 rod....

Cooper S ( and Midget ) which have a 1.625" big end

GT/A Series Rods which have a LARGE big end cap and 1.750" big ends.

Innocenti rods which are similar to S rods in shape and material, but have 1.750" big ends.... Also can be identified by a reinforcement bar across the middle of the con rod, however it is important to make sure they have the right caps, as some GT's were also made using the rod but with the GT cap.. and very often mistakenly advertised as Inno' rods but they are not.

A+ rods which again have the small cap, with 1.750" big ends

Edited by GuessWorks.co.uk, 01 September 2008 - 11:10 AM.

[dgear1984]

thanks,

so what are AEG177, AEG521, AEG625 s rods? i see them all advertised as s rods but my research does not seem to enlighen me much.

thanks for your help with the blocks. the gt block visually looks like an a+ from the outside castings?

basically i am restoring a mk1 which i would like to be built to s spec but the costs seem huge for proper cooper s mk1 engine parts and im thinking maybe going the gt or a+ route as it is so much cheeper and maybe more reliable due to newer parts. I am a long way from the engine stage but its good to have something set in your mind. peoples opinions? I would like to go down the 1275 or 1293 route rather than 1380s etc.

when an engine has the numbers say 20/40/20 what do they refer to. i assume it is bore oversize, mains oversize and big ends oversize but which order? thanks dave

Edited by LOT977F, 01 September 2008 - 08:02 PM.

[Guess-Works.com]

AEG177 are early cooper S rods I think made from EN20
AEG521 being the later version S rod, made from EN24
AEG625 are Spridget (Midget/Sprite) rods

All are dimensionally the same but must be used in sets

Ironically the part number published now for an S rod is AEG624 which is the part number for the Spridget Rod.