Is it possible to fit the crank of the 1098 2" main bearing type into a 1275 blockand then use the powermax mg metro pistons a d con reds to fit this set up.Ive got this set up in my convertible but with the 1275 crank.I'm aiming for a shorter stroke engine.would appreciate comments on this.I've got all mg metro parts cam manifold hif44 andhif 36,aiming to keep 295 head which has been polished ..if possible what would my cc be at 20thou bore regards glyn an after thought the mg metro head with the 1.4" inlett would then fit
The 1098 crank is a LONGER stroke than the 1275 crank. And yes - it will fit - but the pistons will stick out the top of the block slightly (I don't have the sizes to hand) and so they would need to be machined down until flush with the block. Whether or not this can be done safely is another matter! The capacity will then go up slightly - I'm guessing to just over 1300cc. A 295 head will NOT be a good idea on a 1275 engine - it's a head for the smaller bore engines. The MG Metro head and the HIF 44 carb are indeed what you want - with the MG Metro cam - and the matching oil pump of course.
Do you recon this is worth a go i,ve got all tooling to machine pistons do you think it would rev better than standard 1098 block would?or stick to 1098 big bearing block block regards glyn
1098 stroke is 83.72mm and 1275 stroke is 81.3 mm. S o - 1098 crank in 1275 block will push the pistons 1.2 mm (48 thou) further up the block. But the original pistons probably didn't quite reach the top anyway (although note MG pistons were nearer the top than 'ordinary' pistons, that's why the CR is slightly higher on the MG engine) - so I suspect at most you would need to skim about 30 thou off the pistons which I 'think' will be perfectly safe. You would need to do a dry assemble and measure properly - these figures are just my guesstimate of what's required. If you have a good 1098 crank - it's worth a go - I would do it! The final capacity on std 1275 bores would be 1311 cc and a 20 thou rebore would take it to 1330 or thereby - and still without getting close to the edge for gasket blowing etc. . But the increase in capacity is hardly dramatic and I reckon it's only worth doing IF you have a good 1098 crank going to waste - otherwise just use the 1275 crank. The 1098 crank is always going to be slightly less revable than the 1275!
If you are actually aiming at a shorter stroke engine, then the 998 crank at 76.2mm stroke would want something like 2.5mm taken off the block, which should be OK and will give you about 1193cc and fair bit nearer "square" sizing.
But a 998 crank is from a Mini ?? And a 948 crank (same stroke) won't fit the blocks in question here! It would be possible to use the 1275 crank in the 1098 (big mains) block - would give 1066 cc - but really can't see the point!
An ideal combination (not relevant to this thread really - but hey ho) is to use a 948 crank in a 1098 block - it then takes std size Mini pistons (and rods) - and gives 998 cc! A nice small capacity unit which will rev to the heavens!
with the cooper head would work well and maybe mg metro cam and inlett otherwise i'll work on the 1098 big bearing block will probably rev safer than standard 1098 engine
A Question for you on that 1098 block with the 2" main bearings - is it based on a 1275 block or the normal 1098 block ? In other words -is it longer (like the 1275) and therefore needs the long-nose oil pump - or is it normal length and hence using the short nose pump ?
1098 big bearing engine is based on the 1098 original block,1275 had not been developed when they bought them out first,I got a 64 healy sprite this has 10cc engine in and i dont think the cooper s had 1275 at the time...I may be wring here regards glyn
Cooper S was certainly around in 1964 - as 1275 version. The 970/1071/1275 blocks are all 'long' - the 1275 also being 'tall'. At the time I thought the new improved engine for the Midget was described as being 'based on the Cooper S design'. Anyway - you will find out for sure when you go to fit the oil pump!
had to be a hitch somewhere!