Triumph Repair: triumph spitfire 1500 engine, Spitfire, Midget

Question
hi jim, im re-building my 1976 triumph spitfire engine.
(my first engine blow out and i bought the same year mg midget engine to replace it. 1500 engine, everything the same.) my dad was an experienced mechanic back in his day and he says the engine has cam bearings pressed into the block. i order all of my parts from victoria british and for my year in their catalog it does not show cam bearings. im looking at the block and it doesnt look like theres bearings in it. im a little confused.

nick

Answer
Nick,

Lots of people tend to get confused between the Spitfire and Spridget (Austin Healey Sprite/MG Midget) engines.

Over their lifetimes the Spitfire had 4 distinct engines and the MG Midget also had 4 distinct engines.  With a twist.

The Spitfire started life in 1962 with an 1147 cc engine.  The original Spitfire4s did not have cam bearings but within the first year or so they were added.  Cam bearings were also used on the 1296 small main bearing engine used in the Spitfire Mk3.  The MkIV also had a 1296 with cam bearings, but this time had a crank with larger main bearings.  

The 1500 did not have cam bearings, the cams ride directly in the block.  But rather than change the casting/machining of the block, the camshafts have larger bearing diameters to fit the block sans bearings.

The Spridget line started as the AH Bugeye in 1959 using a 948cc A-series BMC engine.  It was enlarged to 1098 in the mid-60s, finally being bored out to 1275cc for the last of the A-series engined cars.  All of the A-series engines have cam bearings.

In 1975 to meet emission requirements MG (part of BL with Triumph) used the Spitfire 1500 in the Midget.  Other than the engine number stamped on the block it's basically a Spitfire engine.  The Midgets got 9:1 compression for all years whereas the Spitfire got stuck 7.5:1 compression for most of the '70s.

So, being a 1500 it should not have cam bearings in stock form.  What the racers/hotrodders have been doing is to use the earlier 1296 cam bearings and run a cam from the 1296 Mk3 engines, they had a bit more get up and go.

So the question is: how do you want to go with your car?  Bone stock?  Or maybe a bit more than stock?


Cheers,

Jim