Fergusminto Posted January 18, 2023 Report Share Posted January 18, 2023 I have inherited an already stripped 1500 engine. However, the main bearing caps have been mixed up! I can see which one is at the rear (recesses for the thrust bearings) but the other two do not have any markings. Anyone have any suggestions? Also, which way round do these caps fit ie shell recesses on same side or opposite each other? Thanks. Link to comment Share on other sites More sharing options...
JohnD Posted January 18, 2023 Report Share Posted January 18, 2023 They should be marked! But can be difficult to see - thorough cleaning and perhaps some buffing with an emery strip might show them up. Shell recesses oppose each other. Again, there should be a recess in the cap for one. John Link to comment Share on other sites More sharing options...
Fergusminto Posted January 18, 2023 Author Report Share Posted January 18, 2023 Thanks John. I will put them under a microscope if necessary! I take it there should be corresponding markings on the crank case body? Link to comment Share on other sites More sharing options...
NonMember Posted January 18, 2023 Report Share Posted January 18, 2023 38 minutes ago, JohnD said: Shell recesses oppose each other. Surely they oppose by being on the same side of the engine, so that the bearings can't move either way? Link to comment Share on other sites More sharing options...
JohnD Posted January 18, 2023 Report Share Posted January 18, 2023 3 hours ago, Fergusminto said: Thanks John. I will put them under a microscope if necessary! I take it there should be corresponding markings on the crank case body? Not necessarily. No1 is the front. Link to comment Share on other sites More sharing options...
JohnD Posted January 18, 2023 Report Share Posted January 18, 2023 3 hours ago, NonMember said: Surely they oppose by being on the same side of the engine, so that the bearings can't move either way? Picky picky. Fergus understands, do need pictures? Link to comment Share on other sites More sharing options...
Fergusminto Posted January 19, 2023 Author Report Share Posted January 19, 2023 Maybe “non-member” should join the Club and build on his knowledge. I am 73, rebuilt many an engine, gearbox and classic car but am still learning. Thanks again John. Link to comment Share on other sites More sharing options...
Sandy Gibson Posted January 19, 2023 Report Share Posted January 19, 2023 On my Mk 111 the caps are marked with punch marks but surprisingly (to me anyway) No 1 is the rear cap and 4 is the front. I expected them to be the the other way round. Link to comment Share on other sites More sharing options...
NonMember Posted January 19, 2023 Report Share Posted January 19, 2023 12 hours ago, JohnD said: Fergus understands, do need pictures? 32 minutes ago, Fergusminto said: Maybe “non-member” should join the Club and build on his knowledge. Is it actually necessary to be insulting just because I asked for clarification of a statment that could have been misleading to other readers who are not "73, rebuilt many an engine"? Link to comment Share on other sites More sharing options...
Clive Posted January 19, 2023 Report Share Posted January 19, 2023 On this vein, A mate stripped a mini engine. I honed the bores for him, left him to build it up. He called me a week later. The crank wouldn't turn. He had randomly fitted the big end and main bearing caps from what I can remember. Took me an hour or so to sort it out. I am not certian all triumph engines hads the main caps stamped from the factory, most I have rebuilt have been rebuilt before and have a variety of types of ID. From punch marks to file marks and some even have numbers stamped. But I too am unsure how to interpret Johns comment about opposite. I am certain the notches go next to each other? (as in the same side, almost touching each other) Link to comment Share on other sites More sharing options...
johny Posted January 19, 2023 Report Share Posted January 19, 2023 sorry Clive that last bit has got to be impossible as the bearing shells halves are identical so you cant put two notches together. Reckon its notches both on same side of journal but one towards front of engine and the other towards the back.... Link to comment Share on other sites More sharing options...
Clive Posted January 19, 2023 Report Share Posted January 19, 2023 2 minutes ago, johny said: sorry Clive that last bit has got to be impossible as the bearing shells halves are identical so you cant put two notches together. Reckon its notches both on same side of journal but one towards front of engine and the other towards the back.... Yes, that is what I meant. They are the same side of the journal, not opposite sides. See, it is easy to get confused! Link to comment Share on other sites More sharing options...
DanMi Posted January 19, 2023 Report Share Posted January 19, 2023 my 1147cc main caps had no markings and were taken off by the machine shop and not labelled. so they just put the 2 on and ran a measure around them to figure it out, took the guy about 30 seconds. He also said although one way was better the caps either way round would have been within tolerance Link to comment Share on other sites More sharing options...
Wagger Posted January 20, 2023 Report Share Posted January 20, 2023 On 19/01/2023 at 10:52, NonMember said: Is it actually necessary to be insulting just because I asked for clarification of a statment that could have been misleading to other readers who are not "73, rebuilt many an engine"? I agree, Nonmember is very thorough and more of a perfectionist than me. Ambiguity is very common. Common sense is not. Tolerance is the key, disputes are unnecessary. Much better to be polite. I have some number stamps so always use my own marking system before disassembly. My brother in law once stripped a mini 1000 engine throwing all parts randomly in a box. All of the con rods are different, so it took my 'Fitter' brother ages trying to match it all up. In fact, it ran like a dog and had to be sold before it shook all dental fillings out. Link to comment Share on other sites More sharing options...
Wagger Posted January 20, 2023 Report Share Posted January 20, 2023 On he subject of markings it is very easy to get it wrong. Offside and nearside are dependent on which side the steering wheel is. On tranverse engines, number 1 cylinder is nearest to radiator on some. On V engines it becomes a nightmare. Then we have those pistons with offset gudgeon pins. (Honda 50) has an arrow on it. Did it mean forward or Upwards? (The cylinder lay almost horizontal). Therefore, use yor own markings before stripping and note it. Link to comment Share on other sites More sharing options...
daverclasper Posted January 20, 2023 Report Share Posted January 20, 2023 6 hours ago, Wagger said: I agree, Nonmember is very thorough and more of a perfectionist than me. Ambiguity is very common. Common sense is not. Tolerance is the key, disputes are unnecessary. Much better to be polite. Here here, Link to comment Share on other sites More sharing options...
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