Mini Mad
Posted 19 May 2015 - 10:38 AM
I just want to make sure, as all i can ever find is people saying, 'install the caps the correct way round'.
When installing the big end caps do the tabs on the bearings/caps opposite each other? Or both on the same side? is it helps its a 1275 metro engine.
Cheers.
Up Into Fourth
Posted 19 May 2015 - 10:56 AM
Mini Mad
Posted 19 May 2015 - 11:03 AM
This looks like it may go very wrong have you got the caps mixed up from different rods ie cap from piston one mixed with cap 4 etc
? What i meant was when i put the caps on the big ends, do i put them so the tabs from each side are on the same side, or so that they are opposite
Moved Into The Garage
Posted 19 May 2015 - 11:05 AM
In nearly all engines, not just A Series, caps are fitted 'tang to tang', ie the cut outs for the bearing locators go on the same sides.
If your unsure, you can try them both ways, without the shells in place and you'll feel them.
As a matter of course when I recondition an engine, I do have the Rods 'Closed and Honed' then checked for alignment and twist. The Clearances are small, so it doesn't take much to have troubles from misaligned rods.
Mini Mad
Posted 19 May 2015 - 11:08 AM
Alright thanks, thought they went tab to tab 
In nearly all engines, not just A Series, caps are fitted 'tang to tang', ie the cut outs for the bearing locators go on the same sides.
If your unsure, you can try them both ways, without the shells in place and you'll feel them.
As a matter of course when I recondition an engine, I do have the Rods 'Closed and Honed' then checked for alignment and twist. The Clearances are small, so it doesn't take much to have troubles from misaligned rods.
Up Into Fourth
Posted 19 May 2015 - 11:19 AM
Uncle Cooperman, Voted Mr TMF 2011
Posted 19 May 2015 - 11:27 AM
What I'm saying though is if you have the caps mixed up your engine will seize up very quick and will run wonky
Quite correct.
OP, check that the caps have not got mixed up during the re-build process.
I do recall years ago being asked to look at a newly built engine which seemed to be 'seized up', only to learn that the owner had just assumed that the rods & caps had no significance as matched items. So he had just mixed caps & rods. The problem, on stripping it, was that the caps & rods had no ident markings. That meant that each rod/cap had the be machined and honed to re-gain concentricity (after we messed about for hours trying to match them up - I couldn't be certain that they were correct, so we machined them all).
Moved Into The Garage
Posted 19 May 2015 - 11:30 AM
,,,,,,,,,only to learn that the owner had just assumed that ,,,,,,,,,,,,
,,,,,,Best avoided,,,,,,,
Mini Mad
Posted 19 May 2015 - 11:40 AM
What I'm saying though is if you have the caps mixed up your engine will seize up very quick and will run wonky
Quite correct.
OP, check that the caps have not got mixed up during the re-build process.
I do recall years ago being asked to look at a newly built engine which seemed to be 'seized up', only to learn that the owner had just assumed that the rods & caps had no significance as matched items. So he had just mixed caps & rods. The problem, on stripping it, was that the caps & rods had no ident markings. That meant that each rod/cap had the be machined and honed to re-gain concentricity (after we messed about for hours trying to match them up - I couldn't be certain that they were correct, so we machined them all).
What I'm saying though is if you have the caps mixed up your engine will seize up very quick and will run wonky
Quite correct.
OP, check that the caps have not got mixed up during the re-build process.
I do recall years ago being asked to look at a newly built engine which seemed to be 'seized up', only to learn that the owner had just assumed that the rods & caps had no significance as matched items. So he had just mixed caps & rods. The problem, on stripping it, was that the caps & rods had no ident markings. That meant that each rod/cap had the be machined and honed to re-gain concentricity (after we messed about for hours trying to match them up - I couldn't be certain that they were correct, so we machined them all).
Hello, well two of the caps have 3 and 4 on them, and the other two are blank, but with caps three and four torqued up aswell as the second one, it turns fine, so i doubt ive got one and two mixed up as the second one torqued down turns fine :/
Uncle Cooperman, Voted Mr TMF 2011
Posted 19 May 2015 - 11:43 AM
That is what we are on here for, to help less experienced owners work on their classic Minis and not have to pay huge amounts to engine or body-building companies.
As an aside, I used to build a few engines after I first retired and I didn't charge a high hourly rate. But I got so fed up with folks wanting engine builds 'on the cheap' that I stopped. I would give a fixed price for the work, only to be told that 'XYZ' Engines quoted less. My reply was always, well, go to XYZ then".
I was asked to look at a newly built and installed 1380 engine which was smoking 'like a train' immediately after initial start-up following a full re-build. I said to take it back to the builder under warranty, but it had been sitting for 2 years waiting for the body to be done, so was out of warranty.
I stripped it and found that the bores were all 0.004" to 0.006" over the correct size, the ring gaps were all around 0.025" and there were 'wobble' marks where the pistons had juddered against the bore walls. It had not been offset bored. The crankshaft had just been polished, but it really needed a re-grind and the pistons were sitting about 0.035" down the bores at TDC. But it had been 'cheap'!
It was easier to find another block and bore it correctly, re-grind the crank, polish the sides of the pistons to remove the slight marking and get a new set of rings. Then do a proper 'trial build', final machining and careful assembly with the cam timed in accurately. A very expensive lesson indeed.
Mine is purple, but I have been told that's normal
Posted 19 May 2015 - 11:45 AM
That is what we are on here for, to help less experienced owners work on their classic Minis and not have to pay huge amounts to engine or body-building companies.
As an aside, I used to build a few engines after I first retired and I didn't charge a high hourly rate. But I got so fed up with folks wanting engine builds 'on the cheap' that I stopped. I would give a fixed price for the work, only to be told that 'XYZ' Engines quoted less. My reply was always, well, go to XYZ then".
I was asked to look at a newly built and installed 1380 engine which was smoking 'like a train' immediately after initial start-up following a full re-build. I said to take it back to the builder under warranty, but it had been sitting for 2 years waiting for the body to be done, so was out of warranty.
I stripped it and found that the bores were all 0.004" to 0.006" over the correct size, the ring gaps were all around 0.025" and there were 'wobble' marks where the pistons had juddered against the bore walls. It had not been offset bored. The crankshaft had just been polished, but it really needed a re-grind and the pistons were sitting about 0.035" down the bores at TDC. But it had been 'cheap'!
It was easier to find another block and bore it correctly, re-grind the crank, polish the sides of the pistons to remove the slight marking and get a new set of rings. Then do a proper 'trial build', final machining and careful assembly with the cam timed in accurately. A very expensive lesson indeed.
With precision comes power
Uncle Cooperman, Voted Mr TMF 2011
Posted 19 May 2015 - 12:06 PM
I have looked into what these 'low-cost' engine builders do, or rather don't do.
They don't do even one trial build, they don't machine the block to bring the pistons right to the top of the bores, the rings gaps are not checked, the cam is not timed-in accurately, just dot-to-dot, which can be several degrees out. No compression measurements or calculations are done. All-in-all, the build is not done carefully and accurately, just as quickly as possible to 'get the cash'. But if 'cheapest' is what is wanted, then so be it.
"Cheap, Reliable, Powerful - you can have any 2 of those 3, but not all three", has been stated in the past, but I'm not sure even that is true. If you want a good engine, it ain't gonna be cheap unless you can do it all yourself.
Moved Into The Garage
Posted 19 May 2015 - 09:32 PM
I have looked into what these 'low-cost' engine builders do, or rather don't do.
They don't do even one trial build, they don't machine the block to bring the pistons right to the top of the bores, the rings gaps are not checked, the cam is not timed-in accurately, just dot-to-dot, which can be several degrees out. No compression measurements or calculations are done. All-in-all, the build is not done carefully and accurately, just as quickly as possible to 'get the cash'. But if 'cheapest' is what is wanted, then so be it.
"Cheap, Reliable, Powerful - you can have any 2 of those 3, but not all three", has been stated in the past, but I'm not sure even that is true. If you want a good engine, it ain't gonna be cheap unless you can do it all yourself.
Cheap usually means corners have been cut.
You (usually) only get what you pay for.
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