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Discussion Starter · #1 ·
How far can a 5mge block be over bored? I have one that is in good shape except for the bores. It is allready 50 over and there are gouges several thou deep in the walls. Or can it be sleaved?
 

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You may be able to replace it cheaper than sleeving, machine work can add up in a hurry and you can get a 5mge or 6mge for under 700.00(plus shipping) But if you have a buddy with a machine shop...........maybe sleeve it.
 

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Discussion Starter · #5 ·
The pistons were stamped 50 on top. The only micrometer I have is a cheap plactic one used for reloading and the graduations are not that fine. I am making the assumption that it is .050.

The rules only let me go .040 over for the class I am in. May be it is time for another junk yard run to get another complete engine to build for a spare and give up on the old block. A professional shop built it and it lasted less than 5 hours. Needless to say I don't/won't use them again.
 

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FYI .050mm = .020 thousanths
 

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If they are Toyota pistons they'll have 0.50 on top of them. They'll be +.5mm pistons, at least thats what mine have on them. Toyota lists the max overbore at +1.5mm. HTH
 

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Hi may I ask what pistons are you using and where you got them?
I am looking for 1.0 cast 84 and up 5m pistons to put in a 7m block
any help would be great! :D

Thanks,
Rob
84 MkII Improted from Germany :mk2vroom:
 

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Discussion Starter · #9 ·
The engine shop supplied them so I am not sure what they were. They looked to be stock replacements but did not have the normal toyota markings on them and had a cheap cast look to them. The skirts were scratched up as bad as the cylinder wall as was the land between the oil control ring groove and the second compression ring groove. I did not want to reuse them and they have been traded off.

Maybe I should go find a real mic and see what the bore really is before I trash it.

What ever happened to metricification? At least that would be one less thing to confuse me, I stay confused enough with out two confliction measuring systems.
 

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jhooten said:
The skirts were scratched up as bad as the cylinder wall as was the land between the oil control ring groove and the second compression ring groove. I did not want to reuse them and they have been traded off.


Did you find the cause for the damage? Sounds to me like the clearances were'nt right or the cylinders were'nt being lubed properly, or both.
 

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Discussion Starter · #12 ·
The biggest piece of the #2 rod bearing I could find was about 3/8X1/4". And every rod bearing had been spun. Bearing material was every where, I even had to flush it out of the lash adjusters. I found chunks of bearing lodged in the rings, filling the oil pump, well you get the idea.

After tear the engine down we found the PROs that buillt it had used standard bearings on a crank which the data sheet from the rebuilder said required required oversize bearings(i forget now how thick they were 'sposed to be, it was the second size up from standard if memory serves). Needless to say they denied culpability despite the evidence and refused to honor the warrenty.
 
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