My brother is currently rebuilding his 1971 Mini 1275GT which he bought as an unfinished project.
He is about to put the cylinder head back on but has noticed that one of the pistons (no 4 cylinder) is facing the wrong way in that the mark for the front is facing the back of the engine.
Will this matter as I presume that a mini piston is circular or is he going to need to remove it and put it in the right way?
Piston In The Wrong Way Round, Will It Matter?
Started by
minrob
, Apr 13 2009 03:01 PM
8 replies to this topic
#2
Pauly
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Posted 13 April 2009 - 04:58 PM
I would say it could matter, they must be marked for a reason. Wont take long to just turn it round. I would rather spend the extra 10 minutes turning it round than add a few extra days pulling the engine out and stripping it to bits just to turn the piston round.
Paul.
Paul.
#3
jayare
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Posted 13 April 2009 - 05:47 PM
Due to the offset on the con-rods you can't just turn it round. It sounds like it has been fitted the the rod the wrong way. To turn it round you would need to get the gudgeon pin pressed out , turn the rod and pressed back in.
JR
JR
#4
minrob
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Posted 13 April 2009 - 06:46 PM
Many thanks for the replies, I will let him know.
#5
Pooky
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Posted 13 April 2009 - 06:50 PM
Just for the record, why does it matter?
#6
Pauly
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Posted 13 April 2009 - 07:04 PM
Where the conrods numbered when removed? Cound be that they have been mixed up, because I think theres 2 offset 1 way then 2 the other.
Paul.
Paul.
#7
SolarB
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Posted 13 April 2009 - 07:06 PM
Though you can't see it the little end hole is not in the exact middle of the piston. This very small offset ensures the piston is always slightly at an angle in the bore and this reduces piston slap. The front of the piston is marked for this reason.
#8
Cooperman
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Posted 13 April 2009 - 07:41 PM
Though you can't see it the little end hole is not in the exact middle of the piston. This very small offset ensures the piston is always slightly at an angle in the bore and this reduces piston slap. The front of the piston is marked for this reason.
If it's a Hepolite 21253 it really doesn't matter which way round they go.
Most engine builders, me included, like to make the markings all face the front, but that is just for the sake of doing it.
However, on early 850 and 997/998 cars it did matter and there was a clear marking to show 'FRONT' on each piston. Pistons without this marking can go in either round.
#9
Andy1275
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Posted 13 April 2009 - 07:50 PM
Though you can't see it the little end hole is not in the exact middle of the piston. This very small offset ensures the piston is always slightly at an angle in the bore and this reduces piston slap. The front of the piston is marked for this reason.
If it's a Hepolite 21253 it really doesn't matter which way round they go.
Most engine builders, me included, like to make the markings all face the front, but that is just for the sake of doing it.
However, on early 850 and 997/998 cars it did matter and there was a clear marking to show 'FRONT' on each piston. Pistons without this marking can go in either round.
Hi
Thanks very much for the help (it's my GT!)
Andy
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