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998Cc Piston Trouble

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#1 MiniMans01

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Posted 28 November 2019 - 07:46 AM

Hi all, I own a 1989 Mini City E, this particular Mini i thought was stock but turned that wasn't the case as taking it apart in found out that it had a old school high lift cam that they stopped making stage 2 head and a few other little cool things. Ive gotten to rebuilding the engine and have come across a problem i cannot seem to find the same piston number anywhere. my piston head is a Hepolite as its stamped inside but doesn't have a sizing stamp on it. it does have a number but the number brings nothing up. the number is 20600 A, is this a discontinued pistons? is it a oversized piston?. Any help will be greatly appreciated. Also the engine is not original apparently its on its third engine so the real age of the engine is a bit of a mystery. Cheers George.



#2 gazza82

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Posted 28 November 2019 - 09:15 AM

Try contacting FW Thornton http://www.fwthornton.co.uk/ .. they supply older and discontinued stock or might at least tell you what you have.



#3 DeadSquare

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Posted 28 November 2019 - 09:47 AM

Hi all, I own a 1989 Mini City E, this particular Mini i thought was stock but turned that wasn't the case as taking it apart in found out that it had a old school high lift cam that they stopped making stage 2 head and a few other little cool things. Ive gotten to rebuilding the engine and have come across a problem i cannot seem to find the same piston number anywhere. my piston head is a Hepolite as its stamped inside but doesn't have a sizing stamp on it. it does have a number but the number brings nothing up. the number is 20600 A, is this a discontinued pistons? is it a oversized piston?. Any help will be greatly appreciated. Also the engine is not original apparently its on its third engine so the real age of the engine is a bit of a mystery. Cheers George.

 

Original pistons are sometimes marked as "Std" = standard, but many are not, (In the same way that a book is not marked as "First Edition"), But oversize pistons are always marked with the oversize by the manufacturer.

 

In rare cases with a modified engine, someone might have found and used a larger standard piston, or even an over size that needed a skimmed compression height, in which case they would be not be marked as oversize.

 

Measuring the top of the bore with an inexpensive Vernier will easily show whether the block has been rebored.



#4 MiniMans01

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Posted 29 November 2019 - 08:05 AM

 

Hi all, I own a 1989 Mini City E, this particular Mini i thought was stock but turned that wasn't the case as taking it apart in found out that it had a old school high lift cam that they stopped making stage 2 head and a few other little cool things. Ive gotten to rebuilding the engine and have come across a problem i cannot seem to find the same piston number anywhere. my piston head is a Hepolite as its stamped inside but doesn't have a sizing stamp on it. it does have a number but the number brings nothing up. the number is 20600 A, is this a discontinued pistons? is it a oversized piston?. Any help will be greatly appreciated. Also the engine is not original apparently its on its third engine so the real age of the engine is a bit of a mystery. Cheers George.

 

Original pistons are sometimes marked as "Std" = standard, but many are not, (In the same way that a book is not marked as "First Edition"), But oversize pistons are always marked with the oversize by the manufacturer.

 

In rare cases with a modified engine, someone might have found and used a larger standard piston, or even an over size that needed a skimmed compression height, in which case they would be not be marked as oversize.

 

Measuring the top of the bore with an inexpensive Vernier will easily show whether the block has been rebored.

hi, i dont suppose you know what the measurments should be if not rebored?



#5 DeadSquare

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Posted 29 November 2019 - 08:40 AM

 

 

Hi all, I own a 1989 Mini City E, this particular Mini i thought was stock but turned that wasn't the case as taking it apart in found out that it had a old school high lift cam that they stopped making stage 2 head and a few other little cool things. Ive gotten to rebuilding the engine and have come across a problem i cannot seem to find the same piston number anywhere. my piston head is a Hepolite as its stamped inside but doesn't have a sizing stamp on it. it does have a number but the number brings nothing up. the number is 20600 A, is this a discontinued pistons? is it a oversized piston?. Any help will be greatly appreciated. Also the engine is not original apparently its on its third engine so the real age of the engine is a bit of a mystery. Cheers George.

 

Original pistons are sometimes marked as "Std" = standard, but many are not, (In the same way that a book is not marked as "First Edition"), But oversize pistons are always marked with the oversize by the manufacturer.

 

In rare cases with a modified engine, someone might have found and used a larger standard piston, or even an over size that needed a skimmed compression height, in which case they would be not be marked as oversize.

 

Measuring the top of the bore with an inexpensive Vernier will easily show whether the block has been rebored.

hi, i dont suppose you know what the measurments should be if not rebored?

 

 

 

Yes, I do.

 

There are four standard Mini bores, 

 

   997 cc = 2.458" or 62.43mm................848 cc = 2.478" or 62.94mm..................998/1098 cc = 2.543" or 64.588mm...........970/1071/1275 cc = 2.780" or 70.6mm.







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