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 Post subject: 1500 Bore Size?
PostPosted:Mon May 04, 2020 11:18 am 
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What is the standard bore size for a 1500 please?


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 Post subject: Re: 1500 Bore Size?
PostPosted:Mon May 04, 2020 11:35 am 
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Location:Auckland, New Zealand
Pretty sure it is the same as the 1300 at 2.9000in (+/-0.5thou). Max oversize is 0.020in. Extra capacity of 1500 is due to longer stroke.


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 Post subject: Re: 1500 Bore Size?
PostPosted:Mon May 04, 2020 11:51 am 
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Location:Halifax, West Yorkshire
73.7mm or as above 2.9"
I'm running my 1500 engine at +60 overbore though... :-)

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 Post subject: Re: 1500 Bore Size?
PostPosted:Mon May 04, 2020 11:55 am 
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Thanks both.

Set of new standard pistons ebay bound shortly!


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 Post subject: Re: 1500 Bore Size?
PostPosted:Tue Mar 30, 2021 6:37 pm 
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Location:Shaftesbury
Hi All

I am looking to buy some new pistons and rings for my 1500 rebuild...

I have contacted a supplier who suggest based on my measured bore size that I need +.0020” ones but I am not convinced...

Measured bore size is 73.74 on 3 bores and 73.71 on the other. Workshop manual says 73.65 nominal giving 0.06 to .09mm bigger.

Based on 73.59mm nominal piston (from the workshop manual) if I go oversize by .0020”. (.502mm) this would make the piston too big at 74.09mm...so too big..

I suspect he is thinking I am going to re-bore based on the wear, but apart from that they are in good condition.

Am I hopefully I can get away with standard pistons and an oversize piston ring.. or am I way out on my calculations...

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 Post subject: Re: 1500 Bore Size?
PostPosted:Thu Apr 01, 2021 11:14 am 
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Quote:
Hi All

I am looking to buy some new pistons and rings for my 1500 rebuild...

I have contacted a supplier who suggest based on my measured bore size that I need +.0020” ones but I am not convinced...

Measured bore size is 73.74 on 3 bores and 73.71 on the other. Workshop manual says 73.65 nominal giving 0.06 to .09mm bigger.

Based on 73.59mm nominal piston (from the workshop manual) if I go oversize by .0020”. (.502mm) this would make the piston too big at 74.09mm...so too big..

I suspect he is thinking I am going to re-bore based on the wear, but apart from that they are in good condition.

Am I hopefully I can get away with standard pistons and an oversize piston ring.. or am I way out on my calculations...
You've given them the measurement of the bore, they think you've given them the piston size hence them saying you need a bigger piston.

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 Post subject: Re: 1500 Bore Size?
PostPosted:Thu Apr 01, 2021 2:41 pm 
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Joined:Thu May 17, 2012 8:34 pm
Posts:731
Quote:
Am I hopefully I can get away with standard pistons and an oversize piston ring.. or am I way out on my calculations...
No. You can't use oversize rings on standard pistons.
Based on your measurements your machine shops advice is correct, you need to rebore and then use appropriate oversized pistons.


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