I have just a quick question and would love some feedback on both pros and cons. I just sent my block SR20DE with a P11 Head to the machine shop. They are recommending that I bore the block to at least 86.5mm. I do not want to go larger than 87 as I will have to sleeve the block. So my question is 86.5 or 87 and why.
Thanks
Sr20 bore size
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Sr20 bore size
1970 SPL 311-29311
Phoenix, AZ
Phoenix, AZ
- Nissanman
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Re: Sr20 bore size
Are the bores damaged?
Boring to an OS requires new pistons and rings, an expense to you that may not be necessary

Boring to an OS requires new pistons and rings, an expense to you that may not be necessary


Nissanman, just trying to help.
1965 SP310 Engine No. G-93326 Car No. SP310-10817
https://photos.shutterfly.com/album/60141836519
On the road again!
1965 SP310 Engine No. G-93326 Car No. SP310-10817
https://photos.shutterfly.com/album/60141836519
On the road again!
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- Roadster Fanatic
- Posts: 246
- Joined: Mon Oct 26, 2015 12:50 am
- Location: Phoenix, AZ
Re: Sr20 bore size
I’ve decided to replace the pistons w/CP’s. Trying to get a bit of extra umph from the motor. The walls themselves appeared clean so I’m leaning toward 86.5 that way I have room in case I do something terribly wrong
1970 SPL 311-29311
Phoenix, AZ
Phoenix, AZ