Boring a DOHC

[89DOHC]

i was wondering what was the maximum u can bore or if it is possible and what rings and pistons u can upgrade to thanks for the info

[Drift Machine]

believe the recommended maxium bore is 1mm

[JNM240]

Actually, Nissan recommends that when you bore, you only go .5mm over each time, twice maximum, for a total of 1mm. In other words, the first time your rebuild your engine, bore .5mm (from 89mm to 89.5mm) then the SECOND time you rebuild your engine (god forbid), you can go another .5mm, or up to 90mm. I asked my machinst about going directly from 89mm to 90mm when i had him bore my block and he said that taking out that much material at once could cause undue stress on the block. He didnt recommend it. So i have 89.5mm bore now and its just fine.

If you DO go to 90mm, the displacement would then be 2443cc, where my 89.5mm bore gets me a displacement of 2414cc. Stock, of course, is 2389cc.

[JNM240]

Oh yea, and for rings and pistons, most engine rebuild kits can come with oversized pistons of the stock compression (check out http://www.flatlanderracing.com for some), and its definately a good idea to get the pistons BEFORE you bore your block, that way the machinst can bore each cylinder to each individual piston or the best possible fit.

[TrunkMonkey]

Actually, Nissan recommends that when you bore, you only go .5mm over each time, twice maximum, for a total of 1mm. In other words, the first time your rebuild your engine, bore .5mm (from 89mm to 89.5mm) then the SECOND time you rebuild your engine (god forbid), you can go another .5mm, or up to 90mm.

did nissan say this or your machinist?

I asked my machinst about going directly from 89mm to 90mm when i had him bore my block and he said that taking out that much material at once could cause undue stress on the block. He didnt recommend it.

i recommend you find a new machinist. you can go from 89 to 90mm with no problems at all. he either doesn't know what he's doing, or he's lazy.

-demetrius

[I am Technoman]

Hear is a tip for any KA rebuild. Always get the 99 Altima rings because their bad *** and only cost 80 bucks!