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LS Vtec pistons....

Discussion in 'Engine Building' started by scottp11, Jun 17, 2007.

  1. scottp11

    scottp11 The Seniorest Member....

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    A friend of mine is building an LS Vtec motor using a B18B block, with stock crank, rods and pistons with a B16A2 head. I was told that he couldn't use the PR4 pistons because the valve relieve's are not deep enough and the valves would hit the pistons... Is that true. This guy is kinda on a budget, cuzz he blew his 2000 Si..... (threw a rod through the block....) Can someone give me a quick answer so I can let him know. Thanks for everyones help in advance!
     
  2. 99sidude

    99sidude Moderator Moderator VIP

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    are pr4's b18a pistons? if so, they should work
     
  3. scottp11

    scottp11 The Seniorest Member....

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    Yeah, PR4's are the same for B18A/B's...
     
  4. dtob

    dtob New Member

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    PR4 pistons will work if he's running the stock cams. He can't use aftermarket cams with them though because the valve reliefs are not big enough. He can use some stock PR3 pistons though and bump his compression to 12:1. They run really well in my car on 91 octane.
     
  5. welfare

    welfare Ancient Member

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    or some p30, basically same as the pr3, then throw a set of gsr cams and call it a day.
     
  6. dtob

    dtob New Member

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    Ya. P30s are good too but they yeild higher compression due to their bigger dome. Might be a little iffy on 91 octane.
     
  7. AcuraTer

    AcuraTer New Member

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    i am runing pr4 pistons in my ls vtec ,runs great. but i need cams and vtec tranny. lol Ls tranny makes gears too long.but those piston will work fine. pr3 or p30 would be alot better.
     
  8. welfare

    welfare Ancient Member

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    p30+91 octane= friendly
    I did them in my old ls/v setup which my brother still has, over 16,000 miles and still running great, just don't advance timing too far or you get ping ping ping :)
     
  9. johnercivic

    johnercivic New Member

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    I would use the P30s for the higher compression or go with the PR3s; essentially the same but a little lower compression. Too bad it wasn't a 2000 SiR, he could've just used the pistons from that (PR3s I believe).
     
  10. vtecsir1

    vtecsir1 Senior Member

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    i run itr cams in my ls/vtec stock bottom:shrug:
     
  11. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    itr cams count as a stock cam. get into bigger cams lik s2s2's and youll have issues with the valve reliefs
     
  12. ls/vtechatch91

    ls/vtechatch91 New Member

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    i'd buy arp rod bolts.. just to be on the safe side... im building my ls/vtec with pr3 pistons and arp main studs and rod bolts...... and jdm b16a head with gsr valve train.....
     
  13. scottp11

    scottp11 The Seniorest Member....

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    Yeah, this dude is kinda on a budget. I just gave him a B18B1 block with crank, rods and pistons (all PR4), and I'm gonna put it all together for him. Use his B16A2 head and tranny. He ordered the LS Vtec kit from inlinefour.com, so... We're gonna get started today probably. I'm making him pull the engine, and label everything so he can learn some shit too...
     
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