Well today my cuzin and i went to pick up his motor that he dropd off at the machine shop( a LT1, trans am).. to do a some work to it.. then he told him to Shave the heads..*deck them* .. so i was like WTF, then he broke it down to me.. closer to the piston, Better compression.. so i was wonderin could that work on our cars VQ30.. say if take the HEads and deck/shave it????? and if so, liek does it make a Huge differnce in TQ/Hp?

thanks in advance
-moo

 

Yes it can be done. No it won't make a huge difference, it'd make a tiny difference in HP and TQ.

 

A few issues that could arise if you do that:

1. The holes in the inner timing cover might not line up anymore (perhaps easily remedied by enlarging the holes, i suppose, but still not a fan of the concept)

2. You might have to modify the lower intake manifold since the heads will be sitting closer together

3. Cam timing will be affected indirectly


Do it right with domed pistons or don't do it at all. Just IMO.

 

Also, from what/how you're asking, i'm assuming you wouldn't be doing the work yourself. For the labor you'd have to pay, you might as well get custom pistons made.

 

thanks nismology.. i see what ur saying.. i was just wonderin like if it made a difference and if it was worth it.. but i think the 3.5 is really whats worth the money..

but 3.5swap is like crzy man, u gotta do alot of lil stuff to get it right, such as the timing align/iacv relocation/ and those lil stuff? i just odnt wana do it and have problems with startin or runin..

But i'ma end up doing it.. Worse case i'd put my old motor back in i guess..

 

I'm going to disagree about the domed pistons - yes it is "the" way to do it correctly but personally I would leave it up to Nissan and not touch the entire shortblock with a 10 foot pole (except of course ARP rod bolts). I've just heard a little too much about some aftermarket pistons going oval in no time and basically screw up your block unless you get .020 over.

And I would not "mill" or "shave" the heads on a DOHC engine at all. If I were to raise compression on a VQ35 I would do a Head/Cam package. I.e fairly priced aftermarket cams and bring the heads to a shop to bump compression and do a port/polish job while they're at it. Just that and a great IM and that 3.5L will breathe much better.

Although I'm not sure at all it's possible to add material to the combustion chamber to raise the comp. But I would MUCH rather do a head/cam package than start playing with block internals and having to have the crank professionaly put back in. Because when that block goes boom it's much cheaper if it's just a normal, stock VQ35 block.

 

You should be going .020" overbore when installing new pistons anyway so that's a moot point, IMO. There's nothing wrong with installing aftermarket pistons as long as the cylinder prep is on point. Just because YOU are scared of touching the insides of a VQ doesn't mean it's not the best option. And one should go with an aftermarket piston that is high in silicone content (on an n/a car at least) so that tighter piston-to-wall clearances can be run and thus avoid some of the typical issues associated with aftermarket forged pistons.
How else can you raise compression without "shaving" the heads or aftermarket pistons? (i left adding material to the heads out of this because i don't even consider it an option)
So aftermarket pistons will make a block go boom? A block with reworked internals and proper installation and prep is often times even more durable and reliable than stock.

And please explain how a "head/cam package" raises the static compression ratio without shaving the heads.