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DOHC head swap?

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Old 08-10-2006, 05:08 PM
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DOHC head swap?

Ok, before you guys start flaming, I did search. Neither of the 2 threads that came up specifically addressed the obstacles of doing this.

So... What would it take to swap DOHC heads onto an SOHC VG? I've been told that the oil passanges and water passages don't quite line up. By how much? Could they be machined out to match?

Could some sort of adapter be put between the head and block to align the passages? I believe this would increase the volume of the combustion chambers though... So I'm thinking thats probably not a good approach.

What I'm really trying to do is put DOHC heads on a VG33 bottom end. The vg33's bottom end is slightly different from the vg30e in the water routing, but from pictures and literature I've seen it is a very simple process to stretch the passages out to line up. So any procedure that would put the DOHC heads on the vg30e, would most easily adapt to work with my 3.3l block.

I don't know a whole lot about engine insides, and thus won't be doing the actual work myself. Just have to figureout what to tell the motorheads that I want done If it will be too difficult or expensive to machine, I'll probably ditch the vg33 and bore out a vg30de's bottom.

Oh, and please no "Just go VG30DETT" type replys

Thanks in advance for any relevant ideas you guys have to bounce around.
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Old 08-10-2006, 06:25 PM
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wont work, they are too different. and i would not suggest a vg30dett for a z31. the process to get it in there would not be worth it. i WILL suggest a vg30et. that is the way to go in a z31, unless you have money you want to waste "just to be different".
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Old 08-10-2006, 09:50 PM
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Just to be different is one of the larger pushing forces here. Its not for a z31 though.

How different are they? If I could get some pictures from similar angles and distances it'd be great. I haven't seen too many pictures of the bottom of VG heads just laying around on the internet though. Or an overlay of gaskets or something. This would be so much easier to play around with if I had a good Z junkyard near to look at things.
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Old 08-10-2006, 10:07 PM
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Here's some pics from Google Images:

Left pic: VG30 Block

Center pic: VG30DE (VG30DETT) block

Right pic: VG30DETT head

If you are serious about it... just get a VG30 head gasket & lay it on top of a VG30DE head gasket & look at the differences.

EDIT... here's a good page about VG engines: http://members.tripod.com/~grannys/2N6VG30.html
Attached Thumbnails DOHC head swap?-vg30-shortblock.jpeg   DOHC head swap?-vg30dett-short.jpg   DOHC head swap?-vg30dett-headbottom.jpg  

Last edited by NismoPick; 08-10-2006 at 10:11 PM.
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Old 08-25-2006, 02:56 PM
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Stick with the VG33 heads.

My cousin just did a Vg33 swap in his 84 turbo. as long as you do the research the engine will do great. We took it to a drag strip and he was doing 8.8's with messed up head gaskets and only about 10 lbs of boost. it does have a higher compression ratio though. . . but it is still fast as could be with much room for improvements. you do plan on putting a turbo on it dont you?
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Old 08-25-2006, 02:59 PM
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1/8 mile im assumming???
and so what is this goin in if it isnt a Z31?
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Old 08-25-2006, 06:48 PM
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Originally Posted by snwbrderphat540
1/8 mile im assumming???
better be or its BS.
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Old 08-25-2006, 11:40 PM
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if you have the money go for it, if i get the funds im swapping in the z33 motor into my z32..
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Old 08-26-2006, 10:13 AM
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????

Are you trying to stay NA?

Originally Posted by hoov100zx
if you have the money go for it, if i get the funds im swapping in the z33 motor into my z32..
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Old 08-26-2006, 01:04 PM
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i would rather pay for an extra 3.7 motor then stay with the stock 3L plus i kinda like the 350z motor more then my z32 motor, just has alot more torque and nearly 100HP more, plus its all bolt in and california legal.
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Old 08-26-2006, 04:13 PM
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Hehe I need to show you a dyno chart with my stock turbo's, you won't come anywhere close to that with the VQ without doing FI.

Originally Posted by hoov100zx
i would rather pay for an extra 3.7 motor then stay with the stock 3L plus i kinda like the 350z motor more then my z32 motor, just has alot more torque and nearly 100HP more, plus its all bolt in and california legal.
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Old 08-26-2006, 04:28 PM
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im not talking about a stock swap, there will be ALOT of mod's, there was a guy down the street from me who pulled his vq and had the heads ported to the max, a 1mm over-bore, custom grind comp cams, bigger TB....etc he spent propably 10-13k on it, didnt dyno it, but it was a fast *****..


anyone know where i can splice into the light switch?
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