Need the brain trusts help with my latest Miata debacle.



i have a 95 Miata I got for 500 bucks after it blew a head gasket. It was a project for my son and I and we tore down the engine, had it machined and we put it back together, with upgraded rods and pistons with the eventual goal of adding boost.

gotnit running naturally aspirated last fall, and put it in the shop for the winter. When bonus hit this spring I ordered the turbo kit from flyin Miata.


took it out for one last spin before it went on the lift for the turbo install and noticed a concerning amount of white smoke from the exhaust. Long story short the head had a crack.


so I start looking for a new head, and by a miracle I found one locally, but it's from an 2004. I jump on it because I'm thinking "great, vvt, better head flow, awesome."

get it home, and then realize I don't have the right valve cover, and that it doesn't have cam gears, vvt actuator, Vic's actuator, etc etc.

I had no idea the vvt cam gear would be $800.
the budget is tight since I still need to buy the megasquirt.

so I have two questions

1. What all parts do I need to get this running with vvt?



2. Can I put my old cam gears on it and run it until I can save up for all the vvt parts?

 

Oh man, that’s a pickle. Some things you’ll need right off:
- new header
- new intake manifold
- NB cam sensor (and crank?) + wiring them into the harness
- the above means you need a standalone ECU
- custom blanking plates for the VVT system?
- probably some custom brackets to make the coils fit in the back of the head? VVT cars have coils on the valve cover
- you may need a new housing in the back of the head where the sensors go. I don’t remember if the NA8 has similar sensor ports to NBs, but maybe.

that’s just a quick list off my head. Can’t say I’ve seen someone using non-VVT cam gears in a VVT head before, so no idea if that works, and what pitfalls you may find regarding spacing and adjustability of the timing belt.

You would be better off short term to sell the VVT head and get the right one for your car

 

I don't think there's any way the non-VVT cam gears will fit, you'd need to machine something totally custom and if you're paying someone to do that it's way more expensive than just doing it the right way.

In addition to the things mentioned already:
- I think the exhaust manifold off the 95 will fit fine, but you'll need a new EGR pipe if you're using that.
- You'll need an oil feed for the VVT actuator. There's a hard line that attaches to the valve cover, but you need to plumb that in to a source from the block.
- You'll also need at least one of the plastic timing belt covers because the VVT cam gear takes more space.
- The coils will work electrically, but the mounting provisions for stuff are different so you'd need to make that fit.
- I think you need a new fuel rail as well.

I agree with selling the VVT head and getting one that fits better. 94-97 would be easiest, 99-00 would be intermediate in difficulty (same fuel rail, intake manifold, and potentially EGR difficulties, but the VVT concerns are gone)

--Ian

 

You'll also want a high flow oil pump to account for the extra flow going to the vvt actuator. A stock 01-05 pump is sufficient, but you might as well get an upgraded one since you plan to boost it.