VVT engine on a NA
 

Hello folks, not much of a poster, more of a reader since I have nothing to contribute.

I do have a serious problem with my ride. The engine has 133K, and uses oil at a rate of a quart every 500 miles or so.

All seals and PCV were replaced within the last 12K-15K miles, there is a small leak from the front crank seal, but it is tiny.

Car smokes only under heavy acceleration, not at start up, so busted rings is the diagnostic.

On Miata.net recommendation, I dumped Marvel Mystery Oil, on the crankcase, but that did nothing.

Anyway since I neither have the know how, nor the tools for a rebuild, a new engine is the answer. Here in Tampa low miles VVT engines sell for the same amount of high miles pre 1999 engines (about $600). The thing is besides the VVT (which will need Hydra or Megasquirt to run) there are other things that I'll need to get this to work. I can get ANY 1.8 engine installed by trusted mechanic for $600 dollars, but I know that there are other things (like fueling) that may need to be "adapted".

Has anyone in here done this, dropping a VVT engine on a NA?

Has anyone seen it done?

What would you do if you were doing this?

Any help will be greatly appreciated!

I believe Savington's new motor is a VVT engine. I would probably do a 99-00 motor just so i could run Adaptronic and wouldn't have to deal with VVT. I suspect in a few years VVT motors will be all the craze once we figure out how to unlock its potential.

Bizzarely I just fitted a VVT motor to my MK1 this weekend just gone.

VVT can't be controlled by a MegaSquirt at this moment in time. You want either Hydra or Adaptronic for that.

The MK2 uses a FPR in the tank and two fuel pulsation dampeners one on the rail, one on a bracket on the intake mani. It's also returnless.

Unfortunately the MK1 FPR won't fit on the MK2.5 fuel rail, (well it will, but when you try to fit it to the head it fouls). So you need to either buy another rail, or figure a way to remote mount it.

MK1/2 coilpacks won't fit on the back of the head because of the VVT Oil supply. I've jerry-rigged mine to the top of the valve cover, but longterm have some Toyota COPS on order, Obviously if your motor comes with the MK2.5 coils this isn't an issue.

MK1 CAS fits the exhast cam like every other MX5 engine :)

MK1 echaust manifold fits like a glove, you NEED, (and want!) the MK2.5 intake manifold. MK1 Throttle body bolts right up so electrically (i.e. TPS and IAC) everything is fine.

If you have an early Oil Pressure sender (I retrofitted one to my 96) it'll foul on the rear starter motor bracket, (this is because the Oil feed for the VVT comes from the original OPG sender location, the new location is 2-3" lower). you can take some material off and it'll be fine though.

Other than that it's a straight swap really.

EDIT:

I blanked off the ports for EGR. and my (non USDM) VVT intake manifold doesn't have VTCS, but a simple RPM switch can control that.

Awesome richyvrlimited, THANKS a bunch!

Couple of more questions? :noob:


1. Which fuel rail did you use, would you mind posting pics?

2. When you refer to the MK 2.5 Coil packs, are this the 2001-2005 engines you are referring to?

3. I won't really have the means for a standalone just yet, but I could run the engine w/o VVT for a while correct?


4. Could you please also post pics regarding the oil pressure sender mounting?


I truly appreciate your comments and help!

Initially I've modified the MK1 rail to fit, but to get it to fit you need to flip the FPR around and remove the 90deg bend of tube that feeds the FPR.

You also need to elongate the mounting holes for the rail. It's a bit of a bodge job that for me is temporary.

This weekend I'll be modifying the MK2.5 rail by putting a barb where the FPR would go and remote mounting the FPR. I'd strongly recommend this option. OR buy an uprated rail that'll have a FPR mounting on it.

Yeah the 'nearly' Coil on plugs. My engine didn't come with them so at the minute I have the MK1 coilpacks tied to the camcover. it's a bit Heath Robinson but it gets me to work until my COPS arrive :)

I've left the VVT unplugged it's at full retard in that situation so robs you of low end torque. That said it's more powerful than my old 96 motor....

I'll try to take pics, but it's a bit restricted for access now the engine is back in. It's pretty self explanatory once you get to it. It's only relevant if you have an early Oil Pressure sender tho.

The M-Tuned Fuel will help with this issue. :)

Sure it will, postage is a bitch for me though ;)

Thanks dude! err bloke ;) ... richyvr, this will be happening within the next 30-60 days, thank you for your info, I'll definitely keep you posted about any progress, and well lack there off...

Shameless :laugh:

Nah, I'm cool with it, he may just get some of my hard earned money! :idea:

Any word on availability?