How to Rebuild a 1600cc Mx5 Engine?

andyling · Post by **andyling** » Tue Dec 01, 2009 8:17 pm

Hi guys, I know nothing about engines, but I'm willing to learn to rebuild one, I found the following on trademe.

http://www.trademe.co.nz/Trade-Me-Motor ... 392348.htm

What you guys think? Is it worth to rebuild?

Thinking about to buying a high km mx5 later on and turbo charge it with the rebuilt engine.

Cheers

dynofiend · Post by **dynofiend** » Tue Dec 01, 2009 8:38 pm

Id be wary of that auction.

"Cams an ported head" means, "It might have been tuned, but youll never know until I'm long gone anyway"

Raced means "its been thrashed to within an inch of its life, to the extent where its not worth me rebuilding it or keeping it, so im selling it"

Head needs a freshen up means "it smoked and clattered, and I dont really know whats wrong with it"

Nothing wrong with rebuilding an engine, but you need to know exactly what you are buying unless you are willing to potentially end up paying for a block of scrap metal.

The MX5 Haynes manual contains pretty much a complete engine tear down and rebuild, pretty much everything you would need. Buy one of those

andyling · Post by **andyling** » Tue Dec 01, 2009 9:12 pm

see, This is Exactly what I'm worrying about! Because I don't know shit to start with.

What about this 4age?

http://www.trademe.co.nz/Browse/Listing ... =256955534

Anyone near CHCH could help me get a rebuildable engine?

poison · Post by **poison** » Tue Dec 01, 2009 9:29 pm

My 2 cents, no point in rebuilding an engine unless you have a goal to
achieve, like a specific car you want to upgrade. Like building a strong MX5
engine for turbo charging, it's not going to cost much more in parts and
you'll end up with an engine with lots of potential. Rebuild or recondition
is also a fairly vague term, you can brighten up a motor with new piston
rings and valve seals quite cheaply but if you want to do a full rebuild it
can cost a few thousand in parts.

If it's just to learn about engines a good place to start is a 4 stroke
motor cross bike, or even a 2 stroke Go-ped, they are fun and you start to
learn about engines. I started with 4 stroke trail bike, then a VW beach
buggy - a few times with upgrades, then a couple of pre-fuel injected fords.
Then in the early 90's jet skis came to NZ and they would break down weekly.
Since then, more jet ski's, bikes, go-peds and nitro RC engines. And at the
end of the day I wish I was rich and someone else could and would do it all
for me.

Start with a small engine, they all work the same or you'll a larger engine
apart into a thousand pieces and think... Oh My God, what now... and give
up.

Habanero666 · Post by **Habanero666** » Tue Dec 01, 2009 9:42 pm

I can think of better things to spend money on, like pimple cream and Swedish bedroom accessories.

I asked a question that was unanswered from the start of the auction: "can you please take a picture of the exhaust ports as they are now please"....... did you see a reply? Buyer beware!

Yeah, it's real easy building engines, but making them last and perform is best left to professionals.

Anthug · Post by **Anthug** » Tue Dec 01, 2009 10:45 pm

I would recommend buying a complete engine that hasnt been mucked around with if you want to rebuild it, that is what I did.

The Miata Enthusiast Workshop Manual. by Rod Grainger is excellent.

You can find information on porting heads on miata.net

If you want to go turbocharged then it is a good idea to become familiar building an engine. After turbo'ing mine I now wish I have supercharged it instead. The power is great but ruins the driving pleasure of the MX5 in my opinion.

Anthony.

andyling · Post by **andyling** » Tue Dec 01, 2009 10:46 pm

Jesz.. Yeh, doesn't sound too good.

Well, I went to see the engine myself. the seller was very nice guy. But I didn't know anything about the engine. So when I asked what needs to be done, he just said just need to rebuild the top end and the heads.

BTW, The engine was from a 1989 mx5, which is replaced by 1.8L and he turbo charged that one as well. looks like a tidy modification.

Euen · Post by **Euen** » Tue Dec 01, 2009 11:11 pm

Anthug wrote: The Miata Enthusiast Workshop Manual. by Rod Grainger is excellent.

I agree with Anthony. There are 2 versions, one for the 1.6 and one for the 1.8. I also have a Haynes one and the Enthusiast Manual is far better.

As Poison said, it helps if you have a goal when planning something like this. Trying to get a significant performance improvement out of these engines can get very expensive. Having said that, the B6 (1.6) and BP (1.

are relatively simple engines compared to some and most parts are readily available.

poison · Post by **poison** » Tue Dec 01, 2009 11:19 pm

Anthug wrote:After turbo'ing mine I now wish I have supercharged it instead. The power is great but ruins the driving pleasure of the MX5 in my opinion.

I have to agree in some ways, the power of a turBO can be way more exciting but much harder to control on corners, where as a supercharger is still way better than a stock MX5 but you retain the smoooooooth power control.

I recall going for a drive with Zoruno round the hills out west on some wet roads. He had me for dead on the corners as the back end would just shoot out everytime I tired to accelerate unless on a dead straight. Even now if you chop down at 60-70k in the wet the back end gets loose, it can be fun but scary at the same time, so I occasionally miss the prdicable power curve for windy roads. All that said I am keen to get a missing 35 HP out of my car due to an annoying boost fall-off and make it even more snappy..... lol. HP is a drug.

andyling · Post by **andyling** » Tue Dec 01, 2009 11:39 pm

If it's a good running engine, How much would it cost to rebuild roughly?

Which one is better to rebuild 1.6 or 1.8?

why would turbo charge a engine so expensive?

I thought small turbos and intercoolers are cheap nowadays...

I only need 180-200bhp at the wheels.

andyling · Post by **andyling** » Tue Dec 01, 2009 11:43 pm

poison wrote:
Anthug wrote:After turbo'ing mine I now wish I have supercharged it instead. The power is great but ruins the driving pleasure of the MX5 in my opinion.
I have to agree in some ways, the power of a turBO can be way more exciting but much harder to control on corners, where as a supercharger is still way better than a stock MX5 but you retain the smoooooooth power control.

I recall going for a drive with Zoruno round the hills out west on some wet roads. He had me for dead on the corners as the back end would just shoot out everytime I tired to accelerate unless on a dead straight. Even now if you chop down at 60-70k in the wet the back end gets loose, it can be fun but scary at the same time, so I occasionally miss the prdicable power curve for windy roads. All that said I am keen to get a missing 35 HP out of my car due to an annoying boost fall-off and make it even more snappy..... lol. HP is a drug.

Agree with turbo cars hard to drive in the corners.

I used to have a Impreza STI, 4 wheel drive, still hard to handle on a race track.

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 2:43 am

andyling wrote:If it's a good running engine, How much would it cost to rebuild roughly?

Which one is better to rebuild 1.6 or 1.8?

why would turbo charge a engine so expensive?

I thought small turbos and intercoolers are cheap nowadays...

I only need 180-200bhp at the wheels.

Start with a decent engine From Mazline.

The 1.8 has 12 more HP ( yawn) a bit more low down torque and is a heavier slab. The con rods are the same part for the 1.8 and 1.6 (133mm length) so a heavy piston can severly limit durability of the conrods at high RPM or high boost.
The early 1.6 B6 has a problem with the crankshaft nose, but is easily fixed.

I have spent a fortune so far on parts+ R&D (and thats doing most of the work myself!).

You will need reliable after market engine management to reach that power level too.....

Or you could just go Ghetto

Post by **jif** » Wed Dec 02, 2009 7:58 am

On Wednesday, December 2, 2009, Habanero666 <horsepower@mx5forum.co.nz> wrote:

andyling wrote:
If it's a good running engine, How much would it cost to rebuild roughly?

Which one is better to rebuild 1.6 or 1.8?

why would turbo charge a engine so expensive?

I thought small turbos and intercoolers are cheap nowadays...

I only need 180-200bhp at the wheels.
I have spent a fortune so far on parts+ R&D (doing most of the work myself).

You will need shit loads of parts and reliable engine management too.....

Or just go Ghetto [Rolling Eyes]
------------------------
Tires aren't cheap!

turboing will probably double your hp , doing the head after that will
gain a lot less ... by then you will no doubt be after a bigger
turbo/ic/injectors etc!! At least that was my experience

you can get some bits cheap yeah, it's just installing, tuning,
replacing them that quickly adds up! I coulda bought a new car with
what got spent on go faster stuff ...

Lotsa fun tho

cheers

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 12:03 pm

I agree with jif,

The final tweeks and fine tuning are just that, left till last.

To TRIPLE the flywheel horse power safely,you will need:
*Turbo system capable of the required FLOW for the HP target (boost is not the defining factor as some might think). Includes intercooling and 2 1/2 -3 " Exhaust system.

*A good condition engine short block (with work done),

*460- 550cc injectors and larger/ higher flowing fuel system,

*B6T conrods

*Good, strong pistons and rings ( I am not just saying "forged" type here),

*Good condition quality fasteners and new gaskets + seals all over,

*Engine management,

*Big testicles to drive it

viscarious · Post by **viscarious** » Wed Dec 02, 2009 3:32 pm

Habanero666 wrote:*Good, strong pistons and rings ( I am not just saying "forged" type here),

What would you recommend in this department?
Forged pistons? Or standard but coated?

Regards
Dave

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 3:41 pm

viscarious wrote:
Habanero666 wrote: *Good, strong pistons and rings ( I am not just saying "forged" type here),
What would you recommend in this department?
Forged pistons? Or standard but coated?

Regards
Dave

Hypereutectic Alloy ( 10% silicon) cast pistons are a good choice when value for money is of concern.

Although the advantage with forged piston use is, they generally result in a more ductile material, with the effect being the piston can take a higher level of detonation before failing.

As far as I am concerned, this is not a big bonus as your engine should be tuned not to detonate to start with.
In extremely high rpm/high horsepower applications, the great strength of the forged piston can add reliability, with ACL recommending they be used once power levels rise past about 80hp per litre of engine capacity ( ...but of cause they want to sell pistons).

Jim

viscarious · Post by **viscarious** » Wed Dec 02, 2009 4:19 pm

MX5 has about 120HP stock, while 80HP/L = 128 on a 1.6. So we should be using forged anyway. Don't think so.

Back to this Hypereutectic Alloy, what advantages do they provide? Lighter?

Anthug · Post by **Anthug** » Wed Dec 02, 2009 4:26 pm

The stock motor can handle 250whp.

Above that, rods and lower compression pistons avoid bang.

Anthony.

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 5:17 pm

I want to see a stock motor run 250whp!
I think you will find, that is at the flywheel, if not I will be impressed.

Low comp pistons are over rated, that is if you call 9.1:1 low compression.
Another motor geek I know is running 9.4:1 forged pistons on 27psi boosted engine. Isn't that why we use an intercooler and work the combustion chambers?? Well thats why I do it, I don't like preignition much.

Yes 128 hp is low for forged pistons, as I said they want to sell pistons at ACL.

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 5:19 pm

viscarious wrote:MX5 has about 120HP stock, while 80HP/L = 128 on a 1.6. So we should be using forged anyway. Don't think so.

Back to this Hypereutectic Alloy, what advantages do they provide? Lighter?

Cheaper, please read the post again

Anthug · Post by **Anthug** » Wed Dec 02, 2009 5:39 pm

Habanero666 wrote:I want to see a stock motor run 250whp!
I think you will find, that is at the flywheel, if not I will be impressed.

Check out miata.net.

Well proven.

viscarious · Post by **viscarious** » Wed Dec 02, 2009 5:55 pm

Habanero666 wrote:
viscarious wrote:MX5 has about 120HP stock, while 80HP/L = 128 on a 1.6. So we should be using forged anyway. Don't think so.

Back to this Hypereutectic Alloy, what advantages do they provide? Lighter?
Cheaper, please read the post again

haha yes I read that, I just thought they would provide some other sort of gain.

By cheaper do you mean cheaper than OE aswell?

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 5:56 pm

I wouldn't advise this. You can follow this advise all you want. Happy rebuilding.

Thats 206kw at the Crankshaft!

Habanero666 · Post by **Habanero666** » Wed Dec 02, 2009 6:01 pm

viscarious wrote:
Habanero666 wrote:
viscarious wrote:MX5 has about 120HP stock, while 80HP/L = 128 on a 1.6. So we should be using forged anyway. Don't think so.

Back to this Hypereutectic Alloy, what advantages do they provide? Lighter?
Cheaper, please read the post again
haha yes I read that, I just thought they would provide some other sort of gain.

By cheaper do you mean cheaper than OE aswell?

Yeah cool, my point I was discretly making was, there are to many companies telling you too do lots of bullshit things so they can gain from it.

Gain:

The Hyp alloy pistons allow controlled expansion characteristics and are superb for mild well tuned street spinners.

From cold they are not as rattlely as SOME forged varieties. And will not wear out as fast due to the silicon alloy matrix.

Anthug · Post by **Anthug** » Wed Dec 02, 2009 6:49 pm

You can find on Flyin' Miata's website www.flyinmiata.com who sell turbo kits and have been around for 25 years the following:

1990-93 FM II Hydra turbo system
The FM II is a legend in the Miata performance world, and this is the latest and most powerful version. Expect approximately 230 hp at the rear wheels at 12 psi, compared to a stock 93 hp. Driveability is excellent and there`s no need to even remove the valve cover. Expect years of reliable high performance with this system. More power is available on built engines.

1994-95 FM II Hydra turbo kit
The FM II is a legend in the Miata performance world, and this is the latest and most powerful version. Expect approximately 265 hp at the rear wheels at 12 psi, compared to a stock 100 hp. Driveability is excellent and there`s no need to even remove the valve cover. You`ll get years of reliable high performance with this system. Even more power is available for built engines - we`ve seen well over 300 hp.

It all depends on what your goals are. You are wasting your money otherwise.