1.8 in my 1990

Archives of Posts to the NZ MX5 List back in 2003
Mikkels
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1.8 in my 1990

Post by Mikkels » Sun Jul 06, 2003 9:26 pm

I have just purchased a 1.8 from Any Mazz and am starting the project of
swapping out a very satisfactory 1.6 for a more satisfactory 1.8.


So far I have lengthened the wires to the Crank Angle Sensor and tested
that with the 1.6 still in the car. Next job is to modify the support
for the throttle cable on the 1.8 to increase the distance between it
and the throttle body to accept the 1.6 throttle cable (seems to need
spacing by 40mm).


I will be shortly removing the plenum chamber from the 1.8 to get the
bottom holes for the throttle body mounts welded up so that I can re
drill and tap them to fit the studs in the correct position to fit the
1.6 throttle body.


Clutch and flywheel are an interesting decision. Do I use the 1.6
flywheel and clutch (clutch is 1 pound lighter). I intend to have the
flywheel lightened (who in Hamilton can do this?) or do I use the 1.8
clutch and have the 1.8 flywheel lightened?. The clutch in the 1.6 is
fairly stuffed so needs new anyway. The one on the 1.8 is unknown as
yet as I have not pulled it off.


This will be a slow project as I want to get it all sussed before
pulling out the 1.6. I am taking photos as I go to document the
process.


Anybody out there who has done this swap?


Don
1990 NA with a 1.8 conversion SOLD
2005 NC Limited edition 2470/3500 6MT

lou Girardin

1.8 in my 1990

Post by lou Girardin » Mon Jul 07, 2003 8:15 am

Use the 1.8 f/wheel and clutch, it has greater torque capacity. You won't
notice 1lb difference and unless you can take 3 to 4 kg's off the 1.8 I
wouldn't bother lightening it either. Best route for a light f/wheel is a
forged steel unit, cast ones can shatter if they're shaved too much.

SLYDIT
Keep calm, Forum Moderator here.
Keep calm, Forum Moderator here.
Posts: 1610
Joined: Sun May 21, 2006 6:18 pm
Location: In the Garage.

1.8 in my 1990

Post by SLYDIT » Mon Jul 07, 2003 5:58 pm

Use the 1.8 clutch wth a lightened flywheel, you just
have to get the "lip" on the back face of the flywheel
machined down flat and that will take about 2 pounds
off the weight, i had my 1.6 flywheel done and it was
a good improvment. Despite what some may say, the i.6
is not a great clutch and i certainly wouldnt want it
behind a 1.8.

Glenn
[...]
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

Muscles

1.8 in my 1990

Post by Muscles » Tue Jul 08, 2003 1:09 pm

How much did you pay for the 1.8? do you think it is a valuable swap? i.e
horsepower for money etc, or is it more viable and easier to put in a turbo or
supercharger, please keep us informed!
Cheers
Gareth.

jeff

1.8 in my 1990

Post by jeff » Tue Jul 08, 2003 2:02 pm

speaking as someone with the good fortune :) to have a 1.8 and a 1.6 in the garage (ok, temporarily) ... the 1.8 is definitely torquier, with a bit more power. But ! The 1.6 is definitely more rev-happy and in my opinion, more fun as a result.

Being less powerful means that you can thrash it around without getting into too much trouble, which is good if you are someone like me ;)

My turbo'd 1.8 requires a lot of self-control, or empty roads, and doesn't make the rorty snorty sounds that it did before.

A 1.6 with cone filter, headers and exhaust would be a fine plaything ! :)


Jeff

Muscles <garethkemeys@xtra.co.nz> wrote:
@page Section1 {size: 612.0pt 792.0pt; margin: 72.0pt 90.0pt 72.0pt 90.0pt; }P.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"}LI.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"}DIV.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"}A:link { COLOR: blue; TEXT-DECORATION: underline}SPAN.MsoHyperlink { COLOR: blue; TEXT-DECORATION: underline}A:visited { COLOR: purple; TEXT-DECORATION: underline}SPAN.MsoHyperlinkFollowed { COLOR: purple; TEXT-DECORATION: underline}SPAN.EmailStyle17 { COLOR: windowtext; FONT-FAMILY: Arial}DIV.Section1 { page: Section1}How much did you pay for the 1.8? do you think it is a valuable swap? i.e horsepower for money etc, or is it more viable and easier to put in a turbo or supercharger, please keep us informed!
Cheers
Gareth.

lou Girardin

1.8 in my 1990

Post by lou Girardin » Tue Jul 08, 2003 4:09 pm

Nothing's easier than a JRSC, 6 hours, a little sweat and blood and voila, 50
extra horsey's.

Scott

1.8 in my 1990

Post by Scott » Tue Jul 08, 2003 4:21 pm

But what's the "Bang for your buck" ratio on a JRSC? +50HP = $$?

lou Girardin

1.8 in my 1990

Post by lou Girardin » Tue Jul 08, 2003 4:45 pm

About $86 per HP.

Muscles

1.8 in my 1990

Post by Muscles » Tue Jul 08, 2003 5:03 pm

sounds nice...i bet the insurance company love it, any idea on a price?

Muscles

1.8 in my 1990

Post by Muscles » Tue Jul 08, 2003 5:05 pm

$4300 dollars...well thats interesting...any reliability issues? loss of
engine life? any other known hiccups?

SLYDIT
Keep calm, Forum Moderator here.
Keep calm, Forum Moderator here.
Posts: 1610
Joined: Sun May 21, 2006 6:18 pm
Location: In the Garage.

1.8 in my 1990

Post by SLYDIT » Tue Jul 08, 2003 5:45 pm

Hey Lou...
You could always use your "heres one I prepared
earlier" sales pitch!!

Glenn
[...]
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

Mikkels
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 140
Joined: Sun Jul 02, 2006 9:04 pm

1.8 in my 1990

Post by Mikkels » Tue Jul 08, 2003 6:04 pm

The engine cost $895 + GST. I will add a new clutch and
have the fly wheel lightened. After listening to everybody
I will stick with the 1.8 set up for the clutch.

The project will be a slow one as I gather the bits and get
the mods done to everything. I want to keep the car on the
road for as long as possible prior to pulling the 1.6 out,
swapping the bits over and plonking the 1.8 in. I am
photgraphing things as I go and intend to fully document the
change as some of the details on the net are a bit scarce in
places.

I have no idea whether this is more viable than a turbo etc.
Just seemed like a neat and not too expensive thing to do.

Watch this space.

Don

[...]
1990 NA with a 1.8 conversion SOLD
2005 NC Limited edition 2470/3500 6MT

lou Girardin

1.8 in my 1990

Post by lou Girardin » Wed Jul 09, 2003 4:09 pm

No probs with insurance because I'm a responsible older person, cough cough.
Around $US2500.

lou Girardin

1.8 in my 1990

Post by lou Girardin » Wed Jul 09, 2003 4:12 pm

60,000km on 1st engine, 30,000 on new one. (Crank nose problem, not related to
blower). It only runs lowish boost so there's no reliability issues if it's
set up right. As mine is.
And guess what, mine's for sale. An absolute bargain too!

Muscles

1.8 in my 1990

Post by Muscles » Wed Jul 09, 2003 5:06 pm

I want to be a responsible older person...damn the youth runing my chances
of cheap insurance...cheers for the help, i guess i better start saving
my money if i want a supercharger.

garethkemeys

1.8 in my 1990

Post by garethkemeys » Thu Jul 10, 2003 10:48 am

Haha, nothing to do with only 60,000 k's on first engine?...how much is it then?
[...]

Mikkels
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 140
Joined: Sun Jul 02, 2006 9:04 pm

1.8 in my 1990

Post by Mikkels » Tue Jul 15, 2003 1:08 pm

Progress so far ahs been slow but steady.

I have decided to ga ahead with the 1.8 clutch so have sent
the flywheel in to be lightened and balanced. A new 1.8
clutch will go in when it is time.
I have cleaned the donor engine and removed the 1.8
igniters. The 1.6 igniters are needed to be compatible with
the wiring. I have mounted the 1.6 igniters in the 1.8
bracket but they sit differently necessitating spacing the
bracket off the back of the engine by 20mm I cant see
another way of doing this. The modification of the throttle
cable bracket is complete by welding some steel 50 mm to the
exiting bracket. The mounting holes need to be about 40 mm
away from existing holes. I will not drill those until the
engine is in the car ready to go so that the cable is set up
in the optimum position.

I have more questions:

Why is an adapter needed to set up the 1.6 throttle body
(TB)? Slotting of the holes on the TB should match things
up. I cannot find enough detail on this part of the process
anywhere on the net.

The firing order of the 1.8 is different. How do I set up
the leads on a 1.6 igniters with the 1.8 Crank angle sensor
and the 1.6 ECU?

There will be more stay tuned

Don
1990 NA with a 1.8 conversion SOLD
2005 NC Limited edition 2470/3500 6MT

lou Girardin

1.8 in my 1990

Post by lou Girardin » Tue Jul 15, 2003 3:31 pm

Alignment of the throttle body is important, maybe slotting the holes affects
this.
The firing order is the same, 1 3 4 2

Fletch
Yes. I might just know (Trusted Advisor)
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Posts: 119
Joined: Thu May 18, 2006 10:11 pm
Location: Auckland

1.8 in my 1990

Post by Fletch » Wed Jul 16, 2003 7:46 am

Throttle-body adapter plate...

I'm not sure of the exact details, but its my understanding that you need
the plate to blank off some idle air bypass passages either in the 1.6 tb or
1.8 plenum... the way that idle speed was controlled changed slightly 1.6
has electric thing under tb AND air-valve on side of plenum. 1.8
incorporated the two...

firing order... controlled by ECU... so if your using 1.6 ecu, unchanged.

Personally, I would have just kept the 1.6 coil-pack :-)

Good luck!

Fletch.
Red '90. Many n/a mods and Link ECU

lou Girardin

1.8 in my 1990

Post by lou Girardin » Wed Jul 16, 2003 8:23 am

Just a correction, firing order is governed by the camshaft and crank design,
nothing else.

Fletch
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1.8 in my 1990

Post by Fletch » Wed Jul 16, 2003 6:56 pm

I would argue that the firing order that is required by an engine is governed
by the things you suggest... But the firing order that actually happens is
governed by the programming in the ECU (and the wiring in the loom).

Luckily for us, with the MX-5's double spark system (two pairs of spark plugs
fire together, and they fire every revolution) makes it much easier to get
right (less wrong possibilities).

Fletch.
Red '90. Many n/a mods and Link ECU

lou Girardin

1.8 in my 1990

Post by lou Girardin » Thu Jul 17, 2003 8:26 am

No, the firing order depends on crank design, eg; 180, 270, 360 degrees etc.
Then the appropriate cylinder is fired at the end of the compression stroke,
this is when all valves are closed, this comes after the induction stroke,
which is when the inlet valves are open. It's an immutable law of 4 stroke
engine design. 4 cylinder inline engines have only ever been 1342 or 1243
firing order. This is because inline 4's have a 180 degree crank.
Don't confuse firing order with ignition timing, or in the case of the MX, a
redundant spark also being produced by the dual ingniters.

Delich, Martin

1.8 in my 1990

Post by Delich, Martin » Thu Jul 17, 2003 8:39 am

Besides V8s and non-fundamental designs, firing order is set by the config
of the cam shaft. Inline 4s and 6s (and most V6, V8 flat 4, flat 6)
regardless of firing order have the same config crankshaft. With that in
mind, also remember unless you intentionally want an engine to run rough
with uneven firing intervals, there is generally only 2 different firing
orders (applies to most engine configs) that will work successfully.

lou Girardin

1.8 in my 1990

Post by lou Girardin » Thu Jul 17, 2003 1:17 pm

Quite right. When you get to multi cylinder engines, there are various firing
orders used. The Ferrari 360 has a flat plane crank, ie, 180 degree. Most V8's
have 360 cranks, this is why a Modena does not sound like a Holden or Ford.
Firing order is completely different.
Then there's oddballs like the Yamaha TRX 850, it's a parallel twin, but has a
270 degree crank instead of 180 or 360 and it sounds like a V twin.
It's all governed by mechanical design, nothing to do with electronics.

Fletch
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1.8 in my 1990

Post by Fletch » Fri Jul 18, 2003 7:30 am

Lou,

I agree that the engines physical design dictates when and in what order the
sparks need to be fired.

But its the electronics that actually make it happen.

You need both of them to be matched to eachother, in order to have a smoothly
running engine.

I can see your argument being true for older engines where the distributor is
mechanically linked to the crank or camshaft, and thus, the firing cylender is
"chosen" by the mechanicals, but MX-5's (and nearly every other modern engine)
dont have distributors...

Fletch.
Red '90. Many n/a mods and Link ECU

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