Engine questions

[crofty1984]

After considering an original fiat 500, I'm actually tempted by an MX5 now as well (both very different cars I know!) I actually prefer the Mazda, but I was worried about parking space. I could slot a 500 in my apartment car park an the corner, but I may have to get a garage anyway, I may as well get the 5!
The problem is, in budget (€2000-€2500 is really as low as these cars go) are mostly later MK1 1.6's
I leuuuurve the MK1 obviously, but I know the power got dropped to 90HP one particular year onwards.

My questions are:
What year did this happen?
How would I be able to tell from an engine number?
How difficult is an engine swap for either an early 1.6 or a 1.8? (I understand the low power 1.6's have lower compression, different heads, etc and are a bd to get back to full spec.)

If you were going to swap an engine, what would you go for and why?
I understand the 1.6 is very revvy (which I like) but obviously the 1.8 has more power.
I also intend to supercharge it at one point.

Thanks all!
Dan

[GravelBen]

Revvy? I guess it depends what else you're used to, but comparing to Subarus I don't find my '89 Mk1 1.6 to feel that revvy - just in terms of how happy it feels at high revs, for sure its not a low-down torque machine but it sounds a bit strained and thrashy over say 6000.

Engine transplant, I think I'd go for the latest Mk1 1.8 I could find. Unless I had a lot of money to spend, in which case it'd be a KL-ZE 2.5 V6.

[Gizmo!]

Really does depend what you're used to - and probably how well-serviced the engine is. Once the oil's warm, my 1.8 zips around to the redline like a terrier after a rat.

[Quick silver]

GravelBen said:

Revvy? I guess it depends what else you're used to, but comparing to Subarus I don't find my '89 Mk1 1.6 to feel that revvy - just in terms of how happy it feels at high revs, for sure its not a low-down torque machine but it sounds a bit strained and thrashy over say 6000.

I'd have to disagree Ben, my Mk1 1.6 loves life above 6,000rpm & sounds fantastic going into the red.

Gizmo! said:

Really does depend what you're used to - and probably how well-serviced the engine is. Once the oil's warm, my 1.8 zips around to the redline like a terrier after a rat.

+1

Dan,
If you are worried about power & intend on fitting FI, I'd suggest an early pre '94 1.6 Eunos Roadster as they usually come fully loaded & due to the lack of salt in Japan are often completely rust-free in comparison to their UK MX5 counterparts..........although at this juncture I'm probably upsetting the majority of UK MX5 owners.

NB: Both 1.6 & 1.8 models produce roughly the same power with FI.

[GravelBen]

Quick silver said:

GravelBen said:

Revvy? I guess it depends what else you're used to, but comparing to Subarus I don't find my '89 Mk1 1.6 to feel that revvy - just in terms of how happy it feels at high revs, for sure its not a low-down torque machine but it sounds a bit strained and thrashy over say 6000.

I'd have to disagree Ben, my Mk1 1.6 loves life above 6,000rpm & sounds fantastic going into the red.

Yours is not exactly standard though, no? I think mine is getting a bit tired too, 137k miles on it.

[J.P.W.]

Simple. Old 1.6 good (pre-'94). 1.8 good. New 1.6 bad. No need to worry about an engine swap - just buy one with one of the right engines. There's loads of them out there at all budgets - right down to the £640 my jammy git of a mate paid for his rust-free, nice running, MOT'd (albeit slightly shabby) example.

Edited by J.P.W. on Wednesday 22 July 18:18

[crofty1984]

J.P.W. said:

Simple. Old 1.6 good (pre-'94). 1.8 good. New 1.6 bad. No need to worry about an engine swap - just buy one with one of the right engines. There's loads of them out there at all budgets - right down to the £640 my jammy git of a mate paid for his rust-free, nice running, MOT'd (albeit slightly shabby) example.

Edited by J.P.W. on Wednesday 22 July 18:18

Cheers for the info on the year. I don't really have a lot of choice on what to go for. MX-5s tend to start at €2500-3000 here, and that's for the bad newer 1.6 ones. Then you add on a grand for a proper early 1.6 or a 1.8.
Think I may have to buy a ratty Fiat 500, do it up, flog it then get a proper MX5. Though I am sorely tempted to buy one from Germany.

[MX-5 Lazza]

If you are intending to supercharge it then I'd look out for a 1.8 as the SC options are better. The M45 is available for the 1.6 & 1.8 but the MP62 is only available for the 1.8. The M45 will be restricted to well under 200bhp without significant work whereas the MP62 can easily go well beyond 200bhp. That's assuming both kits are available/affordable in Italy.
If you were going to turbo then it wouldn't matter much which you went for.

[johnnyboy666]

Well this is the answer I gave to the same question which was also put forward on the MX-5.com forum;



Ok, there are 3 engines in question here. As has been said before there are 2 1.6 engines and 1 1.8. The early 1.6 which goes up to '93-'94 is the original BZE engine which puts about 116bhp or there abouts and gets the car to 60 in just over 9 seconds. The later 1.6 which came in end of '94 were not just detuned but slightly different engines. they put out a significantly lower 90-88bhp (depending on where you read) which made it a fair bit slower. I'm not sure what differences were made to it but I believe the early 1.6 had a variable length inlet manifold which was dropped on the later engines.


The last engine is the 1.8. Brought in in '94 which is the quickest and most powerful engine of the lot with regards to power to weight. It put out 130bhp and got you to 60 in 8.3 seconds. These'94 onwards cars only weighed 20-30kg more. Still under the 1000kg mark I believe.


So a summary is that the later 1.6 is to avoid and the 1.8 is the quickest. ALso worth mentioning is the fact that 1.8s have some extra bracing and have bigger discs on as standard. That pretty much sums it all up!

[GravelBen]

johnnyboy666 said:

I'm not sure what differences were made to it but I believe the early 1.6 had a variable length inlet manifold which was dropped on the later engines.

I've never heard of that before, pretty sure my '89 Mk1 doesn't have one. The Mk1 MR2 has TVIS though which you may be mixing it up with?

[MX-5 Lazza]

Variable length intake (VICS) was fitted to Mk2 1.8.
Earliest Mk1 1.8s were the same weight as the latest 114bhp 1.6s and were the quickest of the Mk1s. The additional bracing & safety bars were added over the following years and weight crept up. Weight of the last Mk1s was around 1050Kg, pretty much the same as Mk2.

[TwistingMyMelon]

Ive got an early 94 MK1 1.8 and it feels a bit quicker than other MX5s ive driven, I guess the point about it having less bracing and more power than the 1.6 makes sense.

[TwistingMyMelon]

Ive got an early 94 MK1 1.8 and it feels a bit quicker than other MX5s ive driven, I guess the point about it having less bracing and more power than the 1.6 makes sense.

[johnnyboy666]

Correction on my part, it's a B6ZE engine. Looks like I may be mistaken there, Whilst several of the B6 engines do have the VICS system the B6ZE skipped it. Sorry guys! Still the point I tried to make to the original person I posted that to was that it wasn't the same engine detuned electronically and as such it can't be easily put up to the power of the early 1.6 engine. The rest should be about right though.