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Discussion Starter #1
#-o

Yep, I have just discoverd the early signs of the 4 slot crank wobble.
I'm not confident in the reliability of the locktite fix, so would ideally like to swap in a newer 8 slot 1600. Money's quite tight at the moment.

Question is, does this sound like a reasonable thing to do? Or does an 1800 swap with the FM kit imported from the states make more sense? :roll:
 

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Mufasa in Training
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The Loctite fix does work. For the record, ANY Miata could have crank wobble if the crank bolt is not torqued right. My 97 is a victim, for example.

Since money's tight, just fix your existing crank nose and move on :)
 

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Out of interest, what is the mileage and have you had the cambelt changed?
 

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Proper engineered fix here:
http://www.fizzindi.demon.co.uk/crankshaft.htm

Loctite fix is hit and miss, and depends on a lot of factors for longevity. The only epoxy fix over this side of the Atlantic I have heard last well used a special wing adhesive supplied by Bombardier, probably nigh on imposible to obtain ordinarily.

In many ways, a 1.8 Mk1 swap makes sense; one reason is that, in the UK, getting a decent 8-slot engne is a bit complicated by the 90hp engines being externally identical. All of the import engine suppliers I have spoken to are unaware of the 4-slot and 8-slot difference, and don't bother to record the exact age of the donor car they pull the engine out of in Japan.

The engine number cutoff for 4-slot is B6-127441, and should apply in all markets. Note, different VIN systems in different markets, so US tips for using VIN as a guide don't apply. But a supplier, if you are not able to view the engine, should be able to check for you, if they shrug as 4-slot questions.

Before embarking on a 1.8 swap, check with your insurers. Some are happy to treat the car as a factory 1.8. Others might treat the car as modified, and engine swap motors tend to be pricey to insure.

Not sure when the 90hp engines kicked in; my guess is B6 300000 and above, but they may not be numbered exactly the same as 115hp engines.
 

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Discussion Starter #5
Out of interest, what is the mileage and have you had the cambelt changed?
Well she's coming up on 116,000 miles, cambelt changed at 107,00, so plenty of beans left in there.

I was sitting in pub thinking 'what if I end up with a 90bhp one'.
Mind you, if someone is swapping out the engine from a 1991 1.6, in an unaffected VIN bracket, I could have the engine in and out in a weekend which would be fine. Ill have a look around for the exact VIN codes.

The £100 FM 1.8 conversion seems to make sense on paper a least, give the car a spot more power and hopefully the conversion isn't too hard. Dumb question, but which was the best period for a 1.8? Or is it just better to find a low mileage example where possible?

Spare engines are fun to have anyway. :D

 

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Im not trying to hijack.... but where on the block can one find the VIN number? I recently had a new motor installed and it has the 4 slot pulley and I want to know if it has a affected VIN
 

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Hi Al shame about the engine, my white 5's original engine shared the same fate.

i didnt get to it soon enough and it died when the other componants died from the timing etc.

i got a jap 8 slot engine fitted by everythingmx5, he only has the japanese engines as he imports cars to strip from japan so there are no worries about the 90bhp one.

if i were you i would take off the crank to see how far the damage has gone it may be early on and thus work well with the loctite fix..
 

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Im not trying to hijack.... but where on the block can one find the VIN number? I recently had a new motor installed and it has the 4 slot pulley and I want to know if it has a affected VIN
The VIN is the chassis number, not the engine number. The VIN isn't foolproof, as engines can get changed.

From http://www.fizzindi.demon.co.uk/engineno.htm

As you look at the engine from the front of the car it's at the back left side. That's the drivers side near the bulkhead, above where the gearbox joins and under the end of the intake manifold. You will find a small flat on the engine where it meets the cylinder head which sticks out towards the drivers side of the car. You have to have double jointed wrists but you have to sand this flat to remove the corrosion. A number will appear on the flat edge in the following format.

Of course this is for rhd cars. For lhd, substitute "driver" for "passenger".

And bear in mind, for Roadsters at least, the swap was somewhere in April 1991, and it doesn't seem to ahve been applied smoothly at the factory (ie. the cars weren't exactly built in sequence).
 

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yea the 4 slot makes me very nervous lol... good thing Im gonna start rebuilding the original motor that came in the car.
 

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I also had a crank slot/key failure from someone not correctly torquing the pulley bolt when changing the timing belt. I have a '95 that had the wobble. I cleaned up the slot with a file, bought a new pulley plate, a new key and bought a tube of the Loctite 660. I put it all together and tightened it up, let it sit two days and its been strong ever since (done in early May 2006 now about 2500 miles later) Still smooth and strong - though I still grab it and try to shake it once and a while.
 
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