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Crank is forged as stock
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I'm a bit stumped, the only other thing I can possibly think of is that one or two pushrods are interfering with the head, the noise is too localised for anything else. Got oil, the rocker adjusters look perfect to get the geometry right, the stripe is across the centre of the valve tip (or as close as it's going to get.)
I'll try tweaking the preload for the most proximal lifters once more, then the rocker shaft is coming out on that bank to look for witness marks on the pushrods. It'll be fucking typical if it is interference as that means the head has to come off again. Gah....
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Yep, it would seem that everything happens for a reason, even wasting a day of my life looking at crap cars. I absolutely love the Z4.
Anyway, she might be an older model, but she remains elegant and scrubs up well. But enough of Mrs B, after 6 hours of cleaning a car has emerged from beneath the dirt....
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...and for some reason the text of my last post appeared but the images didn't. Let's have another go at posting pictures of a much cleaner Z4.
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Very fresh! Wheels look great, enjoy it!
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I say that as I'm browsing mx-5's
https://www.carsales.com.au/private/details/Mazda-MX-5-1991/SSE-AD-5458022
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Crank is forged as stock
An insight into what it takes to get an M96 to spin to what your Mazda can do out of the box:
- 100mm bore, 72mm stroke, giving 3.4 litres, utilising a standard Porsche crank and rods. This gives the maximum overlap between the big end pin and main bearing journal, leading to what would be most suited to very high rpm.
*RPM@ 20.148 m/s, 8395 - 100 bore, 76 stroke, giving 3.6 litres. This would require a bespoke crank and rod set up, but a very good engine size to achieve Dammit’s goals. In EN40B, this crank would be very strong, and along with having the rods made from 300M material, would be happy to rev hard.
* RPM, 7976 - 100 bore, 77 stroke, giving 3.63 litres. As above but with a fraction less pin overlap.
* RPM, 7842 - 100 bore, 78 stroke, giving 3,675 litres. This is the stock 3.4 stroke, so could utilise standard components. The feeling is that the stock parts would not be up pulling 8k rpm, at least, not for long. A billet crank and decent rods would put that right. This was our initial favoured configuration.
* RPM, 7745 - 100 bore, 80mm stroke, giving 3.77 litres. Again a bespoke set up required.
*RPM, 7576 - 100 bore, 82.8 stroke, giving 3.9 litres. This is the stock 3.6 stroke, so a standard crank and rods could be used, but are unlikely to take kindly to the increased rpm. A steel version would survive, but there will be considerably less pin overlap than with the 3.6/3.7 configuration.
*Base RPM, 7300 - 100 bore, 84.5 stroke, giving 3.98 litres. Potentially tricky to assemble, Baz has said that the clearance between the rod bolts and the bottom of the cylinders would require attention, also the window for gudgeon pin fitting could become an issue. As a one off experiment, we feel that an engine of this capacity represents a risky proposition at this juncture. Besides, it would lift torque at the low end and most probably run out of breath at the top, the exact opposite of the end goal here.
* RPM, 7153
*In terms of hitting the required rpm, I have looked at the stock 3.6 996.2 stroke and calculated the mean piston speed. This works out to 20.148 m/s at 7300 rpm. Translating this number to the various configurations, a 4 litre would have a redline at 7153 rpm, whereas at the opposite end of the scale, the short stroke 3.4 could be pulled to 8395 rpm. These numbers are shown above for reference vs. the various stroke lengths. So keeping the standard Porsche mean piston speeds as a reference, Neil’s target of 8k is met with a stroke of 76mm, at 7976 rpm. Did anyone say Mezger?! With the components being fitted to this engine, these numbers are very safe in terms of bottom end reliability. For reference, a well-developed race motor would happily stand 24.5 m/s .
- 100mm bore, 72mm stroke, giving 3.4 litres, utilising a standard Porsche crank and rods. This gives the maximum overlap between the big end pin and main bearing journal, leading to what would be most suited to very high rpm.
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After the talk of Audi TT’s I’m liking the look of this
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302778006095
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How many people have thrown caution to the wind, ignored the prospect of voiding a warranty, and gotten a spicey remap?
Clio is going to ktec racing for a service later this year, will prob upgrade pads, lines and fluid while it's in. Seems a shame not to get it mapped while it's in. 270bhp is a conservative estimate...
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Thanks for the kind comments folks, strangely the best thing about the Z4 so far is just how docile it is at low speeds in town.
TRA; the safety is irrelevant, the Mrs has excellent life insurance!
Simpson; I got lucky with this one, but having checked before I bought it, you would be looking at £4.5 to £5k for a half decent one.
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How many people have thrown caution to the wind, ignored the prospect of voiding a warranty, and gotten a spicey remap?
Not yet, but it's on the cards, together with removing the speed limiter. Warranty expired long before I bought the car, and a Stage 1 map should give an extra 130bhp or so.
My plan is to do a 200mph run while listening to Radio 4. Or Radio 3 if I'm feeling wild.
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A lot of car for the money if you get a good one, a lot of money fixing it if you haven't.... The prices I suggested were for an 03/04 one.
Dammit
NurseHolliday
Jung
BRM
jambon
ColinTheBald
Soul
Nahguavkire
TRA
Simpson
Colm89
Brommers-
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Car appreciation... the aesthetics, the engineering, etc
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This. Good old flame surfacing!