ChasR
RR Helper
motivation
Posts: 10,189
Club RR Member Number: 170
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Rotary Engine RebuildChasR
@chasr
Club Retro Rides Member 170
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Jan 13, 2019 10:04:36 GMT
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So, like a couple of threads asking 'Is x a retro ride', I've noticed RX-8s have been a fringe car here for quite some time, albeit with photos of them housing LSx conversions, alot like forebearer, the FD RX-7. There is no doubt the reasons behind this are down to it being a very smart design even back when it was released, being a 'smart' 4 door car with style, and of course, being the last of a long line of successors to having a rotary engine. Whilst this engine variant tarnished that reputation due to emissions and cost-cutting, there is no doubt that it has a number of USPs  . So for those of you who can put up with Car Throttle's AutoAlex/Alex Kersten, here is a video of rotary going back together! I can see a little more about why port sizes can affect things, as luckyseven pointed out it being similar to cam timing (after all, where the port begins will affect the mixture/induction process depending on where the rotor goes), but am surprised at why certain parts went into the engine like the oil bypass valve, but also how different they are to assemble compared to a piston engine. Naturally we (including me) may have a few questions regarding the assembly methods, but it's an interesting illustration nonetheless: |
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ian65
Part of things
Posts: 276 
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Jan 13, 2019 10:28:10 GMT
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They are easy enough to rebuild... it's the cost of the replacement parts that's more difficult to come to terms with.
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luckyseven
Posted a lot
Owning sneering dismissive pedantry since 1970
Posts: 3,839
Club RR Member Number: 45
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Rotary Engine Rebuildluckyseven
@luckyseven
Club Retro Rides Member 45
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Jan 13, 2019 13:27:46 GMT
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...and the difficulty in finding the damn parts  I always found it easier to think of rotaries in two-stroke terms... they're not, but have many similarities such as the piston (rotor) is what controls intake and exhaust via ports, and where the ports are and how long they open for and overlap is the black art bit of it |
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ian65
Part of things
Posts: 276
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Jan 13, 2019 14:05:12 GMT
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Last Edit: Jan 13, 2019 14:07:01 GMT by ian65
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Paul
Posted a lot
Posts: 1,903
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Jan 13, 2019 17:40:16 GMT
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I am one of those who was bitten by the RX8 bug - spent a premium to get one that had been rebuilt, only for it to pack up 6 months later and require another rebuild.
I took a bath and sold it on at scrapper money...last seen sporting a huge rear spoiler and silly stickers on eBay. Doubt the current owner has managed the rebuild.
It's a shame, they're great fun and make a fantastic noise - but they're just too fragile and too risky for me...
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ChasR
RR Helper
motivation
Posts: 10,189
Club RR Member Number: 170
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Rotary Engine RebuildChasR
@chasr
Club Retro Rides Member 170
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Jan 13, 2019 17:43:30 GMT
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They are easy enough to rebuild... it's the cost of the replacement parts that's more difficult to come to terms with. From what I have heard and can tell, aren't they meant to be simpler in some ways to rebuild over many piston engines out there? It's certainly interesting to see this being the case. |
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ian65
Part of things
Posts: 276
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Jan 13, 2019 18:01:23 GMT
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they are simpler to rebuild than a piston engine ( depending on the engine!) but it's their fragility and the cost / lack of good usable 2nd hand spares that causes the grief.
A bit of detonation in a piston engine, you just tweak the timing and it's fixed.... seldom is it terminal. Not so with a rotary, just one instance of detonation can destroy the engine.
With a piston engine if it loses a touch of compression or starts burning oil you can just drop the pistons out, glaze bust the bores, put another set of standard rings in it and for a few quid and a bit of time you'll probably get another 15,000 - 20,000 miles out of it. Not so with a rotary though, as they wear they slowly lose compression, power and are difficult to start and the only fix is a full tear down and rebuild costing £££££'s... which is why the classifieds are full of RX8's going for peanuts.
When you're looking at £1500 - £2000 for a specialist to drop the engine, strip, rebuild and then put it back in the car it's easy to understand why owners just bale out of them.
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Last Edit: Jan 13, 2019 18:05:16 GMT by ian65
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Good to see another rotary rebuild video. I have been watching a few of them lately, just in case...
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Current cars:
Mazda RX7, Subaru Legacy, Citroen Saxo VTS
Previous Cars:
Mazda RX7, Toyota MR2, Toyota Yaris TSport, Mazda MX5, Nissan 350z GT4, Citroen Saxo VTS x2, Citroen Saxo VTR x2
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