richard thomas
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| posted on 19/5/12 at 01:52 PM |
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Rotary engine rebuild
There must be someone here who knows...there always is....
Mazda RX8 requiring engine 'attention' on ebay look incredibly good value, and I was wondering if anyone here has the inside info on
rebuilding - specifically where to get cheap parts i.e. gaskets, o-rings, rotor seals etc....
Having had a quick look around on the intraweb, looks like cars requiring a rebuild are very cheap for a good reason, because the parts to do so are
incredibly expensive....and having one rebuilt by an 'expert' looks even more terrifying....
But they look very simple in principle, looks like the knack is getting really tight tolerances when rebuilding - easy?
Methinks I can get a cheap car here if the parts to rebuild are cheap enough....but all the kits i have found look like £6-800!
Why so expensive?
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jollygreengiant
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| posted on 19/5/12 at 02:26 PM |
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Taking them apart is easy. Getting them back together, not so easy. The critical part is really that of getting someone you know and trust to get the
engineering re-working done to the highest standards and closest tollerances so that when and IF you do get round to putting it back together, it will
work first time with NO problems.
And the reason why they are so cheap when 'requiring work' is that there are not so many capable of doing the 'work' properly.
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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ChrisW
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| posted on 19/5/12 at 02:27 PM |
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I've been tempted by an RX several times, although I'd go for the 7 rather than the 8.
However, I'd then throw the rotary away and fit an LSx V8. See http://www.grannysspeedshop.com/ for inspiration!
Chris
My gaff my rules
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richard thomas
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| posted on 19/5/12 at 02:38 PM |
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Always fancied a V8 into RX7....but an RX8 for way less than a grand is looking very tempting....
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Bare
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| posted on 19/5/12 at 03:19 PM |
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Erm price the cost of 'replacement' sides of the Rotary engine before deciding
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big_wasa
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| posted on 19/5/12 at 08:02 PM |
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I want an rx8 as a project but I would ditch the rotary and go with an s14 / s15 turbo lump.
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bi22le
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| posted on 19/5/12 at 09:20 PM |
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If it really is that cheap and perfect other than the engine then give it a go!
Or buy an engine from a scrapped chassis.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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Antnicuk
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| posted on 19/5/12 at 09:27 PM |
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good rx8's can be had cheap, i would only buy one that needed a rebuild so you know that once rebuilt you have a good car. They use oil as
part of the design so require topping up which a lot of people dont do, this means they are often run low which is obviously critical on any engine
but especially rotaries. The key is to find one that needs rebuilding for the right reasons, if its got water seal damage and has been overheated,
forget it, its likely you will need to replace most of the block (no prolem if you are sure it hasnt been overheated) . If its bearing failure,
usually given away by oil coming out between the engine and gearbox bell housing, then you are taking a chance as it may just require a new stationary
gear bearing or it may have knackered the whole rotating assembly. The safest option is lack of compression through an apex seal breaking, you may
need to replace a rotor housing but generally the rest of the engine will be ok.
As for rebuilding its quite easy. If you go to atkins rotary you can buy rebuild kits at various levels but you dont generally have to replace that
much. You can also buy rebuild DVD's which show you everything you need to know, thats i how i learnt. Also,once you can build one rotary,
you can build any as they are pretty much the same.
As for engine swaps, Craig at Dyno torque is building a kit to convert the RX8 to use the VAG 1.8 turbo engine mounted to the rx8 6 speed box. I
love the rotary but wouldnt consider buying an RX8 due to low power, torque and MPG but to have the same car with a 300bhp 1.8 turbo set up, i could
be tempted, you get torque, more power, better MPG and keep the great handling, brakes and gearbox from the RX8. The engines can be had cheap as
chips and they are easy to look after.
A V8 conversion aint cheap if you are going LSx, i know quite a few people who have done it.
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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Panda
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| posted on 20/5/12 at 07:34 AM |
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Doable but nerve racking. There is no chea source of parts as they're just not available.
Iirc reyland was developing a 20v conversion on one
Because Race Car
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Antnicuk
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| posted on 20/5/12 at 07:48 AM |
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There are loads of cheap sources of parts, just Need to look and don't go to Mazda. It only gets expensive if you need engine housings but they
can be had second hand
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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parkiboy
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| posted on 20/5/12 at 07:59 AM |
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I currently have an rx8 which I'm sellin, it's been compression tested with near perfect compression only done 40k and in great condition
and I'll be lucky to get 3 grand for it, unless you can get it done very cheaply it's not worth doing. I bought the rx8 because I wanted
the rotary engine but IMO if I was to get another rx8 I'd rip the rotary out and put an rb25 or something in there! They are good smooth engines
but I've seen as low as 15mpg under normal driving and a maximum of 26mpg on a 300 mile run, the car doesn't have the performance to
warrant that poor mpg.
Now a rx7 is a different story all together, one of my favourite cars ever, I wish I got one instead!
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big_wasa
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| posted on 20/5/12 at 08:13 AM |
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Reyland have put the vag 1.8t into a few things, most being MG rover like the Zs, Zr and a metro 
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richard thomas
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| posted on 20/5/12 at 05:07 PM |
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quote:
Originally posted by Antnicuk
good rx8's can be had cheap, i would only buy one that needed a rebuild so you know that once rebuilt you have a good car. They use oil as
part of the design so require topping up which a lot of people dont do, this means they are often run low which is obviously critical on any engine
but especially rotaries. The key is to find one that needs rebuilding for the right reasons, if its got water seal damage and has been overheated,
forget it, its likely you will need to replace most of the block (no prolem if you are sure it hasnt been overheated) . If its bearing failure,
usually given away by oil coming out between the engine and gearbox bell housing, then you are taking a chance as it may just require a new stationary
gear bearing or it may have knackered the whole rotating assembly. The safest option is lack of compression through an apex seal breaking, you may
need to replace a rotor housing but generally the rest of the engine will be ok.
As for rebuilding its quite easy. If you go to atkins rotary you can buy rebuild kits at various levels but you dont generally have to replace that
much. You can also buy rebuild DVD's which show you everything you need to know, thats i how i learnt. Also,once you can build one rotary,
you can build any as they are pretty much the same.
As for engine swaps, Craig at Dyno torque is building a kit to convert the RX8 to use the VAG 1.8 turbo engine mounted to the rx8 6 speed box. I
love the rotary but wouldnt consider buying an RX8 due to low power, torque and MPG but to have the same car with a 300bhp 1.8 turbo set up, i could
be tempted, you get torque, more power, better MPG and keep the great handling, brakes and gearbox from the RX8. The engines can be had cheap as
chips and they are easy to look after.
A V8 conversion aint cheap if you are going LSx, i know quite a few people who have done it.
Thanks,
I guess one to go for is with 'hot start' issues, I suppose that means less worn parts....apex seals only, hopefully...
Cheers, Rich.
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