The RX7 rebuild thread

Awesome work DreXeL. Looks like things are really coming along :)

I can't remember if you ever said the engine was rebuilt by the previous owner, but is the water seal one of the things you should change when doing a rebuild normally (even if it didn't fail)?

And what's the reasoning for having to rebuild rotary engines after so many miles?

Best of luck with it. Hope it's back to its previous glory soon :)
 
agw_01 said:
Awesome work DreXeL. Looks like things are really coming along :)

I can't remember if you ever said the engine was rebuilt by the previous owner, but is the water seal one of the things you should change when doing a rebuild normally (even if it didn't fail)?

And what's the reasoning for having to rebuild rotary engines after so many miles?

Best of luck with it. Hope it's back to its previous glory soon :)
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I believe the reason is down to the water seal mainly as that is what degrades after about 60k miles.

Also, I think the rotors do tend to get gammed up with Carbon deposits, but I think the engine getting flooding it a bit more serious :p
 
Yes mine is being rebuilt due to water-seal failure, but the tips normally wear by around 60k miles too.
 
when you say the tips, do you mean the end of the triangular things?
sorry for my rubbish non technical knowledge! im just quite interested in rotary engines.
 
VBDub said:
when you say the tips, do you mean the end of the triangular things?
sorry for my rubbish non technical knowledge! im just quite interested in rotary engines.
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Yep, the actual term is Apex Seals, but most people refer to them as rotor tips.
 
I might be looking at buying an rx7 in the next few weeks as my 620Ti seems to have gone kaput, i dont suppose you have any usefull links for me drexel (or anyone else) as i'm going to really have to think about this one, i need to know about common faults/general reliability and the rebuiuld issues, im not worried about fuel or insurance costs, just the relibility of the engine really.
 
benneh said:
I might be looking at buying an rx7 in the next few weeks as my 620Ti seems to have gone kaput, i dont suppose you have any usefull links for me drexel (or anyone else) as i'm going to really have to think about this one, i need to know about common faults/general reliability and the rebuiuld issues, im not worried about fuel or insurance costs, just the relibility of the engine really.
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My advice if you are going to get one, is make sure it has had a recent rebuild. Freshly rebuilt, there is no reason they shouldn't be unreliable if looked after properly (oil/filter change every 3k miles, make sure it's warmed up before booting it etc., the same as any other high-performance turbo car really). I know you said fuel costs don't bother you, but seriously, bare it in mind you will probably average 12-15mpg.

Mazdarotaryclub is a great source for info.
 
Thanks for the link dude, and im ok with the petrol costs, i'll also be running a 1300 beetle by mid september lol, but it pretty much seems a toss up between an rx7 and a 200sx (either modded to run around 280-300 bhp) but alas i shall hit the web and book a few test drives, it's just the reliability of either im majorly concerned with really, everything i touch seems to develop problems!. But lets face it, the rx7 is damned damned sexy, i saw another 2 today.. Yumyumyum.
 
the 200sx would be a much more cheaper and user friendly car, friend has his upto 305bhp, it is preferable to have a recently built engined rx7 when looking to buy but if possible try to find someone who has done a recent compression check, this gives a good indication of the life left in the engine... of course that wont warn you of a dying water seal.

I say this mainly cos there can be a big price differance between a freshly built one and an older high miledge one. When i bought mine i took a bit of a risk but got it compression tested straight away and it was all clear :) ....hated selling it :( ....damn mortgages..

oh yes they do drink, fit around £60 in a tank, with the way fuel prices are rising it's probably just as well i sold, it would also be running on Super unloaded, preferably the highest Octane... Shell is one of the highest.

...i'll get another 1 day
 
Just a quick update. The rebuild kit is on it's way from the states as I type this, and I took the parts to RX-Motors to be checked over and ported today. Got a bit of bad news, the rear end plate (big piece of 'bread' in the rotary 'sandwhich') is warped and unuseable, so I have to have a new one at a cost of £250. Also the stationary gear bearings are worn, there goes another £100 :(

More overtime then........
 
DreXeL said:
Just a quick update. The rebuild kit is on it's way from the states as I type this, and I took the parts to RX-Motors to be checked over and ported today. Got a bit of bad news, the rear end plate (big piece of 'bread' in the rotary 'sandwhich') is warped and unuseable, so I have to have a new one at a cost of £250. Also the stationary gear bearings are worn, there goes another £100 :(

More overtime then........
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Keep thinking about how good it will be when its done :p

Im sure you can justify the cost then :D
 
OK, the rebuild kit arrived last week, and I have all this week off work to put it all together. I picked the plates/housings up from RX-Motors today, they have done a really nice job of the porting, they even cleaned up my housings too.

Anyway here's the new plate I had to have, just after I fitted the new water-seals:

rebuild23.JPG



First rotor, housing and eccentric shaft fitted:

rebuild24.JPG



Centre plate in place:

rebuild25.JPG



Second rotor and housing:

rebuild26.JPG



And finally the rotary sandwhich is complete with the end plate:

rebuild27.JPG


So that's the core engine built, tomorrow I'll start fitting all the ancillaries.
 
Hoping to have it up and running by the end of this week. Then the painfull running in starts :(
 
DreXeL said:
Hoping to have it up and running by the end of this week. Then the painfull running in starts :(
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What's this running in you speak of :confused: :p

What is the procedure for a rotary anyway? I guess it's nothing like bedding in piston rings
 
The way most people do it is no boost and less than 3k for around 1k miles, then oil/filter change, and gradual increase of RPM and boost. Some people say 500 miles rather than 1k, but I'll stick to 1k to be on the safe side ;)
 
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