The RX7 rebuild thread

[DreXeL]

As promised, here is the thread that will follow the progress of the engine rebuild of my RX7.

Today I maganed to get the engine more or less ready to be removed, apart from a couple of small things to do it's ready to be pulled. Wasn't too bad a job to do, the exhaust downpipe was a bit of a PITA, and the workshop manual I downloaded from www.iluvmyrx7.com was for LHD cars, so there were a few differences, but nothing major. Anyway a few pics, apologies for the quality, these are phone pics, I'll take my camera out tomorrow.

Front bumper removed, shows that the GReddy intecooler is pretty big, and mostly obscured by the bumper, which is a shame:

Here are some of the parts I had to remove:

And here is the engine basically ready to come out (compare it to the first couple of pics and it looks a lot more bare in the engine bay):

I should get the engine out tomorrow, then comes the strip-down.

 

[DreXeL]

Yeah I'll get those hoses covered up tomorrow. I'm putting all the bolts back into the holes as I remove everything, I'm also labeling everything up, so hopefully I wont get any lost/left over bolts and stuff. Hopefully.......

 

[DreXeL]

Cheers for the advice, and messages of good luck

Anyway I didn't get the engine out today, I had to go into work this morning and this afternoon I took the missus and kids to the cinema, but in the couple of hours spare I that I had I got the engine completely ready to come out, it's literally just a case of hoisting it out now. I'll be doing that on Friday afternoon.

 

[DreXeL]

OK, I got the engine out yesterday afternoon. It came out really easily actually, splitting the engine and gearbox was easy because I unbolted the clutch through the service hole on the bell housing, so it was just a case of attaching the hoist and lifting it out. Some pics then:

The empty(ish) engine bay:

The engine out and on my garage floor (yes, I know my garage is a mess.....)

And of course, the obligatory standing in the engine bay pic:

I'll probably start stripping the engine down tomorrow.

 

[DreXeL]

Making good progress matey! Must be a good feeling to do all that yourself. Have you got the parts that need changing already?

Not yet unfortunately, it's an expensive couple of months with holiday etc. coming up, so im just gointg to strip it down and clean it etc. untill I get the parts.

 

[DreXeL]

DreXeL, what has this cost you so far? I heard that the special engine hoist cannot be hired and costs a lot buy and the gaskets can cost upto £400.

You don't need a special hoist to lift the engine out, infact it is dead easy as it has lifting eyes bolted on to it, you just attatch a standard hoist. I can only assume you mean a special engine stand, which is partly true. You use a normal stand, but you need a special adapter to fit the engine to it.

It's not 100% neccessery to put it on a stand anyway, it just makes it easier to work on.

As for cost, all the parts required (gaskets, all seals etc.) come to between £600 and £1k, depending weather you buy from the UK or the states. That's assuming the rotors, housings and plates are OK.

 

[DreXeL]

Right, this week's update. I haven't done a huge amount this weekend, mainly due to having the cold from hell, not nice in this weather.....

I got the Twin-turbo pack off, along with the upper intake plenum and throttle, lower intake manifold, alternator and pulleys, and exhaust manifold.

Pics then.

Here is the twin-turbo pack:

The intake plenum,throttle and intake manifold:

The alternator, pulleys, exhaust manifold etc.:

How the engine looks now (apologies for the quality):

I've also been polishing the Greddy intercooler pipes and intake elbow, really pleased with the results. I just used Autosol and elbow grease:

So now there isn't much left to remove before I get to the internals......

 

[DreXeL]

Are you sure it won't be ready in 6 weeks? It looks like its coming along great.

You know, there is an outside possibility It'll be finished

 

[DreXeL]

TBH once all the external parts of the engine are removed, the actual internals aren't too bad atall.

 

[DreXeL]

how the hell do you know where all the bits go back?

braver man than me drex

Good old Mazda workshop manual. Clear, precise instuctions, better that any haynes manual

vanpeebles: There are loads and loads of places that do all the parts required for a rebuild. Here is a list of all the parts included in a kit:

Rebuild Kit From Rotorsports

That's probably where I'm going to order my kit from. That includes everything you need, assuming the rotors, housings and end plates are OK.

 

[DreXeL]

Small update.

I didn't get anything done last weekend due to being at JAE all weekend, and as of tomorrow I'll be away for a week, but a got a bit more done today.

I removed the rats-nest, water-pump assembly and coil-pack, and some other small bits and pieces. The engine is now virtually ready to split:

I'm going to order the rebuild kit when I get back off holiday, then I'll really crack-on. The next update won't be untill the sat after next, but it will include internal pics as I'll have the engine split next time.

 

[DreXeL]

Yep, 2x683cc Rotors (Classed as 2.6 by most insurance companys) Twin sequential Turbos.

Was dyno'd at 341bhp by previous owner, I have since fitted an Apexi Power FC and had it mapped, and the car felt a lot stronger, so I estimate it was around 350+ before a waterseal went (nothing to do with the extra power).

Engine mods are:

HKS Mushroom induction x2
Greddy front-mounted intercooler + hardpipes
Greddy intake elbow
Greddy pully kit
Greddy downpipe
HKS Profec B boost controller
Apexi Power FC ECU
Kakimoto full decat exhuast
Sugita Works uprated radiator
Blitz BOV
Airpump removed
Colder plugs all-round (10's)

Whilst it's apart I'm probably going to get some porting done, and maybe get some 1600 secondary injectors, with uprated fuel pump and regulator. That will allow me to run more boost, and I should see near 400bhp with the porting.

 

[DreXeL]

Best of luck, you will need it - what a horrible engine to work on.

Externally yes, the ancillaries are a pain to strip, but internally they are much simpler then a piston engine to rebuild. Loads less moving parts.

 

[DreXeL]

Internal parts pics!!!!

Right, sorry for the lack of an update, I haven't had a lot of spare time over the last couple of weeks. Cracked on today though, and the engine is completely stripped now.

Internal components seperated:

The rotors are coked-up pretty badly, but are in good condition otherwise, (sorry for the quality of these pics):

And here is the reason I am having to rebuild it, the arrow points to the water-seal, and the circle is where it has perished, allowing water into the chamber:

All the housings etc look in good condition, but I am going to take them to RX-Motors to get them checked over. Oh, they'll also get ported whilst they are there.

With the porting and the de-coking, I should get a nice power gain when it's all back together. I have also discovered that I have a lightened flywheel, which is nice.

So now it's a case of cleaning it all up, and then it's time to put it all back together when I get the rebuild kit, which I'll be ordering next week.

 

[DreXeL]

Looking good fella.

Out of interest what did Mazda do to solve the 60k rebuild problem with the RX8, and has anyone turbocharged that engine yet?

They use ceramic apex seals (rotor tips) on the RX8, apparently good for 100k+ miles. There are a few Turbo'd RX8s about, and some supercharged ones aswell. A friend of mine has the first supercharged RX8 in the UK, but it still has a few teething problems.

Mike306dt: Yeah, I intend to catch the initial start-up on my DV cam

 

[DreXeL]

Looking good and it looks like good (expensive) fun... I want an RX7 now!

What rotor tips will you be using? (uprated?)

You can get uprated tips, 3mm as opposed to 2mm, but you have to get the rotors machined to take them, and they can cause problems at high revs. I'll be sticking with 2mm tips, but the kit I'll be getting includes stronger 2mm tips:

Rebuild Kit.

And yes, I will be sharing the vid

 

[DreXeL]

Not everyone with a powerful performance car is loaded mate. I personally spend most of my money on mine, and I therefore dont have loads spare to get garages to do all the work when something goes wrong.

I should imagine DreXel has a similar situation because getting a garage to rebuild an engine is always expensive.

Yep, that's about the size of it. A rebuild would cost £2.5k+, then add the cost of getting it ported.....

Doing it myself, the total cost including the porting will be less than £1k.

As for ceramic seals, they are around 6 times more expensive.

 

[DreXeL]

Yes mine is being rebuilt due to water-seal failure, but the tips normally wear by around 60k miles too.

 

[DreXeL]

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.

Yep, the actual term is Apex Seals, but most people refer to them as rotor tips.

 

[DreXeL]

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.

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.