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Rebuilding a rotary

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Old 01-24-07, 03:58 PM
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Rebuilding a rotary

is rebuilding a rotary really that hard? i really want to try rebuilding it myself, but i'm worried that i'll **** something up and then have to do all this work all over again. what do you guys think?

also, is there anyway to test the motor without having to install it in a car?
Old 01-24-07, 04:12 PM
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Yes they are worth rebuilding, and testing on the engine stand is a piece of cake... We do it all the time. If you want we have a special going on for the DVD 25.00 shipping anywhere in the USA or PR.
Old 01-24-07, 04:16 PM
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If you're considering doing a motor build, get Bruce Turrentine's video and watch it -

http://www.rotaryaviation.com/overhaul_video.htm

Really, the core motor itself isn't that hard to rebuild at the end of the day. There are a few little tricks you pick up over time to make things easier, but it's not too bad. You spend a helluva lot of time just CLEANING - everything has to be VERY clean.

Most people run into problems not with the motor itself but all the crap that's bolted on to it. That's where I see people take shortcuts, use crap parts, etc. and that's why you see a lot of "why won't my car start" threads. You have to BIG TIME document, label, and organize EVERY part on the motor. What seems obvious now is a mystery 6 months later.

There's really not an easy way to test a motor out of the car. In general, if you use new apex seals, properly fit the side seals, and have rotor housings that are in good shape, you're gonna have good compression. If the water seal grooves are clean and none of the water jackets are eroded with corrosion or broken, and the water seals stay in their grooves during assembly, you won't have a water pumper.

Anyhow, everyone has to build their first motor some times . The core of my first motor went just fine, but I had some screwups under the front cover. I've built about 20 now, and I learn some tricks and get better every time I do it. It can also help if you have someone nearby to give you a hand who's built one before, or just at least another car guy for another set of eyes/hands during motor build day.

All in all, it's MUCH easier to build a rotary than a piston engine.

Dale
Old 01-24-07, 04:17 PM
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You're going to have to make a large initial investment in precision measuring tools if you really want to get it right the first time and build a high quality engine... Unless you already have them.

-straght edge from mcmaster carr
-feeler gauges at least
-micrometer (calipers are not accurate enough for all measurements)
-good torque wrenches

You're also going to be better off if you compile alot of information and condense the better points into a how-to guide. There are many tricks that aren't in the Factory Manual that I've learned from reading threads and asking experts like Kevin Landers, etc.

My first engine was a disaster, but I did it on the cheap and it lost a re-used side seal after 200 miles. Lesson learned, I went with ALL new bearings, seals, and springs after that and measured everything against the specs until I ended up with good shortblock parts. Current 13b I built and am driving has 12k on it and perfect compression all around. Currently building a REW for my silver FD

I say do it yourself and take the time to cover all the bases. There is no satisfaction like winding up an engine that you built from scratch.

Off the top of my head, here are some points to consider:

1. balance of rotating assembly
2. measurement of all clearances and specs
3. check for warpage
4. proper cleaning of parts
5. sealants and rtv in all the right places
6. double check everything
7. re-use as little as possible, if your budget permits you to replace everything, do it... not worth another tear-down

I think you need an engine dyno to test out of the car. Expensive I would imagine.
Old 01-24-07, 04:40 PM
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honestly i was hoping you guys would talk me out of it

but i'm really glad that everyone is so encouraging. i think i'll give it a go afterall. i really appreciate everyone's input. i'll go ahead and order a video or two and start getting what i need.

can you guys give me a bit more details on things to get? tools needed, parts, lubes, goop, etc? if you want to give specifics (brands, materials, etc) i'd appreciate it.
Old 01-24-07, 04:41 PM
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Kevin Landers is a pretty cool dude.... Well most of the time that is J/K
Old 01-24-07, 05:31 PM
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Originally Posted by Atkins Mama
Kevin Landers is a pretty cool dude.... Well most of the time that is J/K
Yep, I've annoyed him on several occasions and he took it pretty well
Old 01-24-07, 05:49 PM
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Originally Posted by telum01
can you guys give me a bit more details on things to get? tools needed, parts, lubes, goop, etc? if you want to give specifics (brands, materials, etc) i'd appreciate it.
- Atkins has excellent rebuild kits for really good prices (can I get a discount for saying that?)

- "Hylomar universal blue" for coolant rings instead of petroleum jelly, which swells the rings (permatex stopped distributing it, you can get it on ebay)

- "ultra black rtv" for rotor housing to iron mating surface, fills in any small pits from corrosion

- "honda-bond" seems to be popular for oil pans and front covers

- motor oil works for assembly lube, but you can get better

- I just got a 12" straight edge from mcmaster car for ~$30 that is accurate to .0005". That's what you need to check for warpage, since the spec for warpage is .0016".

- oh, and you should buy a FSM or print out the engine section at least. I got a hard copy for 93 and it rocks
Old 01-24-07, 05:52 PM
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[QUOTE=alexdimen]- Atkins has excellent rebuild kits for really good prices (can I get a discount for saying that?)

Just tell dan on your next order that you want a Free T-shirt.......... heheh3ehh
Old 01-24-07, 05:53 PM
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instead of oil for the prelube use the petroleum jelly, it stays in place longer and wont run off. We show it being used in the video
Old 01-24-07, 07:37 PM
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thanks, i really appreciate all the input and help!

i found the straight edge on McMaster-Carr but the i'm getting an "invalid link" error when i try to create my password (which i have to do because i'm on a "different network"). i'll have to call in the order tomorrow.

i'm going to make a run to Sears tomorrow to pick up a couple things. are there any tools i should get while i'm there?
Old 01-25-07, 12:24 PM
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i've got the vids from Atkins and RWS on the way. i'll try to take as many pics as i can as i go along with it. i'll put them in my project thread (link is in my sig). thanks for all the help, everyone!
Old 01-25-07, 03:00 PM
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I've always said, if you can't afford (time and/or money) to rebuild the engine twice to get it right; pay a professional to do it right the first time. Thats where you money goes when you pay them; you are paying for their experience.

I'm not saying its hard, but its quite easy to not do something right the first time you put one together. And since you won't have done it before, you won't know you aren't doing it right until after its done.

It doesn't appear the pictures are still there, but:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/rebuilt-engine-boat-anchor-pics-inside-466493/
Old 01-25-07, 04:36 PM
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Nah, we all got to start somewhere! Take your time and pay attention to detail. My 1st rebuild worked out great after I took it apart because I put the e-shaft in backwards. Other than that 1 mistake, it was a peice of cake. Good Luck!
Old 01-25-07, 05:10 PM
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that's the way i'm looking at it, Latin. it's my first time, but i have to start somewhere. i've got nothing but time and this car isn't my daily driver. i understand paying a shop to do the work, but i also want to learn to do this myself. i'll do my best to take my time and make sure everything is done properly.
Old 01-26-07, 07:21 AM
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Keep us posted on your progress and we're here to answer any questions you may have! Good luck and most of all have fun doing it! Its not rocket science!
Old 01-26-07, 08:34 AM
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yeah, I had my 1st rotary rebuilt by a professional. I choose that way because It was my 1st rx7, 1st rotary engine, etc... ever. And my first car.
I tore the engine down myself, but I wanted it built back up by a pro. for the "insurance" of it all.

But I have a 2nd rx7 now and am planing on a rebuild myself with a bp. I'm looking forward to it.

Good luck and have fun.
Old 01-26-07, 08:43 AM
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Originally Posted by telum01
that's the way i'm looking at it, Latin. it's my first time, but i have to start somewhere. i've got nothing but time and this car isn't my daily driver. i understand paying a shop to do the work, but i also want to learn to do this myself. i'll do my best to take my time and make sure everything is done properly.
I'm not saying never learn anything. I'm just saying don't always expect to succeed on the first try. For people working on a fixed low budget (i.e. thinking that doing their own rebuild for the first time is going to save them money), I suggest they just get it built by a professional. A first time build can easily turn into one of the most expensive builds you'll ever do.
Old 01-29-07, 08:15 AM
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the initial costs for certain tools (like a $28 2 1/8" socket, and an air compressor i'll hopefully get this week...) and supplies are adding up quickly, but i love this sort of thing and i'm sure i'll be doing it for a long while so this is like an investment. this is my hobby, as expensive as it is, and i love every bit of it. maybe i'm just a glutton for punishment?
Old 04-13-07, 12:29 AM
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good read, I may have some questions later on
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