KansasCityREPU

iTrader: (9)

Here's the background. Rebuilt Atkins 12A. I bought it from a third party about 6 years ago and it has been sitting ever since. I inspected the engine before purchase and could tell that indeed it was a rebuild from Atkins with zero miles. The mating surfaces where new and I could see that the rotors had assembly lube on them. The front housing has a stamp on it. The flywheel was also resurfaced.

Fast forward. About 4 weeks ago we fire it up. The temp starts to climb. The thermostat as not opening so we pull it out and start it without one. It starts up (with a little help from some gas down the carb, and the temp is ok now. We run it for a few minutes and the low water indicator is going off. We check the plubs and the front plugs are black while the rear plugs are clean as could be and the are soaked with what could be gas/water. It seems like more water then gas.

I put some more water in it and start it again. Same results. Low water indicator is going off again and the rear plugs are clean.

I'm thinks it was the o-rings in the manifold. This weekend I replace the o-rings with 20mm freeze plugs and put it all back together. I get the same results again.

At this point I'm thinking it needs a rebuild because the seal are dried. I've never rebuilt a rotary and have a few options. Should I just rebuild it or is there anything else I should try. I'm very frustrated with this project. I've been rebuilding it for 10 years now.

1. Continue troubleshooting
2. Rebuild the current motor myself (I have all the parts including several rebuild kits)
3. Use the brand new NOS 12A housing I bought several years ago and do it myself
4. Pay someone (Prather Racing) to rebuilt it for me.
5. Buy a new engine from Atkins

KansasCityREPU

iTrader: (9)

I forgot to add, I get a lot of pressure (air) coming out of the overflow bottle. And if I leave the rad cap off, it will just bubble out even before coming up to temp.

Jeff20B

iTrader: (13)

You may have commited a rotary offense when you removed the thermostat and didn't block the bypass hole.

I say go for option 2.5. Tear the motor down, inspect, then rebuild it yourself. Why? Because it is the best way for you to physically see what is causing the bubbles in the overflow bottle plus water on the plugs. Then choose which ever set of rotor housings you feel pass inspection for your next engine build, and build it yourself. I suggest this because it's been six years, so Atkins might not honor a warranty, and because you already have all the parts sitting there.

News flash: I built a 12A just this evening with parts I already had here. I say go for it.

KansasCityREPU

iTrader: (9)

Thanks Jeff, I think I'll rebuild it myself. New project for this weekend, pull and and teardown the current 12A in the car. I have the Atkins rebuild VHS and another rebuild video DVD series. I'll watch them this week. I think I have most of the tools. Do I need a dial indicator and calipers also?

Since I did not buy the engine from Atkins myself (and its been six years) I would never ask them to honor any type of warrenty.

As a side note, I put another t-stat in it this weekend and it never opened up. I ran the car for about 1 minute and the temp just kept climbing so I shut it down.

I need to get this project done. I'm 47 now and I don't want to wait another 10 years.

Kentetsu

Or, if you are in the mood for a quick shortcut, you could try Alumaseal: https://www.rx7club.com/1st-gen-archive-71/engine-coolant-seal-repair-maybe-750774/



And I agree, the seals probably dried out due to lack of use over the years. The motor I am running now sat for a number of years and had the same issue when I installed it. Best of luck.





.

Jeff20B

iTrader: (13)

A digital caliper can be used to check crush.

Alumaseal in a new fresh engine? I don't think so. Tear it down to see why it is leaking internally.

For a used engine, maybe, although I don't like what that stuff does to aluminum over time. My RE-SI (GSL-SE) engine died because somebody used that block sealer crap; it rotted the aluminum right where it settles at the coolant port area (there's always a build up there), allowed coolant to leak past the orange coolant seal, it began steam cleaning the front rotor and caused fast wear of the front apex seals. They wore down to 5.5mm and one broke. End.

If Atkins uses petroleum jelly on their coolant seals, they won't be dry, they'll actually be a little too 'moist' which may have caused them to break down a little over time and disuse. Coolant seals, especially the black ones, grow when exposed to petroleum based substances. I once accidentally crushed a black seal during tension bolt tightnening of my brother's RX-4 engine so I had to unstack the engine a few times because I let my brother prep the front rotor. Corner seals weren't aligned so apex seals didn't fit, the little apex end pieces kept jumping down into the water jacket while installing the intermediate plate past the e-shaft etc. I had used vasolene on them and they grew a lot! Why did I use it? As we all know everyone uses it and the Cosmo shop manual recommends it... Coolant leaked on the outside and into the oil pan. My brother was devistated. I switched to wheel bearing grease on my next build. Since then I've experimented installing them dry. Now I only use a little wheel bearing grease if the seals don't stay in their grooves.

I read something I believe on this forum recently where a guy suggested you fire up an engine without coolant in it for a few seconds to "seat the coolant seals". I'm not sure if that actually works, but I ended up doing exactly that on my two most recent 4 port 13B builds without knowing that others had done it and given it a reason: seating the coolant seals. I simply did it to test fire the engines to make sure they worked before moving on to the next (potentially messy) step of adding coolant. The logic I used was if it doesn't fire up and run in a reasonable way or within a reasonable amount of time, that means there is something wrong and it needs to come back out for a quickie tear down to fix whatever may be wrong with it, and I'd rather not have to go through the coolant step if I can avoid it. Make sense?

Example: the GLC's nice little 4 port 13B that I built in July got a set of used apex seals, a questionable rotating assembly (only one available at the time), and some old boogered 74 housings (chrome was decent). The three didn't jive and it took almost an act of congress to fire it up. It wouldn't idle below 1500, it vibrated, once the RPM dropped below about 1400, it would stall and could not be restarted until you pull the plugs, clean and dry them, reinstall, then dump oil and gas down the carb and stand outside with a remote starter switch and a can of starting fluid standing over the carb. Then it would fire back up if you're lucky that time around. Turns out the housings were slightly dished along the bottom at the hot side. They are very early 13B housings so maybe could be slightly warped, but didn't appear to be crushed. A quickie rebuild to swap housings, swap rot-assy and swap to new Atkins apex seals solved the problem. This time it fired up within one second of cranking and held a steady 1k RPM idle. It could be shut off and restarted easily. That's how they all should be. Oh and I switched to hockey puck motor mounts so you feel everything. I could feel very little vibrations from this build.

Twilightoptics

iTrader: (1)

Alumaseal works wonder, but I don't know if it's going to save your rotary. Get a pressurizing device and pressurize the system with the plugs out. See what you find.

KansasCityREPU

iTrader: (9)

Can I make a blocking platte for where the t-stat housing goes and drill-tap and install a pressure gauge in the platte? Sound easy enough to make it work.

One tid bit I did not mention, the engine was rebuilt byAtkins in 1992 based on the date stamp. I called them right after I bought it to find some info on th engine. They said they didn't have info back that far. They did tell me that at the time they only stamped the front housing and that now they stamp both.

Twilightoptics

iTrader: (1)

http://www.pineappleracing.com/cooli...estercspt.aspx $65 PRE-MADE

DivinDriver

iTrader: (15)

Only additional advice I can give is don't wait too long, whatever you choose to do; water left sitting in the working chambers creates serious corrosion problems if left to stand for very long. plate faces, seals, all not corrosion-resistant, but are high-carbon steel or cast iron. Very reactive to water.

Proper antifreeze mix helps prevent this, but the job will get harder if you wait.

KansasCityREPU

iTrader: (9)

Thanks for the advice. I went ahead and drained the radiator and block and started the engine for a few seconds. I'll get the engine tore down this weekend.

john smack

iTrader: (12)

Did it run better without water in it?

KansasCityREPU

iTrader: (9)

It only ran for a few seconds. Not really enough to tell. I have some carb issues to so it's hard to tell. I put on a brand new NOS carb I had because it was hard to start. The idle isn't working right. It will rev up but not come back down the way it should. It also is hard to start. You have to pump the crud out of it or pour gas down the carb. Once I rebuild the engine I'll sort the carb out.

My wife say's she is going to start calling be muligan because I redo things two or three times until I get it the way I want it.

DriveFast7

iTrader: (1)

The motor has to come apart, sorry. FWIW Jesse Prather makes a fantastic motor.

KansasCityREPU

iTrader: (9)

Trochoid (Scott) and I took the engine out yesterday and tore it apart. Everything looked pretty good with the exception of the rear rotor inner housing seal. There was one part that looked questionable. You could also tell that there where small amounts of water. The rotor was very clean - like it had been steam cleaned. I'm also going to replace the rotor bearings and stationary bearings. According to Scott, they look questionable so I'm replacing them because we can.

I bought the bearings from Atkins today along with the bearing tool they sell. I'll also be cleaning up the irons and housing and powder coating the irons. I'll leave the housing and front cover alone - just a good cleaning. I'm scared if I powder coat the front cover and housing at 385-400 degrees they could warp. I might clear coat them with paint though.

KansasCityREPU

iTrader: (9)

Got the rotor bearings, main bearings, main bearing press tool in today. I forgot to order the rotor bearing tool with this order so I ordered it tonight. I guess I'll have to wait another week before I can put the engine back together.

Do I buy a cheap Harbor Freight 12 ton press (~$80) and press the bearings in myself or do I just take them to a shop and have them done?

Jeff20B

iTrader: (13)

I noticed your front cover is the '84-'85 type with the front oil pressure reg casting much fuirther rearward than on earlier front covers. It also has a 12A turbo oil return casting undrilled. Compare to an '83 front cover or an earlier one and you'll see some interesting changes Mazda made to these.

One piece of advice. While the front cover is accessible, you might consider drilling and tapping threads for a possible future turbo or supercharger oil return fitting. For now you can block the hole with an NPT pipe plug. I started doing this on all my rebuilds in the supercharger location recommended by Atkins (on the lower area) because it works fine with PercentSevenC's S5 turbo swapped onto his R5 13B. Uses the same 45° 1/2" barb fitting with 1/4" NPT thread as comes in the Atkins kit.

Not sure on the bearing thing. I always use new hardened stat gears (which come with new bearings) if the situation calls for it. Otherwise the stockers are reused if the bearings look ok.

KansasCityREPU

iTrader: (9)

I bought this engine as a Atkins rebuild that someone had sitting around for a long time. It was rebuilt by Atkins in 1992. It came with a resurfaced 1981-1982 flywheel installed. After tearing it down, I found it had R5 irons and it also has 3rd gen corner springs. I was surprised to find that all the parts where in very good shape.

Is there anyway to tell what year the e-shaft and rotors are from? This is going into a 1985 GSL but since the flywheel was already on the engine, I went with the 215mm clutch.