HOLE in rotor housing?!??!
 

Has anyone seen such epicness?

Just got this '84 GSL:

http://sphotos-b.xx.fbcdn.net/hphoto...48524859_n.jpg

Sold to us for $900, 143K, blown engine. It's untouched mod wise: full emissions, original radio, etc. (keeping it this way too!).

So I'm going through the car, trying to find if it's really "blown", or if it was just a 'good ol' boy mechanic "blown"... lol.

pull on altenator belt, engine turns over! Take plugs out, put in battery, crank, even compression pulses!! Try to start engine- fires right up despite years of sitting (wild!!), runs! Coolant now puking from what I thought was the intake orings

Replace intake gasket & orings from mazdatrix... Surely it's fixed right? Fire it up, STILL pissing coolant out like crazy! Uh oh, did I slip one of the o rings on install?

Waiitttt.... water's coming from the very TOP of the engine, pooling in cavity between manifold & engine, & then raining down... uh oh.. lol

Sure enough, right at the seam where the rear housing meets the center plate, there's a bout a 1/4" hole. Never seen something like this. Now this is where I REALLY REGRET to tell you I didn't take a picture of that just yet, but I will very soon.

So I'm wondering, how is that one possible? Never changing coolant? casting flaw? has anyone seen this before, lol???

Can't wait to rip the engine out & rebuild!!

yup, i've heard of that. a guy here in around 2004 did not install freeze plugs properly.. i think he jb welded them in... it got too cold..he must not have had any antifreeze, perhaps just water in the engine.. cracked and split a chunk of the housing out. i'd really like to see a picture of the carnage that has taken place in your engine!!

My motor in my 79 had some corrosion on the front housing that ate into the outer o-ring groove. initially it just looked slightly discolored but otherwise normal , but when I tore the motor down and media blasted the housing, it was pock marked with little craters all over the intake/exhaust side and on the edge between the spark plugs and intermediate housing was eaten right into the o-ring passage

For what it's worth, the plugs aren't intended to pop out to prevent damage if the coolant freezes, and in practice that doesn't really happen anyway. They are just plugs to fill the holes needed to hold the inner casting molds away from the outer ones.

It's why I always call 'em core plugs, since that's really what they do. Of course, I keep calling the thin aluminum housing under the water pump on a rotary the "timing cover" and not a front cover like Mazda calls it. (Hey, the distributor goes into it, right? Right?)

They probably get called "freeze plugs" because that's what they were called on old V8's & earlier cars... or because they are easier to install if you freeze them first, to shrink them.

they probably did work as intended before years of use cooked them to the block, making it more difficult for pressure to pop them out.

i'm sure they've saved numerous motors in moderate climates but in severe cold i doubt they would work that well.

What I am getting at is, they may have gotten that name either because someone claimed that that is what they were for (ref.: "Road Hugging Weight"), or someone saw them popping out when the block froze, and said "Ah! Those are safety devices!" Kind of like the myth that you need a restriction in the cooling system to prevent the coolant from moving too fast, it could just be someone seeing the effect and getting the cause wrong.

Incidentally, "Dyno Don" got his first 409 SS because the block froze and cracked. It was a brand new 1961 model, and nobody knew how to work on them yet, so he got it really cheap... Point is, they didn't work like that even when the engines were new, 50 years ago.

Further addendum: The 13B that I just took out of my car had severe corrosion. The water passages were full of gritty green jelly that took forever to clean out, and the coolant O-ring grooves were heavily pitted, in many places through to the water jacket. I assembled it with McMaster-Carr O-ring material (Viton 2.4mm inner, neoprene 2.0mm outer) because I'm cheap, and Right Stuff silicone because it's badass, and the engine didn't have any combustion bypass or other coolant loss issues. It just plain wore out without catastrophic failure.

BTW - McMaster-Carr O-ring cord for one engine was just under $20. The silicone for one engine costs more than that :)

I fought correction on my irons and it was a bitch. I bought a Atkins rebuilt engine from a local person. I could tell that the engine had not been ran since the rebuilt but it had sat since the rebuild in 1992. Not a spot of oil or wear on the outside of the engine. You could tell there where new gaskets and assembly lube on the rotors looking through the exhaust port. After putting the engine in my car and getting it started, it was evident that there was a water leak. I pulled the intake off to insured the o-rings where not messed up and for good measure installed freeze plug in the intake water passages. Still no luck. I was making steam.

At this point we pulled the engine and did a rebuild. Started the engine again. It was worse. I had water pouring out the exhausst pipe. Pulled the engine again took it to a good engine builder this time. The conclusion was that the irons where pitted enough to allow water into the combustion side. It was so bad that the cooling system was getting pressurized and shooting water 15 feet out the small hole in the overflow bottle.

Leason Learned: inspect all the parts really well. Trochoid on the forum did my rebuild and even he missed what he thought was a small amount of pitting. I throw the bad irons away and used a set of lapped irons for the next rebuild.

a little bit of high temp RTV on the sealing surface goes a long way to prevent corrosion from getting the best of the inner seals. i do it on all engines as preventative warranty claims and it helps with marginally reusable parts that are still in good condition otherwise. the OEM seals have a rather narrow sealing surface, the white skirts in fact are not there to help seal the engine(they are to prevent the seals from chafing/ripping on the rotor housing walls), the orange part only is doing that sole job which is about half the width of the coolant seal channel, as a result you have a whopping 1.7mm sealing surface holding everything inside the guts of the engine. this is also why i do not use OEM seals any longer, the red high temp silicone they used isn't up to today's standards compared to other synthetic rubbers.

I always used a por15 high temp on the inside water passages, they are capable of taking heat and coolant/water for decades.

if it seals iron boats on the pacific ocean for months at a time, can take the heat of a constantly running piston motors. I have however noticed a 8* difference in stock rads when doing this. no change in temp with a aluminum rad though.

^^never thought of doing that.. seems like a really good idea as it would prevent corrosion of the water jackets!

Didn't they stop making boats out of iron around 1913 or so? :scratch:

You've got nothing to lose try JB weld
 

You've got nothing to lose try JB weld to seal the hole. That would be awesome.

^ thats how I fixed the housing I was talking about earlier. Of course, its much easier when the housing is separate from the engine, degreased, media blasted and washed. I havent put it back into use yet, but I couldnt stand to junk a 12A housing that still had pristine chrome, no flaking ANYWHERE!!! :O

You know, when Racing Beat makes their PP housings, they use a specific epoxy to do required water-jacket mods, & I seem to recall on their site they discuss how to fill in the side intake ports on iron housings as well.

Might be some useful clues there.

devcon puddy? I remember them saying something about that through my old random interwebz searches.

pics or it didn't happen!

^ u want pics of my totally badass "repaired" 12A housing w/ pristine chrome?

lmao! um i was thinking of the original posters engine

Crap guys I left ya hanging!!!

I've got one photo, it's REALLY hard to get a good picture of, as the camera phone kept focusin' on the emissions rack & such. I circled it, tho.

http://sphotos-b.xx.fbcdn.net/hphoto...61190122_n.jpg

It's right where the rear housings meets the center iron, on the top most surface of the housing. We plugged it with quick steel, & got it running "well", well enough to drive it 2 miles down the road before she pegged at H haha, the corrosion is uniform so it's leaking water in while running as expected. O well, I'll get it fixed one day :)

This is prob more common on east coast engines. The engine in my 81 had holes in the rotor housings so bad you could actually see the black oring that seals the outer portion of the rotor housing. The oring was in tact and the motor made great compression so I really couldn't bring myself to tear it down. I believe that it was caused from a previous coolant leak where the coolant pooled on top of the intake manifold and it just ate into the aluminum over time. This was my mock up engine for quite a number of years and then I finally decided to see if I could get some use out of it. I plugged the holes with a good amount of RTV, cleaned up the rest of the engine (new rear main seal etc) and got it running. To my surprise no leaks or overheating, just an exhaust leak out of a broken exhaust stud hole. Who knows how long it will last, but at least I know it runs and serves its purpose of being able to move my project around under its own power while I build another engine.