You caught me in time Carl. Thanks for averting a possible tragedy there. I didn't think there was enough meat in the casting to go drilling holes that big. So you're saying that there are only threads at the back of the hole, and I haven't gone deep enough to see them yet? I was thinking that the hole was tapped all the way through, but apparently this isn't the case?

So you are suggesting that I drill out the brass fitting, and then try to clean up the threads that exist only at the back of the hole, using a 1/8-27 tap? I could've sworn the hole was tapped all the way to the front, but apparently my memory fails me. I guess I don't really have anything to lose by trying it, but I just hope I can get those threads cleaned up enough to get the stock sender back in. After doing this I can take the bottom bolt out and try flushing the chips out with some oil or solvent.

Let me know if I've got the right idea here. I"m pretty sure I understood what you were saying, but I wanna make sure before I do ANYTHING. As many times as I've come close to screwing up on this I"m want to be absolutely POSITIVE before I drill. I may only get one chance to fix this. I'm sure as hell glad I started asking questions instead of trying to fix this on my own. I'd be calling for the cost of a rebuild right now. Looking forward to another response Carl. Thanks everyone.

Jamie

 

Well Im not sure that theres not enough meat there, just that it'll be close. No no no, the threads are at the top of the hole and only extend into the hole approx 1/4". So you wont have to drill far to get the brass out.

Drill out the brass, then try to remove whats left. Maybe even start with a 1/4" bit so you have some meat left on the brass, then try the easy out again. If'n that doesnt work, then carefully go open it up with the 5/16". Im trying to have you make as little shavings as possible, and at the same time, save the existing threads as they are still ok to use at this point. Dont use oil to flush it, the shavings and oil will stick to the walls of the oil gallery. Use solvent and then compressed air. Lather rinse repeat till its clean.

 

Yes, Carl is correct. Luckily, that particular oil passegeway does not flow directly into any bearings. It flows upward on most older and '86-'92 rotaries and downward on FD, JC Cosmo, and '83-'85 12As (where the oil comes in at the filter pedestal). It will make its way through the rear pressure reg and then into the pan. Your engine will be somewhat safe from shavings.

I used a 1/8" 27 NPT tap on mine and only cut threads into it about 1/4" deep. I also made sure to test fit my guage's brass fitting a couple times during the thread cutting process.

 

So do you think I should just flush it out through the bottom bolt for front mount oil cooler? This is on an 85 12A. I imagine that some of the solvent will get washed into the oil pan, don't you think? I'm thinking I'll be able to flush it out through the bottom hole, and then drop the pan to clean out anything that happened to make it into the oil pan. Does this sound like an okay plan? I really don't want to take the pan off because I just put a new gasket on there. But I'll do what I have to....

 

Well to be honest, I'd remove the pan and the rear regulator before I flush it. That'll keep more shavings from staying behind. Flush from the top down. The solvent will come out the lower bolt and the regulator hole. Dont worry about the gasket, it should be fine to re-use. I'm glad Jeff brought up the regulator as I had failed to think about that issue. A couple of cans of brake cleaner should get it clean.

 

Sounds like a plan. I'll start drilling and tapping when I get home tonight. Expect to see some more pictures and maybe more questions as this project progresses. Hopefully I can get some decent threads cut in that hole and i'll be back in business....

 

Yes, if you can remove the regulator, you'll be in good shape. I've never attempted to remove one on an assembled engine, so I don't know what's required in terms of tools and know-how. Good luck.

 

Once the pan is off it shouldnt be bad to get to.

 

Ok guys,

The madness has begun. I regret to say that things are not going well. Here is where I currently stand....

I drilled the hole to 5/16. It was going very nicely until I got to the end of the hole. I didn't even think about the threads giving out and the fitting going inside the engine. Well, it did. So somewhere in the oil passage is a piece of brass the size of a bebe. I decided that I would worry about that after I got the hole fixed. So despite my getting the fitting inside the engine, I had a nice clean hole to tap. Started tapping the hole. Got done. The threads looked pretty good still. Well, the sensor doesn't go in worth a crap. I tried to thread it in and it just screwed up the threads on the sensor. They are all mashed flat at the end of the sensor now. For some reason or another it didn't work. I also tried using another 1/8 npt fitting, and the same thing happened.

At this point I have the remains of a brass fitting inside my engine, a still screwed up hole, and a mess to clean up. I decided to see if I could get the fitting out of the engine. Took the oil pan off the bottom of the engine. I planned to take the regulator off next, but decided to stop before I screw up anything else. How does the regulator come off? Does it just screw in or what? If I am looking at the right thing it looks like a giant 1" nut directly below the oil pressure sensor, with a little tapered point going towards the front of the engine. I tried to see if I had a wrench that would fit on it, but I don't. The biggest I have is 1", which is barely too small. I don't have an adjustable wrench big enough either. Before getting carried away I thought I would share my screwups and see what you guys recommend from here.

If things keep progressing like this I'll have to send the thing out to be rebuilt. I think I'm going to have to try to go with a 1/4" fitting. I can't get anything to thread in the hole at 1/8. My main concern right now is getting that brass fitting out of the engine though. Will it come out if I try and flush it? I don't know how the oil system is mapped out inside the engine. Will it even be able to pass through, or is it going to get caught inside the engine? I'm going to go eat dinner and hopefully one of you guys will catch this by the time I check back.

Desperately in need of help.....
Jamie

 

Maybe I read your post wrong, but are you trying to thread a 1/8 28 BSP fitting into your 1/8 27 NPT thread hole?

 

I'm almost positive that they are NPT fittings. I got them out of one of those adapter packs for an oil pressure gauge at Autozone. So I'm assuming they are NPT fittings.

I tried threaded my stock oil pressure sensor into the 1/8-27 hole and it didn't work. Then I tried using the 1/8 Autozone fitting into the 1/8-27 hole and it didn't work either.

I'll try and post a picture really quick of the hole. The threads are cut in there, but they don't look very good. I think I need to go to 1/4" but it scares the crap outta me to put a hole in there that big....

 

1) Ok first off, is this or is this not the oil pressure regulator? If so, how does one go about removing it from the position I am in? With a wrench of the correct size?



2) Just for the sake of experimenting I took an old junk rear engine plate and tried drilling into it for a 1/4" NPT fitting. I drilled and drilled but never hit the oil passage. This was on an 83 engine. Does it have a different oil system than an 85 12A would? I was able to drill in 5/8 of an inch deep before breaking through the back of the plate. Here is a picture of where it came through. I've been looking at my 85 engine and I don't think I would really need to go in that for for the fitting. Would it be safe to try and drill for 1/4" NPT? Here is the aftermath after going in 5/8 deep on the junk engine.



Here is a picture of that same hole from the top so you can see its location. Just in case you wanted to know.....



Here is the best picture I could manage of the current state of my engine. You can see the depth of the hole I have. Which I think is considerably less than 5/8. I'll have to go measure and see. You can't really make out the threads in the picture because my camera isn't good enough. Do you think it's safe to do 1/4??

 

1/4 might work as there is some iron there, but I'd be scared. Yes, that thing with the big arrow is the pressure reg. Again, I've never removed one from an assembled engine. Maybe a wrench of the correct size (metric!) ground down a bit would work.

 

Ok, so the junk is out, good deal. Now we gotta get that piece out of the oil passage. Remove the oil cooler, on the top of the pedestal look down the hole thats furthest from the center of the engine. You have 2 chioces, 1- (preferred) remove the lower plug or the regulator and blow compressed air up the passage to try and blow it out the top. At least if it gets stuck there somewhere youll be able to see it and can pick it out somehow, or loosen it and blow it out. 2- blow downwards to try and blow it out the bottom, my only concern with that is it may get stuck, and you wont know where, and wont be able to see it. If no compressed air is availible, then you could use a piece of stiff wire (like a coat hanger) and push it up the passage where the regulator sits.

I was hoping you could save the original threads, but oh well. Your not gonna tap that hole correctly with it only being 5/16 in dia. I did a test for you. Using a 1/8" npt female fitting I tried to screw in both a stock sender and a 1/8" npt fitting. The sender was looser fitting in the hole. The threads line up perfectly, but the metric diameter was a tiny bit smaller. What problem are you having with tapping the hole?

 

Yes thats the reg, and I use an adjustable to get them out. Dont give up on 1/8 yet.!!!! 21/64ths is only a little bigger. Re drill it about 1/4" deep and try to re tap it.

 

I'm at my wits end guys... lol. I'm about to go nuts trying to decide what to do. Carl, I played around with the 1/8 fittings one last time and it just isn't happening. The hole is too big from the battle with the brass fitting. I tried to clean up the threads with my tap but I guess it didn't work. I can't get anything to thread in there at all. The factory threads are just too mangled up to save.

This may sound crazy, but I'm actually exploring my options with a rebuild here, which is something I've wanted to do from the beginning of my restoration anyway. Only problem is I'd probably have to find a new rear engine plate since mine is so screwed up. I'd like to get the engine rebuilt, or maybe even get a different one. There is so much stuff screwed up on mine it isn't funny. I actually wonder if its been overheated before. The exhaust studs are all messed up. The obvious problem with the oil pressure sensor. The threads for my distributor locking bolt are botched up too. I'd like to get a fresh start but I don't where to source the parts to replace all this messed up stuff on my engine. Most rebuilders don't have any extra engine housings or components.

I also found a used 85 12A engine at a parts yard near me with 99K on the clock. It says the engine "tested OK" so I'm gonna call and get some more info on that tomorrow. The price on the engine is $250. Plus its close enough for me to go pick it up in person this weekend. I'm not sure that I can really pass up this deal if it is a nice running engine with similar mileage to mine. I'd like to get an engine that hasn't been tampered with as much as mine has. The previous owner on my car screwed up a lot of stuff, and I did my own fair share as well. I've thought about sending this $250 engine to Kevin Landers at Rotary Resurrection in TN.

Then again, I could also grow some ***** and try the 1/4" NPT fitting on my engine and try to find out where that stupid fitting is at in the engine....

I am definitely at a crossroads here with the whole restoration. I can experiment some more and try to limp along with my engine like I've always been able to before. Buy a used on and hope it runs as good as mine did. Or third choice is to buy the used engine and have it rebuilt.

I've got some serious thinking and decision making to do here....

Jamie

 

Well for $250 if it runs and has good compression and no "issues" then its a good deal. Then you can take your time and rebuild the other one at your leisure. I would just run it as is.

 

Carl,

Could you give me a quick rundown of what I should look at on the engine while I'm there? I don't know how to assess them very well other than taking out the spark plugs and cranking it over really fast (with the starter) to listen for compression. I guess I could look in the exhaust ports at the apex seals too right? Other than this I'm not really sure how to tell if it is worth my money or not. Could I go get a cheapie compression tester at Autozone to get a general idea? I'm looking to find a good rebuildable core that I could more than likely send to Rotary Resurrection. I'm not necessarily looking for an engine that I can stick in the car and run right away, however this would be nice.

I would send my existing engine but it has so many small things wrong with it that I'm not sure it would be a good candidate to rebuild. I think the front cover would have to be replaced (threads on the distributor nut), the threads for my exhaust studs are pretty sorry (in the housings), and then I have this obvious problem with the oil pressure thing in the rear plate. Most rebuilders don't have the extra engine parts to fix this stuff, hence I'm looking for another engine....

Any tips on looking over this $250 engine would be greatly appreciated.

Jamie

 

I answered your other thread. You cant crank the engine for a compression test without it attached to a trans with a starter.

Front cover- Those threads can be fixed with a helicoil, problemo solved.
Exhaust studs- cheap to replace.
Oil pressure fitting- Could always expolre the helicoil option there as well, then install a plug and tap for oil pressure somewhere else.

Just what Id think of doing in your situation. Good Luck.

 

This may be a really stupid idea, but what about trying to fill that hole with weld? I could probably fill it up just enough to re-cut the threads. Bad idea?

 

Or another idea. What if I went ahead and tapped for 1/4" NPT and If i did break through the back of the casting, weld the hole shut??? Would this work okay? I don't think it would come through but if I did then I put put a little weld on the hole to patch it up. Is this feasible? Then I could worry about cleaning up the inside of the engine when I was done....

 

Could you weld something like this shut and be okay?

 

Welding cast iron is very tricky. I broke off the tab on a rear plate where the upper starter bolt goes and welded it back on. It came out like crap. Im not knoweldegeable enough to really answer that though sorry. Im not much of a welder.