This is berking stupid, right? (FM Miata turbo content)

So a buddy of mine bought a FM turbo kit for his Miata. We're doing the install tomorrow and I ws talking to him today about the procedure. Turns out he's planning on drilling the drain line for the turbo with the oil pan still mounted on the engine.

This seems like a monumentally bad Idea to me., but he keeps insisting that this is what the instructions say and he's not going to deviate from the instructions. I figure drilling and tapping an oil pan on the motor is a brilliant way to introduce metal shaving directly to the main bearings.

Am I being over-concerned or is he being under-concerned?

The last one I did, I didn't remove the oil pan. I used a punch to make the hole, greased the hell out of the tap and tapped it. No problem. That was a sheet metal pan. It worked fine. That's probably not how I would do it now, just for durability reasons. Sheet metal doesn't tap well.

With a cast aluminum pan, I'd be tempted to add a little air pressure to the engine and drill and tap it with well greased tools. Take your time, and you can capture all the swarf. 

It seems a little counter-intuitive to me as well, but that is exactly what the directions say to do and they had guys way smarter than me figuring that stuff out.  The other steps in there do include to apply a little bit of positive pressure to help blow the shavings out as well as a quick flush with mineral oil.  Anything that's left isn't going to float so the pickup won't, and the oil filter should be able to handle any of the last few particles that might get through.

Personally, I've always removed the pan from the engine, done my drilling and tapping, and then cleaned it thoroughly before re-attaching it.  But I think that falls into the "over-concerned" category.

Toyman01 said:

With a cast aluminum pan, I'd be tempted to add a little air pressure to the engine and drill and tap it with well greased tools. Take your time, and you can capture all the swarf. 

 

The FM instructions say air pressure and a greased tap.  I'm guessing that there have been a lot of FM kits installed this way.  If pulling the oil pan was easy, I'd pull it.  But I'm guessing that it's hard to do with the engine in the car.

It'll be fine.  Yes, ideally you'd pull the pan, but of all of the things you could find in the bottom of your pan, some aluminum shavings is low on the list of things to worry about.  Aluminum is a soft metal and any shavings will be too big to hurt anything.

Heck, if the pan has any sludge in it at all, any shavings that the greased tap don't retain will probably just get stuck in the sludge before it even makes it to the pickup.

I did it that way on my Miata with no issues.

You could get away with following the instructions, but I'd rather pull it for safety, or at least do an oil change after the tap is installed.

After drilling, take out the drain plug and flush through the drilled hole with something like ATF. That should get any shavings that fall in out of there.

I’m sure kieth will be along to placate. The way I see it, if I follow the instructions and fail, my new motor is on the manufacturer. 

Not directly related, but kind of...I drilled the exhaust manifold on my Duramax for a pyrometer.  Greased the bit well, removed often to clean out the shavings and did the last bit and tapped it with the engine running.  All the little filings etc were blown outwards instead of going through the turbo.  That was about 40,000 KM ago. 

So I think with a wee bit of positive pressure and going carefully it should not be an issue. 

Bottom line, it's not my car, but it just seems like an unnecessary corner to cut after spending that much money on the kit.

Trackmouse said:

I’m sure kieth will be along to placate. The way I see it, if I follow the instructions and fail, my new motor is on the manufacturer. 

The instructions are a guide and not a guarantee. They're a series of steps that we know will lead to a successful install if carried out properly, but there are always ways to do things incorrectly despite good instructions. We do not give out replacement motors if you screw up. You may want to have yours professionally installed if the job contains steps that beyond your comfort zone or ability. That’s why the very first step in the instructions is (paraphrasing here) “read these instructions and evaluate your skills honestly”.

People have been drilling Miata oil pans on the car for a couple of decades now - no exaggeration. Thousands of installs. About the only thing that can happen to cause problems is to keep drilling once you get through the pan. Next step is the oil pickup tube, and it doesn’t like having extra holes. Takes a fairly aggressive approach to get there and keep going through the steel tube, but it does happen once every few years. Figure this happens on about 0.25% of the installs. If you’re enough of a mechanic that you’d even consider pulling the pan, you won’t have this problem.

Contamination is not an issue if you grease the bit and flush the pan when you’re done. The slight positive pressure helps as well but I think the grease is the key. Drill slowly and it’ll happen quite easily. IIRC the kit comes with a new drill bit so you’ll have a nice sharp tool to help. 

It’s psychologically challenging, but not all that difficult to do in reality. Pulling the pan is actually a lot more difficult, and getting it to seal when the engine is in the car is a pain. 

One other thing you can screw up when drilling the pan in the car is to put the hole in the wrong place.  I got it too high on mine such that the fitting would interfere with the AC bracket and had to pull the pan off to fix that.  Be very careful if you're holding the drill at an angle.

Don't see a problem, the E30 guys have been doing turbo installs the same way for more than a decade as well.

Prevents either pulling the engine or dropping the subframe.

But I'm also the type of guy that when I built my track rat Miata, I replaced all the bushings in all the control arms.................every bolt that came out, a fresh OEM bolt went back in. Not just the adusters.