Dropping the subframe to change the pan gaskets...
 

Hey guys I'm just a lurker around here, but I'm in the middle of a project and part of this project I will need to replace pan gaskets/RTV and while I am at it I was thinking about being proactive and go ahead and drill/tap for a return line.

Is this a good idea, bad idea? What fittings would be best to use (done right) to allow me to "plug" it until FI is installed?

I use the "while I'm here" mentality and my projects usually turn into much longer one.

My running log of the project here >> As Time allows, this BRG NB2 will get off the lift REPAIRED (pics) - MX-5 Miata Forum

Thanks guys

Yank the engine. It's actually easier

Considering in your link you've already got the trans removed it would definitely be easier to remove the engine than the subframe.

I was about to post to say that I've done it and it was a major PITA and it's easier to pull the motor. Then I noticed you have the car on a 2-post lift, and that might well change the equation.

--Ian

Wait until you blow the engine the first time. Then do it all. :)

Issue being: The engine mounts directly to said subframe. IF you were gonna pull the trans, and lower the SF while having the engine suspended by an engine crane or support, that's one thing. It would also be a pain using a cherry-picker, so unless you have an engine support bar, and want to pull the trans first....


I didn't enjoy lining up the motor mounts in the subframe when I dropped in my VVT engine. Even with a 2 post lift, pulling it out the top would be faster. Additionally, reinstalling the subframe will likely change your toe angles. If you can afford to tie up a rack for a while, drop the front/rear subframes, with drivetrain attached. That's the "have access to everything, get it 100% done now, and paint parts" option.

Realistically, take it out the top. Unlike many FWD cars, there's no time to be saved with moving subframes in and out.

Thanks guys, my original thought was to pull the motor rather than drop the subframe for the fact if it's on the stand it will be easier to have gravity as my friend placing the seals and doing the work in general.

You guys have a cheat sheet for removing all components, any tips or tricks for the ones that have pulled these motors before?

Having it out will give me a better look at all things too in case I decide something else needs changing.

And....Where is optimal placement for a oil return line, I'm going to go ahead and tap the pan too while it's out and place a bung and plug on there. Then when time and money allow move on to FI. Once I finish the shop addition and move my 1950 Studebaker truck in its new home :)

I have a 2-post and would never dream of dropping the subframe to do pan gaskets

Standard location is on the side at the front, but that's because you can drill it on the car. IMHO, if you have the pan off, you're better off putting the drain port right in front of where the motor mount attaches. Also, if you have the pan off, you really want to get a bung welded into the pan rather than drilling/tapping. You should probably also weld in a port for an oil temp sensor.

This is my drain hose:

https://www.miataturbo.net/attachmen...ine=1466143857

Thinking about the 2-post lift thing some more, yeah, I see what you mean. Dropping the motor out the bottom on the subframe requires all the same prep work as taking it out the top (which is really what takes all the time), plus you have to disconnect suspension, steering, and brakes.

--Ian

I did it by dropping the subframe, however the trans was still in the car, although I don't think that really makes it easier or harder either way you decide to do the oil pan.

The determining factor for me was that I had already done every seal on the car except the leaky pan seals. So I had no other reason to pull the engine other than the pan seals.

It went like this:
-Support engine from above (I have a bridge support bar)
-Remove brake calipers, suspend from strut/springs.
-Remove rotors (because no set screws and they would likely fall off anyway)
-Disconnect sway bar end-links.
-Remove lower shock mount bolts.
-Remove steering rack mounting bolts and spline, tie steering rack forward to give more pan clearance.
-Remove engine mount "nuts" from the studs
-Remove sub-frame mounting bolts, lower sub-frame out with jack

-Let the cleaning/cussing/oil pan shenanigans begin.

I did have the car on my 2-post Rotary, and air tools. Before removing the sub-frame I drilled 1/4" locating holes through it into the chassis rails. Installed 1/4" pins on re-install to make sure it didn't mess with the alignment.

Total time took 7 hours and some change, including cleaning up the shop after.

On an optioned street car a lift is the game changer for dropping IMO. Access to the things that need to be disconnected are easier and there's less of them. I've got a stout caster-equipped table that I lower the car down too (after following NBoost's list), then just back off the subframe hardware, raise the lift and done.

I never paid much attention, I assume since yours is welded these are not cast aluminum pans. Are they milled?

If so that's another reason to pull the trigger on my spoolhead attachment for my Hobart. I have a smaller Lincoln set up for aluminum but it's not ideal. My spoolhead option would be ideal.

I think I have decided to pull the motor. I can take my time and get some good pictures. Do the timing belt and WP/seals. Maybe paint the valve cover and clean up around firewall.

I honestly looking for an excuse to hold off on laying the hardwood floors the wife bought... hehe

No, they are cast aluminum pans, and it's supposed to be a fairly challenging welding project. I took mine to a local fabricator for him to TIG rather than trying it with the spool gun on my MIG.

--Ian

OK I was thinking they are cast. I have a good friend who owns a turbo shop (Honda Aura) and he has a TIG but I may just bung it. Chances of me and him making our schedules work might be tricky.

Thanks

One of the first real things that I TIG aluminum was a bung onto my oil pant. I cleaned up both sides the best I could then welded a bung on. It was not that bad at all. I cleaned up the welds with a wire brush and they came out looking pretty good. I would not consider TIG welding the oil pan as hard to do.

While you have the engine out, consider a coolant reroute and a clutch hard line delete. Also, mount the trans to the engine & put them both in at the same time. Replace the oil sump tube to oil pump gasket while you have the pan off.

I was told that aluminum oil pans are usually porous, making it difficult to get all of the oil out of it, and that this would contaminate the weld and make it harder to achieve a water-tight seal.

I dunno, I'm very much a beginning welder, and I don't even have a TIG machine. :)

--Ian

It really depends. We've had ones that were simple to weld, but some that absolutely fought the whole way. both degreased and cleaned. they're not all the same

I have found heating the area up with the torch first (not making a puddle) will burn/bake some/most of the oil out. Let it cool, some 600 grit and some denatured alcohol and it should weld tons easier.