Just finished off a successful engine swap, replacing a blown engine with one from a member here (THANKS ROTARY-GUY!), and extensive searches.

Been having fun with it, but...ran into a few issues. It's a fully emissions/cold start removed engine.

1: The oil pressure sensor threads are what specifically? Searching revealed they are either BSP or BSPT, but both are explicitly stated. Additionally, I have also seen 1/8th and 3/8ths as the size for it. I want to replace it with an aftermarket sensor for now (I'll later do a more proper swap, but it'll do for now). On a fitting note, what is the water temperature sensor's fittings/size? I'd like to replace it with a more accurate sensor if possible.

2: Braking is VERY HARD suddenly. I'm not talking about "Wow, braking got a bit harder". I'm referring to, "OHDEARMOTHEROFGOD, if I brake like this for a week, my right leg and foot are going to rival Mr. Universe's". What do I need to look for? Searching didn't exactly reveal anything...revealing on the topic, unfortunately.

3: Vacuum leaks. I've got at least one, I think I know where it is. However, do I have to worry about it running lean with a vacuum leak? I'd like to iron out a few bugs before I address it. Searching for this topic ran into mass "I HAVE VACUUM LEAK!" issues, rather than my concern .

4: There's an exhaust leak coming from the front, where the "header" of the engine meets the exhaust proper (Not the exhaust manifold gasket, the gasket after that). Do I need to worry about this like I would on a piston engine, or can I just say "Eh, good enough", and take it in to an exhaust shop the way it is to get it fixed?

 

on the braking part, its just hard to push down the pedal?
is it like pushing the brake pedal with the car off?

if so, that can also be one of the reason why you have a vacuum leak.

I am 90% sure the oil sending unit is 1/8 size.

Do you have the stock exhaust? if its after the manifold gasket, then it is the gasket before the precat. Its a 2 bolt gasket, an exhaust shop should have the right gasket to replace it.

 

If you are thinking brake booster line, first thing I checked. Brand new tube ran . I could run more tube/get new fittings for it if you think it would help?

No, aftermarket exhaust. But yes, it's the gasket before the precat effectively. Also bought brand new gaskets, but I seem to be having no luck with fixing it. Do I need to worry about "backpressure", so to speak, like on a piston engine however? Am I going to wreck this new motor by running it as it is?

 

well, the brake booster itself might be bad. I mean its a 20 year old car after all.
Also what year is your car, S4 or S5.
If you have S5, you dont really need any back pressure, but if its a S4, you will need it to activate the 5/6th ports.

 

1.) I reused the stock oil pressure sender fitting. I cut it near the top. The I drilled and tapped into the inside the threads to match up with my aftermarket sender. Its a little long but it's easy to install and remove.

 

1. 1/8 british straight pipe tapered (BSPT). A lot of people think that BSP (british straight parallel) and BSPT are the same; they are not, hence the confusion in the old posts. It is definitely NOT 3/8".

2. Check that the check valve in the brake booster valve is facing the right way: the arrow should point towards the engine. Check it physically by blowing: you should be able to blow towards the engine. The TII check valve attaches with clamps to the vacuum line; the N/A check valve is physically inserted into the hose.

3. Depends on the size. I would fix it before pushing the engine hard, but if its small enough that the engine will hold an idle at a reasonable rpm, it will not cause engine damage during engine driving.

4. It will be fine until you can get it to an exhaust shop, but again, I wouldn't push the engine too hard.

 

I replaced the hose several months ago, and never noticed this. Is there a reason I suddenly notice it now, months later?

 

Sorry, I thought this started taking place after some recent work. I would check to make sure the brake booster line is still attached, and not leaking, and after that, follow the booster testing procedures with a hand actuated pump as described in the FSM.

 

It did take place after some recent work, but it did not take place after the relevant work happened if that makes sense. Disconnection of the hose to the LIM + reconnection to the LIM is all that happened.