Today I started up my new setup after having the car down for almost a year.

Car is an s4 T2. Specs on the motor:

-- s5 T2 irons and manifolds, low mileage JDM
-- s4 housings, used but carefully spec'd with no chrome flake or warpage
-- Rotary Aviation super seals
-- McMaster-Carr teflon inner coolant seals
-- all springs replaced
-- brand new OEM corner seals
-- brand new OEM side seals, hand clearanced to .002"

The car fired right up and idled pretty well after fiddling with the throttle stop screw. It only smoked for about 30 seconds and didn't leak anything anywhere. I even hot started it and it fired right up with no flooding.

I realized something. I made a lot of mistakes on this build but I always caught my mistakes because I took my time and checked over all my work.

Mistakes I made:

-- crushed a thrust bearing. Caught that when I had way too much endplay

-- broke or over-filed 6 (!) side seals in the process of clearancing them precisely. literally every seal was clearanced to .002" or slightly more. While attempting that I filed down four seals too much and two seals too little (resulting in those 2 getting stuck and breaking). Now though I think this made a big difference on the car because my old motor had .006" clearance (factory spec is 2 to 6 thousandths) and burned oil while warming up due to blowby.

-- sealed the oil pan sloppily with RTV. I felt uneasy about how I had done it so I pulled the pan off after 20 minutes and redid it after cleaning everything up.

-- fuel leak. Caught that with the fuel pump check connector before starting the car.

-- vacuum leak. Caught that when I pressure tested the engine while it was still on the engine stand.


Mistakes Avoided

-- I was VERY concerned about getting my timing right--so much so that I bought a brand new crank pulley and hub from Mazda because I didn't trust the old one that was on there and I didn't want to attempt a DIY timing jig on a turbo car.

-- I was concerned about building oil pressure so I made sure to pack the oil pump cavity with a bit of vaseline and put some oil down the filler pipe after assembly

-- I was concerned about blowing my front cover o-ring out so I spent a very long time looking over all the writeups about it and making sure I had the correct setup here. In this case I needed the white spacer ring and then used a factory 2nd gen front cover gasket.

-- I was concerned about locking the motor up due to dropping a corner seal piece so I made sure to turn the motor over many times to make sure it moved smoothly and made strong compression sounds.

-- I was concerned about overapplying assembly lube to the rotors. I used Crisco to hold in all the o-rings because I think it is cleaner than hylomar. I used a little bit of vaseline to hold the seals in but I was careful to make sure that every seal moved freely. Because of this judicious application of lube it didn't take long to burn it all up. I did apply a decent amount of oil etc to the bearings, housings, and e-shaft.

-- I was concerned about pinching a coolant seal. I cleaned the grooves very thoroughly and pressure tested the block using the Pineapple Racing coolant seal tester tool.


Now I haven't broken the motor in, but I can say now that slow, careful work is the way to go, along with anticipating any problems. I read a lot on here about people who rush builds and then spend twice as much time fixing their mistakes.

 

oh so true!!! sounds like ur happy tho!

 

Nice!!!! It feels good to have a car that starts up on first try aye? To bad I don't know the feeling anymore, lol.

 

I hope my rebuild goes as smoothly.. I think I had everything you mentioned covered. I should be starting up in a few weeks.