breaking in a turbo prepped motor.. without the turbo

[Kaiser soze]

hoping you guys can help me on this one. ive spent a few days trying to search but nothing concrete has been found

i got my block and head machined, but im doing the assembly myself. now the thought of improper break in ruining all my brand new turbo parts really worrys me. and for my own piece of mind, i would really like to break in the motor NA, and then throw some parts at it. so i have a few questions

1) i will have the cometic .140 headgasket and ARP studs. will this be an issue non boosted or will i just run a slightly lower compression. running issues?

2) OBD1 M52 with S50 cams. will i need a chip tune, or will i be able to pull a few thousand trouble free miles without it. i was hoping to use stock injectors, MAF, and tune on my S50 cams. since they will all be changed upon forced induction, i wanted to avoid buying twice

i know i will have to deal with exhaust but thats not a huge deal.

3) ZF trans to a 86 325 - ive been told the 328is is the driveshaft i need?

4) the 413 DME can be found in OBD1 M50 cars correct?


i appreciate all the help

[R1dd1ck913]

I got my 413 red label out of a 95 525i obd1 m50 car.

[shocwav3]

Why do you want to break it in NA? Its built for boost, just keep it low for the first few thousand if you are worried about it.

I think you will have running issues on the stock DME due to the lowered compression, but nothing a tune wouldn't fix. Hell it may adjust on its own enough (someone with more tuning knowledge can chime in here).

No help on the ZF/driveshaft option, but I am positive I have read it in the FAQ's

You want to make sure you get a 413 red label, not the silver, pre 95 (I believe). Anything after has the immobilize. Mine is a 94, so its an M50tu.

[Kaiser soze]

ive done a few motor swaps in VW's and its never really a fire and go operation, seems like it always ends up being a month of dinking around and testing things before its actually running right, i feel if that were potentially hte case, an NA motor would be much easier to sort

[shocwav3]

ive done a few motor swaps in VW's and its never really a fire and go operation, seems like it always ends up being a month of dinking around and testing things before its actually running right, i feel if that were potentially hte case, an NA motor would be much easier to sort

Understood. At the end of the day your own piece of mind can be priceless.
;)

[Kaiser soze]

precisely. i just want to do it right. car is near mint, motor is brand new... i would be devastated if it went south quickly. so would my wallet

[Kaiser soze]

anybody else have an opinion here

[GunMetalGrey]

When I was doing my build I was thinking the same thing, and at the end of the day I just broke it in with 6 psi, and I was learning to to MS3X while breaking the engine in lol. I have since checked the bore and done a compression test and everything is good to go. I wouldn't be too concerned if I were you.

[ZekeTheSneak]

Running an s52 with mls and arps. Stay out of the higher rpm range as it gets angry. My car runs just fine running rich.

[The Dark Side of Will]

anybody else have an opinion here

Do some research on hard break-in.

As long as your AFR's and EGT's are decent (which they should be unless you magically detonate an engine with lower than stock compression), beat the F@#$ out of it.

The rings wearing into both the bores and the sides of the piston ring grooves is what constitutes "break in". That only happens if the rings are brought against those surfaces with high loads. Those high loads only happen with high cylinder pressures, which only happen at wide open throttle.

Use WOT whenever possible. Drop it in 2nd and go WOT to redline, then engine-brake back to 4000 RPM, then do it again. Repeat x20 or more as soon as you get it well enough sorted to keep the coolant temp steady.

One thing I strongly suggest is breaking it in on M50 cams, so that your tune and cams are a known quantity. Get it broken in on the stock tune, then get your tuning capability up and running, then swap the cams, then retune, then build the turbo system, then retune.