recently blown engine
 

a little over a week ago i blew the engine on my 07 speed3, pressure tested and scoped all cylinders and all 3 are good except the 4th. just beginning to weigh out my options to get her fixed back up. not sure whether or not to get a salvage car and do an engine swap and possibly a tranny swap as well, or just buy an engine from a shop.

Nice first post bro. Ill be easy on u tho. How did it blow? Rod? Bent valve?

Any rate might as well buy a new built motor instead of stock replacement. Do some reading and when ur done read again. U will find all the info you need.

What are your HP goals? EDGE AUTOSPORTS remaned motor is the most economical choice for average hp levels.

What are your mods?

Are you tuned?

Did u just get the car and do something stupid or have you had it for a long time?

More background and detail would greatly assist us in offering reasonable options. It really depends on the history of the engine and what went wrong.

There are lots of step by step examples on here of folks "fixing" their own. If you like to work on your car, that could be an option as well.

Like others said, more details and we can probably help you more

I was just driving down the freeway and the engine light started flashing so I got off and realized it was a misfire of some sort, and when I scanned the obd it was a cylinder 3 misfire. I bought a new coil pack for my 3rd cylinder and replaced all 4 spark plugs as well. fired it up after and it felt slightly different but still the same misfire. rescanned it and it was #4 now. pressure tested all 4 cylinders and 4 got 0 pressure at all. used a scope to look around inside and nothing looked out of the ordinary according to my dad (a mechanic who was fully restored over 5 cars alone)

So u are calling it blown due to a misfire? How many miles?

Zero compression on one cylinder could mean many different things. A valve not closing, an open fuel injector or leaking injector ring, are a few things that have nothing to do with the block. On the bottom end a broken ring or damaged ring land might be repairable without having to rebuild the engine.

Was it using oil? Is the dipstick level normal? Is coolant level normal? Has it been run hot? Is there oil or coolant inside the engine bay or on the underside of the car?

It needs to be properly diagnosed.

?

All are good but 4th or all get 0? Scope look at valves?

Take oil fill cap off, stick finger in toward PS and see if timing chain is tight.

Location in profile can also help to see if anyone near you that wants to help.

how many miles on the motor?

sorry I'm slow on the posts works been busy for me, but the engine has 131k on it, I had the timing system redone by the Mazda dealer by me. I'm in Milwaukee Wisconsin. coolant levels have always been good, never ran hot or anything it always stayed under the halfway mark. the oil is a different story, it's always burned oil but I checked it daily and never let it get below the minimum amount needed

recently blown engine
 

I would suggest doing a leak down test to figure out where all the cylinder pressure is going. A simple leak down test can tell us if an exhaust/intake valve is stuck open or it if it's leaking through the rings into the crankcase. Doing this will help you decide on what direction to go.

also, when I checked the cylinder out with the scope, it was obvious and easy to see the scoring on the cylinder walls

Just noticed your sig - DP - did you upgrade internals and/or have a tune?

That could be the cause

Well that isn't "nothing out of the ordinary then"..

Sent from my LG-D850

Open injector/leaking seal isn't going to cause 0 PSI. You'll see pressure build to slightly below normal numbers and then start to bleed off.

no I didn't do either, I put the dp on just over a month ago and was gonna get new internals and an accessport this week or the next

My 1st engine blew about a month after gutting my cats. Hadn't upgraded my HPFP yet either. Sucks man.

DP and no tune may be the culprit. I disagree with dissing of my reasoning on zero compression on one cylinder. Need more info from OP for how he did the test.

Just put stock dp back and blame mazda since they did the timing

I second that motion!