Cylinder 4 Down. Home Engine Rebuild Thread

[tdstuart]

I have a 2015 Mustang GT with 110k miles. Car is fbo N/A (2018im, headers, no cats, e85).

The other night I made a small pull and the check engine light started blinking, no biggy. Got home read the code and it was a miss fire on cylinder 4. The next day I pulled the spark plug and it was melted... I installed new spark plugs and still had a miss fire. Swapped injector coils, swapped injectors, checked that coils and injectors were getting power, and still had a miss fire. Finally got the balls to do a compression test and it is was I had feared, 50lbs on cylinder 4 and 200 ish lbs on cylinder 1.

I had been harder than usual on the car recently and engine temps had gotten hotter than ever before. I have also been having issues with fueling so it was probably my fault cylinder 4 quit.

This is going to be the thread of me rebuilding my engine in my garage. Going to finish work on my mom's car then ill work on pulling the engine and rebuilding it. Before that, Im going to try and get a borescope and compression test the other cylinders. Hopefully, the block is okay.

If you guys have any suggestions on threads for me to read, what you think ultimately lead to the failure, and any suggestions when pulling the engine and rebuilding it, it would be much appreciated. Any suggestions for parts I should replace while I am at it would be much appreciated as well. Ultimately I have an extremely tight budget. About 4k I am willing to spend, and another 4k I really don't want to spend but have access to. I am only 18, so funds are tight haha. If you live in the Mesa/Pheonix area and want to help out that would be appreciated. Luckily I've built a shitty chevy small block before and done a decent amount of work on cars. Just never needed to build an engine to run more than 1min.

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[tdstuart]

Consider one of the auto recyclers for a replacement they are littered with wrecked GTs....

The last time I looked I couldn't find one. I found one on Instagram but he is charging 10k for a motor and trans with 50k miles. He only sells motor and trans together.

 

[Zrussian13]

How hot did you run it?

 

[tdstuart]

How hot did you run it?

260+ my first pull and stopped right at 250 my second.

 

[Zrussian13]

260+ my first pull and stopped right at 250 my second.

Your cht hit 260???

 

[tdstuart]

Your cht hit 260???

Ya looked at my gps for a second and the cooling reached its limit and the temps were just climbing, saw it go from like 240 to 260 in just a few seconds. Again not really surprised the engine finally gave up

 

[HKusp]

These guys are far from you, but you might be able to make a deal worth not having to do a rebuild. Just an idea.

https://leecparts.com/search?page=2&q=mustang+engine

 

[Zrussian13]

Ya looked at my gps for a second and the cooling reached its limit and the temps were just climbing, saw it go from like 240 to 260 in just a few seconds. Again not really surprised the engine finally gave up

Yeah no kidding. I don't think I've ever gone above 235° and if I start approaching 230° I get off the fun pedal. Heat is a big killer with these engines. Good luck with the build.

 

[tdstuart]

These guys are far from you, but you might be able to make a deal worth not having to do a rebuild. Just an idea.

https://leecparts.com/search?page=2&q=mustang+engine

The only thing that looks promising is they have a gen2 shortblock for about 2k. Not a terrible deal.

 

[tdstuart]

Yeah no kidding. I don't think I've ever gone above 235° and if I start approaching 230° I get off the fun pedal. Heat is a big killer with these engines. Good luck with the build.

230 seems to be a safe temp. And thanks hopefully it will be back soon. Probably will upgrade my cooling too haha

 

[tdstuart]

Looks like piston melted a bit. Some scarring on the cylinder walls. Trying to get my pictures of the micro and card but I don’t have a reader smh

 

[tdstuart]

Here are some bad photos of the screen. Will probably need to buy a micro sd to the normal sd card slot.

 

[ice445]

With that much scoring I'd be looking for a used engine, unless you're planning on spending a lot of time and money at a local machine shop. How did you get up to 260 BTW? Sounds like your water pump gave up on life lol

 

[tdstuart]

With that much scoring I'd be looking for a used engine, unless you're planning on spending a lot of time and money at a local machine shop. How did you get up to 260 BTW? Sounds like your water pump gave up on life lol

Naw it’s called going for a top speed. Water pump quickly cooled it down when I let off.

And ya it looks like a good amount of scoring although hard to tell. Current plan is to pull the engine. Disassemble it. Then send it to a shop for them to see what can be done to fix the block. Honestly no idea what to expect for it to be bored and sleeved.

 

[Zrussian13]

Naw it’s called going for a top speed. Water pump quickly cooled it down when I let off.

And ya it looks like a good amount of scoring although hard to tell. Current plan is to pull the engine. Disassemble it. Then send it to a shop for them to see what can be done to fix the block. Honestly no idea what to expect for it to be bored and sleeved.

Alright now I gotta ask where'd you top out at before you over heated the shit out of it?

And why on earth are you going for max speed in AZ in May? That's January/ February type stuff out here.

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