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Discussion Starter · #1 ·
As you guys may have read in my other thread; I lost compression in one cylinder under boost. Just when it was running great and pulling hard. My build took over 2 years with countless obstacles just like everyone else in this hobby. I'm retired and bouncing off of the walls. I need my Mustang fix.
Anywho....There isn't an available machinist in sight and won't be for some time. Who knows about parts availability. I can't find a fresh short block anywhere.
If any of you have an engine source that isn't backed up for months; please let me know.

My build is just a stock bottom end/cam with boost. I think I'll switch to forged pistons and Total Seal rings for oil control due to wider ring gaps. What are your thoughts on ring types and packages for 12lbs of boost?
Thanks!
 

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Well, that's no bueno. I'd try to determine what actually happened before doing the rebuild, as you don't want it to repeat itself. For example, an injector died or something like that. Good luck with your diagnosis, I'm not help past that.
 

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Discussion Starter · #3 ·
Well, that's no bueno. I'd try to determine what actually happened before doing the rebuild, as you don't want it to repeat itself. For example, an injector died or something like that. Good luck with your diagnosis, I'm not help past that.
I suspect that the ring ends butted under boost as there's no sign of detonation. Thanks.
 
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Discussion Starter · #5 ·
What was your power level?
Is this a common issue?
I haven't been on a dyno yet but the build is usually good for 500rwhp. It's hit or miss with broken rings and ring lands when adding boost. The rings really need wider gaps and that's what I would have done if I built the engine from scratch. This is a 53k original mile engine.
 

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I haven't been on a dyno yet but the build is usually good for 500rwhp. It's hit or miss with broken rings and ring lands when adding boost. The rings really need wider gaps and that's what I would have done if I built the engine from scratch. This is a 53k original mile engine.
That surprises me. I have several friends that ran gobs of boost through 100% stock short/long blocks without any issues. Usually it was poor tuning and detonation that would kill them. That or constantly blowing head gaskets.

Fastest options are finding a junkyard 5.0 or online ordering a shortblock. One of mine I bought from CHP. It ran great.
 

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Discussion Starter · #7 ·
That surprises me. I have several friends that ran gobs of boost through 100% stock short/long blocks without any issues. Usually it was poor tuning and detonation that would kill them. That or constantly blowing head gaskets.

Fastest options are finding a junkyard 5.0 or online ordering a shortblock. One of mine I bought from CHP. It ran great.
It surprised me too, but I have the worst luck. My friends love to tease me about it. Lol. To be honest; I don't trust high mileage junkyard blocks due to said luck. If I have the engine out; I might as well have it machined and use proper pistons and rings. I've looked everywhere online and all I get is "Out Of Stock".
 

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easy peasy.... i do this all the time.. we actually are getting more and more parts in daily and a 302 with 12 lbs of boost is a cakewalk to build.. biggest question WHERE are you and how far are you willing to travel. I have friends that do this all over, so even if your not close, maybe i could point you in the right direction.
 

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Discussion Starter · #9 ·
easy peasy.... i do this all the time.. we actually are getting more and more parts in daily and a 302 with 12 lbs of boost is a cakewalk to build.. biggest question WHERE are you and how far are you willing to travel. I have friends that do this all over, so even if your not close, maybe i could point you in the right direction.
Right? It should have been a smooth deal until it wasn't. Lol. I had oil puking out the breathers under boost. What a mess. It's a good thing that the header wrap didn't catch on fire.
I'm in Phoenix.
 

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If the oil was puking out of the breathers, wouldn’t that indicate that the rings were not sealing well or had too big of gaps? That is compression getting past the rings and pressurizing the crankcase, right?
 

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dang.... hummm thats a ways over there... i know woody is backed up... may could get on his list... if your in a bad hurry, use a ford boss block and build a 331 for boost... any builder can do that... just a slow go for many of them because of the back log of work they are doing. our machine shop isnt performance first... more farming... so we're use to making our own parts... and we arent too far out of availability. mark on here is the piston / ring guy... you may could tear yours apart... sleeve a damaged hole if it's bad.. order the rings and pistons from him... slap it together and go haul ass again. have you inspected your block yet?
 

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Discussion Starter · #12 ·
If the oil was puking out of the breathers, wouldn’t that indicate that the rings were not sealing well or had too big of gaps? That is compression getting past the rings and pressurizing the crankcase, right?
Yes sir. Ring gaps are stock and boost definitely pressurized the crankcase. I drained 6 ozs of oily goop out of the catch can. It went suddenly. I can't wait to pull the pan. I did drain the oil and found nothing. Engine rotates fine by hand. No gouges in cylinder wall.
Either way; I need a fresh shortblock.
 

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Discussion Starter · #13 ·
dang.... hummm thats a ways over there... i know woody is backed up... may could get on his list... if your in a bad hurry, use a ford boss block and build a 331 for boost... any builder can do that... just a slow go for many of them because of the back log of work they are doing. our machine shop isnt performance first... more farming... so we're use to making our own parts... and we arent too far out of availability. mark on here is the piston / ring guy... you may could tear yours apart... sleeve a damaged hole if it's bad.. order the rings and pistons from him... slap it together and go haul ass again. have you inspected your block yet?
I can't finish pulling the block until I'm done mocking up new wastegate locations. The kit is still bolted on partially. It won't take me long to do but I'm hoping to reduce turnaround time by having a block ready to drop in.
 

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Discussion Starter · #14 ·
The culprit; number 8. Looks fine up top.
Automotive tire Motor vehicle Wood Gas Automotive wheel system
 

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Discussion Starter · #19 ·
Here you go.

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