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Discussion Starter #1
Hey guys,

Just thought I'd throw it out there some pictures of my brother's '97 Cobra engine that let go. I think this displays pretty well what happens to a non-HCM 4.6 does when you do a long hard pull, and its exacerbated by gunky IMRCs!

Design Flaw - Ford 4.6 Coolant Flow and IMRCs - Did It Myself
 

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Interesting... You think that black "gunk" is from the IMRCs? What happened to motor when you say it "let go". What was the set up?
 

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My brothers Cobra was mostly stock when he bought it at 118k miles. I'm ashamed to even admit it because it seems so silly now but this car had the perfect storm of issues. For one, I think someone messed with the gauge cluster and PATS system because if you unlock the door with the key, the alarm goes off, but using the remote is fine. We also came to find that the gauges had been messed with. The tach was reading, #### you not, 1,000 rpm low and the speedo was about 10 mph high, but the was static, not increasingly high with speed. He took a while to recover from the purchase of the car and had other things to deal with so he couldnt get things figured out right away. It wasnt until I bought him an OBD2 scanner tool for christmas that we got the gauges figured out and came to find it had 4.10s, we corrected the gauges, and also confirmed our suspicions that the IMRCs were shut the whole time and it was running in 2v mode. When youre in your first 4v after having nothing but 2vs, gears and messed up gauges makes it very hard to figure things out. Anyways, we dropped it off at the local mustang shop and they dynod it at about 160 rwhp before, 255 rwhp after locking the IMRCs open and cleaning up the tune. Thus, phase 2 began and it felt like a totally different car. We went on a pleasure cruise one day and did some nice, riteous romping on it, including a long pull in third and fourth, and it popped. It made it home but struggled to even start, blue and white smoke like crqzy, knocking, etc. Thus, phase 3! We got the engine out and compression teated it and it didnt hold any lol. I think so much gunk had built up from running in 2v mode for so long that releasing the untapped 100rwhp and the heat that came with it passed all that garbage on into thr combustion chambers and ruined the valves. As seen in the pictures, #7&#8 got hit the hardest, but it also had 142k miles on it when it died and we know it lived a hard life so its alright. Just wanted to post up the pics of 7 and 8.
 

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Sounds like your trouble is with the previous owner, and not with Ford. What do you mean by 2v mode? IMRC changes intake runner length

The amount of garbage in the cylinder is impressive, sorry about the motor. Hope the block is still good
 

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Discussion Starter #6
The previous owners definitely ran this car hard, I'm not contesting that at all.

What I mean by 2v mode is the IMRC actuator wasn't working and not opening the secondary intake ports above 3k like it should. They don't change runner length. They block the secondaries. Technically I should say 3v mode since both exhaust ports are open all the time.
 

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Discussion Starter #8
He bought and rebuilt a 99 cobra motor. We're just waiting til spring to drop it in and get it tuned. I'm going to buy his teksid shortblock from him if the block and crank arent ruined and build it for my 99 GT to cut some weight off the nose :)
 
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