Dyno Video: 5500 RPMs And It Broke!

R

ROADWARRIORSVT

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I was breaking in my F-2M blown 97 Cobra, not a 94 as said in the vid. Absolutely the best parts $$$ can buy. It was assembled at local machine shop here in Hawaii. Can't point a finger at anyone until I disassemble the motor and try to see what went wrong. Three pulls at 1/2 throttle, was gonna make three at 3/4 throttle. On the first pull at 5500 RPMs, the throttlebody elbow blows off. I'm guessing that is why all the black smoke at the end? Cranked it up for the next pull and have a clanking under the valve cover. It has now gotton worse. It has Diamond pistons, Manley billet rods, forged crank, etc. So a parts failure at 5500 RPMs is doubtful. I may try a scope to look inside before pulling the brand new motor. Here is a pic of the #8 spark plug I took out during a compresion test. No scrapes, nicks, etc. on it or any of the plugs. Oil pressure is good still.

Compresion Test Results
Cylinder # 1: 200
Cylinder # 2: 170
Cylinder # 3: 165
Cylinder # 4: 155
Cylinder # 5: 165
Cylinder # 6: 130
Cylinder # 7: 145
Cylinder # 8: 140 (bent spark plug grounding strap)



Please "Right Click Save As"
Motor Break In Dyno Pulls


sparkplug.gif
 
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ScrpnVNM

ScrpnVNM

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#6 has the lower comp. why not check that one? heck almost all cyl. have very diff. comp readings :shrug: (I may need schooling on this topic!)
 
J

JP96cobra

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Say it aint so Tommy. That sucks so bad. I know you worked your a$$ off to get that car together. Hopefully its not a big expensive problem. Looks like your going to have some more long nights in the mustang garage. Let me know if you need a hand or moral support. lol
 
R

ROADWARRIORSVT

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ScrpnVNM said:
ok, I don't get that one. not a nitrous guy here, but I say that's a pretty narrow gap there!
Click to expand...


ScrpnVNM,
We're just joking around about the "gap" on the spark plug. Something slammed the grounding strap against the electrode. This may be the cause/source of my problem. I'll be visiting the machine shop tomorrow that assembled the shortblock. :bash:
 
D

dirtchicken

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That sucks. Alan dyno'd my Lightning when I first got the engine back together. I need to go back again sometime. Hope you get everything worked out.
 
R

ROADWARRIORSVT

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Going down to Ted's Machine Shop and see what they will/won't do for me. They assembled the shortblock. They may want to open up the engine themselfs. Either way, the engine is getting unbuttoned! :mj: :cuss:
 
EV1L_SVT

EV1L_SVT

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Just curious... Would it have been better to break it in without using the blower? I hope it's nothing serious though, good luck to ya...
 
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Booyah

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I wouldn't let the machine shop that assembled it dissamble it. If they left something in the bore or didn't assemble something correctly I highly doubt they'll admit it if you let them tear it down. Kind of like letting the Wolf investigate missing sheep.
 
Demonio1023

Demonio1023

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What isthe 'prefered' cylinder compression for your engine? and why do they all vary by so much? Good luck with your car .
 

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