Teardown and rebuild Thread: Converting GT350 race motor to CPC

guzie

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This thread has me freaking out now. I just put long tubes, Borla cat backs and BMR poly motor mounts on my car, not to mention the flex fuel tune from PBD. :crying:
Your fine. The long tubes and motor mount with tune aren’t going to cause this. The headers are not part of the engine balance. This engine in the tear down has been exclusive use on track at constant high rpm with a non oem balancer. Jury is still out on that. Don’t equate what you read here to ”my motor is going to grenade if I put a tune or long tubes on it”. The tune is just tweaking fuel/air ratios, timing advance, etc to make the most power with given components. The motor in this thread was in no way killed due to tuning. No detonation. Tune was fine. Power he was making wasn’t pushing it be any means. If anything, the tune was conservative with just 500 at the wheels on E85 and with long tubes. 510-520 at the wheels is pretty common with E85 and long tubes. Don’t mess with the internals, flywheel or dampener. Those will impact the motor balance and vibrations.

 

Lorne34

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I have to say that I appreciate the honesty and balanced perspective. I for one came into this understanding that this is a unique motor and FPC build. I was not planning on modifying my 350 other than some cosmetic things.
After wrestling with all of the voodoo motor threads on oil consumption, I decided to take the lleap anyway. My though was that if the engine ever failed down the road and there were availability issues with the Voodoo motor I would just put a solid CPC engine in because I love the looks and dynamics of this car even without the voodoo sound (but I would miss that sound).
 
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honeybadger

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I have to say that I appreciate the honesty and balanced perspective. I for one came into this understanding that this is a unique motor and FPC build. I was not planning on modifying my 350 other than some cosmetic things.
After wrestling with all of the voodoo motor threads on oil consumption, I decided to take the lleap anyway. My though was that if the engine ever failed down the road and there were availability issues with the Voodoo motor I would just put a solid CPC engine in because I love the looks and dynamics of this car even without the voodoo sound (but I would miss that sound).
Sounds like you have the right approach. Just enjoy it and don't over analyze. But when the time comes, switch to CPC if warranty isn't paying for it!
 

Gogoggansgo

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You also stated problems most likely to be in the 5 to 8k rpm ranges. I wonder,
does anyone know how the Ford school cars held up since they probably
mostly lived in that range?
Thanks
they didn’t hold up all that well, as far as i know 90 percent of the school cars had replacement engines and some with multiple replacements. Also they had a lot of issues with cracked headers
 

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The stroke of the Voodoo is a lot more than what Ferrari used on their FPC engines. Ferrari has similar bore sizes but the strokes are close to 3" not the 3.66" and that can cause issues with balancing. Maybe it needed a balance shaft to help with the harmonics, but not all FPC engines have them. I think Ford just compromised to much with trying to retain coyote like architecture instead of giving it a clean slate like it deserved. Also the use of timing belts vs. chains would probably help since belts absorb harmonics better, but would require more frequent service due to belt stretch and rpm. Maybe GM will get it right, just have to wait and see once they get into real world scenarios and not in controlled tests.
100 percent correct, as a Ducati V4 owner the only issue i see for the LT5 is the fact it’s an mechanical valve train, that apparently doesn’t need any servicing. I don’t buy that
 


shogun32

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100 percent correct, as a Ducati V4 owner the only issue i see for the LT5 is the fact it’s an mechanical valve train, that apparently doesn’t need any servicing. I don’t buy that
probably correct in so much that heavy/constant use of 5000-8000 will require shim changes reasonably often. Isn't it cool that Corvette owners get to join the Desmo valve adjustment club with eye-bleeding shop labor prices? :)

GM should do a marketing push - a Ducati in every Corvette garage... I mean you both carry VISA as your road-side assistance program.
 

CANTWN4LSN

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Sounds like you have the right approach. Just enjoy it and don't over analyze. But when the time comes, switch to CPC if warranty isn't paying for it!
My thought is the same. Unfortunately for those of us without your talents, for street use there isn't a 5.2L CPC available, correct? Wonder if the cost to have someone build and install one for us would be much cheaper than just replacing the voodoo? Doesn't look like the S650 will come with a Boss version with a 5.2L CPC which is what I was hoping for.
 

Bluelightning

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My thought is the same. Unfortunately for those of us without your talents, for street use there isn't a 5.2L CPC available, correct? Wonder if the cost to have someone build and install one for us would be much cheaper than just replacing the voodoo? Doesn't look like the S650 will come with a Boss version with a 5.2L CPC which is what I was hoping for.
You can buy a complete 5.2 crate engine from Ford Performance, or there are multiple builders that will build a short block for you.
 

JeremyPro5.0

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Admittedly I did not read the full thread.
Looking at the pics in the first post for #5 cap it looks like a dark greying area in between the cap and the block.

Any chance you were getting detonation???
That would definitely not help engine vibration in a big way.
 

azshelby350

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they didn’t hold up all that well, as far as i know 90 percent of the school cars had replacement engines and some with multiple replacements. Also they had a lot of issues with cracked headers
Bingo. My #9 car blew its first motor at ~7k miles and took out the clutch and trans too. Both headers were replaced separately thereafter due to cracks. Then engine two blew up around 13k miles. Good news I now have a car with only a 3k-mile old Gen 2 block and the clutch, shifter, and exhaust are getting replaced with aftermarket components next week and we’re rebuilding the rear end too.
 

Bullitt Tooth Tony

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Maybe I'm naive, but wouldn't an FPC in the typical UDDU configuration fix a lot of these problems?
Obviously it's not as simple as that and would require more work than just replacing the crank, but I assume there aren't any aftermarket cranks with the pins in UDDU configuration due to lack of demand to break even?
 

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Maybe I'm naive, but wouldn't an FPC in the typical UDDU configuration fix a lot of these problems?
Obviously it's not as simple as that and would require more work than just replacing the crank, but I assume there aren't any aftermarket cranks with the pins in UDDU configuration due to lack of demand to break even?
yes it would help because the engine wouldn’t be a rocking Couple anymore “this is why the gt350s have so many nvh issues that can’t be solved just by adding weights to the crank” i work for ford and I’m not talking dealerships level here. For a good while the gt350 project was going to canceled because frpp kept having major engine failures on the stand, it’s was a mess. They eventually buttoned up the engine enough to make it viable for production . But back too a traditional FPC crank The big problem would be tuning “Ferrari uses two independent ecus For each bank” and making an intake manifold to work properly. This would be extremely expensive to do but possible
 

Gogoggansgo

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probably correct in so much that heavy/constant use of 5000-8000 will require shim changes reasonably often. Isn't it cool that Corvette owners get to join the Desmo valve adjustment club with eye-bleeding shop labor prices? :)

GM should do a marketing push - a Ducati in every Corvette garage... I mean you both carry VISA as your road-side assistance program.
After Audi bought out Ducati in 2012 any reliability jokes go out the door, my V4 has been more reliable from abuse than my coyote was lol
Joking around aside the dealer network is no worse than bmw or Audi. I always heard people crying about Ducati service then take the bikes to a shop in the city like no crap lol. I use motorworks chicago for my yearly and Ducati Indy which is 120 an hour for anything else.
 

shogun32

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i work for ford and I’m not talking dealerships level here. For a good while the gt350 project was going to canceled because frpp kept having major engine failures on the stand, it’s was a mess.
I always wondered if you're going to abandon the sound and UDDU why not do a big-bang.
 

 
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