Teardown and rebuild Thread: Converting GT350 race motor to CPC

[shogun32]

Per your point, if you're not going to rev it to the moon, you better have stroke to make up for it.

one american boutique supercar shop just released their v8 and it revs to 12,000. Name escapes me ATM.

With all that room in the V, a secondary shaft might have been possible.
PS. Oops, sorry to clutter the thread.

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[Angrey]

I'd like to explore this idea some more, is it possible to run a coyote PCM and change the firing order?

 

[honeybadger]

I'd like to explore this idea some more, is it possible to run a coyote PCM and change the firing order?

No need. You just re-pin the harness to changing the firing order. Dropping in a new ECU will add an entire other set of problems.

 

[Angrey]

No need. You just re-pin the harness to changing the firing order. Dropping in a new ECU will add an entire other set of problems.

Does that create all sorts of logic and sensor workarounds? Or does a tuner patch all that so when it misfires on a cylinder or a bank goes lean or whatevs. Seems like it will work, but will it create frustrations elsewhere?

The reason I'm asking is because it would be REALLY interesting to hear a coyote with the modular firing order. I wonder if it could be done just temporarily to see how it works for a bit.

 

[Cobra Jet]

@honeybadger

Very interesting thread.

Aside from the findings on YOUR engine, for someone else with a completely stock, untouched engine - should a crack at the crank snout or main cap bolts falling out be of any concern?

What if someone with a complete stock VooDoo needed a new clutch kit, but didn't want to go with stock? Do they have to fear of crank snout cracks?

Also have you sent photos of the dislodged main cap bolt or the cracked crank to anyone at Ford or Ford Performance to get a response to the matter?

Was the harmonic balancer on the engine ever serviced? What condition is that in? Was it still the stock balancer?

Usually a cracked or broken crank snout could obviously result from an imbalance and sever harmonics - but could also result from:

A harmonic balancer that is failing or was not installed/torqued properly

or

The replacement of a harmonic balancer OR flywheel where the weight of each part did not match. For hypothetical instance, if flywheel is a 50oz flywheel, the balancer should always be the same to "match" so that the rotating assembly is not out of balance.

 

[RPDBlueMoon]

Yep - I've followed both Nick and Fred's journeys closely. I plan to add to their efforts with details on the motors themselves. I'll be doing the re-assembly in the ol' garage this time. Tim is just sending me a balanced crank to drop in.

So basically your engine is going to be extremely similar to the 5.2L crate engine called the Aluminator? I think it was you who told me that only difference between the engine in the GT4 by multimatic and 5.2L Aluminator is the GT4 class regulations.

 

[Captdistraction]

I still contend the crank crack is a combination of the vibration in use with the tightness of the aftermarket damper interference fit. When they're too tight and put into road-race type duty cycles, the damage makes its way there. Thankfully it didn't shear like mine (and others did).

Excited to see this setup come to fruition, I'm sure it will be turned up to 11 like most things you do.

 

[Hack]

The crack in the crankshaft is a fatigue failure. Usually there is a higher stress area like a small radius or a small material defect that serves as the origination point for the crack. Something like a scratch or a casting parting line can serve as a stress riser as well. Load and cyclical vibrations cause the crack to propogate (grow) over time. It would be interesting to look closely at the crankshaft and try to determine where the crack started.

Once a part has completely failed due to cyclical fatigue, you can tell that fatigue is the cause by looking at the crack. The originating areas will be polished or worn over time from vibrating against each other, and then the final failure area will be sharp and new. In this case, I believe it has to be fatigue because there's nothing else that would cause the crack. Obviously the crank wasn't loaded to beyond the material yield point. In that case it would have failed immediately, rather than having a slowly growing crack.

Congrats for catching this prior to a catastrophic failure, Kevin! Completely amazing that you managed it. The rebuild would have been a lot more costly if the crank had completely failed.

 

[JAJ]

Does that create all sorts of logic and sensor workarounds? Or does a tuner patch all that so when it misfires on a cylinder or a bank goes lean or whatevs. Seems like it will work, but will it create frustrations elsewhere?

The reason I'm asking is because it would be REALLY interesting to hear a coyote with the modular firing order. I wonder if it could be done just temporarily to see how it works for a bit.

No need. You just re-pin the harness to changing the firing order. Dropping in a new ECU will add an entire other set of problems.

The ECU has a table for firing order. It has to be changed in addition to rewiring the fuel and spark harnesses. The ECU has to know which cylinder fires when so the knock sensor works right and so things like misfire detection detect the right cylinder. Tuners who've done a conversion before will have figured it out already.

 

[WItoTX]

Thanks for posting this. I have feared since day 1 of my car having something catastrophic happen to the engine much like you ran into. I knew all this going into the purchase, but I mean c'mon, one of the best looking Mustangs ever, combined with a FPC?!

I know the day will come, and am thinking I will do exactly what you are doing, so this thread might be immensely helpful one day (hopefully not). Look forward to the updates!

 

[stanglife]

I hope everyone realizes this isn't the norm. This is the most extreme example you're going to see. Ford sold a track day car, not a race car. Not many of us would have bought the race car because no matter what, you're measuring major service by the hours at that point, and not the miles...FPC or not.

 

[Epiphany]

So basically your engine is going to be extremely similar to the 5.2L crate engine called the Aluminator? I think it was you who told me that only difference between the engine in the GT4 by multimatic and 5.2L Aluminator is the GT4 class regulations.

The Aluminator is done by Performance Assembly Solutions.
https://www.performanceas.com/

The GT4 engine is done by Roush/Yates Engines.
https://roushyates.com/engines/ford-mustang/

 

[honeybadger]

@honeybadger

Very interesting thread.

Aside from the findings on YOUR engine, for someone else with a completely stock, untouched engine - should a crack at the crank snout or main cap bolts falling out be of any concern?

What if someone with a complete stock VooDoo needed a new clutch kit, but didn't want to go with stock? Do they have to fear of crank snout cracks?

Also have you sent photos of the dislodged main cap bolt or the cracked crank to anyone at Ford or Ford Performance to get a response to the matter?

Was the harmonic balancer on the engine ever serviced? What condition is that in? Was it still the stock balancer?

Usually a cracked or broken crank snout could obviously result from an imbalance and sever harmonics - but could also result from:

A harmonic balancer that is failing or was not installed/torqued properly

or

The replacement of a harmonic balancer OR flywheel where the weight of each part did not match. For hypothetical instance, if flywheel is a 50oz flywheel, the balancer should always be the same to "match" so that the rotating assembly is not out of balance.

I haven't sent the crack in the snout to FP, but I might depending on what I hear back on the other questions I have out to them.

Regarding your other questions, the ATI Super Damper I was using was the first time I've run it on this engine. In fairness, that was a change from the previous "versions" of this engine. Possible it could be related...Could also be coincidence timing and the crank finally failed from fatigue. There's evidence to suggest both options are viable.

Regarding your own/stock engine, my suggestion is to change nothing related to NVH - motor mounts, balancer, flywheel/clutch, exhaust manifold, or trans mount. All are bespoke to the FPC 5.2 and all are a potential cause of failure. None of them are particularly weak points in the engine, so I really don't think you need to change them. As Billy J told me, the further you go from stock that faster it will fail...

So basically your engine is going to be extremely similar to the 5.2L crate engine called the Aluminator? I think it was you who told me that only difference between the engine in the GT4 by multimatic and 5.2L Aluminator is the GT4 class regulations.

In broad terms, correct. Roush Yates is fairly quiet about the GT4 from what I've seen, but it appears to be largely similar to the 5.2 XS with some of their special developed parts to improve reliability (chain guides, dry sump, springs, etc.).

I still contend the crank crack is a combination of the vibration in use with the tightness of the aftermarket damper interference fit. When they're too tight and put into road-race type duty cycles, the damage makes its way there. Thankfully it didn't shear like mine (and others did).

Excited to see this setup come to fruition, I'm sure it will be turned up to 11 like most things you do.

I think this is a valid concern. I need to speak to Roush Yates or Watson to see if I can uncover why the GT4 cars use what looks like an OEM balancer.

And yep, goal is to still have something a bit wild, but going to listen to the experts on some of the key items to longevity (proven dry sump setup, etc.). But would like 540-550 hp to the wheels

Thanks for posting this. I have feared since day 1 of my car having something catastrophic happen to the engine much like you ran into. I knew all this going into the purchase, but I mean c'mon, one of the best looking Mustangs ever, combined with a FPC?!

I know the day will come, and am thinking I will do exactly what you are doing, so this thread might be immensely helpful one day (hopefully not). Look forward to the updates!

Glad I can contribute and hopefully help others now and in the future.

I do just want to reiterate what @stanglife said. There's a big difference in what this car does compared to what a stock motor in a dual purpose car sees. I have plenty of friends with cars that have been tracked hard for 5 years and have had zero issues--but they're all stock.

 

[honeybadger]

I finished fully disassembling the block today. No surprise. Pistons show no signs of being "cooked" like after the V1 cycle and the chambers look great. Couple areas where it's clear the pistons have rubbed, but nothing deep enough to be concerned. Still lots of cross hatching. Looks like we're in luck and will just need new cams, crank, bearings, piston rings, and timing stuff.

 

[earlrengland]

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.

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