GT350 Engine Refresh Time!

[EF300]

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This is why you need to decide what you will really do with the car and how much HP you will want to make...this will tell you what you need to upgrade and to what level,

Mine current 5.2 is very stout and has lived for two race seasons at 500+ hp level with another 125 shot of nitrous used on occasion. It has mostly stock components. Stock main bolts and stock head bolts. I use old bolts to do the torque plates when it s honed or the rings are measured and only install a fresh set of OEM bolts with lube and torque them for the head install. I am looking into studs now for this engine. they get pricey!! This is still not a full FI fire breathing motor build...yet! Twins someday are coming. So far 600+ hp and 500 torque is really nice and pull like a SC car but without all the extra weight and no extra heat issues. I'm 3600 # and 615 crank hp now. better Power to weight ratio than a Hellcat!

You are 615 at the crank NA ? What mods do u have ?

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[AceOne]

You are 615 at the crank NA ? What mods do u have ?

5.2 Voodoo with CPC crank. CJ Manifold with 65 twin mm TB on pump gas...E85 pump gas. Local pumps are always over 80% ethanol. Longtube headers and very mild headwork. Great tune from local guy. Langs Stangs. 400 torque to the wheels from 3100 to over 7000 rpm. VCT NOT locked out! 438 peak torque. I used the same percent for calculation from 530 SAE wheel hp to get crank numbers as I got when I first dynoed the 2016 5.0 motor using the 435 SAE ford rating to keep the same drivetrain losses. It was right at 14%

 

[AceOne]

Not chasing power this time around. Really looking for an engine I can continue to beat the snot out of for another 2-3 years before I get serious about building an NA monster. Stock power is fine. I won’t argue with more if it comes with better reliability and doesn’t make it temperamental.

Harmonics are the only issue with the FPC so if you change the pistons or rods from OEM just realize the crank needs to be rebalanced. It not that much unless you have to add weight though. So try to keep weight of parts in consideration if you replace with aftermarket. My OEM parts have really held up well and the newer tighter pistons should improve things even more imo. I however, believe my nitrous use might have benefited from the looser setup and may be what keep this motor alive for so long. It all just n educated guess though.

I would not worry about REM finishing. That is only really for highly competitive use IMO . Pics look nice and I am sure there is a benefit but after looking at surfaces of parts that are " Broken in" the surface sure seam to be well polished at that point. Not sure that REM adds durability but Cryo treating parts does seam to add durability.. ie brake rotors for sure and tranny gears maybe. imo

 

[Tomster]

This is all excellent information Kevin. It seems you are putting a LOT of time into this and I would too to make sure it was 100% correct. I'm sure that you looked at the cost of doing it yourself vs having a reputable shop do a refresh like this. Do you have any kind of comparison numbers?

 

[honeybadger]

This is all excellent information Kevin. It seems you are putting a LOT of time into this and I would too to make sure it was 100% correct. I'm sure that you looked at the cost of doing it yourself vs having a reputable shop do a refresh like this. Do you have any kind of comparison numbers?

Yep. From what I can tell, there are 3 paths forward.

1. $300-400 for a DIY essentials only refresh of the bottom end. This would be necessary bearings, piston rings and bolts.
2. $3k for a more thorough refresh (pistons, rods, balancing, etc)
3. $7-10k for a full rebuild. This would include skeeved block and a fully matched, balanced, polished, etc. rotating assembly.

The conundrum for me is no one has suffered a bottom end failure that wasn't caused by an oiling issue from what I've been to gather/find (admittedly lots of reading between the lines). Ford included some damn good internals from the factory. The justification for a tougher bottom end at stock power levels isn't very strong. And I'm hesitant to do a fully built motor because I'm not really wanting something fussy.

And of course everyone has had different recommendations on paths forward

 

[Tomster]

I ask, only because I don't plan to sell the TY R and after reading that Ford recommends a refresh after only 40 hours of track time, it is only a matter of time before I wind up in your shoes. So I take it 3K for all the parts and limited outside work and DIY for all the rest?

I'd opt for option #2. If you are keeping track of your time, it would be helpful for others down the road to estimate labor costs and make a decision to tackle this or sub it out.

I have a friend with a very large shop that I could use, but it comes down to time vs money.

Thanks and nice job so far!

 

[Offboost]

HB

I think you are on a pretty solid path just finish cleaning everything up and replace the bearings and rings (Or you could buy new pistons and rings from a 18 MY) do not hone the block I think you will be asking for trouble as the block is torque plate honed from the factory and even with the minor scoring you see in the cylinders this should not cause any issues.

Put the upgraded heads and springs on add the headers and tune it and you should be good to go. If it was mine I would also at a minimum have the rotating assembly balanced by a good machine shop just for peace of mind it may actually run a little smoother as factory balances leave room for improvement.

If everything is assembled correctly you should have a very solid reliable setup no need to overthink it!

 

[oldbmwfan]

Tend to agree with Offboost. I would avoid a hone if possible. The cost increment from 1-2 is big enough that the incremental benefits of 2 are not worth it - and I think a worst-case outcome means you lose MAYBE a month of track season (probably less). I would be willing to bet you a beer that you can get another 40+ hours out of a ring and bearing job, esp. with the oil pump, cooling, and valvetrain upgrades you're already committed to.

Separately, I applaud your cojones for digging in this far yourself, and I'm impressed at the speed you're moving with it.

 

[bauern]

No worries at all. I just didn't understand the connection so was hoping you could help. It makes sense .

Did you need to gap the rings at all? Or were they correct out of the box for you?

Stock rings were on the tighter end of spec out of the box.

 

[bauern]

Was this a new unbalance crank? We took weight off the front and rear of mine. My OEM pistons varied from 388.1 to 389.6 grams. My bobweight was 1696gm using 51%.

My weights were as follows:

Piston-401 grams
Pin-91
Pin locks-2
Rings-25
Total Rod-607
Rotating rod-431
Bearing pair-52
Oil-5

Total bob weight 1666

 

[honeybadger]

Some added details for us to ponder. I spoke with Ford Performance this morning and got some interesting responses. Summary below:

1. Ford does indeed recommend NOT boring/honing the 5.2 Voodoo block when refreshing/rebuilding. If the cylinders aren't heavily scored, leave as is.
2. The OEM rings are specially designed for use in blocks with the PTWA coatings. It's in the way they break in. It was specifically mentioned that there were "alternatives." Interesting.
3. Refreshing the engine with new rings/bearings only was fine as long as wear looks good (such as in my case).
4. They could not tell me anything about the 2018 piston revisions.
5. When I asked about what they've heard from most folks doing engine refreshes, they said most are upgrading to Mahle pistons.

I got the feeling that the aftermarket pistons from J&E/Mahle, etc. were sort of unofficially endorsed. Could be reading too much between the lines, but there was never a recommendation for the OEM pistons. Hmmmm.....

 

[482supersnake]

It's about 1.523" but not perfectly round. A little narrower top to bottom.

Thanks! That is what I was looking for.

 

[AceOne]

Some added details for us to ponder. I spoke with Ford Performance this morning and got some interesting responses. Summary below:

1. Ford does indeed recommend NOT boring/honing the 5.2 Voodoo block when refreshing/rebuilding. If the cylinders aren't heavily scored, leave as is.
2. The OEM rings are specially designed for use in blocks with the PTWA coatings. It's in the way they break in. It was specifically mentioned that there were "alternatives." Interesting.
3. Refreshing the engine with new rings/bearings only was fine as long as wear looks good (such as in my case).
4. They could not tell me anything about the 2018 piston revisions.
5. When I asked about what they've heard from most folks doing engine refreshes, they said most are upgrading to Mahle pistons.

I got the feeling that the aftermarket pistons from J&E/Mahle, etc. were sort of unofficially endorsed. Could be reading too much between the lines, but there was never a recommendation for the OEM pistons. Hmmmm.....

With the cost of the new OEM pistons at over $1,200 a set I would agree that aftermarket is the way to go now. I am waiting on on confirmation on the pricing from the engineer. As to honing the block yours looks good and just new rings would probably work. When mine was at the 1000 mile mark and I pulled it apart for more head work and crank balance, I hit the walls with WD 40 and scotch brite by hand with 45* cross hatch pattern (I was concerned with the PTWA coating) and new rings and after thorough cleaning the block it has done performed great so far. It might have been the FP guy that suggested this to me or my Engine machinist. That was the first time I had tried that but also my first encounter with the PTWA coating. The hone limit of 94.015 mm is only going to allow for a light honing.

Can you or @bauern post a pic of the full crank? Also get a real weight of it? I would like to see what it came out to compared to the CPC crank, I need to look up some old pics that with mine on the scales. Here is a pic with with 5.2 CPC crank on left and a Coyote crank from an F150 that spun a rod. I used it to verify the stroke differences of the two. CPC 5.2 crank ($1000+) is 93mm and the coyote ($300 ish) is 92.7mm.
extra stroke is to improve quench on the 12:1 engines. Boss cranks are also only 92.7mm.

I'm just curious how much counter balances wound up being used to resolve the harmonics for the FPC.... that was supposed to be an advantage and allow them to be lighter and rev quicker.

Looking at your piston pics...your rings show lots of tension left in them too. I would double check individual piston closely. I am just going by how much they are protruding from the ring lands while laid flat on side of piston. There would be very little protrusion if any had lost tension. I think I cleaned the carbon off the tops of my pistons with Carb cleaner and soft scotch brite.. Make sure ring grooves are REALLY clean. Stiff toothbrush is pretty handy for this.

 

[bauern]

HB will have to give you this. I dont have any photos and only memory of the weight which I want to say was 48.3 lbs. so about three pounds lighter than the CPC.

Can you or @bauern post a pic of the full crank? Also get a real weight of it? I would like to see what it came out to compared to the CPC crank,

$1200 for OEM pistons convinced me right away. The J&E pistons cost me less than $700. AND included the rings in spite of what J&E's website says of rings not included.

 

[honeybadger]

@AceOne here you go. Looks like 47.2 lbs for me (atleast according to the bathroom scale )

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