GT350 Heads w/ Coyote Cams?

[JDMac34]

I'm rebuilding my engine and noticed that I'll probably not be able to reuse my heads like I was planning. The cams might be reusable but the caps are scored pretty bad.



I haven't completely ruled out the possibility of line boring my heads, but I don't like the idea of it. My next plan was to find some Gen2 heads but I don't see any good sets for sale anywhere. When I called the dealer that has my Gen3 short block they told me that Gen2 heads are on backorder. I'd still like to go the Gen2 route but stumbled upon a set of GT350 Voodoo heads that are reasonably close to me. I like the idea of GT350 Voodoo heads on a Gen3, but have heard some questionable things about fitment. MMR has a set of rockers that allow you to use Voodoo valves and valve springs with Coyote cams. Since this is going in my 2011 I'd likely run L&M Gen1 "Intake Only" cams, Gen2 exhaust cams, and Gen1 timing set. Ford Performance seems to have offered a set of cams with the Voodoo base diameter and spacing but with the coyote firing order, but they don't seem to be in stock anywhere for the Gen1 option. Here is a link to another forum where MMR explains this problem.

Does anybody on here have GT350 Voodoo heads on their Gen1-3 Coyote? If so, do you use the MMR rockers or did you opt for the Ford Performance cams?

 

[bauern]

I'm rebuilding my engine and noticed that I'll probably not be able to reuse my heads like I was planning. The cams might be reusable but the caps are scored pretty bad.

View attachment 97213

I haven't completely ruled out the possibility of line boring my heads, but I don't like the idea of it. My next plan was to find some Gen2 heads but I don't see any good sets for sale anywhere. When I called the dealer that has my Gen3 short block they told me that Gen2 heads are on backorder. I'd still like to go the Gen2 route but stumbled upon a set of GT350 Voodoo heads that are reasonably close to me. I like the idea of GT350 Voodoo heads on a Gen3, but have heard some questionable things about fitment. MMR has a set of rockers that allow you to use Voodoo valves and valve springs with Coyote cams. Since this is going in my 2011 I'd likely run L&M Gen1 "Intake Only" cams, Gen2 exhaust cams, and Gen1 timing set. Ford Performance seems to have offered a set of cams with the Voodoo base diameter and spacing but with the coyote firing order, but they don't seem to be in stock anywhere for the Gen1 option. Here is a link to another forum where MMR explains this problem.

Does anybody on here have GT350 Voodoo heads on their Gen1-3 Coyote? If so, do you use the MMR rockers or did you opt for the Ford Performance cams?

Ford performance dropped the Gen1 Voodoo cross plane cams from the catalog a while ago so they won't be available. Judging by the installation instructions, I don't think you can use a Gen2 cam with Gen1 phasers, the pins on the phasers won't line up with the cam nose, with the cams still in the neutral position especially if you combine a Gen1 cam with a Gen2 cam.
Just my own opinion, but I wouldn't use the machined MMR rockers because I don't know how the mixing of parts effects the cam/rocker relationship. Modular head shop grinds Gen1 cams for Voodoo heads but they seem to be race cams
FWIW only the left side Gen2 head is on back order.

 

[JDMac34]

FWIW only the left side Gen2 head is on back order.

I called two different parts guys yesterday and both of them said that both heads are on back order. Is there a chance that your dealer might have them in stock?

 

[bauern]

I called two different parts guys yesterday and both of them said that both heads are on back order. Is there a chance that your dealer might have them in stock?

I looked on parts.ford.com, the right one is available (as of time I checked)

 

[MrBD1348]

Here’s the only dealers in the country with gen 2 coyote heads. Backorder is accurate for both and no ETA for off backorder date unfortunately. But you can try calling those dealers and getting your hands on them.

 

[captdistraction]

If you are open to tracking down some valves, I know a guy with some new Gen1 boss heads (and a couple used sets)

 

[JDMac34]

Here’s the only dealers in the country with gen 2 coyote heads. Backorder is accurate for both and no ETA for off backorder date unfortunately. But you can try calling those dealers and getting your hands on them.

View attachment 97234View attachment 97235

Whatever website this is, it looks super helpful. I'm trying to track down an oil filter adapter now. Is that a dealer-only thing?

 

[MrBD1348]

Whatever website this is, it looks super helpful. I'm trying to track down an oil filter adapter now. Is that a dealer-only thing?

Yeah it’s only dealer available. Happy to track down some parts if you need help

 

[JDMac34]

Following-up on this thread, and I don't think that it is a positive one.

Everything seemed to fit great and started up fine. No weird noises, smooth idle, and whatnot. I did an oil change after a short break-in period and did my first datalog for Shaun at AED. He noticed that the long-term fuel trims were off.

Long-Term Fuel Trims (Datalog 1)	Bank 1	Bank 2
Part Throttle	1.06	1.08
Idle	1.07	1.18
WOT	1.05	1.09

After this was pointed out I replaced the O2 sensors (since they were probably fouled from my catch can overflowing before the engine blew up) and fixed a loose bung in the intake tube that could have been a leak. I'm still on the same base tune that I was given.

Long-Term Fuel Trims (Datalog 2)	Bank 1	Bank 2
Part Throttle	1.00	1.00 - 1.02 (tapered up towards the very end)
Idle	1.11	1.21
WOT	1.00	1.04

The part throttle and WOT trims are a lot better now, but still off by a little. The idle trims are off by more, which is unfortunate. I have checked for vacuum leaks and ruled those out. I swapped injectors from bank to bank and have ruled those out. I don't hear or feel any exhaust leaks.

I've gotten to the point where I'm ready to throw in the towel and hand the car off to somebody with more experience. I was calling around to a few different shops to see who was available and one of the shops asked what cams and heads I have in the car. When I told him Voodoo heads, Coyote Cams, and MMR modified rockers he responded with "yep..." He explained that the modified rockers on the longer valve could cause one bank's valves to open and close a little early and the other bank to be a little late. Apparently, he looked into it before and decided to go a different direction. He gave me L&M's phone number and suggested that I talk to him about my situation. L&M agreed that could be what is happening and that an exhaust leak causing my trims to be off by 10% from bank to bank would be audible.

So here I am, stumped more than ever. The cam/valve theory makes sense to me, but I want to be sure that is my problem before I drop the engine again and spend another $3k on cams and all of the parts/hardware to do it right. Has anybody else seen this issue?

 

[mwjscn]

Set the engine to TDC on any cylinder so the valves should be closed and sealed and install a leak-down tester in the spark plug location on that particular cylinder. You can also unscrew the valve core out of the leak down tester and just shoot straight shop air into the cylinder and listen if you hear it whistling past the valves, but the leak-down numbers would be more empirical. That would be my first least-invasive test.

From what I can find, the Voodoo valve springs have a different installed height at 46mm than the gen 1 Coyote at 40mm, so unless the seat is lower they would definitely be taller. I understand the idea of the MMR pieces is to get around that, but it may be worth measuring the MMR ones compared to your old Gen 1 version if you ever do take the engine down. Maybe they forgot to fully machine the set, or whatever changes they make to it.

 

[JDMac34]

Set the engine to TDC on any cylinder so the valves should be closed and sealed and install a leak-down tester in the spark plug location on that particular cylinder. You can also unscrew the valve core out of the leak down tester and just shoot straight shop air into the cylinder and listen if you hear it whistling past the valves, but the leak-down numbers would be more empirical. That would be my first least-invasive test.

From what I can find, the Voodoo valve springs have a different installed height at 46mm than the gen 1 Coyote at 40mm, so unless the seat is lower they would definitely be taller. I understand the idea of the MMR pieces is to get around that, but it may be worth measuring the MMR ones compared to your old Gen 1 version if you ever do take the engine down. Maybe they forgot to fully machine the set, or whatever changes they make to it.

My understanding is that MMR machines the clearance into an OEM coyote rocker so that the larger base diameter of the lobe doesn't hit the rocker outside of the roller. I didn't get to spin the engine over much before I put the covers on, but I did check to make sure each rocker I installed had the relief machined into it.

I'll add a leak-down test to the list - good idea

MMR also ships the rocker out without the little metal clip on the end.

 

[Dave_W]

He explained that the modified rockers on the longer valve could cause one bank's valves to open and close a little early and the other bank to be a little late.

That sounds like a cam phasing issue. Can it be fixed with some kind of VVT adjustment? Maybe program the ECU to advance/retard one bank's cam a few degrees compared to the other bank (if you can control that)?

 

[bauern]

My understanding is that MMR machines the clearance into an OEM coyote rocker so that the larger base diameter of the lobe doesn't hit the rocker outside of the roller. I didn't get to spin the engine over much before I put the covers on, but I did check to make sure each rocker I installed had the relief machined into it.

I'll add a leak-down test to the list - good idea

MMR also ships the rocker out without the little metal clip on the end.

That is my issue with the modified rockers. If properly aligned over the roller, the cam lobe should never hit the rocker arm body, even with a larger base circle cam (it would just hold the valve open). The misalignment changes the cam numbers that the valve sees, open/closing times, duration and lift.

And FWIW Voodoo engines didn't use the clips.