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Voodoo 5.2 block for a DIY A52XS

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ArizonaBOSS

Because racecar.
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Thanks for sharing your learnings, regardless of what happened. Sounds like some painful lessons but you are on-track for some real good stuff. Shaun is the man.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
voodoo child21 said:
Steve
What about just using the GT350 rods and piston package? Are the big ends a different size? I don't think so and they are in engines warrantied for 8250 RPM operation. Valve reliefs shouldn't be an issue since they are bigger. I would ask around.
Steve
thats a good potential option. i have no idea what their part numbers are, but its worth looking into. the biggest potential issue is the valve reliefs might be in the wrong spot. since the voodoo heads have spread out the valves, the angles may have changed to the point that the PTV clearance may end up on an angle. I do have less lift than the voodoo cams, so that may negate any angular differences. then as you mentioned, we don't know if the crank side rod journals are the same diameter. its just so risky.
 
pufferfish said:
well, my conversation with Tim at MPR was enlightening. Basically, my pistons are wrong and so are the rings. So, I'm going to have to cough up another $1100 or so and wait 4 weeks for custom pistons to be made. UUGGH!

I am now very glad I didn't decide to push through the weekend on track.

Heres the synopsis. While Ford claims no special rings are needed for the voodoo block, they do actually need special rings. When he discussed ring materials, I had no idea what they were or if they differed from standard rings, but what caught my attention was the need for high tension oil rings. The higher cylinder expansion needs higher tension rings to control oil better. Next, the top ring land in the piston neeeds to be vented to allow the top ring to stay seated. The Manley pistons do not have this. On the plus side, I am dialing up 12:1 compression, cuz it costs me nothing more and will push out more torque.

So, this is officially not a low cost 5.2L build. The special parts required are pushing the price to the point of a sleeved big bore aftermarket short block. I do think there are a few distinct advantages to the voodoo block, such as lighter curb weight, better cylinder cooling (for 12:1 compression on 93 octane), better piston squirter technology. But, on the downside is long-lead specialty parts and the inability to recondition the cylinders at the end of its lifespan. The block strength is probably negligable, when comparing a sleeved aftermarket block to the voodoo block.

Holy schnikes that is a blow to the gut. I'm with you on the GT350 rotating assembly. Until someone can confirm the rod journal size it is a no go at all. Even the valve relief with the smaller lift i think would be a bit risky. I do know some people have put GT350 heads on cars, but I don't believe many companies will make a specific piston for the GT350 heads spaced out valves so I don't believe that they would be any different. Any plans on the motor as of yet or are you still in the wait and gather info phase?
 

Mad Hatter

Gotta go Faster
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Santiago, Chile
In the end you will end up with a awesome engine! Do you think that the Ford 90mm TB would work well with out waiting for someone to make a updated tune for the GT350 TB?
 

TMSBOSS

Spending my pension on car parts and track fees.
7,530
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Illinois
pufferfish said:
well, my conversation with Tim at MPR was enlightening. Basically, my pistons are wrong and so are the rings. So, I'm going to have to cough up another $1100 or so and wait 4 weeks for custom pistons to be made. UUGGH!

I am now very glad I didn't decide to push through the weekend on track.

Heres the synopsis. While Ford claims no special rings are needed for the voodoo block, they do actually need special rings. When he discussed ring materials, I had no idea what they were or if they differed from standard rings, but what caught my attention was the need for high tension oil rings. The higher cylinder expansion needs higher tension rings to control oil better. Next, the top ring land in the piston neeeds to be vented to allow the top ring to stay seated. The Manley pistons do not have this. On the plus side, I am dialing up 12:1 compression, cuz it costs me nothing more and will push out more torque.

So, this is officially not a low cost 5.2L build. The special parts required are pushing the price to the point of a sleeved big bore aftermarket short block. I do think there are a few distinct advantages to the voodoo block, such as lighter curb weight, better cylinder cooling (for 12:1 compression on 93 octane), better piston squirter technology. But, on the downside is long-lead specialty parts and the inability to recondition the cylinders at the end of its lifespan. The block strength is probably negligable, when comparing a sleeved aftermarket block to the voodoo block.


Steve

Is it possible to modify your current pistons, add the venting?

Some machine work and new rings??
 

pufferfish

Supporting Vendor
1,094
66
Maryland
so, i have ordered 1 piston and rod assembly for the gt350. when it arrives, i will evaluate it for its viability. i am hoping the piston will work with my I-beam rods, as i like those much better than the sinter forged H-beams, but if I have to use the gt350 rods, so be it. they are designed for rpm.

as for the throttle body, I do believe the 90mm Ford Racing would make great power. I just don't trust them to be reliable on track.

this has been a tough learning curve and I am not really sure where its all going to end up. i have been giving some serious thought to running NASA American Iron. whether that is with the ole 2011 gt boss or a v6 body with a coyote swap, remains to be seen, as well as how serious i am about running. i have a lot of seat time piloting this 3800lb pig of a car with its mostly stock suspension and my 2nd place TT3 finish was just a few tenths shy of the AI lap record at Summit Point. after a drive in a much better suspensioned boss this weekend, my eyes have been opened to what i could do if i had it setup right. so, maybe this little beast ends up for sale when this is all done? who knows?
 

pufferfish

Supporting Vendor
1,094
66
Maryland
Project update:
I have had multiple conflicting information sources recently, that makes deciding on a plan to fix the blowby issue a bit muddy. I have been told the rings need to be special material, special gap, special tensions. The pistons are fine, they need gas ports for the top ring, they need a tigher bore fit. Blah blah blah. I am getting nowhere.

But, ford designed the block to work with their pistons and their rings, so i am looking at that option. I received 1 LH, 1 RH, 1 pin, 1 ring pack and 1 rod to test fit and measure. Heres what i have learned...
1) the rings are too small to use in the manley piston. The piston design uses a smaller pin and tapered pin bosses that require the little end of the rod to be tapered as well. The piston and rod assemblies each weigh 20 grams less than mine, so a rebalance of the crank would be required to use them. The big end of the rod uses the same size bearing, but there are no locating pockets for the boss bearings. Yhey are also slightly narrower, producing a larger end gap. I dont yet know what that gap is or what ford recommends to know if it is ok or not. Or maybe the rod bearings have extended features to fill the gap? Who knows. Im just pointing out whst i have seen so far. Lastly, the gt350 pistons do not have gas ports for the top ring, so the claim that they are necessary is questionable at best.

I did a squish test of the piston to see if there would be any PTV issues. I am aware that the gt350 heads use a different valve location and thought the valve angle had changed. I say "thought" because in measuring the pistons, they share the same relief angle. So, the play-doh method used to measure PTV clearance showed similar gaps between the manley pistons and the gt350 piston when squished with valves closed. I then felt confident in putting the cams in time and testing again. And again, the clearance was more than adequite. I used the same play-doh in higher quantities to measeure total volume at TDC to verify the 12:1 compression and again, it all checks out. I dont have the specs on the gt350 heads, but based on this data, i can safely say the combistion chamber size in the boss and gt350 heads should be identical. I believe i would go with the gt350 pistons and rods, in spite of the rebalance, but there is no stock of the -D pistons and no ETA on them.

In the effort to run parallel efforts so as to minimize my potential dow n time, i have also spoken with Total Seal about rings for this engine. They contend that the PTWA used in other applications (Nissan GTR) use standard gaps, but if I wanted to produce the tighter Ford spec top ring gap, they could put together a custom setup for me. That custom setup should be here early next week. I plan to run the combo as is with Ford gaps and see what i end up with.
 
160
110
NJ
You are a brave man:)

I know some time back you were debating the standard GT vs Boss intake. Just to throw another option in here, I was able to use the GT350 intake on my 2012 with minimal fabrication. Basically just a spacer for the GT TB, extending the purge valve wiring and pinning the MCV's open. Did a before and after dyno run, never lost more than 3 1/2 ft/lbs anywhere in the RPM range and after 5000 RPM it just took off. Motor was stock other than an AED tune and Airaid intake. As you mentioned, there is no SCT support yet for the GT350 87mm tb so I'm waiting as well. Shaun also mentioned that for road course work he felt the stock TB was the best dialed in for progressive throttle and recommended it over anything else. Understanding that it would compromise peak #'s to some extent. Some companies will port the stock TB, which might be another useful option. Just installed Kooks headers and a new tune, will be curious to see how that affects dyno numbers with this intake.

Dyno was mistakenly run in 4th, hence the lower than expected #'s in the chart.
2012MustangGT350IntakeComp_zpstiwnwe7j.jpg
 

pufferfish

Supporting Vendor
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66
Maryland
I haven't been on the site in a while. I have been battling computer issues for the past month, as well as trying to keep the business moving along in the day-to-day. I also have not had the time to get the car put back together. I decided to work on a new oil cooler setup with some trick custom billet stuff. I intend for this to be a kit for the S197 guys to work on either the 5.0 or 5.2 blocks. I just haven't had the time to finish it up. I am working on the remote oil filter mount design now, but it won't get into the cnc machine for a couple of weeks, as some more pressing items are ahead of it. Looks like another summer of not driving my car. Wish I was baller status to be able to have one car for development and one to play with.

On a side note, I kept my order open for the GT350 pistons and keep getting teased on their impending release, but week after week ,they never show up.
 
160
110
NJ
My understanding is that Ford will frequently keep a certain amount of parts aside for warranty repairs, even if they are not available over the counter. Maybe that's incorrect, but what I have been told by Ford employees in the past when asking similar questions.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
so, the backordered pistons just showed up...i had nearly forgotten i ordered them! i don't have a need for them right now, since i already went down the path of regapped rings for my other pistons. maybe i will revisit another cross plane voodoo build with these pistons this fall and then either sell the engine or find another car to dump it into?

as for how the current engine is doing, well i just couldn't say. i got the engine back together and was working on the oil cooler design, got sidetracked with work and decided to put her back together without a cooler, just in time for the painter to come take the decklid and hood for body work and paint (i had been waiting over a month for him to show up). i had given up on ever getting those parts refinished and then he shows up a day before i got the car ready to roll out. so, now i am waiting for the body parts to go test drive it. i can't win!
 

Mad Hatter

Gotta go Faster
5,237
4,227
Santiago, Chile
Mad Hatter said:
Murphys law is always waiting to prove itself yet again.

Sent from my SM-G900M using Tapatalk

My apologies for sounding down!! Your project is something I guess all of us are tuned into and wishing you all the best to a speedy successful conclusion!!
 

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