And the 331 project finally begins...

[cgrey8]

I dropped my heads and block off at the machine shop and brought him up to speed on what I wanted to do and what the plans are. He said he recalled that the stock dual sump pan would have interference issues with the stroker crank...he admitted that he was fuzzy on that detail, but suggested I look into it. Does anybody else know about that? I didn't recall anybody along the way warning me that I'd need a special oil pan to work with a stroker crank. So I ask just to see if anybody else has ever heard of this issue and knows if there's any truth to it or not.

[Soul]

Crank doesn't hit the pick up tube so I say your fine

[carvinmark]

My 331 has a OE pan, seems fine.

[cgrey8]

I didn't think there was any issue. I even got on Summit Racing to get some pics of some 347 crate engines, and they had dual sump pans just like the one I have. In fact, the pan I have was pulled from a crate engine...I just have no clue if the crate engine was stroked or not. It's quite possible he was getting Chevy and Ford stroker kits confused. He does a lot of both. The shop was filled with random Ford, Chevy, the occasional Hemi, and a slew of L6s and small engines that I didn't recognize.

[carvinmark]

At least he's trying to help out, just too many engines to remember all of them.

[plowboy34]

There is no issues with it, there are many fox body cars running 331 and 347 and they have no problem and they have to run double sump pan.

[cgrey8]

Now that I've gotten tax return money, I've been making some forward progress. The heads are almost done...should be done right now in fact. I pick them up tomorrow. They decked both, 3 angle valve job, blended the bowls into the chamber, back-cut the valves, and machined the valve stems to be the same length from seat to tip. I was originally not interested in having them decked unless they found that they had deformity or twist. After checking, sure enough both had issues. One was slightly twisted. The other had a dip in it. The machinist had to take .010" off them to get them true. He said if the CCs weren't off from chamber to chamber, they are now so I've got some work ahead of me to get them all the same. So this week will be spent ccing each chamber yet again to find out how much I need to Dremel out of the smallest chambers to get them equal to the largest. I'd like to get them within 1cc of each other.

Once I got all chambers relatively the same cc, I'll know what 331 kit to get ordered and how much to have them locate the pistons out of the bores. I'm looking for around 8.3:1 dynamic compression ration (DCR) and to get that, I'm going to need the pistons popping out of the bores at least a few thousandths. He said he can pop them out up to .010" but I doubt I'll need to go that far. I think I'm looking at something in the .004-.006" range which will give me .035-.033" quench as well as get me in the low to mid 8s for DCR...in static compression ratio numbers, that'll be 9.8 to 9.9:1 range.

I've also got to get some gaskets from Autozone (oil pan gasket, pickup screen gasket, timing cover gasket, etc). I'm also going to get rear main seal and spark plugs. Since the water pump on the engine I have in the truck now is an AutoZone pump, I'm going to wait until the swap to get the pump so I can take the one on the existing motor back as a warranty replacement and get a free replacement for the new engine. I pondered whether that was unethical, but as it turns out, this one is going bad anyway. It's squeaking. And I think there's a slight leak coming from it too. I just hope it can hold on long enough for the 331 to get complete. But just in case it goes to pissin' the green stuff, I'm keeping a bottle of water with me so I don't run the thing hot.

I also still have the lower intake to port. After doing the heads, I'm not nearly as worried about doing the intake. I just have to take the time to do it.

Hopefully I'll have it all complete and ready to swap in the next few weeks. That's the hope anyway.

[Dave]

Hey Chris,
Sounds like you at least are moving. They were calling for more snow today. Did you ever figure out your rocker arm clearance problem with the VC? I had that same problem with the stock Explorer covers and the FRPP rockers hitting the baffle but not the corners. That's why I went to the Cobra covers in that picture I sent the other day. One thing led to another.
Dave

[cgrey8]

Thicker VC gaskets take care of the interference across the top of the cover, but I'm still deciding what I'm going to do with the rockers. I'm heavily leaning towards knocking the corners off with my aluminum porting bits. It'd be a VERY minor cut to the top corners of only the ones on the ends. And for the RPMs I'll be turning, I doubt it'll make much difference. If it does, I'll chock it up to learning experience and then I'll have the pics to prove why not to do it for others asking the same thing in the future. Otherwise, I'll run it as long as it lasts that way.

If I'd gone with Crane/Cobra rockers, I don't think I'd have this problem since they narrow up right at the pushrod where the Scorpion rockers I have are about as wide at the rocker end as they are at the roller end.

[cgrey8]

Update...

Well, I finally picked up my engine from the machine shop. And there were some things that weren't as I requested. I specifically requested that when he order my crank, that he order one intended to be used with stock 50oz balance equipment (50oz flywheel and 34oz balancer). Well by the time he ordered the kit, he forgot to order it that way and what they sent was one intended to be internally balanced. Most are balanced for 28oz equipment, but this crank is fully internal. So he had to completely remove the counterbalance in my flywheel and turn down my balancer making them almost zero-balance parts. The down side is this means I can never replace either the balancer or flywheel with over the counter parts without having them modified to work. That sounds like a big deal until I consider that I've never had to replace any previous engine's balancer or flywheel, so this isn't likely to ever be an issue. The upside is a completely internally balanced 331 has less balancer/flywheel weight and the counterbalances on the crank are also smaller than the counterbalances on my 302 crank (I expected them to be larger). So with less rotating mass on the crank, balancer, and flywheel, the engine is going to rev MUCH faster than it would've. He said he usually charges people more to balance internally balanced engines, but since this was his goof, he did the extra work at no extra to me. I'm not sure if that was true or if just spin. Either way, it is what it is.

So I got it home, started to put it together, and decided before I started putting too much together that I better check the pop on the pistons and make sure they are where they are supposed to be. I requested the pistons popped above the decks .005" to give me the compression and quench I wanted. And that's where things got disappointing.

Best way I've found to measure piston deck clearance is to find TDC for a piston using a depth gauge. Then press the piston down on either the top or bottom as hard as you can to get the piston to tilt to one side in the bore. I prefer the side opposite the quench pad so I can get an idea just how close the piston can get to the head. Once you got the piston cocked in the bore as far as it will, then measure the piston-to-deck depth at the top and bottom of the piston. Add the two and divide by 2 to get the average. Positive values are below the deck and negative values are distances the piston is above. Example:
One side measures .014" above the deck.
The other side measures .004" below the deck.

(.004 + -.014)/2 = -.005" or .005" above the deck

My intended target was a .005" pop above the decks. My pistons varied from .004" above the deck to .010" below the decks. That's not even close. In fact, that's piss poor. On top of that, the difference from piston-to-piston in value on the quench pad popped side was drastic. Some were just barely above the deck. Another was .020" above the deck. With only a .039" gasket, that puts the piston REALLY close to the head at high RPMs. So I called the machinist and explained what I found. I took it back this morning to show him what I found. He agreed, that wasn't right and wasn't intended. So they got the block back and will have to redeck and possibly redeck the pistons to get them more consistent. But that was a bit disappointing to have to take it back to them. But it was nice that when they saw what I saw, they didn't make excuses. They admitted they screwed up somewhere and actually credited me for taking the time to check it.

I also asked them about machining away the sides and/or tops of those Scorpion rockers I got. He said there's no problem with taking off material as long as it doesn't get too deep. He said they do it all the time and have reved those engines to the 7000s never having a single issue from modified rockers. So for an idle-5500 daily driver, it shouldn't be a big deal to do what I need to get the VCs to fit.

[MalcolmV8]

Man that sucks on the machine shop. I've had a few experiences like that myself over the years. It's like they hear what you're asking for and just do what ever. At least this guy is trying to work with you. He could have told you to get lost and you'd have to pay another shop extra to fix it.

[Dave]

That does suck Chris. What's that old say, "Measure twice and cut once"? Maybe they ought to remember that. There are zero balanced flywheels out there but being that an Explorer balancer, might be tough. They usually last a long time. Why the 34 oz balancer, never heard of one?
Dave

[cgrey8]

28oz balanced engines use a 28oz imbalance flywheel and harmonic balancer.

However the newer setups that use the 50oz imbalance flywheel actually use a 34oz imbalance balancer even though most people refer to the balancer as a 50oz imbalance.

[cgrey8]

Well, I finally got my engine back from the machine shop. The long story short is I go there and ask for a 331 stroker short block with the pistons .005" out of the hole and balanced for 50oz flywheel and matching 34oz balancer (the balancer weight that always accompanies 50oz flywheels). They said that they could do that +/-.001" without much trouble. They gave me a price for that along with head work, and we all agreed. I also requested either Mahle or KB pistons with the valve lash cc in the 6-6.6cc range. I preferred Mahle just because they come with ring packages and teflon side-skirts.


The heads came out great 1st time and have been setup, assembled and ready to go for months now. 3 sets of pistons, 2 sets of bearings, 2 blocks, and over a year after taking everything to the machine shop, they got me a short block with the pistons out of the hole .006" +/-.002". Close enough I guess...


Now the long story.

First they try cutting the piston tops to get the pistons the height I needed but the 1st attempt had the piston deck clearances ranging from +.014" to -.014". That was clearly not acceptable. On this attempt, the guy also figured out he ordered an internally balanced 331 stroker crank, not a 50oz balance crank. Note, the standard 331 crank is setup for a 28oz balance. While most people go with that, I already had a 50oz balanced flywheel I intended to use with this build. And I needed to use the Explorer's 34oz balancer to work with my Explorer timing cover and accessories. Buying a 28oz balancer wasn't really an option. To overcome that, they machined my flywheel and balancer to work with an internally balanced crank. The good news is internally balanced setups have less rotating mass and thus rev much faster than other setups and according to the machinist are only done on racing setups. Too bad all that effort goes to waste on what'll be a mild daily driver build that won't ever rev past 6000RPMs and will rarely see 5000.

So their second attempt on the pistons got the pistons ranging from one in the hole .002" to one being out of the hole .004". Better, but still a bit "too much" variance than what I wanted with most of them around the .002" range.

For the 3rd attempt, I asked them to fix 2 of the 8 and I'd take it like that WITH a thinner set of gaskets to make up for the lower deck clearance than I wanted. What they wound up doing was somehow cutting the block deck more than he was comfortable with so he just got me another block...one with an E7 (1987) casting year which was fine with me. I wasn't married to my block so I didn't care. As it turned out, he said the 87 block cut much better and smoother than my 97 Explorer block did. His best guess was the quality of the iron was better back in 87 than what Ford used for the Explorers in 97. This 3rd attempt came with JE forged pistons, completely uncut which was a good thing. The laser-cut numbers are still in the top of the pistons. I originally wanted Mahle pistons only because Mahle comes with rings and have the teflon pads on the sides.

Getting there today, they told me they got things as close as they could. They said they mixed and matched pistons in the holes to get as close to .005" as they could. And what they found in all their testing is that with the rods bolted down dry, the deck heights were all over the place. They could measure, then turn the crank over and retest and the deck height of the same piston and it would measure something entirely different. So they figured they had "bad" bearings and replaced the bearings with another set of bearings. The new bearings did the same thing. So they tried testing the bearings with oil, the deck heights got more consistent. Assembly Lube got them even more consistent, but what they found worked best was a mix of oil and assembly lube. Their measurements seemed to reproduce over and over. So what they ended up with is exactly how I found the block and measured them myself. The pistons measured as follows (all out of the hole):

PS
1 - .008"
2 - .0075"
1 - .007"

DS
2 - .006"
1 - .0045"
1 - .004"

They said they mixed and matched pistons left and right to get the most even combination of pistons possible. I just thought it was interesting how even this build had all the pistons on one side of the block higher than the other side like the crank was in the mains slightly off. But this was the same story as with the other 2 attempts...one side was consistently different than the other.

One thing they did say is that when the engine gets up to temp, I can expect the deck heights to increase another .002-.003". So my highest piston is .008" out of the hole, so at running conditions, he said figure the piston is closer to .010-.011". That puts my Dynamic Compression Ratio for that piston just over 8.5:1...so I'm probably going to retard the cam to get the DCR below 8.5. Retarding it 2-degrees will get be to 8.47:1 with the pistons closer to .004" out of the hole at 8.38:1.

Another option is I can touch up the passenger side head and increase the CCs for that side to lower the compression to match the driver's side. The big question is...is it worth all that? At this point, I'm thinking not mainly because the intent is to run Natural Gas in this engine which at these compression ratios will hit MBT way before hitting ping being NatGas is 120 octane rated. And even if I run E85, I'll still be hitting MBT before ping since it is something like 96 octane rated, but "acts" much closer to 100-110 due to other combustion characteristics. With 92/93 octane gasoline, I suspect I will hit ping before MBT. With any luck, I'll only use gasoline when I can't use NatGas and then only when traveling out of town away from my NatGas pump, so I won't be doing a lot of WOTing while burning gasoline.

[MalcolmV8]

Damn. I hate those kind of machine shop experiences. I don't know how you put up with that for a year. At least you have it back and can continue with the build.