If the bores are finished to a plateau, with good moly rings, there isn't much to 'break' in. Not like the old hard chrome rings that required the coarse bore finish.

Going through the process of lots of oil flow and cylinder pressure....clean out the trash left in the crankcase...etc then drop the oil soonest. Check the filter if you can.

Run a good low calcium oil, with zinc in the 1400ppm area. You'll be gtg.

The new SP rated oils often drop the calcium as a detergent. It was displacing the zddp.

Tartilla,

https://cimg5.ibsrv.net/gimg/www.off...627c11f3a.jpeg
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Bores are plateau honed. Extremely fine finish. Machine work was done on some of the latest equipment in the industry.

https://cimg0.ibsrv.net/gimg/www.off...0eba5ee07.jpeg

Not my block, but really cool machine. It does pretty much everything. It probes the block, aligns it and goes. I didn’t get a pic of the hone, but it’s pretty cool, too.

Final home was done by spindle pressure, which means the machine detects when the hone is to size. They are all within a couple ten thousandths of an inch, and identical finishes.

I‘ve got PennOne 30w break-in oil in it right now. After about 5hrs run time, I’m going to replace it with VR-1 and the remaining PennOne (I bought a case, and used 10qts) for the next 10hrs. Then I’ll swap back to AmsOil 20w50. Probably run that for another 10hrs and change it again.

Thanks. Brad.

Nice clean shop...looks like the place where i work :D

Guys,

We spent some time last night working on the tune. We've got it idling stably, but we have to start it at ~15% throttle and then feather it back to idle. The builder has suggested the 1.8 rockers are asking for more air than the TB will allow. He's suggesting opening up the hole in the throttle plate, which I'm not opposed to. I'm told that Merc put a larger hole in the HO throttle plate than they did for the MAG, so it stands to reason. I'd just like to take some of the guessing and T&E out of it. Anybody ever been here before and have a suggestion on hole size? I hear tell of an old Raylar post that suggests Ø5/16", but I can't find it.

Thanks. Brad.

is there a mechanical stop on throttle body? If so, start turning in on it and re zeroing your tps each time. If not, start by poking a 5/32 hole in it and go 1/32 bigger at a time, dont be surprised since its a monoblade if you end up at .250 or even more. I just dynoed a gen 6 496 at my shop w procharger, cammed etc, after adding more mechanical throttle stop to it, rezeroing the tps which is 50 X harder on Mefi then holley, I ended up putting 1 1/8 hole in each throttle blade then went up to 2 5/32 holes which took IAC counts from 115 at a warmed up idle to 15 to 20 which will give the IAC the ability to do its job AND it started then without touching throttle, have range etc. I tuned a mefi4 sbc recently on water that had went from a 305 to 383, it TOO needed about a .250, .270 hole to start, idle and get iac in "range". Smitty

I've had to do the same to most modded engines.

What is your IAC percentage or count? Your cam is not that radical to justify drilling holes in the TB and 1.8's aren't the problem, IMO. (and it worked before without drilling) I'd first get it to run with the IAC unplugged and the blades cracked by adjusting the throttle stop at operating temperature. Zero out TPS at that point and plug in IAC. You want to have as close to 0 IAC operating at this time. This will also allow the IAC to catch the engine during shifting and open accordingly when cold. Make sure the IAC is working, do you hear it? Make sure the harness is wired for GM IAC, it is default wired for a Dodge IAC and I believe pins A and C need to be swapped.

Rookie,

The Holley software shows AIC stays pegged at 100% at idle. There is already a hole in the throttle plate, and I understand that Merc increases the size of the hole between the 496MAG and the HO, specifically because of the difference in the cam, which isn’t much. While it’s the stock HO cam, I’ve increased the lift from .510” to .540” with the 1-8 rockers, so an additional increase seems logical. I also got a response from Larry Hofer indicating they prescribe an increase to 1/4” for their 202 cam and 5/16” for their 203 cam. I don’t disagree with what you’re saying at all, but the fact that the IAC is pegged tells me the engine wants more and the IAC can’t deliver.

Good info on the wiring. I’ll pass it along, but I’m assuming the builder already knows this.

Thanks. Brad.

Smitty,

I don’t know if the OEM throttle body has a mechanical stop adjustment or not. I’d assume it does. We’ll have a look at it.

As mentioned above, the throttle plate already has a hole in it. I’ll have a look and see what size it is when I’m back in town.

Thanks. Thanks.

Get it running up to temp in current configuration. Unplug IAC and if nothing changes fix IAC, if it dies then you know your IAC and blades are not set correctly yet. I spent a month on this and was also going to drill blades.

rookie brings up a good point and also jars my memory of a "glitch" with holley, IDK why but half the holley efi is pinned wrong on iac and iac doesnt wont do anything because the wires come pinned for a Chrysler iac vs gm and needs wires/pins switched fwiw. So ID determine if iac is even doing anything before getting too crazy with anything else. IF its IS working, since its takes like 30 seconds to rezero tps on a holley, IF you have a mechanical stop id do all my adjustments THERE before rxring tb to drill it repeatedly, Smitty
https://forums.holley.com/forum/holl...ndom-questions

unless we're using a holley TB with a built in IAC we have to swap two wires around on every holley IAC plug we use.
swap purple/white with purple/blue.

This is good info from you guys, I have been starting to talk with my builder about new 540cu long blocks and using most of my 500EFI ass, including the intake with Holly EFI. Sounds like we will run into the same issue.

Thanks, what OSO used to be like!

Rookie,

When you say “fix”, do you mean physically replace or make adjustments in the Holley software?

Thanks. Brad.

he means wire the iac properly so it actually functions. read above.
Just because the computer is calling for it to be at 100% doesnt mean it actually is
Unplugging it would confirm or deny what me, arctic and rookie are telling you

Johnny,

Thanks. Forwarded all this to the builder. Like I said previously, he has worked on several Merc 496’s and he’s worked with the Holley stuff, but this is the first time marrying the two.

Thanks. Brad.

Exactly what TeamSaris said.
Post 191 and 196 in my thread.
https://www.offshoreonly.com/forums/...ersion-10.html

Rookie,

I will look at my connector and see where we are. This sounds like something even an experienced builder that has never dealt with it might miss.

Just to be clear… The Merc IAC is actually a Ford part, and I haven’t heard/read any reference to Ford here. Same/same?

Also…. The builder has mentioned the use of a stepper IAC vs the PWM (I guess???) type Merc uses. I understand the Chrysler IAC is a stepper. Would I be better off just getting a Chrysler IAC? Is it just that easy? Are they interchangeable, as far as the physical mounting and connecter?

I’m definitely into solutions that don’t require permanent alterations to relatively non-replaceable parts.

Thanks. Brad.

Hey Brad I have an idea.. why don`t you just switch the wires before you go off the deep end again.
Or verify that the IAC is actually opening.

Heres another tidbit, when you set up your closed loop learn, compensation, leave it turned off at first, manually tune idle, part throttle etc on the dyno. Once you get it close manually, let it auto tune CAREFULLY watching your learns, afrs etc, manually transfer them to the tables ONLY if they make sense and arent huge numbers or youll be chasing your tail, killing plugs, washing rings. all this holley stuff comes with those tables pre-populated at 100% or 50 % (Id have to look) but thats too much, the slightest false lean and youll be rolling coal, the most I let them learn is 25% while on dyno while i watch the afrs during pulls on my computer. In vehicle I never let them learn more then 10% fwiw. When we dynoed Rookies 454s we were still learning this and killed plugs, 02 sensors so fast it wasnt funny, Smitty

Dan,

I'm away from home for the holiday weekend d ATM. And there’s the very real possibility the builder has already addressed the issue when he replaced the connector on the harness for the Merc connections. I’m just asking questions so I can properly address the issue when I get back.

Thanks. Brad.

One more tuning tidbit, do NOT allow any compensation. learning to occur at idle , set minimum tps to at least 2 if not 3% and I usually go 200 to 400 rpms above idle too because no matter what holley says about 02 placement vs tip, a 4" ID exhaust ALWAYS seems to false lean a little at dead idle and the holley will keep adding fuel because its off target, Smitty

Fair point here. 4" diameter for an idling engine would pretty much appear to be atmoshere. The exhaust flow boils about bringing air upstream.

My Yamaha R1 on a high idle, would shoot slugs of exhaust out 10ft. Insane how much exhaust energy and a slug of air mass can have. It was also very random, as the pulses moved about.

I run 10 02s on my dyno, 11 when running most holleys and you can see the cylinder 02s getting richer and richer at idle while holley reads off target lean at dead in tailpipe trying to keep adding fuel if not kept out of learn until rpms pick up even fully muffled. Hot rods, vehicles shw up here with aftermarket efi to be "tuned" that have added so much fuel customer can keep it running to get off the trailer, oil full of gas, plugs killed, chugging

Smitty, Tartilla,

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O2 Sensor Bung

Does this change the context in regard to the false lean?

Thanks. Brad.

You're a ways away from the transom. 3" risers?

The O2 sensor is a bit closer to the exh port than what most O2 sensor manfacturers would recommend. But also at the collector merge point. It's likely more a heat factor, and guys that run late timing or poor atomization...a lot of the A/F charge is burning in the port/pipe.

Smitty would best know what would be sufficient. Many ecx tails have the O2 sensor well down stream, vloser to atmosphere that has an easier time coming up the pipe. Reversion of air, not just water is also happening.

Dual 3" pipes will support a lot of HP dry, and less wet of course. That's with effectively zero pressure restriction from the pipe size.

Brad
where you have it,it will work.would have liked it more towards the middle of the adapter in reference to the outside 90° pipe.

Sutphen jogged my memory that you fab'd up the O2 sensor bung plate. One of the specs for install was a 10° angle down. Something like that. Likely to drip off any condensation and moisture.

Sutphen,

I put it where I could put it.

i can tell you, by observation of the software, the WBO2 is working beautifully.

Thanks. Brad.

Tartilla,

Somewhere here on OSO is a thread by Eddie Young, where he details how he installs an O2 bung in the side of the Merc elbow, and it’s pretty much exactly where I have it in my setup, relative to the top of the manifold, and I believe he has it pretty much square to the exhaust path. Mine is rotated around the axis of the C/L a bit, just because it was where I could squeeze it in there. I realize I’m probably getting a lot more reading from a particular cylinder than a general exhaust charge, but it is what it is.

Thanks. Brad.

Im gonna RE-ITERATE on my false lean comment, at DEAD IDLE ive seen false lean even on 3" exhaust in a hot rod , its a well known thing in tuning world hence the delay auto learn until a few hundred rpms above idle and 2 or 3 % TPS , you should be manually tuning idle anyways, otherwise your idle afr will usually end up richer then it shows on afr gauge and it will be wandering all over, once your off idle you got nothing to worry about, let it do its job, just LIMIT how much it can tune/compensate, Holley sets the range way too high in factory settings.

Smitty,

The builder has it in open loop below 1000RPM and has been working on the idle tune manually. He also assures me the IAC wiring is correct, and that the volatile idle is due to the VE table not being dialed in.

I just checked, and the IAC is a 2-wire unit. I'm told that's the typical Ford PWM IAC, which is what Merc used for the 496, as opposed to the GM or Chrysler 4-wire stepper. I'm assuming this tosses the wire swap idea out...?

Thanks. Brad.

Guys,

So there have been a few…. Developments….

I don’t want to get into a bashing session on the builder, as I’m confident in the engine he built, mechanically, but he was struggling to get anywhere and admitted to not having a strong grasp of the Holley stuff. I have a new guy doing the tuning on the engine. A mutual friend turned me onto the guy that does his drag engines, and this guy REALLY knows the Holley stuff. After making a few changes to the basic tune parameters, like enabling “idle spark”, we have it starting at zero throttle and purring like a kitten…


On his suggestions, we also made some hardware changes…

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The old Ford IAC adapter plate

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Machining a block-off plate

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Old IAC location deleted

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New GM stepper IAC installed on the throttle body

No more hose from the IAC at the rear to the throttle body.

We also adjusted the throttle stop a bit. There is a ~5-16” hole in the throttle blade; OEM Merc. IAC now runs ~5-10%.

The TPS also seemed to be getting flaky and losing signal, so he gave me a new one. The new wiring is laced into the harness and everything is all buttoned up. Prop is on the drive and the drain plug is in. Looking at either tomorrow or Tuesday to head to the ramp for (hopefully) final tuning. I’m going to download the software on my wife’s laptop and he is going to to show me how to further adjust the tune through the learn table transfer. I’m hoping to not have to do that, but we all know how this goes.

Thanks. Brad.

Sounds good Brad. Since your wallet is open I'm thinking hydraulic steering, 280 K-Planes and a nose cone:drink:

glad you got it sorted out.can't wait for the water report

SecondWiind,

What on earth makes you think the wallet is “open”…? :angry-smiley-038: I wish…..

Baby steps, man. Baby steps.

Thanks. Brad.

Guys,

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We had a very productive day on the water. We spent about three hours running the boat through its paces, live tuning using the closed loop learn function, from idle to WOT, including many planings of varying intensities. By the end of it, the “learn” was making 0% corrections from the base tune. Tuning is essentially done.

Overall, the engine runs very well. I’m a little underwhelmed with top speed, but I think much of that is the fact that the prop needs some work after finding the bottom early last year on this very lake (all four blade tips have reduced cup/pitch).

Thanks. Brad.

Brad what kind of mph did you see on the top end today? And what was your previous best mph?

had to feel great to get it back on the water!

Brad, is that the CFO doing a spot check on the finccial investment? Or Doing a DOGE investigation?

Glad you got the boat in the water and running up.

No shame on the builder. EFI is largely governed by known knowns, or cylinder bore washout can become a reality.

Don't be shy on the MPH...even if it's a bit less than you had before. The primary exercise was to repair and refresh the problem engine.

Tartilla,

I don’t begrudge the builder. I believe he built a stout engine. Part of me wishes he’d been more honest about his grasp of the Holley stuff, but then, if he had, I’d probably still have the 555, so…

No. That was the tuner’s CFO. They had to drop a vehicle off in the area, and she was his ride, so she tagged along. My CFO had to work. She was miffed about not being there, but glad we got it on the water. It worked out, as that gave us a chance to tune the engine at expectable weight loads.

We maxed out at 70-71GPS, which, if memory serves, was about all we’d get with the less-than-perfect prop, 600lbs of human and 3/4” tank of fuel. The tuner indicated that IAT was probably our primary limiter, at ~110-115° (ambient was ~85°). He wasn’t worried about it, just not getting the air we’d want for more power. We did see almost 5lbs of boost, though. The smaller blower wheel gave on the boost, but took on the IAT.

I am very happy. I think with a fresh prop, just the CFO and I and 1/4 tank, we’ll be back to previous performance levels (76-77MPH), or maybe a bit more. At the end of the day, I have a functional boat. With a few leaks (water and coolant) that I need to track down.:rolleyes:

Thanks. Brad.