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,





Bores are plateau honed. Extremely fine finish. Machine work was done on some of the latest equipment in the industry.



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

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.