This may not be the problem but something you can chase if all else fails. Not knowing where and how the crate motor was put together? The link talks of the wrong head gaskets causing overheating depending on the engine block used. Had this problem with a 454 years ago do not remember all the details.
Good point. As the Gen IV 454 transitioned to the V and VI versions, changes were made in the heads and gaskets. IIRC, the IV and VI can interchange, but not the V. This goes for the heads, too. But I have been assuming that the OP "crate motor' is an OEM product, not simply a rebuild so a crate. So gaskets/heads/block match should not be an issue. I hope that the OP posts the solution when it is found.
I'm going with the water pump wrong rotation thing. Serpentine belt impeller blades curve the opposite direction from the V belt ones. Only actually looking at them will tell the differencen I would not trust just the part number. Or
I would reinstall the old water pump---eliminate that one thing first.
I confess to having never examined the difference between a serpentine pump and a v-belt pump. If the two have different direction impellers, I would certainly examine the possibility of an incorrect pump. Will the serpentine drive fit a v-belt pump's nose? The oem or after market part number for the OP's RV should tell the story. YOU ARE CORRECT — LEARNED SOMETHING NEW AFTER ALL THESE YEARS — SOME SERPENTINE PUMPS RUN CCW ROTATION. But I still don't know if you can mix them up. It seems that the pulleys don't interchange from the v-belt to the serpentine. But serpentine pulleys may. I dunnnnoooo.
I've built and played with Chevy 454 engines for decades — both performance and towing. There is absolutely no way that a new engine should over heat due to "new engine friction" or choice of lubricants. Were that the case, it would not last but a few minutes. I can't guess what is causing your problem, but it's not friction. Your new crate motor should have ceramic rings that require no break-in. Timing can be an issue, but 4 or 8 degrees should not make a huge difference. Running lean will show up on the spark plugs. Beware of your carburetor rebuild and what was done with the metering rods and the secondary air valve on the Q-Jet (an excellent carb). Unless the serpentine system can change the pump rotation, long and short pumps are the same except for spacing to the radiator. The long pump will have space between it and the block. I've never heard of an HD pump — and I've used both after market as well as OEM pumps (latter are nicely powder coated). There are many variables in your description — but I am suspecting radiator/fan operation (though the temps you mention are so extreme as to make me wonder about the sending unit). That's the one in the head — easy to change. BTW, the only time I ever heard of a problem like this was with a new Pontiac. After many trips to the dealer it was finally discovered that the new vehicle had come without a radiator shroud! Oh, and I do know of a 454 that arrived new with a restrictor dropped into a water passage — hell of a time diagnosing that one. And it was clearly deliberate in the manufacturing process.
One tech firm tested a number of the iPhone apps against very sophisticated meters. They found only the SPLnFFT app to be accurate. In fact, that app was reported routinely as accurate as a very expensive meter. But in all of this discussion, the suggestion to measure my Hondas against a new one is the only reasonable approach. The actual decibel count is not the issue. It's the change that matters. The "Noise and Directivity" test would also provide a reference point. IMHO, I would guess that the muffler packing deteriorates with run time.
Your I phone app for measuring db is not accurate nor calibrated. I have one of the same apps on my phone.
Soooooo, which app is it and how far off is it? I am not nit picking and the issue is not the measurement — the generators are louder than when new. My posting intention was to determine whether anyone else has had the same experience and what the cause may be.
With my trusty iPhone app (which I well recognize may be less than precise), the Hondas measure about 80 decibels in Eco mode, warmed up, 30 paces away, with the exhaust pointed away. I agree with my wife; they are louder. Now the app-meter may be off — but off by 30 db? OTOH, this "meter" does allow for calibration. So, next time I will calibrate to the "normal speech" of 60 db at one meter and measure the generators again — though such a calibration may not be accurate throughout the curve. What I would like to do is try a new muffler, but at that price, it's not going to happen.
We have two Honda EU2000 generators. Normally we run them alternately unless the AC is needed. So each one has about 400 hours. DW says they are louder than when new — confirmed by a db meter check (iPhone app). Any ideas on why or what to do? New muffler runs whopping $140. Have cleaned the spark arrestor — will do again.
My three AC Delco series 30 RV/Marine batteries are now 8 years old. Load tested them in the spring and they are still very strong. They are true maintenance-free batteries. I've used AC/Delco for years in different RVs (and in vehicles) and have never had a single problem. No need to check water — they are entirely sealed. I keep the RV batteries on a battery minder each winter. Golf cart batteries are not an option due to their height. To each his own, but I'll continue buying AC/Delco. BTW, I found that comparable AGM batteries don't have as high amp hours.
Easy to do as described – wire from each 120 outlet to a common box with a plug that will accept your land line. I used good quality stuff (flexible cable, fittings, box with receptacle and lid, etc.) from Home Depot. Yes, there's a risk of a hot lead if a plug is pulled while the generators are running — or getting hit with a meteorite. But I used high quality plugs and they are very hard to pull out — never had a problem. My two Hondas easily run the AC. BTW, I have the proper shielded banana plugs but have never seen the need to install them (my Hondas have the receptacles for them).