How hot is too hot!

[Guest ratchethack]

I've thought about that "overheating" quite a bit. I do admit to worrying now about taking the Guzzi into very hot areas After letting it cool for about 1/2 hr. and pouring bottled water over the heads it fired right up.

Gil, I'd be mighty careful about throwing water on any motor that's not cooled all the way down, very close to ambient. This is a classic, oft-repeated scenario, where a bucket of water is thrown on an overheated motor, followed by dumping all the oil through a brand-spankin' new crack in the engine block.

 

Many's the moto and car alike that's suffered the same fate at the hands of someone spraying it off to clean the motor.

[raz]

FWIW, my first hit when I googled for what oil temperature would be damaging, was http://www.abc.net.au/science/k2/trek/4wd/june99_1.htm

The second half of that story is quite interesting... the oil wouldn't even come out at the bottom

 

Oh, and I know how to get room for a fan behind the cooler. Just ditch the headlight:

[FuelCooler]

Gil, I'd be mighty careful about throwing water on any motor that's not cooled all the way down, very close to ambient. This is a classic, oft-repeated scenario, where a bucket of water is thrown on an overheated motor, followed by dumping all the oil through a brand-spankin' new crack in the engine block.

 

Many's the moto and car alike that's suffered the same fate at the hands of someone spraying it off to clean the motor.

 

I am not disagreeing with you ratchethack, but I wonder if this is one of them 'old timer' tales. I heard this warning growing up as well. Many times I had wheelied or other wise ran my XR 75 Honda, 1978 RM125, Maico 440 thru standing water and was terrified of them cracking. Then when I was older, I did the same with my XR 250 and EX250 quad and was a little less worried. None of them cracked. And some were plenty hot (and old!) when I did it. It still worries me, and perhaps its because I never shut one down immediately afterwards and continued to throw water at them. To be honest I have never personally seen a cracked block, cylinder or head on an air cooled bike that wasn't caused from some internal part trying to exit. Don't get me wrong, it may happen all the time, I just haven't seen it. I have some knowledge of aviation motors developing cylinder head cracking from rapid temp changes (P&W radials), so it is possible.

Any one else with first hand experience on water cracked air cooled bike motors?

Cheers,

Steve

[Guest ratchethack]

Any one else with first hand experience on water cracked air cooled bike motors?

Not first hand, and not on a bike, but I'll never forget the extremely credible 2nd-hand story of a guy named Tom (last name withheld to protect the guilty) in my High School, who lunched the motor of his Dad's Pontiac by running it at -- shall we just say, "excessively inspired speeds". The reason it was extremely credible? There was no denying the evidence at hand. Tom had performed the stereotypical classic "quick cool down" with the bucket o' water when it overheated, then had to "explain" the cracked engine block to his ol' man. . . But wot was to be far worse than facing his ol' man, was that over the years to follow, he suffered the never-ending mockery of all his "Pals" as a regular reminder until he graduated.

 

I've run many a stream with a hot motocross bike and various other offroad bikes with no problem. Been caught out in lots of downpours with no problem. I submit that gradually cooling circumstances may be entirely different than a heavy splash on a dry, hot motor with a direct dousing! Now this is just me, but the above and similar "stories" notwithstanding, I wouldn't risk it on my Guzzi, but that's just me.

 

YMMV, but are you gonna take the risk?

[raz]

I've heard (second hand) the opposite too: people trying to quickly clear their car windshield from ice, in say -20°C (~0°F) using a hose or a bucket, with hot water... go figure

 

Uh-uh sorry that was quite the opposite if this thread subject

[Ryland3210]

Cast Iron is more susceptable to thermal stress cracking than aluminum, especially decades ago. More ductile versions of cast iron are used these days in many applications.

[guzzi jon]

I live in the San Fernando Valley, arguably the hottest place in the US next to death valley. We get many days over 115 each summer. I've ridden my eldo, SS, Lemans and Griso in stop and go traffic, all in temps above 115 with no ill effects. I do use good oil, mobil 1 synth in the eldo, ss and lemans and that fancy 10-60 syn stuff in the griso, but never had a problem with over heating. I have a thermometer dip stick in the eldo, it never gets spooky hot. My belief is that the rider will keel over and fall off the bike from the heat before the bike gets damaged. All of my bikes but the griso are properly fueled though with PCIII's and proper jetting on the eldo

[dlaing]

I live in the San Fernando Valley, arguably the hottest place in the US next to death valley. We get many days over 115 each summer. I've ridden my eldo, SS, Lemans and Griso in stop and go traffic, all in temps above 115 with no ill effects. I do use good oil, mobil 1 synth in the eldo, ss and lemans and that fancy 10-60 syn stuff in the griso, but never had a problem with over heating. I have a thermometer dip stick in the eldo, it never gets spooky hot. My belief is that the rider will keel over and fall off the bike from the heat before the bike gets damaged. All of my bikes but the griso are properly fueled though with PCIII's and proper jetting on the eldo

Haven't you been schooled by Todd in how to lane split?

I am not a big lane splitter my self, but the hotter it gets and the slower the traffic is, the more likely I am to lane split, even in states where it is prohibited.

[dlaing]

There's got to be literally dozens of highly speculative, nonsensical solutions to yet another problem that doesn't exist. . .

 

It never gets really hot here in Seattle. The hottest day I remember here in 14 years was 97-degrees F. A very warm summer day is in the mid-80s F. Here's what I have seen as typical for oil temps on a calibrated thermostaic dipstick on my V11 Ballabio on a day in the 80s F. (all after the machine is fully warmed up):

 

Steady state cruising on the freeway: 100-105 C.

 

Running really hard through the twisties: 125 C.

 

Heavy traffic stop-and-go: 140 C.

 

140 C. is way too hot for yak fat. It's iffy even with top-shelf synths if the oil stays at those temps for long. Even the best oil is cheap compared to, say, a crankshaft. Save the yak fat for your lawnmower . . .

[Anthro]

Just make sure you use gear that will not expose yourself to the sun, even in an attempt to cool you down.

The Guzzi+synthetic oil should be OK...

 

Here are my hands after 5 hours riding at 105F in the summer heat of Texas... I was wearing nice thin leather driving gloves with openings:

 

 

It was hot but I had a great ride

 

Anthro

[Steve G.]

I've thought about that "overheating" quite a bit. I do admit to worrying now about taking the Guzzi into very hot areas where I may be forced to idle the bike for any time.

 

What happened was that it was a very hot day (100+ degrees Fahrenheit), idling and waiting to cross over into the U.S. from Baja. Just after I crossed into Calexico the bike started miss severely. I was traveling at maybe 10 m.p.h. After a final belch it quit altogether. I wheeled over to an empty parking space and tried to restart. It wouldn't. After letting it cool for about 1/2 hr. and pouring bottled water over the heads it fired right up. I had no more problems on that trip but avoided hot areas where I might be caught in traffic.

 

However, in re-thinking the incident I'm not now 100% sure that the bike overheated. I had been running for 2 days on Mexican, "regular" gasoline and had just filled up the bike a few miles earlier. So a fresh tank of "unknown" gas. Could have been dirty, could have had water in it, I don't know for sure.

 

I haven't returned to any hot climates since that happened so I can't really say what really happened or if my concern about hot areas is reasonable. I am encouraged that most Guzzi owners have not had many problems with heat.

 

 

Dr. Gill,

Your bike showed all the signs of the fuel system overheating, with heat induced fuel vapourisation, not the engine overheating. A seriously overheated engine would show signs of the pistons synching up in the cylinders, seizing, but would show serious oil smoke out of the exhaust, burning up.

Steve