[betty55]

My son's 55 chevy truck with a 350 engine was running great. He took it to dyno it and all hell broke loose. My son is the quiet type but after the experience I feel like he is a volcano waiting to explode. He was not at all impressed by the operator of the dyno. My son tried to explain a few things about his shifter, etc.. this guy was capped and didn't hear anything he said.
He did 4 runs in overdrive and did not pay attention to the gauges at all. He got the truck so hot it damaged several parts. All the water in radiator exploded out, it went everywhere. After long cooling period, he left the shop drove to stoplight, tried to U turn but couldn't get into first or second gear. He then said it got HOT FAST and he waited for a good hour for cool down. Then he noticed that it was shifting at higher RPMS than before dyno disaster. We worked the shifting probem out but this engine NEVER ran hot before dyno and has run very hot since. It seems its ok on freeway, but he
gets off the exit up to a stop light at idle and that sucker climbs up fast to 210 +.
We just spent $2500.00 to diagnose overheating issue. We've bought new starter, new water pump, new bigger fan, thermostats, etc..... did not fix it. had our machinist go through and make it brand new again. Rebuilt it last week and it still overheats. On rebuild we notice the aluminum radiator fins were all bent and appear to have swelled outer casing,the core tubes and fins are all blocked off closed. You can't see through at all.

COULD DYNO PRESSURE AND HEAT HAVE WARPED AND DAMAGED THIS RADIATOR TO THIS DEGREE?
AGAIN WE ARE SURE THIS IS THE CAUSE AND FIX, SO OF COURSE WE'VE ORDERED A NEW RADIATOR $$$$
WE THOUGHT EACH PART WE REPLACED WAS THE CAUSE AND FIX. IT WASNT.




ANY INPUT IS GREATLY APPRECIATED.

[carsavvycook]

Did the dyno operator make any changes to the tune, as in retarding the timing, or carb jetting?

It just seems odd after 4 dyno pulls the radiator would distort enough to block air flow. I would look at the frame by the steering box for cracking. It just seems to me, that there is a flex issue in the truck somewhere contributing to this distortion.

[dinger]

I am moving this to engines, there should be some answers to this problem.

[cobalt327]

Originally Posted by betty55

He did 4 runs in overdrive and did not pay attention to the gauges at all. He got the truck so hot it damaged several parts. *SNIP*
COULD DYNO PRESSURE AND HEAT HAVE WARPED AND DAMAGED THIS RADIATOR TO THIS DEGREE?
AGAIN WE ARE SURE THIS IS THE CAUSE AND FIX, SO OF COURSE WE'VE ORDERED A NEW RADIATOR $$$$
WE THOUGHT EACH PART WE REPLACED WAS THE CAUSE AND FIX. IT WASNT.

First thing- if ever you are "uncomfortable" about a service person's expertise, qualifications, or attitude- PULL THE PLUG!!! Don't wait to see if all will be fine- usually your gut instinct is accurate, IMHO.

That said, the damage is done. So, I will ask this- was the "dyno" (chassis dyno?) equipped w/a large- preferably ducted- fan to cool the engine/tranny while the runs were conducted?

That the coolant was forcibly expelled from the cooling system, there was overheating- for whatever reason.

Could have been a bad thermostat, for that matter. But w/o air flowing to cool the engine while under load, all bets are OFF!

And, the tranny shouldn't have been in OD for testing. IMO, it's better to test in a lower gear, besides, most trannys don't have a lot of holding power in OD.

BTW, what is "capped"?

[Jake_Dragon]

Did something hit the radiator? I agree I would have shut him down and left. Better safe than sorry.

[carsavvycook]

I hope he will respond


Last Activity: 05-21-2009 11:48 PM
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[4 Jaw Chuck]

If it overheated on the dyno it would have overheated on the road eventually, now that it happened you are aware of the issue so it appears to be the fault of the dyno operator?

Whatever, your rad is swollen and blocked...install the new rad and see how it runs. It didn't get blocked on the dyno obviously. BTW how is a starter related to this cooling issue that cost $2500 to diagnose when the rad is shot?

I'm not getting this at all?

[powerrodsmike]

If the dyno guy didn't pay attention, and the owner who was there watching what went on , paid attention, but didn't do anything...well a comedy of errors

Like 4Jaw said....Aluminum radiators are not happy at all after a severe overheat, especially if the motor blows a head gasket. Common problem.

The aluminum is thin, the tubes have larger flat sections than a regular brass radiator and when they see too high of a pressure the tubes get oval shaped, which crushes the fins together and it gets hard to get air through the fins to cool anything.

At freeway speeds the air pressure was probably enough to force air through, but at slower speeds the fan can't pull it as well...so it overheats.



Did the truck owner make the dyno operator note that the truck unnecessarily overheated on the dyno, but it had been fine before?

If you spent a ton of money on the truck to fix the problem, before the dyno guy had a chance to look at anything, or acknowledge the problem, it's now all on the owner.

Later, mikey

[carsavvycook]

Mikey, I agree about the radiator swelling under extreme heat, but that did not happen to this 'vette. It just melted the plastic fan shroud enough to stop the electric cooling fan.

I wish that dyno operator lived here. I can't trust the two dyno shops around here at all. One installed the wrong spark plugs, spark plug wires that were not in holders, and burning on the headers, and metering rods in the carb's, that was $900.00's and called it good. The other one, claimed it was smoking out of the tail pipes, and pinging under a heavy load. They also advanced the timing another 2 degrees to 38. It does neither They wanted to pull the cylinder heads, to check the quench, and by the way, the compression test, and leak down was identical in all 8 cylinders. I think they saw a cash cow..........Not. This was another $580.00

[powerrodsmike]

A new guy in town opened up a Harley shop ..I asked him about putting the shovel on, (if it actually could read any hp below 1/4), and see if he gouldn't get it to go over 95..he said he didn't guarantee that he wouldn't blow the thing up on the dyno....

No thanks. Most of the guys who are well respected tuners around here don't own dynos.

But to each their own...wasn't there a guy here a while back who cared more about how his car sounded than how good it ran?

Later, mikey

[carsavvycook]

Mikey, I just want a true in chassis dyno tune on it now, after the much work I have put into it. It run's, and performs beautifully. This long time project is 100% complete. It got started in 1973, and the only original parts left from the drive-train, steering, and suspension, are as follows.

Block, and cylinder heads. (have been rebuilt, and modified)
Rear suspension leaf springs.
Front sway bar.
Upper and lower control arms.
Power steering pump.

Heck, even a 5 speed face plate was made to replace the factory 4 speed pattern.

[oldbogie]

Originally Posted by betty55

My son's 55 chevy truck with a 350 engine was running great. He took it to dyno it and all hell broke loose. My son is the quiet type but after the experience I feel like he is a volcano waiting to explode. He was not at all impressed by the operator of the dyno. My son tried to explain a few things about his shifter, etc.. this guy was capped and didn't hear anything he said.
He did 4 runs in overdrive and did not pay attention to the gauges at all. He got the truck so hot it damaged several parts. All the water in radiator exploded out, it went everywhere. After long cooling period, he left the shop drove to stoplight, tried to U turn but couldn't get into first or second gear. He then said it got HOT FAST and he waited for a good hour for cool down. Then he noticed that it was shifting at higher RPMS than before dyno disaster. We worked the shifting probem out but this engine NEVER ran hot before dyno and has run very hot since. It seems its ok on freeway, but he
gets off the exit up to a stop light at idle and that sucker climbs up fast to 210 +.
We just spent $2500.00 to diagnose overheating issue. We've bought new starter, new water pump, new bigger fan, thermostats, etc..... did not fix it. had our machinist go through and make it brand new again. Rebuilt it last week and it still overheats. On rebuild we notice the aluminum radiator fins were all bent and appear to have swelled outer casing,the core tubes and fins are all blocked off closed. You can't see through at all.

COULD DYNO PRESSURE AND HEAT HAVE WARPED AND DAMAGED THIS RADIATOR TO THIS DEGREE?
AGAIN WE ARE SURE THIS IS THE CAUSE AND FIX, SO OF COURSE WE'VE ORDERED A NEW RADIATOR $$$$
WE THOUGHT EACH PART WE REPLACED WAS THE CAUSE AND FIX. IT WASNT.




ANY INPUT IS GREATLY APPRECIATED.

The dyno operator doesn't know what he's doing, you never run a chassis dyno with the machine to be tested in a high gear, the first and foremost event is the drive shaft coming out, which is why this is done in lower gears.

Running it the way this guy did sure could take out the radiator if it got so hot the coolant just exploded out of the system.

Bogie

[sunsetdart]

What happened to the radiator is the tubes inside balloned . That happens when the pressure inside the tube gets so high for the heat being made. When that happens no air can flow through the finned area to dissipate the heat. They also do not go back to regular size after they cool. I work for a cooling company and have seen this before.