Very bad dyno experience
Drifting
Joined: Jul 2008
Posts: 1,873
Likes: 27
From: Sonora CA
It's pretty scary putting any car/engine on a dyno. I don't really see where the mechanic/shop would/could be held responsible. (in this case)
My 2 C's
Pro
Joined: Jun 2004
Posts: 543
Likes: 2
From: Miami FL
St. Jude Donor '11, '14
Really???? We own a marina, if a customer wanted to follow every single moment we are working on their boats/engines, it would be the last time. Honesty goes two ways, if you don't trust anyone, then do it yourself. Go ahead and buy thousands of dollars of equipment and tools every year. Plan on stocking 10k to 20k of parts on hand also. How would you like someone watching every single thing you do, and also commenting on every single item. Oh, also second guessing what ever is wrong. Geeeez, Al
Pro
Joined: Nov 2007
Posts: 721
Likes: 105
From: hernando fl
i agree 100% with alswagg. if you are so worried about whatever service someone is providing that you need to be involved and monitor the situation and help.......do it yourself. if you can't do it yourself you are in no position to give someone who can advice or direction.
Melting Slicks
Joined: Jul 2006
Posts: 2,291
Likes: 493
From: Salmon Arm, BC
i agree 100% with alswagg. if you are so worried about whatever service someone is providing that you need to be involved and monitor the situation and help.......do it yourself. if you can't do it yourself you are in no position to give someone who can advice or direction.
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
When ever I had a dyno tune the operator had me sign a max RPM limit and the he's not responsible for the motor hand grenading!
Is your motor knocking bad? You may have dumped a bunch of gas in the oil and thinned it out. Try a fresh oil change with 20/50 oil and enjoy the summer and you'll have a nice winter project. The damage is already done
Is your motor knocking bad? You may have dumped a bunch of gas in the oil and thinned it out. Try a fresh oil change with 20/50 oil and enjoy the summer and you'll have a nice winter project. The damage is already done
Melting Slicks
Joined: May 2000
Posts: 2,029
Likes: 63
Countless motors are destroyed in dynos every year. That is the risk you take when going to a dyno.
IMO its better it blows on dyno stand than on road/track while going fast. Its only an indication that the engine was bad or going bad to start with.
IMO its better it blows on dyno stand than on road/track while going fast. Its only an indication that the engine was bad or going bad to start with.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
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Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Thats the reason mine hasnt seen one unless I can operate the go pedal its not going to happen and no dyno operator in their right mind will allow that.
I know where mines startign to drop off every noise etc etc.
Doubt too many 25-30 yr old kid will be able to recognize a slight ping valve float etc. The 2 I did have dynoed they were about at valve float level higher than I told them too. No thanks.
Rahter blow it up myself.
I know where mines startign to drop off every noise etc etc.
Doubt too many 25-30 yr old kid will be able to recognize a slight ping valve float etc. The 2 I did have dynoed they were about at valve float level higher than I told them too. No thanks.
Rahter blow it up myself.
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
I've been to a couple of dyno shops that had no problem with me doing the "driving". Personally I'm fine with the dyno operator doing it. I have a rev limiter so I figure if the engine does a hand grenade impression, it was already bad before the dyno and I'd rather find out at a shop than on the freeway.
Pro
Joined: Nov 2007
Posts: 721
Likes: 105
From: hernando fl
stocker31......its not a hard concept to follow.do a little research and if the person is reputable ,let them do their thing, being on hand to observe and answer questions is one thing, telling them how to do it is quite another.
i dare say most people don't tell their doctors how to do their jobs.and i can just imagine TELLING a surgeon you are going to observe just to make sure he does it right.
after all its your hard earned money that is paying him. i would love to be a fly on the wall for that conversation
i dare say most people don't tell their doctors how to do their jobs.and i can just imagine TELLING a surgeon you are going to observe just to make sure he does it right.
after all its your hard earned money that is paying him. i would love to be a fly on the wall for that conversation
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
After you tell them that, they'll probably throw you out of the shop before you have a chance to say "I'm going somewhere else".
Thread Starter
Instructor
Joined: Jul 2011
Posts: 246
Likes: 15
From: Pell City AL
Sorry about the broken engine, but why would the dyno shop cover the repairs?
Why did you have it dyno'ed in the first place??
If I take my car to a shop, and they are going to take my engine to the limit of it's performance...and I'm going to PAY for this service....then I'm going to be involved. Otherwise they don't get my business. Is this a hard concept to follow???
The engine analysis shows the #7 piston burned the top ring out, #8 tested good. Heads and valves are OK.
Thanks everyone for your information and support! I will let you know how it turns out.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
I do believe that they should offer to help you in some way, even though they probably don't accept responsibility for engines that are being run on the dyno.
heres why I think so.
3. your power valve in the carb got trashed because of a backfire.
it happens with holleys and holley clones, its a weak point in the design of the carb. there are mods that can be done to prevent this.
heres why I think so.
3. your power valve in the carb got trashed because of a backfire.
it happens with holleys and holley clones, its a weak point in the design of the carb. there are mods that can be done to prevent this.
THE TRUTH ABOUT POWER VALVES USED WITH HOLLEY CARBURETORS
There still seems to be a lot of misconception about Holley carburetors blowing power valves. Nothing could be further from the truth. Holley performance carburetors built since 1992 have utilized a power valve check system that effectively eliminated this infrequent problem. Consisting of a spring, brass seat and check ball, the check ball system is 100% effective protecting the power valve diaphragm from damage due to engine backfire.
The power valve check ball is designed to be normally open but quickly seals to close off the internal vacuum passage when a backfire occurs. One closed, the check system interrupts the pressure wave caused by the backfire, thus protecting the power valve diaphragm. There is no way that the power valve's diaphragm can rupture due to an engine backfire!
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
Instructor
Joined: Sep 2010
Posts: 236
Likes: 0
Here's my experience as a bystander and a comment on dyno shops. My son had a Subaru WRX and was trying to get maximum performance out of it. Took it to a reputable shop in Portland, OR. As they were running the engine up at top rpm's it would make a horrible "bang" sound at top rpm's and I thought "jeez, that doesn't sound good". If it had been my car I would have stopped them. But on the 3rd run up, BAM! They took it off the rack and the top of the engine (remember, Subaru) it looked like the guy's chest in the first Alien movie. They figured the blow off valve hadn't worked. But, good news, they did take total responsibility. The owner said he wouldn't be in business long if word got out that they blew up engines and said "tough".
Thread Starter
Instructor
Joined: Jul 2011
Posts: 246
Likes: 15
From: Pell City AL
Got the vette back yesterday. The mechanic admitted that because he was unfamilar with the AED modfications that are made to the Holley carb he inadvertently leaned it out to much causing the damage. Based on your feedback I feel we were able to reach an agreement on cost that we both felt was fair. Thanks again!
Below is the chassis dyno sheet taken as the engine was starting to fail. The speedo is off due to a gear change. I did not do another one after the rebuild because I am leaving for the Power Tour tomorrow and did not want to take any chances.
Specs - 383, bowtie heads, 11:1cr, XE284H, Performer RPM intake, AED Holley 650, 700R4, 3:70 gears
Below is the chassis dyno sheet taken as the engine was starting to fail. The speedo is off due to a gear change. I did not do another one after the rebuild because I am leaving for the Power Tour tomorrow and did not want to take any chances.
Specs - 383, bowtie heads, 11:1cr, XE284H, Performer RPM intake, AED Holley 650, 700R4, 3:70 gears
Last edited by obas; May 31, 2013 at 01:43 PM.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 246
Likes: 15
From: Pell City AL
Nope, just trying to provide a full picture of the car. Also, my understanding is engine HP/TQ is 20% more than chassis due to drive line loss. Not sure if transmission type has a significant impact on loss.
Melting Slicks
Joined: Jul 1999
Posts: 3,030
Likes: 17
From: White Pine / Dandridge TN
Good point. I had my vette on the dyno soon after purchasing rebuilt vortec heads back in 2000. Knowing my engine was a little tired on the bottom half and that I would never run it that hard on the street, I only ran it up to about 4,800 rpm on each pull (about 16 pulls). Dyno operator was tuning the carb each pull. I know I probably did not hit max hp numbers but also did not suffer any engine damage.