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View Full Version : OT: Fun with a borescope



tlfamm
10-21-2014, 10:07 PM
(told to me by a mechanic friend)


Yesterday, at a large local auto repair shop, a very late model sedan (v8 + twin turbo) was being studied for a possible fuel injection problem. A plug was pulled, and a borescope inserted into the cylinder to examine the injector (looking for a leak apparently). The mechanic was a bit careless attaching the tip accessory to the scope, said tip apparently falling into the cylinder, but not visible. (The tip was described as the size of a 22 caliber round.) This unfortunate type of accident is not unheard of, and the usual approach is to use "fishing" tools to recover the "foreign body" - some labor being involved in the effort, possibly including removing the injector.



However, the shop "guru" had a better idea: "We can't see it - it's probably not there, but let's just crank the engine: if the tip is there, it will be blown out (where?). The suggestion is not universally welcomed, but the guru prevails: the engine is cranked, horrible sounds result, and wide-eyed looks are exchanged. On visual inspection through the plug hole, "glitter" is seen on the piston top; shop guru opines, "its probably just carbon". With a second borescope (can't have just one, eh?), the assembled crew can easily see the crushed remains of the accessory tip on the display screen, the destroyed tip now embedded into the top surface of the piston. The cylinder wall of the all-aluminum block is heavily scored; compression in the cylinder is in the pits.


Cost of the replacement engine: $75K + labor.


All in a days work...




(further detail withheld to maintain anonymity)

A.K. Boomer
10-21-2014, 10:13 PM
What a hack...

it's like take your worst fear and make it happen - welp - he did... duh.

Paul Alciatore
10-22-2014, 04:02 AM
Two questions:

1. What auto engine costs $75K? I am not questioning that price, just want to know what one.

2. Why would anybody EVER use that shop for anything? I wouldn't trust them with a lawn mower.

OK, three questions, is this story for real?

Royldean
10-22-2014, 08:05 AM
I have repeatedly heard from "professional mechanics" that the way to get a foreign object out of cylinder is to "blow it out by cranking the engine". Which is exactly why I have not taken any of my cars to a professional mechanic in the last 20 years.....

I am not surprised. In addition to the "guru", all the bystanders should be equally ashamed of themselves.... for allowing it to occur.

Rustybolt
10-22-2014, 08:21 AM
I could see turning it over by hand just to get it close to the opening, but crank it? You don't have any control just turning it over. I would think that would be obvious.

ptjw7uk
10-22-2014, 08:21 AM
My father in law did something similar in which he was cleaning the carb by taking the top part off but unknowingly lost the ball bearing from the acceleration pump down the manifold. He then put it al together stated the engine and was puzzled by the rattling noise!!
Upon stripping the head the piston looked like the moon's surface where the ball bearing had bounced around - a sure case of a little learning does some damage but you just couldn't(still cant) tell him !

Peter

Willy
10-22-2014, 08:41 AM
Absolutely incredible, but considering the hacks I've seen, totally believable.
It just boggles the mind that a person could call himself a mechanic with ideas like "blowing it out" firmly ingrained in his head. Has the man not one iota of the concepts of physics?

If it would have been my car I would have had the shop, and I use the term loosely, to order a new engine and have it sent elsewhere in order to have it installed there.
Like Paul said, they shouldn't be allowed near a lawn mower

tlfamm
10-22-2014, 09:15 AM
Two questions:

1. What auto engine costs $75K? I am not questioning that price, just want to know what one.

2. Why would anybody EVER use that shop for anything? I wouldn't trust them with a lawn mower.

OK, three questions, is this story for real?

1. Upscale foreign sedan. The marquee does include some hand-built engines - but I'm not sure if this one was.
2. Unlikely that the customer would be informed in detail about the causes of the "engine failure", preserving the reputation of the shop.
3. Yes, it is (but your scepticism is understandable). My informant witnessed the affair from a distance, but deliberately stayed away from the car, knowing that the involvement of the "guru" could lead to problems. Definitely a Tar Baby situation.

Guido
10-22-2014, 12:19 PM
What were they smoking?

While trying to babysit 104 grown(?) people, on call 24/7, something was always interesting come Monday morning. It seemed nine times of ten, drugs were involved.

vpt
10-22-2014, 12:44 PM
All aluminum, no cylinder sleeves? I've only seen that in the cheapest of pos lawn mower engines.

Royldean
10-22-2014, 02:52 PM
I could see turning it over by hand just to get it close to the opening, but crank it? You don't have any control just turning it over. I would think that would be obvious.

Most modern engines, you can't even do that, there is very little clearance in certain areas of the combustion chamber (usually the open valve and the top of the piston). Cranking the engine (manually or with the starter) with a foreign object in the cylinder is a BAD idea.

I once dropped a nut while closing up the valve cover on my old isuzu p'up... For a split second, I convinced myself that there was NO way it could've fallen into an open sparkplug hole (I was manually cranking the engine to adjust valve lash). My skeptical side stepped in and I peeked into each cylinder with a flashlight, and sure enough the nut was sitting right on top of a piston.... I learned that lesson the EASY way!

Royldean
10-22-2014, 02:53 PM
All aluminum, no cylinder sleeves? I've only seen that in the cheapest of pos lawn mower engines.

Don't most high-end dirtbikes just have plated bores? I'd still consider them "all aluminum"....

Glug
10-22-2014, 02:54 PM
Wow. I wonder if the brainiac who pushed for turning the engine over knew the Quench clearance of the engine? And Quench aside, there was still the probability that the piston to valve clearance could cause interference. Especially if the object fell into a piston valve relief.

Even if there was sufficient clearance, I question whether there could be sufficient gas velocity to expel a tiny object from the engine. Particularly when you consider that the exhaust valve is only open wide enough for a very brief time.

Noitoen
10-22-2014, 03:10 PM
Something's not right. f they had a second borescope, why didn't they use it to confirm the presence/location of the lost piece inside?

justanengineer
10-22-2014, 03:28 PM
JMHO, but that story has quite a few holes and embellishments in it.

Doc Nickel
10-22-2014, 03:54 PM
There's plenty of $100K-$150K sports cars out there where replacing or rebuilding the engine could easily be $75K. If one adds labor- somebody paid for the labor- then even an $80K car might cost $75K to replace the engine.

Also, by "sparkly bits", I suspect what happened is the first borescope was using a clip-on right-angle mirror, which probably snagged on the plug hole and slipped off. That's a smaller part than the whole tip of the scope, but also far more likely to come off- don't ask me how I know. :D

Either way, it was indeed quite stupid to just try to "blow it out". I can understand the guy's reasoning- hell, pulling the head off even an old small-block Chevy in a 70's pickup truck is not a trivial job. But it was still supremely stupid.

As for missing the lost part, that's fairly easy- those borescopes aren't the most flexible things in the world, and exterior restrictions can easily keep you from twisting the internal tip to all possible angles. I recently used mine to check on an old race engine that was supposedly 12.5:1 compression. I scoped it- albeit just through one hole) and from what I could see of the piston top (limited by the cramped engine compartment) I saw no dome or pop-up. I told the owner it probably couldn't be 12.5:1, they looked like flat-tops to me. 10:1 at best.

Naturally, when we broke it down, the pistons turned out to have actually pretty significant domes- I could only see the upper half where it was flat.

What I and the turbo engine guys should have done, is manually roll the engine so the piston was toward bottom dead center- then it's easier to see the whole piston top, and any debris thereupon. In my case, though, we were already planning on tearing the engine down, the 'scoping was just out of curiosity. :D

Doc.

sid pileski
10-22-2014, 04:12 PM
Well..... Let me relate my story on my Coupe's engine.
While working on my eight stack sytem. I was diassembling the old throttle bobies off the plenum.
I got everything off. I should have had 16 washers and 16 5/16-24 12 point
nuts to put in my nice little baggy for later reassembly. Guess what? Only 15 washers!
Got out my ridgid borescope. Sure enough, a nice shinny washer on top of the piston!
It could not come out though the spark plug hole!
Fortunatly, the intake ports are huge on this 514 and with the eight stack setup, I didn't have to pull the intake manifold off.
It was a stainless washer so, no magnets. With a series of forcepts and wire, I was able to pull it back out through the valve it fell past!
I'm glad I counted like a surgen counts tools and sponges before they close!!!

Sid

tlfamm
10-22-2014, 05:02 PM
All aluminum, no cylinder sleeves? I've only seen that in the cheapest of pos lawn mower engines.

Mercedes, BMW, Porsche, and ? offer alusil liners in some of their aluminum blocks; the engine block is typically described in shorthand as "all aluminum", because the liner itself is an aluminum alloy (might include silicon, copper, magnesium, etc).

goodscrap
10-22-2014, 05:15 PM
If anyone else gets in a similar position I always think It's amazing what a vacuum cleaner, gaffa tape and small bore screen hose will let you extract with suction

Brian

CarlByrns
10-22-2014, 05:40 PM
The time-honored way to remove foreign non-magnetic objects from a cylinder (like a broken spark plug) is to use a long nose air gun and poof it out. Tool dealers sell air guns with long, small diameter tubing attached that work perfectly for this situation.

Whoever cranked the engine -or suggested it- would be loading up their tool box if they worked for me.

justanengineer
10-22-2014, 06:51 PM
Also, by "sparkly bits", I suspect what happened is the first borescope was using a clip-on right-angle mirror, which probably snagged on the plug hole and slipped off. That's a smaller part than the whole tip of the scope, but also far more likely to come off- don't ask me how I know. :D


No worries Doc, many of us have done exactly that in the past, which is why most any professional shop (and many techs) here in civilization has a modern borescope with an articulating head. Compared to the hardware and software necessary to troubleshoot a modern vehicle (nvm a high end one), theyre cheap at only ~$1-2k.

Head articulating demo at 1:08 for the older fellas.
http://www.youtube.com/watch?v=NMzQbD2QzsY

Peter.
10-22-2014, 07:07 PM
All aluminum, no cylinder sleeves? I've only seen that in the cheapest of pos lawn mower engines.

Just about all high performance Japanese bikes have ally cylinders with nikasil plating. Many now have the cylinders integral to the top casing too.

vpt
10-22-2014, 07:46 PM
Bubble gum on a stick.

EddyCurr
10-22-2014, 10:24 PM
If anyone is interested in reading about retrieval of a glass
eyedropper from the combustion chamber of a Chev V8, have
a look at this 2005 thread on CorvetteForum:

http://www.corvetteforum.com/forums/c4-tech-performance/1148938-help-my-goof-may-have-killed-my-vette-borescope-needed.html

Along with the 'Crush it and blow it out, what could go wrong'
contingent, several of the suggestions posted here were also
offered. In the end, the OP applied what still strikes me as an
ingenious technique to successfully extract an awkwardly-shaped
non-ferrous object through a small opening in a difficult-to-access
location.

The impatient can skip to Post #44 after reading P #1

.

TRX
10-23-2014, 10:21 AM
Having done the "drop a nut down the spark plug hole" schtick before, I'm paranoid about stuffing paper towels or shop rags into anything I can't tape over.

Paul Alciatore
10-23-2014, 03:21 PM
There's plenty of $100K-$150K sports cars out there where replacing or rebuilding the engine could easily be $75K. If one adds labor- somebody paid for the labor- then even an $80K car might cost $75K to replace the engine.

...<snip>...
Doc.

Well, I guess that is just totally out of my league.

krutch
10-23-2014, 04:35 PM
What a maroon! As Bugs Bunny would say. Use a brass rod and gum or some other sticky substance to fish with.
Friend had to replace engine after installing spark plus and one failed and took out cylinder/piston. We were part way back from Daytona when the symptom's started showing. And we had a trailer with four bikes on the back. By the time we got home the engine could barely pull the truck. Was his call to keep driving. We didn't have the tools nor place to pull the head or piston on the road.

The Artful Bodger
10-23-2014, 04:53 PM
We had one of these micro cars:-
http://upload.wikimedia.org/wikipedia/commons/1/14/Suzuki_Fronte_Coupe_001.JPG

358cc two stroke 3 cylinder water cooled, good for 110kmph all day and could go around corners at the same speed! A real jewel of a little car which we had and drove for more than 20 years. I wish we still had it!

One day the engine began to struggle while climbing the Rimutuka hill road, I stopped and was standing by the engine which was still running when a small piece of piston ring came out the exhaust! The head was taken off and all loose bits picked out then we drove home on two cylinders.

larry_g
10-23-2014, 05:47 PM
http://www.garagejournal.com/forum/showthread.php?t=266171&highlight=borescope

I'm starting to wonder if this is myth, starting to make the rounds of the internet?

lg
no neat sig line

Willy
10-23-2014, 06:46 PM
http://www.garagejournal.com/forum/showthread.php?t=266171&highlight=borescope

I'm starting to wonder if this is myth, starting to make the rounds of the internet?

lg
no neat sig line

I believe that "MFolks" is a member here as well and judging by the time he posted this at the GJ forum he likely copied the entire OP's story verbatim. Not nice or original.
The least he could have done was to acknowledge the fact that he borrowed it from tlfamm as first presented here on this site.
At least that's how it looks from here untill someone can shed more light on it.

tlfamm
10-23-2014, 08:57 PM
@Willy:

I can't see the GJ post without joining the forum (no interest) - but taking you at your word, MFolks has committed plagiarism.


The story is not myth.




Edit: on further consideration, I think that correct attribution of the material is all that is required; deleting the offending posts is not necessary.

larry_g
10-23-2014, 11:26 PM
I can see the GJ thread and it was posted a day before this one was posted so it could not have been copied from here. 10-21-2014 7:49 pm is the date stamp at GJ

I have to correct this as this forum is at GMT and the GJ is at GMT-7 So if I figure right the GJ was an hour+ after this thread start.

lg
no neat sig line

Willy
10-24-2014, 03:47 AM
Looks like our illustrious MFolks has copied and pasted his way to internet celebrity status at yet another site with the OP's story clearly intact.
http://www.workshopaddict.com/forum/off-topic/5165-id-hate-shop-guru-who-offered-advice.html
Shades of our old friend Nelson at work? Nah he would have posted it at his own site.:)

EVguru
10-24-2014, 07:18 AM
We had one of these micro cars:-
http://upload.wikimedia.org/wikipedia/commons/1/14/Suzuki_Fronte_Coupe_001.JPG


Long time since I saw a Suzuki 'Whizzkid'!

I have a Honda Beat as a daily driver, when I'm not riding a Yamaha GTS1000.

mike4
10-24-2014, 07:01 PM
This reminds me of why I do my own engine work.

A lot of so called professionally qualified people know jack**** and dont care either.

Michael

J Tiers
10-24-2014, 08:40 PM
A "professional" may be someone who was pushing a broom yesterday, but is wrenching for pay today.

There are a surprising number of blame fools.