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Coming home from 2022 G.N. Our 55 Fleetwood Misfiring!!

Started by Bob Kielar, July 04, 2022, 12:24:04 PM

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Bob Kielar

66F895A5-7656-4B2C-B8FA-6B2F583785F2.jpeg On our way home from Grand Nationals in our 55 Fleetwood I had to stop for fuel so I had to use Mobile ethanol premium. Annie(the name of our 55) started to misfire when we got on the tollway. I just thought it was a fuel problem so we limped her home to Janesville Wi. I could only due 60-65 mph and she would not idle without killing. Annie has run fine but not great on ethanol before so I thought of checking the points and spark plugs. Points a little worn so I change them no help. I then started pulling the spark plugs and look what I found on #4 cylinder. Took a compression check on #4 cylinder and it reads 0.😩 Always wanted to buy a borescope I'm afraid something broke and smashed the spark plug. Any thoughts would be appreciated?

Regards,
Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

TJ Hopland

No noises it just seemed to loose power?  A bore scope would be nice.  Is it easy to pull the valve cover on that side?  Look and see if the valve spring looks normal and to be closing all the way.  Maybe spring broke and valve hit the piston?   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Alan Harris CLC#1513

Had a similar problem once on a 1950 Chevrolet. Boroscopes weren't invented yet. When I removed the cylinder head, I found that the top was missing from one of the pistons. Something had come loose and hit the top of it.

UGLY

Bob Kielar

That's the side the a/c is on I don't know if I can get the cover off to look at the valve springs. My gut feeling is that the head will have to come off. Might as well remove both heads and have them reworked. Hopefully there is no piston damage borescope is due to arrive Wednesday.

Thanks for the replies,
Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

Bob Kielar

To answer your other question there is no real bad noises like a rod knock. 🤞

Regards,
Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

Standardoftheworld

I'd be interested to know what caused that . Best of luck to your Cadillac !
Jay Zerrin. 
Sin City Nv
1961 Cadillac S&S Victoria Hearse
1969 Coupe

Bob Kielar

Used my new borescope today and here is what it revealed. Broken valve top of piston looks to be ok. What do you think about the cylinder walls due they look scorn? I wonder what caused it to break? I bumped the engine and the valve did move.

Regards,

Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

Caddy Wizard

Looks like a relatively clean break across part of the valve.  Perhaps a defective part.  A rather unusual failure mode, in my experience.  The missing piece of the valve probably went out through the exhaust port very quickly and thus probably did little or no damage to the head or piston.  The scoring of the cylinder walls was probably pre-existing.  The missing piece of the valve is probably lodged in the exhaust (muffler or just ahead of the resonator).


Remove the head, check the head for damage, have it rebuilt with new valves and hardened steel valve seat inserts.  Drop the oil pan, undo the connecting rod cap of #4 piston, push piston and rod out through top of the block.  If scoring of the cylinder wall isn't bad, a flexible hone might be employed to VERY LIGHTLY(!!!) hone the cylinder and reinstall the piston (preferably with new rings). Reinstall the rebuilt head.

The car is a very, very attractive car with a lovely paint job.  So as a reminder to all mechanics and weekend warriors out there, don't rest your elbows on the top of the fender, especially when trying to remove something heavy like the AC compressor or the cylinder head.  Doing so will leave little dents in the top of the fender!  Don't be that guy!

Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

James Landi

I think Art has covered it entirely... (you may find that the cylinder wall is fine). I'd be wondering why the damn valve broke that way... did you replace all of the valves during a rebuild? If so, how many miles since the new valve(s) were replaced Perhaps search the inter net for folks having similar failures.   I've been messing around with Cadillac engines for over 60 years, and I've seen my share of cracks in cylinder heads, burnt exhaust valves, and worn piston rings, but never seen or heard of a valve face breaking off as yours has... Even if you "over rev" these engines, the valves will "float" thus protecting them from that kind of damage. Keep us in the loop regarding your progress... hope this helps get other opinions and advice  James

CadillacFanBob

#9
Here is a valve issue, NOT with Cadillac, but my son-n-law's PT Cruiser, it ran fine then upon next start up 1 dead cylinder and 25 lbs compression.  Bob I love your dated photos, I will keep following your posts to see the completion.

Bob
Frankfort, Illinois

Dr. John T. Welch

Which bore scope did you decide met your needs? 
John T. Welch
CLC   24277

Bob Kielar

#11
The borescope is a Teslong NTS300 it has three lenses and a 16.4 long cable. I watched several videos on this model before purchasing it. The manual is a little vague I called Teslong and they picked up right away. My question was how to connect it to a computer. All I had to do was use the charging cable and the pictures loaded to the computer using my F drive. I'm not that computer savvy so there might be a easier way. It is a robust camera with a lot of great features. Bought it thru Amazon for $180.00.

Regards,
Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

Bob Kielar

#12
Oh Crap! Yesterday I decided to pull the rest of the spark plugs and found this on #1 cylinder another bent plug. I checked compression and it is 150psi. I wonder if I have to long of a plug but one would think it would also be on the rest of the cylinders. Might it be the connecting rods? Any replies would be appreciated.

Regards,
Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

dn010

At this point, I think it's hard to tell you more until you gather information. You can take a lot of the guess work out of this by pulling the head(s) and then assessing. If you can find any sort of number on your Champion plugs, you can then see if they are correct for your 55 but if they were wrong, they'd all have some sort of damage to them.
-----Dan Benedek
'57 Cadillac Sedan Deville 6239DX
'81 DMC DeLorean

Jeff Rosansky CLC #28373

Valves are a big issue on airplane engines. There could be a small chip that doesn't let the heat disapate which causes that part of the valve to get hot and then it just snowballs..... Well, not snowballs because of the heat 😉. Then it finally got to the point where it gave up the ghost. I had a complete valve head break off in our 70. Beat the crap out of the head but not a single scratch on the cylinder wall. Hopefully you are that lucky.
Please let us know what you find. Would also appreciate a few pictures of rhe head and block when the head is pulled.
My son and I have been discussing having the heads redone on our 55.
Good luck

Jeff R
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

hornetball

I once got a set of too-long spark plugs for a late-model Chrysler minivan.  It misfired and when I pulled the plugs I found one closed up like your pictures.  You would think the parts store would be able to get the right plugs for a late-model, common car, wouldn't you?  But it they messed that up, I can only imagine they could mess yours up too.

In any case, only one of the pistons hit enough to close the plug.  There are manufacturing tolerances in deck heights and different amounts of piston rock at TDC.  So, I don't think it would be too unusual to only have issues on a few cylinders instead of all.

BTW, all I did on the minivan was have the parts guy double check, installed the new set of plugs and drove the car for several more years.

Caddy Wizard

Bob,


I now suspect that something was ingested into your engine and did the damage on these two cylinders.  A little bit of metal was in the #4 cylinder and was going out the exhaust valve opening when the valve closed on it.  The momentum of the valve face hitting the obstruction snapped it off.  A little bit of something was in the #1 cylinder also and when the piston came up, the obstruction was smashed against the plug.

Piston alone didn't crush the plug -- it would be stopped by something else in the combustion chamber first before hitting the plug.

Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

James Landi

"I now suspect that something was ingested into your engine and did the damage on these two cylinders.  A little bit of metal was in the #4 cylinder and was going out the exhaust valve opening when the valve closed on it.  The momentum of the valve face hitting the obstruction snapped it off.  A little bit of something was in the #1 cylinder also and when the piston came up, the obstruction was smashed against the plug."

Art's theory is an interesting possibility.  Way back in the late 60's, a colleague with a 64 Cadillac convertible found the missing lock washer to his carburetor in one his combustion chambers...apparently it took many months to work its way there to do some substantial damage.   James

Bob Kielar

Latest update. Here are some engine pictures of my 55. The broken valve pieces ruined the piston and scored the cylinder walls. The engine has to come out and be rebuilt. The problem is the reputable machine shop near me is backed up with work may not get the Cadillac back until spring.

Keep Cruzin,
Bob Kielar
Keep Cruzin
1955 Cadillac Fleetwood

Dave Shepherd

Sorta looks like some detonation damage on the piston, if it was there would be evidence on other piston, cause of all this is critical for a proper repair of course.