GMCer in distress

Mike Hall is hoping to get the 455 started for a few hours of running today. While it's still in the front frame member. ( GMC body has been removed. ) If everything comes together as planned for Pat. I want to get down there later this month to get the bad 455 apart. Because I'm willing to bet some cash. That the plastic/aluminum cam gear pieces took the bearings out in a good running 455. If that's the case. It will be the 4th engine that I've seen this happened to in the last 2 years. Bob Dunahugh 78 Royale
 
I >thought< I had a rod bearing gone coming from Chattanooga. Quiet little tap and falling pressure, in the half mile into the rest area - I was
lucky on location - the tap became a clatter and the pressure went Dixe totally.
I took it to John B when I picked up the new one. The vibrations damper and crankshaft up front had maybe a quarter inch of end play, the flex palte
didn't move at all. I'll get him to tell me where it broke when he strips it for useable parts.Surprisingly, I had to move it maybe 100 feet into my
covered shed, and it fired up and clattered in. Go figure.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
 
That would indicate a broken crank? Unusual for the massive 455 crank but anything is possible.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
If the crank is broken it must be just the snout on the front end, otherwise the cam would not turn and it wouldn't have made it that last 100 feet.
Maybe the nuts came off the converter and the flex plate flexes enough that it won't move the crank through the thrust play, but that 1/4 inch at the
front end is beyond the ability of the internal components to avoid collision with other parts, like the block.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Sometimes, when cranks break, they break on an angle through a main
journal. They stay together when the engine runs slowly with no load. When
cranks break at high rpm and heavy loads, the results are nearly always
spectacular. Ask me how I know this. Very expensive for sure.
Jim Hupy

On Sat, Mar 16, 2019, 4:57 PM Terry via Gmclist
wrote:

> If the crank is broken it must be just the snout on the front end,
> otherwise the cam would not turn and it wouldn't have made it that last 100
> feet.
> Maybe the nuts came off the converter and the flex plate flexes enough
> that it won't move the crank through the thrust play, but that 1/4 inch at
> the
> front end is beyond the ability of the internal components to avoid
> collision with other parts, like the block.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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To keep on topic It looks as if Pat has his problem in hand, so I'll go ahead and bolt the new engine up in the next couple of days. As to the broken
carnk, I don't think the snout broke, because there was no side play at all. And the accessories kept turning. I broke the crank in a VW van
(improper machining of the main journals) and ran it 20 miles to home. Totally destroyed the cases when it let go though.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
 
I wanted to give an update. The coach is now in the process of an engine swap in the capable hands of Mike Hall, with assistance from Lyle Rigdon and
Richard Grooms in Pawnee, Il. Mike believes that the rig will be running down the road this Friday, April 12, which also happens to be my birthday. If
all goes as planned, I will be Amtraking down to Springfield and then catching a ride from Mike to the coach on the following Friday, April 19. The
engine we sourced was recently rebuilt and the coach was destroyed by a fire in the rear, so the engine was not affected. It will be interesting to
see what the post-mortem reveals about the failed engine, my money is on Bob Dunahugh's speculation that the plastic teeth on the timing chain
sprocket failed.
Once again, let me express my sincere and humble thanks to all who gave their best suggestions as well as research and time for my sorry behind. I am
not, by nature, a joiner of clubs, but I will be joining GMCMI very soon and I hope to meet all of you in the near future. The frosty ones are on me.

Thanks again.
Pat
 
Pay it forward.... and let everyone know what the problem actually was when the motor comes apart.
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased