Update from Colorado!

[robert peesel]

I wish I had something to add to this conversation, but you all are far more well-versed in this topic than I am! All I can say is Thank you!

My next question assumes the worst case scenario.

Assume that the timing belt slipped and needs to be replaced. With the possibility of damage that may have been done during my driving and testing
combined with the fact that we were going to install an EFI system due to the altitude here, would a modern engine replacement be a better long-term
solution?

Just trying to get a handle on how best to move forward!
--
Robert Peesel

1976 Royale 26'

Side Dry Bath

Conifer, Colorado

 

[Rdenney]

That's a big step without knowing the problem.

Replacing the timing chain is within the reach of amateur mechanics, and if
you do it yourself it isn't expensive. If you bent pushrods from valve
contact with pistons, then it's time to consider a fresh engine, perhaps,
but it's cheap enough to be worth trying it first. The timing chain is
about a hundred bucks (last I looked) for a Cloyes double-roller, and
you'll need gaskets and sundries. And when you do that, there will be some
things you might as well do while you're at it, including a replacement
fiberglass fan shroud (which makes things much easier to access), belts and
hoses, maybe a water pump.

You can pull valve covers to check pushrods, if you want, but removing the
AC compressor and bracket is required for that, too, and that's a big
percentage of a timing-chain project. So, maybe the strategy I would
attempt is to pull the AC compressor (hang it on straps to one side) and
brackets and remove the valve covers. If the pushrods look straight and
good, continue and replace the chain.

But even if the news is bad, a conversion to a modern engine is a much
bigger job that just rebuilding the one you have or buying a rebuilt 455 or
403 from one of the usual suspects.

If I was going to replace the 455 with a modern engine, I'd probably go
diesel. Manny has a kit for that, but it's tens of thousands of dollars.
Too much for me. Any engine conversion to a modern engine will be that
expensive.

The FI Tech fuel injection system looks very appealing, and by all reports
works very well on the Olds engine for solving altitude problems. No need
for a modern engine conversion to go that far.

Rick "one step at a time" Denney

> I wish I had something to add to this conversation, but you all are far
> more well-versed in this topic than I am! All I can say is Thank you!
>
> My next question assumes the worst case scenario.
>
> Assume that the timing belt slipped and needs to be replaced. With the
> possibility of damage that may have been done during my driving and testing
> combined with the fact that we were going to install an EFI system due to
> the altitude here, would a modern engine replacement be a better long-term
> solution?
>
> Just trying to get a handle on how best to move forward!
> --
> Robert Peesel
>
> 1976 Royale 26'
>
> Side Dry Bath
>
> Conifer, Colorado
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com

 

[dave king]

Thanks to Bruce Hart for the write up on rocking the crank one way and then the other
to see how much slack is in the chain. I was going to write down this procedure then type it into the
forum, but Bruce beat me to it.
Re "loose" timing chains. I had a 1977 Dodge van with a 360 cu.in motor and 100K miles.
A mechanic friend said to me that with the long trips I was tacking to car race tracks, I should do
the timing chain so as to NOT get stranded miles (MANY) from home.
When I took it apart the top gear had "nylon" ?? teeth. There was enough wear in the "system"
that if you started with the slack side you could walk the chain, by hand over the teeth of the
sprocket. It had not slipped only because of LUCK not Good Management When I replaced the chain and
sprockets with a Cloyes double roller and the timing, (spark and valves) was back to spec, I had to turn
the idle down at least 1 turn on the screw(maybe lots more) and the on road performance was a LOT
better. Just what I did and know.
--
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada

 

[roy keen]

If the chain is retarded 1 tooth yuu probably didn't bend the pushrods if your motor is 8-1 compression.I saw a 455 coach run a couple of hundred
miles retarded 1 tooth it just didn't have much power. When it was corrected it ran just fine for many thousands of miles.
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[Jim Hupy]

I subscribe wholeheartedly to the premise that, "If it can go wrong, it
will!"
"And, at the worst possible time, too". So, that being said, please do not
associate ANYTHING said in this thread by anyone contributing to it, as a
recommendation by me to run that engine one bit more before it has a timing
chain set replaced. Your experience may vary.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> If the chain is retarded 1 tooth yuu probably didn't bend the pushrods if
> your motor is 8-1 compression.I saw a 455 coach run a couple of hundred
> miles retarded 1 tooth it just didn't have much power. When it was
> corrected it ran just fine for many thousands of miles.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
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[Matt Colie]

> I subscribe wholeheartedly to the premise that, "If it can go wrong, it will!"
> "And, at the worst possible time, too". So, that being said, please do not associate ANYTHING said in this thread by anyone contributing to it, as
> a recommendation by me to run that engine one bit more before it has a timing chain set replaced. Your experience may vary.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403

Jim,

Many of us just have experience with the simpler version:

Murphy was an optimist.

A friend watching me work once and noted the double (and more) checks. He mentioned that he though I was kind of paranoid. I told him to note that I
was paranoid and OLD. On the water, the two are closely related.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Jim Hupy]

Amen. Been there, done that. Got lots of broken engine parts to prove it.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> > I subscribe wholeheartedly to the premise that, "If it can go wrong, it
> will!"
> > "And, at the worst possible time, too". So, that being said, please do
> not associate ANYTHING said in this thread by anyone contributing to it, as
> > a recommendation by me to run that engine one bit more before it has a
> timing chain set replaced. Your experience may vary.
> > Jim Hupy
> > Salem, Or
> > 78 GMC ROYALE 403
>
> Jim,
>
> Many of us just have experience with the simpler version:
>
> Murphy was an optimist.
>
> A friend watching me work once and noted the double (and more) checks. He
> mentioned that he though I was kind of paranoid. I told him to note that I
> was paranoid and OLD. On the water, the two are closely related.
>
> Matt
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Still Loving OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>