7000 Miles/Year

K

Ken H.

Active member
Sep 9, 2000
19,427
5
38
Since I installed the new dash and VDO digital speedometer some years ago,
I've been running with about a +5% speedometer error. Being my usual
prompt self, I finally corrected that today. While doing so, I got to
running other numbers and was a little surprised: Since buying the coach
in Kerrville, TX on 30 April 1998, I've put 143,273 (corrected) mile on
it! That's better than 7000 miles per year.

On only 3 Olds 455's (with 3 overhauls) and 2 Cad 500's (with 3
overhauls)! Gotta tell you, though, the second of those Olds engines, the
first I'd built in over 30 years at the time, now has 80,000+ miles on it
in my son's GMC. And the latest Cad 500 has 60,000+ on it.

There are others with lots more miles than that, but those have sure been
happy ones for us (except for a few little "adventures")!
​​
Ken H.
 
Colonel,
7000 miles per year at 8 MPG = 875 gallons x $2.50 per gallon = $2,187.50 total divided by 12 months in a year = $182.29 per month divided by 30 days
in a month = $6.08 per day. All in all, not too expensive to really put miles on these classics!

Heck, a cup of coffee at Starbucks cost that much.

Use or loose it, and drive it like you stole it! (Actually that's the beer talking on our Florida vacation) !!!
Scott
--
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
installed MSD Atomic EFI
Houston, Texas
 
Scott,

PLEASE don't calculate the purchase & maintenance costs to go with your low
operating cost estimates!!! I don' wanna know!

And I SURE don't want HER to know. :-)

Ken H.

> Colonel,
> 7000 miles per year at 8 MPG = 875 gallons x $2.50 per gallon = $2,187.50
> total divided by 12 months in a year = $182.29 per month divided by 30 days
> in a month = $6.08 per day. All in all, not too expensive to really put
> miles on these classics!
>
> Heck, a cup of coffee at Starbucks cost that much.
>
> Use or loose it, and drive it like you stole it! (Actually that's the beer
> talking on our Florida vacation) !!!
> Scott
> --
>
 
Ken, I also have a VDO speedometer that shows +5 @ 60mph , what did you do to correct yours?
thanks
Joe
--
Joe Williams
1978 Royale rear twin
 
Joe,
Do you still have the VDO documentation? If not, you can get it here:
https://docs.google.com/viewer?url=https%3A%2F%2Fwww.vdo-gauges.com%2Fmedia%2Finstructions%2F0%2520515%2520012%2520051%2520--%2520Programmable%2520Speedometer(c).pdf
or
https://goo.gl/QNtKYg

What that does not tell you is how to calculate the pulse rate required.
It's really simple math. Just determine your correct speed when the
speedometer reads 60 mph. Then use this formula: (New Pulse Rate) = (Old
Pulse Rate) x (Actual MPH)/60 or, calculate the percentage the speedometer
reads fast, then reduce the pulse rate by that percentage -- the new rate
should be the same as from the formula.

Their instructions are a little bit confusing: For some reason, they don't
allow you to enter the least significant digit -- it's always 0. So, if
your new pulse rate is 5192, you'll wind up with 5190, with the 0 already
entered when you start.

I should admit that I have not yet road tested my correction -- but the
math's so simple, I'm confident.

Ken H.

> Ken, I also have a VDO speedometer that shows +5 @ 60mph , what did you do
> to correct yours?
> thanks
> Joe
> --
>
>
 
> Since I installed the new dash and VDO digital speedometer some years ago,
> I've been running with about a +5% speedometer error. Being my usual
> prompt self, I finally corrected that today. While doing so, I got to
> running other numbers and was a little surprised: Since buying the coach
> in Kerrville, TX on 30 April 1998, I've put 143,273 (corrected) mile on
> it! That's better than 7000 miles per year.
>
> On only 3 Olds 455's (with 3 overhauls) and 2 Cad 500's (with 3
> overhauls)! Gotta tell you, though, the second of those Olds engines, the
> first I'd built in over 30 years at the time, now has 80,000+ miles on it
> in my son's GMC. And the latest Cad 500 has 60,000+ on it.
>
> There are others with lots more miles than that, but those have sure been
> happy ones for us (except for a few little "adventures")!
> ​​
> Ken H.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Hi Ken, are you saying that over the 143,273 miles you have gone through 5 engines and 6 overhauls?

Just want to be sure I read it correctly.

Thanks,
Mike
 
Mike,

I'm afraid so:
1.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

> > Since I installed the new dash and VDO digital speedometer some years
> ago,
> > I've been running with about a +5% speedometer error. Being my usual
> > prompt self, I finally corrected that today. While doing so, I got to
> > running other numbers and was a little surprised: Since buying the coach
> > in Kerrville, TX on 30 April 1998, I've put 143,273 (corrected) mile on
> > it! That's better than 7000 miles per year.
> >
> > On only 3 Olds 455's (with 3 overhauls) and 2 Cad 500's (with 3
> > overhauls)! Gotta tell you, though, the second of those Olds engines,
> the
> > first I'd built in over 30 years at the time, now has 80,000+ miles on it
> > in my son's GMC. And the latest Cad 500 has 60,000+ on it.
> >
> > There are others with lots more miles than that, but those have sure been
> > happy ones for us (except for a few little "adventures")!
> > ​​
> > Ken H.
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> Hi Ken, are you saying that over the 143,273 miles you have gone through 5
> engines and 6 overhauls?
>
> Just want to be sure I read it correctly.
>
> Thanks,
> Mike
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Mike,

I'm afraid so:

1. After 875 of the 950 miles toward home on 1 May 98, the original engine
ate #4 intake valve, totalling the engine (cracked cylinder wall). I
attribute that one to the shortly-before installed Edelbrock cam having
caused the spring to break.

2. I found a replacement engine, from which the pistons were removed with,
literally, battery acid. I personally did a complete rebuild of that one
under my open carport, despite having not rebuilt anything during the
previous 30 years. There's a long story behind why I did that. About
50,000 miles I later moved that engine to the X-Palm Beach my son's still
driving -- with over 80,000 miles on it.

3. I replaced engine #2 with a complete front clip which had been stripped
to bare metal, powder coated, and reassembled with everything "new or
better". Another long story. After 25 miles, #7 rod bearing spun. That
engine came out of "the best engine shop in Nashville" under the watchful
eyes of a VERY experienced aircraft and outboard engine mechanic.

4. After replacing those bearings & cleaning everything up, I ran that
engine for about 25,000 miles until the Cad500 which had come my way
finally persuaded me that it should go for a ride with me.

5. The completely rebuilt Cad500 ran great until one day, about 23,000
miles into its residence, I was under it and found the crank would move
fore & aft in the block about 0.120". The thrust bearing was inexplicably
worn that much.

6. After having the crank repaired by a very well thought-of crank shop,
the first trip was 160 miles and I got back underneath. The crank end play
had already increased from 0.008" to 0.060". :-(( Since I'd fairly
recently replaced the torque converter, I was suspicious of it -- and
everything else.

7. Unwilling to gamble on any part of the drive train, I found another
Cad500, "freshened", and installed it, with a NEW TH-425 from Manny, and a
torque converter from another rebuilder. That engine now has 60,000+ miles
on it. Not entirely without trouble: I had two of the weird "T" pedestals
for the valve lifters break during our 2013 trip to the West coast -- those
are all gone now, replaced with rocker shafts.

So, yes, I've been through all those engines, and don't REALLY know why any
of them failed. Such is the fate of those of us addicted to 40+ year old
vehicles, I guess. :-)

Ken H.

> Hi Ken, are you saying that over the 143,273 miles you have gone through 5
> engines and 6 overhauls?
>
> Just want to be sure I read it correctly.
>
>
 
Thanks for the explanation Ken, hopefully your latest will provide many more miles with very few issues.

All the best,
Mike
 
Hi Ken,
With today's oil, I would think these engines should go well over 100,000
miles. Am I wrong?
Are there any alterations required to run the Cad500? How does it
compare to Olds455?

> Thanks for the explanation Ken, hopefully your latest will provide many
> more miles with very few issues.
>
> All the best,
> Mike
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
Even with "old" oils, they were good for more than 100,000 -- some have
gotten 300,000+, but not many. At around 100,000, most need a timing chain
& gear set, after that, with continued decent care & feeding, they should
keep running. It's when someone starts tinkering with them, like the shop
that installed the Edelbrock cam in mine (before I got it) that they start
"blowing up".

Since the Cad Eldorado was very similar to the Olds Toronado, including the
use of the TH-425 transmission, the Cad500 is an easy swap into the GMCMH.
Slight front motor mount modification and re-routed radiator hoses are just
about it. There's at least one good writeup on the mod posted at several
web sites.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

On Wed, May 23, 2018 at 10:39 PM John Phillips
wrote:

> Hi Ken,
> With today's oil, I would think these engines should go well over 100,000
> miles. Am I wrong?
> Are there any alterations required to run the Cad500? How does it
> compare to Olds455?
>
>
>
 
wow Ken, thats not the kinda story a new GMC seeker likes to read but you have some serious determination to get it right after all that!

dang! removing pistons with battery acid? I thought I had heard it all! how long does that take anyway? was that because it was seized in the bore?

an ace mechanic/machinist showed me how to break free a seriously locked up engine with a grease gun (and lots of grease)

I have been tested on other smaller machines (no 'acid tests' though) many times but those lessons will hopefully carry over to a GMC someday and
hopefully I can avoid new ones. at least the major ones.

I am pretty set on finding one that is mostly original with an original engine that runs. mileage less than 100,000 preferred but one that hasnt been
F'd with by some unknown 'mechanic' is the main thing to me. hopefully there are still some 40 year old virgins out there. ;)

 
Ken,
Other than the 10% more displacement, is there a good reason to go to the
Cad? If you had a 455 and a 500 new engine to choose from would you do the
extra work to put the 500 in?
I found a 9-page pdf on how to convert but I did not find anything on why.

On Wed, May 23, 2018 at 7:55 PM, Ken Henderson
wrote:

> Even with "old" oils, they were good for more than 100,000 -- some have
> gotten 300,000+, but not many. At around 100,000, most need a timing chain
> & gear set, after that, with continued decent care & feeding, they should
> keep running. It's when someone starts tinkering with them, like the shop
> that installed the Edelbrock cam in mine (before I got it) that they start
> "blowing up".
>
> Since the Cad Eldorado was very similar to the Olds Toronado, including the
> use of the TH-425 transmission, the Cad500 is an easy swap into the GMCMH.
> Slight front motor mount modification and re-routed radiator hoses are just
> about it. There's at least one good writeup on the mod posted at several
> web sites.
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI & EBL,
> Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
> www.gmcwipersetc.com
>
>
> On Wed, May 23, 2018 at 10:39 PM John Phillips

>
> > Hi Ken,
> > With today's oil, I would think these engines should go well over 100,000
> > miles. Am I wrong?
> > Are there any alterations required to run the Cad500? How does it
> > compare to Olds455?
> >
> >
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
Fred,
At this stage of the game if you find a MH with 90,000 indicated it is
really hard to tell if it is 90, 190, or 290K miles. Might even be 390k
miles.

On Wed, May 23, 2018 at 9:12 PM, John Phillips
wrote:

> Ken,
> Other than the 10% more displacement, is there a good reason to go to the
> Cad? If you had a 455 and a 500 new engine to choose from would you do the
> extra work to put the 500 in?
> I found a 9-page pdf on how to convert but I did not find anything on why.
>
> On Wed, May 23, 2018 at 7:55 PM, Ken Henderson

>
>> Even with "old" oils, they were good for more than 100,000 -- some have
>> gotten 300,000+, but not many. At around 100,000, most need a timing
>> chain
>> & gear set, after that, with continued decent care & feeding, they should
>> keep running. It's when someone starts tinkering with them, like the shop
>> that installed the Edelbrock cam in mine (before I got it) that they start
>> "blowing up".
>>
>> Since the Cad Eldorado was very similar to the Olds Toronado, including
>> the
>> use of the TH-425 transmission, the Cad500 is an easy swap into the GMCMH.
>> Slight front motor mount modification and re-routed radiator hoses are
>> just
>> about it. There's at least one good writeup on the mod posted at several
>> web sites.
>>
>> Ken H.
>> Americus, GA
>> '76 X-Birchaven w/Cad500/Howell EFI & EBL,
>> Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
>> www.gmcwipersetc.com
>>
>>
>> On Wed, May 23, 2018 at 10:39 PM John Phillips

>>
>> > Hi Ken,
>> > With today's oil, I would think these engines should go well over
>> 100,000
>> > miles. Am I wrong?
>> > Are there any alterations required to run the Cad500? How does it
>> > compare to Olds455?
>> >
>> >
>> >
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
>
> *John Phillips*
>

--

*John Phillips*
 
To tell the truth, I "did it 'cause I could". :-)

Seriously, a friend put me onto a 75,000 mile '76 Eldorado engine for $150,
complete. I couldn't pass that up, so hauled it home and put it in the
shop. After a couple of years working around it, I decided "what the
heck...", and rebuilt it (mistake #1; I should have just installed it; it
required NO machine work).

​Now that I've got it, I would not consider returning to the 455. Aside
from the distributor location, the Cad is actually easier to work on than
the 455. For example, its oil pump is external; and, there's a bolt on
each side of every exhaust port so it seals better.​ More importantly, it
is much more content hauling the 13-14,000+# of GMC+CRV with which we
always travel. And it's un-strained at any speed I want to drive, from 50
to 80+. It doesn't get quite as good gas mileage as the 455 (perhaps
because I cruise at the speed limit), but at the mileage we get, what's a
little less matter? Acceleration is considerably better and there are few
hills that slow it down between here and the Pacific.

Especially if one is going to have the engine out anyway, the swap is
trivially easy. I recommend it.

Ken H.

On Thu, May 24, 2018 at 12:13 AM John Phillips
wrote:

> Ken,
> Other than the 10% more displacement, is there a good reason to go to the
> Cad? If you had a 455 and a 500 new engine to choose from would you do the
> extra work to put the 500 in?
> I found a 9-page pdf on how to convert but I did not find anything on why.
>
>
 
> At this stage of the game if you find a MH with 90,000 indicated it is
> really hard to tell if it is 90, 190, or 290K miles. Might even be 390k
> miles.

not with valuable, proper/verifiable, service and maintenance records. for the ones out there without those, pedal wear is a pretty good indicator.
one of the photo site contributors has posted some good info on that here: http://www.gmcmhphotos.com/photos/g4794-brake-pedals-and-mileage.html

the pedals could have been swapped out though but not likely.
 
> Hi Ken,
> With today's oil, I would think these engines should go well over 100,000 miles. Am I wrong?
> Are there any alterations required to run the Cad500? How does it compare to Olds455?
> --
> *John Phillips*

John,

Most of today's oils do not contain enough EP additive to protect our flat face lifters.
>> Warning, the following is the professional opinion of a man that work in durability for several OEs.
 
Ken, thanks for the links for the speedo, did not have any paperwork as the gauges were installed by P.O.
will add to my to do list!
thanks again, Joe

--
Joe Williams
1978 Royale rear twin
 
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