Discussion - Engine break in driving

[LQQKatJon]

As some may have know, on July 29th my GMC had to be towed home because a busted #6 exhaust valve broke off and took out the piston.

fast forward to this past weekend, I spent friday-monday installing the rebuilt transmission, new radiator, tranny cooler, and all the other work that
goes into installing a rebuilt engine. My friend came over Monday, we primed it up, fired it up, and ran in the cam for 20 minutes. All went
well, the engine sounds good and seem to be running well. Last night I re-torqued and checked everything over, bolted my driver seat back in, and
took it for a drive and all seems well. 37 days it was parked in the driveway.

Anyway, I have followed the engine re-builders recommendations to a T up to this point. This is pretty much where the instructions ended and opinions
on what to do next started. only thing left on the checklist from the Rebuilder has to change the break in oil at 500 miles.

So I am putting up for discussion, and I am sure I will get many suggestions as I already have, as to how one would drive this coach with the new
engine for a while, but what I would really like to know is what NOT to do. I know I will be sitting out the radar run this Saturday. I need to
drive it to the RV dump, and then off about 75 miles East this weekend. another trip next weekend an hour north. So I should have some pretty
decent road trips to get the next 500 some miles on the coach.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

 

[Matt Colie]

> As some may have know, on July 29th my GMC had to be towed home because a busted #6 exhaust valve broke off and took out the piston.
>
>
> fast forward to this past weekend, I spent friday-monday installing the rebuilt transmission, new radiator, tranny cooler, and all the other work
> that goes into installing a rebuilt engine. My friend came over Monday, we primed it up, fired it up, and ran in the cam for 20 minutes. All
> went well, the engine sounds good and seem to be running well. Last night I re-torqued and checked everything over, bolted my driver seat back
> in, and took it for a drive and all seems well. 37 days it was parked in the driveway.
>
> Anyway, I have followed the engine re-builders recommendations to a T up to this point. This is pretty much where the instructions ended and
> opinions on what to do next started. only thing left on the checklist from the Rebuilder has to change the break in oil at 500 miles.
>
> So I am putting up for discussion, and I am sure I will get many suggestions as I already have, as to how one would drive this coach with the new
> engine for a while, but what I would really like to know is what NOT to do. I know I will be sitting out the radar run this Saturday. I need to
> drive it to the RV dump, and then off about 75 miles East this weekend. another trip next weekend an hour north. So I should have some pretty
> decent road trips to get the next 500 some miles on the coach.

Jon,

If you saw how we broke in engines in a durability lab, you would be horrified. But by the same token, we also knew what mattered for engines we
needed to live a long life.

The real answer is for the most part, don't worry about it - BUT - For the first 10~12 hours, don't stress the engine while it is cold. Once the oil
is hot (~150°), run it like you plan to for the rest of its life.

And, once you get about 4~5 hours, going to your preferred oil would be just fine.

It took me a much longer time to build my engine, but then, I am a paranoid old engine builder.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[johnny]

Local builder runs the cams in on a test stand before he rel;eases the engine. Warm it up, drive it like you stole it.

--johnny

--
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

 

[Rdenney]

The traditional method is to run it at varying speeds for the first hundred
miles or so. A minute at 55, a minute at 70, a minute at 60, a minute at
50, a minute at 65, etc.

Beyond annoying the drivers behind you, it at the very least does no harm.

I also changed my break-in oil at about 300 miles. It’s been about 1200
miles since then and I’m getting ready to change it again—the oil has timed
out.

Rick “who followed this procedure” Denney

> As some may have know, on July 29th my GMC had to be towed home because a
> busted #6 exhaust valve broke off and took out the piston.
>
>
> fast forward to this past weekend, I spent friday-monday installing the
> rebuilt transmission, new radiator, tranny cooler, and all the other work
> that
> goes into installing a rebuilt engine. My friend came over Monday, we
> primed it up, fired it up, and ran in the cam for 20 minutes. All went
> well, the engine sounds good and seem to be running well. Last night I
> re-torqued and checked everything over, bolted my driver seat back in, and
> took it for a drive and all seems well. 37 days it was parked in the
> driveway.
>
> Anyway, I have followed the engine re-builders recommendations to a T up
> to this point. This is pretty much where the instructions ended and
> opinions
> on what to do next started. only thing left on the checklist from the
> Rebuilder has to change the break in oil at 500 miles.
>
> So I am putting up for discussion, and I am sure I will get many
> suggestions as I already have, as to how one would drive this coach with
> the new
> engine for a while, but what I would really like to know is what NOT to
> do. I know I will be sitting out the radar run this Saturday. I need to
> drive it to the RV dump, and then off about 75 miles East this weekend.
> another trip next weekend an hour north. So I should have some pretty
> decent road trips to get the next 500 some miles on the coach.
>
>
> --
> Jon Roche
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
>
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>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com

 

[john r. lebetski]

Referring to GM owners manuals "from the day" it was suggested to keep speeds below 55 and vary the speed, avoid jackrabbit starts and avoid idling
where possible. .
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Carl Stouffer]

Jon, Since oil and filters are relatively cheap, I changed out the cam break in oil (Rotella T-4 with Lucas zinc additive) Right after the cam run in
and a trip 3 mile around the block to seat the rings. It had a lot of assembly lube, etc in it, including the Moroso Molly Paste that Jim B
recommended as a cam lube.

I then changed it (again Rotella T-4 + Lucas) after about 200 miles to the regular oil I have been running all along. I have about 1200 miles on the
new engine and will probably change it again at about 2000 miles then resume the 3000 mile interval. My mechanic friend also cut the filters open for
me and we didn't find any surprises (besides the molly).

Just what I'm doing
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member