Home » Public Forums » GMCnet » Discussion - Engine break in driving (Best practices and what to avoid)
| Discussion - Engine break in driving [message #336747] |
Wed, 05 September 2018 12:19  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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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
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Discussion - Engine break in driving [message #336749 is a reply to message #336747] |
Wed, 05 September 2018 13:26  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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lqqkatjon wrote on Wed, 05 September 2018 13:19As 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 - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Discussion - Engine break in driving [message #336750 is a reply to message #336747] |
Wed, 05 September 2018 14:21 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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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
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
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| Re: [GMCnet] Discussion - Engine break in driving [message #336759 is a reply to message #336747] |
Wed, 05 September 2018 15:04 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Senior Member |
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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
On Wed, Sep 5, 2018 at 1:20 PM Jon Roche wrote:
> 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/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
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| Re: Discussion - Engine break in driving [message #336774 is a reply to message #336747] |
Wed, 05 September 2018 20:49 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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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
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| Re: Discussion - Engine break in driving [message #336777 is a reply to message #336774] |
Wed, 05 September 2018 21:48 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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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
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