I've had two catastrophic crank failures in my 1995 K 3500 within 100,000. I owned a 6.2 in an 85 K 1500 that went on and on but finally gave up due to starter bolts failure cracking off the block. Found 1984 6.2 engine in a Winnebago 95,000 actual. The engine so cleans it doesn't even have usual oil residue under air cleaner. I am a professional diesel mech and have rebuilt ebuilt several 6.5 and 6.2's. plan on at least putting new rod and mains with H/V oil pump and using 6.5 parts on the engine. Any recommendations? I am 60 and just plain tired of changing engines.
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Going back to 6.2.
- Thread starter stopit
- Start date
The main difference or trouble area is a turbo, most 6.2's aren't turbo, the turbo adds so much cylinder pressure that over time the main webs fail and in turn the crank, I would highly recommend splayed main caps, I stock them if you go that way... If you do add a turbo then droping down to 18:1 compression will greatly help, I also offer piston machining if needed...
Will L.
Well-Known Member
Welcome.
Above info and his services are on point.
In huge fleet of 6.5 where we did testing for gm, learned what the main issues are to bottom end failure.
bad harmonic balancer. The rubber ages and it slips the outside ring devastating balance. The 6.2 blocks live longer for 2 reasons- no piston oil squirters and less power. Both are worth the trade off. Power is needed and more power means needing to cool those pistons. You can boost a 6.2 but coat the pistons and everything else along the way to deal with the heat.
Hands down the #1 thing to do: get the lower rotating assembly balanced at a machine shop just oike you would a serious race engine. The machinist is gonna have a heart attack when he see the bob weight required for these tiny pistons and rods. They weight like 1.8 times that of anything they normally do because most people that will spend the $ to do it buys race rods& pistons. Anyways, replace the balancer and pulley at EVERY 100,000 miles is a must and you have one choice- AC Delco - there are other brands but folks learn the hard way they can fail at 30,000 miles.
That one choice is to spend $490 and get a fluidampr balancer that will not need replacement. It also works better, even on fully balanced engines because there is always a harmonic. Then the pulley choice: again AC Delco at 100,000 or Leroy’s makes a billet one for $165. Word of warning- there is a ton of chinese knock off parts labeled as AC Delco - VERY cautious where you buy- Authorized dealer only if you want Delco to stand behind it. Same for Bosch parts and I had a less than 1 year use bosch glowplug destroy a piston in my optimizer I bought from rock auto- ZERO responsibility take and because they aren’t an authorized dealer, Bosch won’t even accept the parts back to inspect if they are really theirs or a knock off. Rockauto wont even talk about it because the parts was bought, problem occurred within the 1 hear warranty but I didn’t disassemble the engine until after the 1 year mark. So be forewarned.
Coming out of an RV- you have a 90% chance the block has started to crack cylinders 8 or 7 so inspect that carefully. 30% chance the main webs started to crack so check that next. 99% chance the heads are cracked between valves so plan on doing the sleeve- heck if you buy new optimizer heads still do the sleeve as expected cracking innthe future- i am doing mine like that or best yet spend a half million dollars on the p400 heads. They flow better and cool better both.
there is a ton of improvements on these engines you can do that if you have the $ to invest are worth it longterm. Only a. Delco 60G glow plugs. Ceramic coatings internal engine; better valve springs; roller rocker arms-if stock arms go bolt mod instead of plastic pins; gapless second rings; p400 rods, maybe pistons too? If you can find one because out of production st the moment is gearded timing in place of chain; powermaster starter over Ac Delco; the new injectors from bosch are now coming balanced output to within 25 psi which is the spec you want. So swap them now and have your old ones rebuilt for swapping at the next 100,000 mark. Head studs if you are going over 13 psi boost on stock compression. Main studs if you don’t do splayed mains. The turbo you run has HUGE impact on engine life. No turbo is horrible for engine life if you put your foot down over 70% of the way with it.
There is a ton you can do for improvements get a notebook and make a new page for each one with cost and benifits to weigh out how much you want to spend and whats worth it to you. Work out the list of the above two posts given and go from there.
Definitely dont buy a single thing until you bring it up what part and where because there is a ton of us here that learned the hard way what and who to avoid.
Be more detailed with what power you want and what money to spend helps a lot.
Above info and his services are on point.
In huge fleet of 6.5 where we did testing for gm, learned what the main issues are to bottom end failure.
bad harmonic balancer. The rubber ages and it slips the outside ring devastating balance. The 6.2 blocks live longer for 2 reasons- no piston oil squirters and less power. Both are worth the trade off. Power is needed and more power means needing to cool those pistons. You can boost a 6.2 but coat the pistons and everything else along the way to deal with the heat.
Hands down the #1 thing to do: get the lower rotating assembly balanced at a machine shop just oike you would a serious race engine. The machinist is gonna have a heart attack when he see the bob weight required for these tiny pistons and rods. They weight like 1.8 times that of anything they normally do because most people that will spend the $ to do it buys race rods& pistons. Anyways, replace the balancer and pulley at EVERY 100,000 miles is a must and you have one choice- AC Delco - there are other brands but folks learn the hard way they can fail at 30,000 miles.
That one choice is to spend $490 and get a fluidampr balancer that will not need replacement. It also works better, even on fully balanced engines because there is always a harmonic. Then the pulley choice: again AC Delco at 100,000 or Leroy’s makes a billet one for $165. Word of warning- there is a ton of chinese knock off parts labeled as AC Delco - VERY cautious where you buy- Authorized dealer only if you want Delco to stand behind it. Same for Bosch parts and I had a less than 1 year use bosch glowplug destroy a piston in my optimizer I bought from rock auto- ZERO responsibility take and because they aren’t an authorized dealer, Bosch won’t even accept the parts back to inspect if they are really theirs or a knock off. Rockauto wont even talk about it because the parts was bought, problem occurred within the 1 hear warranty but I didn’t disassemble the engine until after the 1 year mark. So be forewarned.
Coming out of an RV- you have a 90% chance the block has started to crack cylinders 8 or 7 so inspect that carefully. 30% chance the main webs started to crack so check that next. 99% chance the heads are cracked between valves so plan on doing the sleeve- heck if you buy new optimizer heads still do the sleeve as expected cracking innthe future- i am doing mine like that or best yet spend a half million dollars on the p400 heads. They flow better and cool better both.
there is a ton of improvements on these engines you can do that if you have the $ to invest are worth it longterm. Only a. Delco 60G glow plugs. Ceramic coatings internal engine; better valve springs; roller rocker arms-if stock arms go bolt mod instead of plastic pins; gapless second rings; p400 rods, maybe pistons too? If you can find one because out of production st the moment is gearded timing in place of chain; powermaster starter over Ac Delco; the new injectors from bosch are now coming balanced output to within 25 psi which is the spec you want. So swap them now and have your old ones rebuilt for swapping at the next 100,000 mark. Head studs if you are going over 13 psi boost on stock compression. Main studs if you don’t do splayed mains. The turbo you run has HUGE impact on engine life. No turbo is horrible for engine life if you put your foot down over 70% of the way with it.
There is a ton you can do for improvements get a notebook and make a new page for each one with cost and benifits to weigh out how much you want to spend and whats worth it to you. Work out the list of the above two posts given and go from there.
Definitely dont buy a single thing until you bring it up what part and where because there is a ton of us here that learned the hard way what and who to avoid.
Be more detailed with what power you want and what money to spend helps a lot.
MrMarty51
Well-Known Member
Welcome to the truck stop SI
Yeah, get something else. At least start with a brand new 6.5L Optimizer engine not some rode hard put away wet RV engine that has been overloaded 100% of the time. As these are expendable engines only one step above the Olds 5.7 diesel and still use a timing chain...
My dad was stuck on GM. We parted out the 6.5TD pickup he and I worked on because we couldn't get good parts for it anymore. Specifically another good used engine. The Injection pump hell we went through. Glitter dust bomb reman power steering pumps, bad starters, I hope the GM beancounter(s) that designed and later used the shit R4 compressor on R134a has a special hot place in hell... The communist clones of the Harrison R4 are even worse.
Maybe start with a nice complete gas GM crate engine. The 6.0L has power in the upper RPM range for a change. Rather than the all blow and no go this '90's GM era is famous for. So yeah a 6.2 GM gas engine would be fun...
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