Best 6.2 rebuild

[Gamehunter2277]

What is the best parts and where to find them to do a rebuild ona 6.2 diesel out of a 88 surburban

[More Power]

Silvolite pistons don't have as a good a reputation as other brands. I recommend Fel-Pro gaskets. Otherwise, you can order rebuild kits from www.northernautoparts.com (http://www.northernautoparts.com) or www.usdieselparts.com (http://www.usdieselparts.com).

Jim

[MaxPF]

Like MP said, Silvolite pistons have a reputation for cracking. Clevite pistons are just rebranded Silvolites. I also wouldn't use Sealed Power pistons, since they don't have an armored top ring groove (the top ring in most diesel pistons rides in a steel insert which is cast into the piston). The groove will get worn out relatively quickly causing low compression, blowby, etc.

The only pistons worth using are either stock pistons or Mahle. Stockers are only an option if they are NOS or good used pistons and the bores have no wear or they are going to be sleeved and bored to stock size. For overbores, Mahle's are it. Kennedy Diesel has Mahle pistons for a reasonable price.

I also agree with MP on Fel-Pro, especially for the head gaskets.

Finally, if the motor has more than 100k on it I would replace the crank with a new unit. NOT a regrind or reman, but a NEW GM crank. Here's the problem with that suggestion; NOS GM 6.2 cranks are like hen's teeth - they don't exist. There are no aftermarket 6.2 cranks either, and even if there were I wouldn't use it since it would probably be a Chinese POS (If you wonder why I wouldn't use Chinese parts, read this thread (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=27636)). This leaves 3 options: have a billet crank made (big time $$$), get a 6.5 crank (either NOS GM or AMG/GEP new manufacture) and modify it to fit the 2-piece seal 6.2 block, or reuse your old crank. I am doing option #2 on my build. The only drawback is that the crank won't have much of an oil slinger, so the rear main seal needs to be installed perfectly and the CDR valve maintained or else it will leak for sure ;)

[Robyn]

There is one good option for a crank that was not mentioned.
SCAT is offering a cast steel crank.They are made here in the states.
Scat has a good reputation in the hot rod world and I would not be at all afraid of using one of these.

They sell it as a 6.5 crank, they are all the same. The pistons on a 6.5 and 6.2 weigh the same so your good to go. Stroke is the same and all the bearings and such swap too.
Now there is one caviat. The scat cranks are for the one piece rear main engines.
Im not sure just when the one piece units came in. Some 6.2's did get them but I am not sure what year that started.

The rotating assembly should be ballanced anyway just because it a good idea.

Personally I would not hesitate to use a scat crank.
The stock GM cast iron shafts are rated at 85000 PSI tensile strength and the Scat steel units are 105000 PSI

Unless you are going to turbo the crap out of your 6.2 you should not see any issues.

The little 6.2's usually did not make enough power to hurt themselves.

Just some options

Robyn

[MaxPF]

My only concern with a Scat crank is that it does not have rolled fillets. Rolled fillets add a LOT of fatigue resistance to the crank. Will the Scat crank last a long time without the rolled fillets? I don't know - nobody has had one long enough to see what kind of lifetime it has.

The difference in tensile strength is irrelevant - even severely modified engines don't come close to exceeding the tensile or yield strength of their crank (Top Fuel drag racing is an exception :D ). The failures are almost always fatigue related, aside from defect-related failures.

Like a GM 6.5 crank, there should be no trouble modifying a Scat 6.5 crank to fit a 2-piece seal 6.2 block.

[ronniejoe]

My 6.5 crank had 158,000 on it when I did my engine project. I had it precision index ground to 0.010 under, balanced and it now has over 40,000 more in the new engine.

There is absolutely no reason to change cranks just because it has over 100,000 miles on it and no reason not to precision grind them either, if done properly.

[Robyn]

I could not agree more.

As long as the crank mags good and there are no other issues a .010 under should run a life time.

[sidehackbob]

Marginal machinists and mechanics are the root evil many of the threads here.

If you know your machinist on a first name basis then trust his suggestions.

If you have never been in a machine shop then you should dial one of the advertisers here and purchase a rebuilt or new engine.

Just because a guy owns a boring bar and seems to have cast iron coming in and out all day doesn't give him the experience needed to work on your engine.

There is a ton of work done to marginal production standards. If I take the time to pull and rebuild an engine regardless of use or origin I want it to last as long as possible. My guy is a massive PITA, he is slower than slow but when we finish an engine it screams! nad lives beyond any reasonable expectation.

I hate doing things TWICE almost as much as I hate paying for things I dont need.

[Robyn]

Well now that was a mouth full :D

Sure is the truth.
I have recently found a young fellow who has worked in the business for some time now and knows what he's doing.

I certainly understand the not wanting to do things twice part.
I do however avoid shops that promise me Friday and friday never comes.

The shop I am using now for machine work tells me next week then calls a day or so later and says "ITS DONE" :eek: :D

Gotta love it.

Shoddy machinists just make me shudder. This is actually worse than ripoff mechanics that want to sell you stuff you dont need.

The guy who sells you stuff you dont need is not very honest but at least is not hurting anything.
The clown who hasn't a clue as to what he is doing and is full of BS and is not afraid to spread it around is dangerous and costly.

The folks that advertise here have a reputation for good quality and customer service.

Just give your project a lot of thought before you start spreading the $$$$$$$ around.

The folks here can and will give you enough advice that you can make a good decision based on facts and then adjust things to suit your budgit.

Best to ya

Robyn