My 6.2L rebuild update

Discussion in '1982-Present GM Diesel' started by arveetek, Nov 10, 2005.

  1. arveetek

    arveetek 1/2 ton status

    Mar 1, 2002
    Likes Received:
    Granby, MIssouri, USA
    As requested, here is an update of my 6.2L performance rebuild.

    I have only put on 5,047 miles since first firing the engine up at the end of May. However, it's still running like a champ. The power is unbelievable, I really couldn't ask for much more power. It tows my 29' 5th wheel like it's not even back there. I'm sure I would be wishing for more power if I headed into the mountains, though, but who wouldn't?

    I do have cooling issues I'll need to address, but only when towing large loads in the summer heat. Right now, simply unclipping the spring on the fan clutch keeps it cool enough. That keeps the fan engaged all the time, and so for now, before I head out on a trip, I unclip the spring. When I get back, I put it back to stock, and the fan acts normally. For some reason, the fan won't kick in automatically until it's really, really hot, and it makes me nervous. Leaving the fan on manual prevents the temperatures from getting too high. I believe converting to a serpentine setup, running the later HO water pump, and adding the dual thermostat crossover will be the ultimate solution.

    Cooling is not an issue during cooler weather. My wife and I took the RV to Branson last weekend, and I had no trouble at all. Without high ambient temperatures, and no need to run the a/c, the engine stayed perfectly cool without manually engaging the fan.

    I'm also fighting a rough idle problem. Initially, the engine had a miss at idle, and it turned out to be a faulty injection line that wouldn't seal up tight. I replaced a pair of lines, and that helped, but I still had a slight miss. I had one new injector that leaked upon installation, so Tim at sent me another injector to replace it with, and that cured the miss problem. However, I still have an idle problem in that it sounds like crap. I can't stand the way it idles. It feels smooth when you put your hand on the engine, and it doesn't rock around, but it sounds awful. I've finally decided that what I'm hearing is the "ching-ching" sound of the gear drive. I'm starting to think that perhaps I have a worn rocker assembly causing the gears to load and unload. I'm still trying to figure that one out.

    Fuel economy is down. When the engine was n/a with 3.42 gears, I averaged 19.5 mpg. Swapping to 4.10 gears averaged me 18.5 mpg. Adding the turbo and increasing fuel delivery dropped me to around 17.5-18 mpg. All the other mods I did dropped me to 15.5 mpg. However, each mod has yielded a significant power increase. Basically, more power = more fuel, there's just no way of getting around it. Like I said before, the power is great. I'm estimating 200 HP, and it tows about equal to my Dad's 95 7.3L chipped Power Stroke.

    Things I might have done differently? I would have checked my rocker arms more closely. I have since discovered that the older, cast rocker arms wear out and can rock around. Even though the newer stamped rocker arms are held in place with plastic retainers, they can be lubricated much better and won't wear out. I'm thinking this might be part of my rough idle problem.

    I also would have purchased injectors from Tim at did a great job rebuilding my pump, but the initial leaking injector made me wonder about the quality of the injector rebuilds. I purchased the injectors from Tim because they were much, much cheaper. But I have since learned that Tim doesn't rebuild the injectors himself, but just buys them from a third party. The pumps he rebuilds, just not the injectors. I'm thinking my engine would idle better with better quality injectors. This is one area where you get what you pay for.

    That's it as far as doing things different goes.

    I do have a new problem: the lock-up torque convertor on my transmission is not holding any more. It will lock up, but then giving it extra throttle causes the engine to overcome the lock up function and the rpms start to raise. The tranny has over 150K miles, perhaps closer to 200K, so it's time has come for service anyway. I'm sure increasing the power output of the engine hasn't helped any, though.

    That's about all I can think of for now. I'll continue to update ya'll as time goes on. One thing's for certain, though: the 6.2L does NOT have to be a gutless wonder!

  2. imiceman44

    imiceman44 1 ton status Premium Member

    Aug 5, 2002
    Likes Received:
    Sacramento, CA
    I just posted a few questions on the other thread so I am not going to repeat here but I can tell you to expect some questions as I start my rebuild :D :bow:

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