6.2L Rebuild?

[TanM998]

What are the best places to get the rebuild kits for a 6.2? I am thinking about this, as I have a coolant leak at the water cross-over tube on the left head... however, there is coolant all along the top seam of the head to block on that side, and the valley has coolant in it also.

I am thinkin that if I have to put a new head gasket on, I might as well just rebuild the engine as it is 18 yrs old. - Drained oil and there was no coolant in the oil, but with it being this cold I can't tell if the exhaust is white or not... if I set the truck in snow and let it run it will turn the snow black...

Any recommendations as to mods during a rebuild to improve performance? I heard that a 6.5 injection pump would be a good idea...

Or, should I just go with a 6.5NA? Maybe it is a tad stronger?

Scott
'85 Tan M998

[britannic]

It may not need a head gasket yet; my crossover leaked as well with the same symptoms you described. I simply removed it, cleaned up all the surfaces and then reinstalled with fresh gaskets and sealant - no leaks now!

[dieselhumvee]

Scott, are you the one with the Tan Humvee on the IHOG website? I like those pics and videos of the mounds run, you put your humvee to the test!!!

There is a LOT of potential in your engine, judging by the white/gray smoke in some of those videos, your injection pump timing might be a little retarded, easy to adjust. A few mods will give you even more power, install a K+N air filter, Kascar resonator pipe, and turn up the injection pump screw 1/6th of a turn. I did these things to mine in a few hours and it feels a lot stronger now. The NA engines can be made to run about 180 HP take a look at Dr Lee's engine buildup http://www.thedieselpage.com/reviews/avanteng.htm

Although your engine is 18 years old, I would do some mods and leave the rest alone until it "throws a scrap iron fit" to quote my father. I have a 93 hummer with the 6.2 NA that was very low on power, since I did the previously mentioned mods, I am very happy with it.

There are a lot of good articles in the members area and product review area. A hot rod NA diesel is within reach. Ask specific questions in the DR Lee forum, he's the resident NA power expert. Do some searches about "injection pump timing" and "turning up pump" etc, in the 6.2 forum.

You could also get your military injection pump rebuilt to DB2-4911 specs, but you need to use 6.5 turbo injectors with it if you do. Yours has a 24v solenoid, you may be able to simply buy a 4911 pump and swap your solenoid onto it.
I am considering the 4911 pump and injectors as my next step and maybe a cam swap as well, there is a performance cam available for the 6.2. Again search for "cam" and "4911" in the 6.2 and DR Lees forums, there is a wealth of information on this site. This site is to the 6.2/6.5 engine what the HML is to the rest of the Humvee.

[dieselhumvee]

One more option a banks turbo, but you need the old style banks manifold, they changed it about a year ago. Enjoy the pics http://64.83.76.92/hummer/attachments/banks.jpg http://64.83.76.92/hummer/attachments/banks2 http://64.83.76.92/hummer/attachments/banks3.jpg http://64.83.76.92/hummer/attachments/banks4.jpg .jpg

[dieselhumvee]

One more... http://64.83.76.92/hummer/attachments/banks2%2Ejpg

[TanM998]

Yeah, I beat the heck out of the truck.... those pics that you saw on the IHOG website are of my truck (probably one of the very few Tan Humvees in civilian hands) but that was back when I was having fuel / timing problems as you have suspected. I have since fixed the fuel problem (leaky line at the tank - air in fuel) and the injection pump was rebuilt by DIS down in Tx, and the timing, even though it was on the marks was set 9 degs off... all of which has been fixed. I am impressed with the power from the engine at high RPMs, but I am not to impressed at lower RPMs...

I am hoping that its just a leak at the cross-over tube, but I am not sure so I figured I should ask... I found all of this from trying to remove the PS pump which was whinning at me wose then my wife....

Scott
'85 Tan M998

[britannic]

dieselhumvee: which Banks turbo is that? It has a wastegate and doesn't look too dissimilar to my Banks TE06H.

[dieselhumvee]

Britannic, I am really not sure, those pics are from a humvee and one from a civilian 94-95 hummer that were for sale at one time or another, i just ran across them for sale online in the past and saved the pics for future reference. I would love to find an old banks kit and retrofit it to my 93 hummer, but I have A/C lines that run right across there, so I have to figure that out first. I hope to do the 4911,TD injectors and cam first, I think these will be quite enough, and later when I work out the A/C lines put an old banks on it, I know it will fit....I have pictures to prove it!!

A lot of old hummer owners put the whipple supercharger on, but these are nearly 5K now, a used banks kit could be found for 1K or less, so that is the route I want to take.

[dieselhumvee]

Scott, as for the lack of low end power, I would call Kascar and order a resonator pipe (replaces the factory muffler) or take it to an exhuast shop and have a straight pipe put in. Then put a K+N air filter in and turn up the fuel screw on the injection pump 1/6th of a turn(under the tiny cover on the driver side) you will have to take the throttle bracket off to get to it. These mods will make the low end torque a lot better off the line, and at minimal cost. As long as you don't go crazy and turn the fuel screw as high as it goes you should be OK. Many here are cautious about fuel settings without a pyrometer, but they also tow a lot, even if your fuel is too much for short full-throttle bursts through the mud, the engine deosn't spend enough time under high EGT's to hurt anything. Mostof your tiem 4 wheeling is just idling around or driving slowly.

Replacing the restrictive factory air filter and muffler will let you flow enough air to squeeze in some more fuel, bringing up the power. The humvees have a good flowing intake manifold and headers, so if you take away the only 2 restrictions(air filter and muffler) you can increase power by 20-30 or so HP and maybe 50-60 FT lbs or more. Your Humvee is lighter than my 93 civvy hummer, so yours should feel even more powerful.

As a reference, mine used to require full throttle from every stoplight and I would lag behind traffic, now I can take off at the same pace as the rest of traffic with 1/2 to 2/3 throttle. I can now accellerate up hills that I used to floor it to maintain speed on. I now gain speed on hills that used to slow me down.

The biggest difference aside from stoplights is merging, it used to be scary merging on the interstate at 45, now I can get up to about 60 on the same on ramp, which makes it much easier to merge with traffic, it does still require full throttle the whole way up the ramp, but to me it's a big improvement.

And in 4 low, the 6.2 NA is (dare I say it) a neck snapper!!

As for the leak, mine leaked at the intake crossover too for a month and just when I was ready to fix it, it stopped. I also have some slight coolant seeping between the head and block on the drivers side, but it comes and goes and doesn't leak a lot, so I don't worry about it.

The fuel screw isn't easy to see or get to, but it is not impossible either, mine took about 2 hours to adjust, and that was by myself. you need to turn it clockwise, and the only way to see it is with a small mirror and flashlight, it is a 5/16ths allen head and the engine msut be turned over in small increments with a breaker bar and socket on the crank pulley nut. I had to climb up and down turning the crank and then checking if I could see the screw, if you have a buddy, it will help a lot and take half the time.

Since you drive a humvee (used to a lot of noise), I am pretty sure it won't be a big deal but with the increased fuel setting and lack of a muffler your NA 6.2 will sound like a big block chevy.... I am not joking it sounds mean. I put the extension pipe that goes out the back, the side exit pipe like the humvees and 92/93 hummers have was too loud for me at highway speeds, but it sure sounded mean when I stepped on it!!

[TimK]

Tad,

I guess it comes down to how much money you want to spend and what your short term and long term plans are for the truck. The faults you are describing can easily be replaced with a couple of dollars worth of gaskets. The water you describe running along the edge of the head gasket is most likely from the cross over pipe leak. The side of the head closest to the center of the engine is where the push rods come through the head. There are no water galleries there. The water galleries are located on the front, rear and outside edge of the block.

If you are really interested in rebuilding the motor, I strongly suggest buying the R&R Guide and Trouble Shooting guide sold by this web site. They go into detail describing the known weak points in the engine. Such as the cracking around the main bearing webs and the coolant leak issue in the head. There is no point in you rebuilding the block if these cracks are evident.

If you are going to spend the money on new parts do spend a few bucks and get a cylinder compression guage. Matco sells one for about $75.00. Remove the oil pan and check out the bearings. Pull the caps and look for wear. If wear is not evident, check the clearences with some plastic guage. Get the oil changed and next time when you change the oil, get the oil analyzed. You can buy a kit from NAPA or on-line through any AMSoil dealer. These 3 items and a visual inspection can tell you a lot about the health of you engine.

Most of the advertisers on this web page that have rebuild kits are worth looking at. The 6.2L and 6.5L diesel engines are unique enough that not every machine shop is turning on cheap parts such as with a Chevy 350. I bought a rebuld kit through NAPA and was very pleased with the parts and had no problems with the parts fitting or performing. However, where the R&R guide recommended a specific gasket or bolts (such as the Felpro head gaskets and Torque To Yeild - TTY bolts)I did use those instead of the items provided in the NAPA kit.

Good Luck.

TimK

[TanM998]

Well... honestly I don't want the truck much louder then it already is... for all I know the muffler might be shot as it is 18 yrs old from all I know...

As far as going down the freeway, I have never had any issues with my truck slowing down or not wanting to go up grades... I also do not drive it around in the mountains. I drove it from ft worth tx, to detroit and all around michigan, never having any problems with that.

My power loss issues have come during my time off-roading. At the same tire pressures, I have not been able to get up the same hills as some of the 6.5TDs... and my truck seems to work extremely hard through snow... only breaking through the snow at high RPMs.... for this I have a set of chains... but I would like to just be able to use the engine power... all in all I am happy with the engine, as with your truck mine is incredibly powerfull in L... I have even pulled a 86,000lb semi out of my front yard... he got stuck delivering some dirt... I was actually able to spin all 4 37" x 12.5" tires on dry 70 deg pavement... I was rather impressed.

Maybe my issues are more with weight then power? I believe my truck weights about 6,000lbs.... where the TDs I compair to are about 8,000lbs

Scott
'85 Tan M998

[dieselcrawler]

Hey there,
I don't have a Humvee, but my truck is a CUCV, so it should be compairable. 6.2L N/A diesel, TH400, 4.56 gears, 40" tires, 7000 lbs.
I just want to say something about the exaust issue, I have 2.5" duals with glasspacks, and it makes the truck sound great. Nice low rumble at idle and up to mid-throttle/rpm, then it really wakes up the naughborhood... however, there was no noiceable power change when I put them on...
My truck spends alot of time in low range, pokin' around in the woods, and is also the tow truck at the local mud pit when the others get stuck. In low range, it's a champ. However, on the highway, it's a dog. Find a modest hill, and I need a SMV triangle like we have on dad's farm tractor. I may try some air filter mods, and if the weather ever warms up and I feel like spending some quality time with my truck, I'll turn up the pump a little. Lower gears (5.13's) would help too, and of course, a turbo!
Well, might not be any help at all, but it's just my 2 cents worth... Take care.
Greg

[TanM998]

Thanks for the info on the rebuild and what to look for... I don't know if I have to go through with it... I hope not... but if I do... I will be sure to use those resources... I wasn't thinking about the valve guides.... and thats a good point... makes sense why it probably isn't a bad head gasket...

Scott
'85 Tan M998