to 6.2 or not to 6.2

[malswood]

I have a 80 'ish (no surpintine)6.2 i put in a '90 G.M. automatic half-ton
I love the simplicity(I need not the wire or the sensor-just give me a gauge)and as I heard someone say-'I'd rather do it 3 times than buy it once
now the question-the compression is down to 240-per cyl.Do I tepid rod it in a rebuild and or do up another (turbo and block twist-tye around it)or maybe find a 6.5?Money is a bit more of an issue than time.I would replace the tranny in time and rear end as I go along.What I want is some half decent pulling power (or lots) and a project muscle that will do the occasional trip to my garage for a week then back on the road -faster each time. First 6.2 or 6.5? Will the 6.5 bolt in/on? cutting and welding is fine.:confused:

[john8662]

A 6.2 will bolt right in.

As far as the compression, how long as the engine been sitting? If for a long time, your results may be skewed.

Skip the turbo, if your truck is geared correctly, you can pull quite a lot with the 6.2 tuned properly.

Make sure you get all the diesel equipment for that year model you're converting, like radiator and fan shroud, proper Hydroboost brake system, etc.

Wiring won't be that hard, most of it you can adapt from the harness in the truck, was it gas before?

[malswood]

I guess I wasn't clear.The 6.2 has been in for 2 years.The compression was tested last summer.I didn't change the tranny at all.Will a torque convertor do the trick-get a new one from a shop?What should I get?

[DmaxMaverick]

The 6.2 and 6.5 are interchangeable, for the most part. Accessories (from year to year, not necessarily specific the engine size) may or may not fit, or may require some modification to fit. It's the chassis and/or model year, not the engine itself.

Replace the torque converter if it is bad. Don't replace if it isn't. Stock is pretty much stock, OEM or aftermarket. High performance TC's are available.

Were all your cylinders at about 240? If so, it may not be as bad as it appears. Most often, they will be very different between them as wear becomes an issue. Consistency between cylinders is much more important than gross pressure. Also, to get an accurate test, it must be done on a hot engine with all the glow plugs removed. Disconnect the ESS wire (pink/front wire on the pump) and do not "wet" the cylinders. The batteries should be fully charged (able to sustain at least 100 RPM's), and crank for 6 puffs per cylinder for your result. You'll need a compression tester with a check valve to do a correct test. Anything less than the above will yield less than accurate results.

[malswood]

The tranny was gas 305 originally.First shifts at high rpm,everything else is o.k.Is there a quick fix for a little more power?The compression was checked at a diesel shop when I had timing checked ( I had moved pump when removing heads)They only checked one side and the whole side was consistant 240.

[DmaxMaverick]

If the compression test was only done on one side, and was reported a consistent 240 on all cylinders, I'd be suspect of it. The test, not the results. Do a correct and complete compression test. Otherwise, at this point, you may never know the truth. I would not rely on the results you have, no matter who did it. It is entirely possible the compression is low, but I would not confirm it based on what you have now.

Power can be increased easily with a little streamlining and fine tuning. Much depends on more detail of the engine year and series (C or J). Don't expect too much in this department, but it can be respectable. Adding a turbo will offer the most bang for your buck. If you are doing the wrenching yourself, it doesn't have to be very expensive. Many folks here have done it.

The tranny needs a Diesel governor, as well as a Diesel torque converter, to get your shift timing and pressures right for the engine. TV cable adjustment is also critical. If you don't address these, even an anemic 6.2 will kill the tranny over time. If you don't upgrade the torque converter, it will continue to shift higher, and upper gears will also when you increase power.

[malswood]

Thanks so much for the help,I guess now I have to do something.I'll get back to you.