Hi, all.
I thought I'd share this with you folks, in case you're thinking about doing the same as I did ("need more power" is a common thought among owners of older G's).
Some of you may recollect my making inquiries in preparation for an engine swap. It's done, and I just got it back from the shop. It feels terrific, noticeably stronger, but I'll wait for a few thousand miles of proper breakin before I go for a timed acceleration run to compare to my old engine.
Some details to share: I had been using my Gelaendewagen (1985 280GE/LWB) to tow my boat -- but going up the steep highway grades to the mountain lakes of Vermont/New Hampshire was something of an ordeal for my old, stock ~150 hp engine (the G, alone, weighs 6,000 lbs, and then add my boat and trailer, and all our vacation gear); and with 100,000 mi, oil consumption was a bit high, too. the engine, btw, is an M110.994, detuned (as all G's were of that era) to run on lousy gasoline in third-world countries, and so had low compression pistons (a modest 8:1) and correspondingly mild cams.
I had thought of swapping with a V-8 (e.g., 560 M117), but that would have involved major changes to my engine compartment (mounts, accessories such as A/C compressor and P/S, etc.). So after considering my options, I decided to do a "long block" replacement (completely rebuilt/reconditioned "innards") that was built to Euro "car", and some custom, specifications (extra high compression pistons [ca. 9.25:1], hotter camshafts, etc.). Regular M110.987 280SEL engines have 185 hp with 9:1 pistons -- with my special-ordered, slightly higher compression pistons (9.25:1) and some polishing of ports and stuff, I'm probably at the 190+ hp range (maybe even 200 hp?). Since I always used premium fuel anyway (I've got this notion, true or not, that they put more detergent and other good stuff in premium gas), this new requirement that I have to use premium from now on is a "non-issue" to me.
I had my local MB dealership do most of the work -- engine rebuilding was done by a MB engine specialty shop (at a fraction of the price that my dealer wanted), but my dealership nevertheless agreed to take care of removal, installation, etc. The original flywheel and oil sump's pan had to be transferred to the new engine (these are unique to G's and the shop didn't have those parts. Otherwise, the new long block was built up of fully inspected parts (head, block, etc.). Also, my fuel injectors (tested in a chamber) were examined and still marginally good, but I chose to change them as well.
Naturally, since the engine is virtually the same on the outside (standard M110 double cam engine), there were no problems with reinstallation -- I still can't imagine how the mechanics kept track of every nut and bolt so that none are left over :-). BTW, such engine work is real easy on the G, because when the radiator and A/C are removed, taking out a horizontal support lets you pull the engine almost straight out.
Prices: Arond $5,000 for the long block and almost $2,000 for the labor (removal/reinstallation of not only the engines but also all the parts that were stripped off and reinstalled from a "long block").
[for those not familiar with the term, a "long block" is an engine with the heads (and everything inside such as timing chain and gears, cams, crankshafts, flywheel, etc.) still intact, but without fuel systems, water pumps, accessory drives (A/C, P/S, Alternator), or distributor/ignition system.]
Time (for a good break-in) will tell if this is worth it, but I can already feel a little more "pep". I'll keep you all posted.

Congrats Ken. We all anxiously await the results of your breakin.

At one point it sounds like you had your engine rebuilt and then at another it sounds like you did a true long block.

What type of oil did your rebuilder recommend for teh break in and for how long?

__________________
S, J.R. Brown
2000 G500 LWB Obsedian Black
2005 Toyota Tacoma Access Cab Off Road Sport
1993 Volvo 240 Sedan Anthracite
1980 450SEL Champange (owned it for 15 years. Great car)
1986 280GE LWB Anthracite (Sold it and kinda wish I hadn't)

Actually, I just want to confirm, I had a "long block" built from scratch -- while my engine was still being pulled out of my G. The finally assembly of the long block was held up until the oil sump and, especially, the flywheel could be shipped to the facility (so that the flywheel and crankshaft (and all the other parts) could be balanced as a whole unit).

Frankly, I'm not sure I'm familiar with every one of these components, but the brochure reads that their SHORT blocks are prepared with NEW:
pistons, oil pump, timing chain & its guides, rod bushings, crank seals and spacers, freeze plugs & seals, block side covers, oil pump bushings.
...with "replaced as needed":
Timing gears, flywheel ring gear.
...machined to exact factory specs:
bore and hone surfacing, align home (if necessary), connecting rods, reground crankshaft.

And then, for LONG blocks, add (in addition to all short block features):
cylinder head completely machined (pressure test, resurface, cut seats, new guides (honed).
Plus NEW:
Valves & guides, valve springs and rocker arms, new camshafts (of course, mine were special ordered), new chain tensioner.
Replace as needed: cam bearings, valve train hardware.

Whew. That's about it.

re: "...What type of oil did your rebuilder recommend for teh break in and for how long?..."

Actually, I never asked the long-block builder -- he shipped it empty, anyway.

But I had a good talk with my MB dealership's service mgr. (he's a cool guy who appreciates stuff like what we did on my G), both about oil and breaking in the engine. His advice was to NOT use synthetic (I always use this in my cars -- and my boat) for at least 8-10,000 miles. He said that whereas new MB's come with synthetics, their blocks' cylinder walls have special alloy coatings, and have been prepared to very close tolerances -- they don't need to be broken in; while my engine, without the benefits of modern alloys, should be given a traditional break-in period.

He also said that the best break-in technique would be for me to drive it NORMALLY. Don't baby it, don't keep the revs low, etc. Only, don't do any full throttle starts and keep it revved to the red-line, either. Just drive it with some enthusiasm (he knows me ;-), but nothing extreme.

Ken,

In my opinion you have received advice that is consistent with everything I've read on the subject.

A suggestion. When you drop the oil filter, perform a "aircraft filter inspection". It involves inspecting the element and the bottom of the filter casing for metal. You should find less metal each time you change out the filter. Some is always normal and after a rebuild, there appears to be a lot of data in the aircraft business to support "more" at first due to "leftovers" and the normal breakin process. What won't be detected are metal pieces that are larger than the mess of the oil pickup screen. Looks like your headed for about 3-4 oil changes before you switch to synthetic. This should help you build confidence
in the work performed. I can send you an Adobe document on the subject if you would like.

I would like to suggest that you send an email to Larry Bible (or me) about a non synthetic to use during your breakin. I queried him a long time ago as to the brand of oil he prefers. He is a well informed and learned "shade tree" mechanic. In fact he takes "shade tree" mechanic to a whole new level.

ENJOY the transplant.

__________________
S, J.R. Brown
2000 G500 LWB Obsedian Black
2005 Toyota Tacoma Access Cab Off Road Sport
1993 Volvo 240 Sedan Anthracite
1980 450SEL Champange (owned it for 15 years. Great car)
1986 280GE LWB Anthracite (Sold it and kinda wish I hadn't)

Hi. Thanks for the advice, and I am interested in the oil you and Larry Bible recommend for the break-in period. BTW, is that a particular brand and/or variety, or just a viscosity weight?
Let me know.
Thanks.