I am rebuilding an M110 for the 1978 280CE, it spun a rod bearing and beat up the crank.


Trying to order 1st repair size .25mm under main bearings.


Metric Motors tells me there is early and late. Early is 1 oil hole on the mains, later is 3 cross drilled holes on the mains.

Called Mercedes to price bearings, they list and an "up-to" and a "from" the engine in the 280CE, the flat surface where the serial number would be stamped is blank. I don't know if this is a factory replacement block or what.

Called the machinist, I took him a crank out of a '75 280C to clean up for this job. He says the 280C crank is a steel crank with 3 drilled holes, and the beat up crank originally in the '78 is a cast crank with 1 hole.

So my early parts car has the late crank, and my still early, but relatively later car had the early crank.

Confused as to which main bearings I need.

Mercedes claims the rod bearings are the same across all M110s, but the mains either are 130 XXX XXX XX p/n for early or 110 XXX XXX XX for late.

The donor motor had the same rods as the 280CE and I am reusing the original 280CE pistons as they measured in spec, they are also 87mm which is the first oversize implying this motor has been through before, which might explain why it spun a rod at 101k, improperly rebuilt in the past.

If anyone can shed some light on this, or point me towards the part number for the steel crank main bearings I would appreciate it.

Mercedes parts called me back, the crank P/N superseeds to a newer style crank and matching bearings at a certain point, so the question is, is a steel crank the early or the late style

Please no-one suggest just throwing a used motor in it, we are well beyond that point, its a very nice car and a rebuilt motor is going to be the way that it goes given how far in we are. The intent was to preserve the original block, but at given there appears to be no serial number, that point is moot, but the block is machined, the crank is machined, and the machinist is ready to assemble, but he needs the properly sized bearings to put the bottom end in it.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

DP:

Do you still have the old main bearings from each of the two engines/cranks? If so, compare them for configuration. The bearings that were in the crank donor engine would presumably be the correct configuration. They should have identifying numbers on the back side.

1st version crankshaft has T-drillings (3 holes) in the mains (except #4), and grooved bearing shells are fitted to the block only (except #4).

2nd version crankshaft has a single drilling in each main (except #4), and grooved bearing shells are fitted to block and caps (except #4).

It would seem that the crank that you intend to use (T-drillings, 3 holes) is a first version crank.

Also ensure that the #4 bearing cap of the new engine matches the donor engine for groove.

Just in case you haven't seen this

http://www.startekinfo.com/StarTek/outside/12265/program/Engine/110/03-320.pdf

It might help by either adding to the confusion or not!

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Bearing caps stayed with the motor. Machinist line-honed the block and bearing caps. So the #4 cap that is on the '78 motor is the #4 cap that was on it when it came apart.

So it sounds like I need early bearings to work with the '75 crank that I am trying to put in this block.

Thanks for the link stretch, I'll print it and give it to the machinist who is assembling the short block.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

DP:
The main caps will for sure stay with the block.
The point was that the configuration of the groove in the #4 cap of the '78 block match the groove in the '75 donor cap.

YOU HAVE TO BE CLEAR ON THE CAR.

280ce CAME IN A W114 AND A W123.

W114/5 early 280CE may have had a bored out M130 (SOHC 280se motor, w108) while the later had the M110 motor (totally different motors)
The M110 is a distinct DOHC motor.
W123 all had M110 engines.

I hope that helps

Also when You say early or late: include the referenced year to clarify.

W114/5 1972-76.
W123 1976-85

686point3:

Perhaps you did not read the OPs first sentence:

"I am rebuilding an M110 for the 280CE, it spun a rod bearing and beat up the crank."

DieselPaul does know what engines he has, and what he is doing.

I am keeping the

1978 280CE W123 Block, head, and pistons.

I am trying to use a 1975 280C W114 coupe crank.

I am not attempting to use an M130 motor to fix an M110. Though if you take apart a 280SL M130 motor and an "early" M110 the cranks look very similar, and the early M110 main bearing number is a 130 XXXXXXXX part number. But that is a discussion for another day as its irrelevant to my quest.

I am going to order the early main bearing set.

The machinist has the crank as says it has the 3 hole T-drilled crank. And the donor motor that this crank same out of was a 1975 which should be early.

I wanted to clarify the styles because at this point, 40 years later who knows what has been rebuilt and who changed what in the dozens of people who owned these cars before me.

Mercedes offers very little explanation between versions, just up to and from and that's it. They usually don't even tell you what changed, and never say why.

I appreciate your insights as always Frank, I had hoped you would chime in!

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

In fairness to you the first line of my OP does not mention the year of my car. It is a 1978 W123 280CE. I reference "'78" later in the body of the text and my sig shows the '78, but I wasn't super up front about that. I will edit the OP.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

The crankshaft for the M110's in the 123's may well be balanced differently than the earlier crankshafts. The earlier USA versions had flat-top 8-1 pistons, while the 123's had higher-compression pistons, I believe, which may well have been heavier with domes and valve cutouts



Tim Kraakevik
kraakevik@voyager.net

The Euro 185HP K-jet cars had 9:1. The pistons that came out of the 145HP USA K-jet 78 were also flat top and I'd assume to be down in the 8:1 range.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i