OM621 vs. OM615 A/C question.... - PeachParts Mercedes-Benz Forum

Idle · #1 10-24-2016, 08:36 PM

So a W110 with an OM621 is needing an A/C. I am trying to figure out the mount kit for the engine.

I have access to a mount kit, meaning a bracket, brace, crank pully and idler bearing from a 1972 220d with the OM615.

Is the head, block and crank pully different between these two? If I remove them from the 1972 615 with they bolt up to the 66 621?

Or is there a lot of difference between the two engines?

strelnik · #2 10-25-2016, 09:09 AM

Quote:

Originally Posted by Idle

So a W110 with an OM621 is needing an A/C. I am trying to figure out the mount kit for the engine.

I have access to a mount kit, meaning a bracket, brace, crank pully and idler bearing from a 1972 220d with the OM615.

Is the head, block and crank pully different between these two? If I remove them from the 1972 615 with they bolt up to the 66 621?

Or is there a lot of difference between the two engines?

The OM621 is the first overhead cam diesel used in pass cars. OM 615 is the son of 621 and the father of 616 and the uncle of 617.

The York old style heavy duty AC compressor was used from the late 1960s until 1979. I know this because I have a 1979 with York Compressor. My 1980 W123 has the GM R-4 compressor.

Based on this, I am betting that mounting hardware would be similar with maybe a couple parts different.

The AC drive belt may be different also.

Definitely grab the stuff if you can get it, because the older idler set-ups are heavy duty and also expensive.

Check the EPC catalogue for same/similar part numbers.

The good news is that pulley grooves and PS pulleys should be the same on both engines.

If you remove the crank pulley, be careful not to damage it.

But you and the EPC website should become good friends.

Some owner's manuals also list the part number for the belt.
Either way, you can measure them with cable. I use cable in case I have to put tension on the idler pulley.

This really should not be difficult to do. You would only have to remove the crank pulley if your original did not have a groove to drive the AC compressor.

Good luck! Not as daunting as you might think, just tedious to check everything.

Don't forget to write it all down!

Idle · #3 10-25-2016, 11:25 AM

One observation on the crank pully......

On the 114 220d I am looking at as a donor the front crank pully is, of course, attached to the end of the crankshaft. D'uh.....

But the A/C drive pully is clearly bolted on and is another pully stacked on top of the crank pully. Therefore I am sure this extra pully can be removed without removing the crank pully.

I just need to see how it mounts. Hopefully with the three allen head bolts of the Fintail diesel style.

The Fintail style mounting bracket also has an extra pully for the fan, where the belt loops around the crank, over the fan, then over the idler and then around the compressor.

The 114 mount comes across the front of the engine and the idler pully is on the left side of the car, looking at it from the drivers seat. The belt loops around the crank pully, up to the idler and over to the compressor. There is no belt drive on the water pump behind the fan.

Just some observations to help others along the way.....