"Pointing up" is relative since the lobes point about 90* apart. Both lobes should be presenting a small radius to the lifter, the intake having just closed the valve. With the crank indicating TDC and the timing chain set correctly, either #1 or #6 will be at compression TDC. The other will have just completed the exhaust stroke. The cam lobes tell the story assuming the crank indicates TDC when the cam timing mark aligns with the cam tower timing mark. MB could have done a much better job with the cam timing marks. The position of your eyes is so critical to an accurate reading. I guess that's why they recommend a dial gauge.

You can either remove and reinstall the cam or remove and reinstall the IP timer. There isn't sufficient valve-to-piston clearance to turn the cam without simultaneously turning the crank. I'd say resetting the cam is a smidge easier.

The #1 piston is at the top of the compression stroke at TDC. 14* ATDC is a reference point for setting IP timing which has no bearing on what the piston, valves or IP are doing with regards to combustion. IP start of delivery occurs somewhere around 25* BTDC.

Sixto
87 300D

Be a bit careful here.

The compression stroke is determined by the valves. If you rotate the engine exactly 360 degrees..........back to 14°...........the lobes will be pointed upwards away from the valve stems and the valves will be closed.

The real question is whether the IP is properly configured to deliver fuel on the compression stroke.

You can do this by setting the engine to 15 ATDC on the compression stroke (as governed by the valves) and check inside the access port on the side of the IP. With a light and a mirror, you'll be able to see the notch that locks the IP in position when the proper tool is utlized. If you cannot find the notch..........rotate the engine 360 degrees (exactly) and look again for the notch. If you now find it..........the IP is out of phase with the camshaft.

You are correct, a 2nd time around on the crank and the lobes look right. Both point in an upward direction at 14*.

Is it still worth checking the IP timing even if that gear never left the chain that connects it to the crank shaft?

A neighbor came by and had me prove to him that fuel was being delivered to the injectors. The last three all get fuel when cracked. The first 3 however do NOT -- dry as a bone!! The car is parked on a slight incline. Could this be causing it to not bleed fully? Wouldn't the car partially fire with just half of the injectors getting fuel?

Thanks for the help Brian & Sixto!

Yes if you removed the cam and possibly didn't install it with the IP at #1 TDC. Presumably you set the engine at #1 TDC, pulled the head, didn't turn the engine, then installed the cam at #1 TDC. In that case IP timing should not have changed.

It takes a lot of cranking to bleed the fuel system. I crank for 10 seconds at a time with the dry lines cracked at the injectors. Tighten each line as there's evidence of fuel. I get fuel with less than a minute of total crank time.

Sixto
87 300D

You have fuel at 3 injectors, but not the other 3? Was the injection pump worked on at all (delivery valve seals, etc)?

Having found myself in the situation of now doing this repair as well, what shop manual does the group recomend? I have an 87 300TD. I have been unsuccessful in finding a Bentley type manual. The descriptions contained in this post are invaluable as well as the numerous awesome pictures from GSXR however I still need torque specs for the head, suggested replacement items besides head bolts, etc. Besides a manual, who is the best economical source for a -22 head? Are you guys sure a -22 is a direct replacement? Having looked at the pictures I noticed the combustion chamber will be different possibly causing the valves to open closer to the piston and possibly higher compression? I would like to replace it with the best solution as I plan on keeping the car for a long time (my grandfather purchased it new). Thanks in advance, Christian

The factory service manual for the W124 series is available on CD. Check with Phil or MBUSA but bootlegs abound. The CD contains scans of hardcopy manuals. If you happen upon a W126 CD set, note that the shaded arrows that describe the cam tower loosening and tightening sequence does not match the text. The text is correct.

They Haynes W124 manual for UK distribution is, IMO, sufficient guidance for cylinder head replacement. A copy will cost you more than the FSM on CD.

The -22 head is a direct replacement with some caveats - you can either get inclined prechambers and injectors which are what the -22 head calls for, or have your -14 prechambers machined per gsxr's specification so they seal properly in a -22 head. If you go with inclined prechambers and injectors, you can force your old injector lines to attach to the inclined injectors or get a fresh set of injector lines for a 603.97. You also need a couple of longer bolts at the very front of the head into the front cover. IIRC the -14 calls for 50mm bolts, the -17 and higher heads call for 80mm bolts. Nothing special about these bolts. Keep track of where sensors and plugs are on the intake side of the head so you can transfer these bits from the old head to the right locations.

An alternative is to get a used -17 or later casting head complete with prechambers and injectors.

The combustion chamber reliefs are primariy in the pistons. Outside of the valves and prechamber tip, the head is flat. The -22 is no more or less flat than a -14. Also doesn't matter that the -17 and newer castings are also used in the larger bore 3.5l .97 engines. Make sure you get a 3.0l .96 head gasket!

Sixto
87 300D

Sixto's summary above is 100% correct. If you have any trouble finding the factory W124 service manual on CD, drop me an email...