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1979 300SD OM617 uprated cam issue

Started by 79W116, 16 January 2024, 09:53 AM

79W116

I just purchased a 1979 300SD OM617 with a cam that has lobes that are starting to be wiped out (see attached pics) I am thinking of purchasing this used set that is the uprated cam, towers, and followers - https://mbzparts.com/mercedes-camshaft-tower-rocker-arms-uprated-set-5-cylinder-om617-diesel-w115-w116-w123-w126/?srsltid=AfmBOorn8tT1HenYJN8rhRbFWisE5cYxd7LxIRin8ZRM0kKbEU2qUU4_dys

But looking at the service manual (screenshot attached) it states that I also need to use the hard chromed nuts for the valves, but it doesn't show that it comes with the set. I sent a message to the company asking if they could include them.

The questions is, would the conversion be complete with 1980+ cam, towers, followers, and nuts? Also, does anyone have a source for these hardened chrome nuts? I couldnt find a part number or anyone who sells them.

Additionally, I'm planning on replacing the bolts for the towers since they are TTY style single use generally. Are the towers the qty. 8 140mm length triple square 12mm? Does my model have hex or triple square head bolts (also known as XZN style)?
1979 300SD

rumb

'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

79W116

Thank you for the quick response. I am struggling to tell if this is the upgraded hardened one. It says it should be chrome, the one pictured is not. But, the part number is certainly a good start, thank you.
1979 300SD

rumb

'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

UTn_boy

From February 1979 they started using the double hex head bolts.  They're either 10mm or 12mm (socket size).  For length, it'll depend on what style bolt you have.  If you have early hex head, then they're 144mm long, if you have the later double hex bolts they are 145mm long.  Not sure where your figure of 140mm came from, as I don't see any that are 140mm long in this picture out of the factory manual. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

79W116

#5
Thank you @UTn_boy that's a great find. I got the 140mm length from benzforce.com (https://www.benzforce.com/collections/om617/products/om617-cylinder-head-bolt-12-x-140-mm-12-point-xzn) The part number of 615 990 03 12 shows 140mm in multiple vendors, probably a generic round number, but its actually 144MM. I did read somewhere in the service manual that you can reuse the bolt if it has not exceed 145mm, that is why it's listed as a range. But it's a few bucks to buy new and get piece of mind, which is what i will do.

So after tons of research lets see if you all agree with what i have found, and what my next steps are. First my 1979 300SD has a VIN of 11612012008762.

My first attachment shows that I DO have the upgraded valve springs since my chassis number is higher then 006303.

The second attachment shows that I DO NOT have the upgraded chilled cast iron camshaft, or rocker arms with carbide brazed on since my chassis number is lower then 010351.

The third attachment shows there are 3 versions of cap nuts, but no corresponding chassis number to verify. Fortunately the fifth attachment shows that cap nut spare parts are all only the upgraded chromed and hardened version. (615 053 00 72)

So, that path forward for me is to purchase the upgraded camshaft with chilled cast iron (05, 08, or 11 stamp on end) along with corresponding cam towers and rocker arms with carbide tips. And then purchase new hardened chromed cap nuts.

I may take the valve cover off to verify dots on the springs, cam shaft stamp of 00, and verify bolt head sizing. Since this is a low mileage car (124k miles) and it sat for long periods of time, I can only assume that my cam is smoked as a result of old oil getting things gummed up. When I purchased the car I had every oil and filter replaced. And when the engine is running I can see plenty of oil going onto the cams. Also, other items are starting to work better as I drive this on a more regular basis.

Anyway, do you think there is anything else I'm missing before I purchase? Thank you all for your research and input, much appreciated.
1979 300SD

UTn_boy

 There never were any kind of footnotes for the cap nuts.  All it says, both in EPC and factory service manual, is to exhaust the stock of the old early style cap nuts up to engine number 617-950-12-010605.  According to your VIN, your engine number is 617-950-12-009008.  So if you were replacing JUST the cap nuts on your engine back in the day, the dealership would be required to order the early style to exhaust the stock of the old style nuts.  But since you're replacing everything with the later style parts, the later style nuts go hand in hand.  They show to still be available from Mercedes for around $6.00-$7.00 each.  Rocker arms are also still available, but they're over $200 each......It's a hard decision to make spending over $2,000 for a set of rocker arms, but I've had to myself.  There are aftermarket versions, or there used to be, but they had a short life.  Then again, if the rocker arms are ok and are kept in order to their original mating lobe on the camshaft, then it's plug and play. (After lash adjustment of course).  It's funny, you can buy a brand new camshaft from Mercedes for around $300.  Go figure. 

Looks like you have everything.  Though, I do have one other thing I strongly advise you to consider doing.  While the camshaft is out, and whether or not you renew the springs, I'd go ahead and renew the valve stem seals.  They come in a kit, are still available from Mercedes, and are around $70.  Part number 617-050-00-67.  Try to avoid aftermarket.  Just make sure that the cylinder you're working on has the piston all the way at the top of its travel.  Otherwise, the valve can fall out of its guide, and the cylinder head would likely have to come off to retrieve it.  It's not a bad job, but necessary given both the age and mileage.  Might want to roll a new timing chain in, too.  Rule of thumb for those is 100,000 mile intervals.  But that is something you would want to do before or after the scope of work you're going to be doing to avoid the chance of the injection pump sprocket skipping a tooth.  Essentially, you take advantage of the chain tensioner still being installed to keep tension on everything when rolling the new chain in. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

79W116

Thanks again @UTn_boy. After I purchased the car I immediately poured tons of money into the car replacing every single fluid, filter, timing chain, all guides, alt., battery, and much more. I've spent more then double then the purchase of the car, and I bought it for $7k. You would think my prepurchase inspection would have caught that... but anyways. So I am good on the timing chain. I have ordered the nuts and all necessary tools for the job. But I am planning on purchasing a used set of upgraded camshaft, towers, and rockers. Just waiting to hear back from the 2 places that show they have a set available.

Could you share where you identified my engine number relative to my VIN? There's something I haven't found.

I was happy to see I have the upgraded set of springs so I don't have to deal with the valves, but then your logical suggestion of replacing the seals is making me reconsider taking the valves apart to complete that job as well. The engine runs so good, and fires up so fast with no smoke currently. So I'll have to think about that one for sure.

Thanks again for your research and input. Hopefully I will get this fixed in a few weeks.
1979 300SD

79W116

@UTn_boy Ugh...you might have convinced me about the seals. I am right there, why not. I could not find the seal mandrel 617 589 00 43 00, do you have an alterative, maybe just a deep whatever MM socket?
1979 300SD

79W116

#9
Well, now I've ordered new valve adjuster nuts and valve springs since, again, I'm already in there.
1979 300SD

UTn_boy

Lubed up with oil, they usually push right on.  Just make sure you feel/hear the inner lip of the seal snap into place on to the top of the valve stem guide. A socket can work well, but so can our hands and fingers.   The installation mandrel, while a neat too to have, isn't necessary if we're careful.  Plus, the lasts time I checked (maybe 2-3 years ago) the mandrel was around $400. 

Regarding getting your engine number from the VIN, if you have access to EPC, typing in the VIN will reveal the engine and transmission number on the cars data sheet.  I think the EPC subscription price is around $100 per year. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

ptashek

Quote from: UTn_boy on 20 January 2024, 01:49 AMRegarding getting your engine number from the VIN, if you have access to EPC, typing in the VIN will reveal the engine and transmission number on the cars data sheet.

W116 data cards are not digitised. You won't find any of that data there.

Also, there's no EPC since 2018, if not earlier.
It's called Xentry now, and only available to MB dealers, and members of approved MB clubs.
The annual subscription available to private users was killed off with EPC.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

79W116

Ok @UTn_boy, I'd rather feel the seals go on with my fingers as you had talked about, good to know it's not that tough to install.

And thanks for the EPC lookup. I wasn't able to find one as you described, although I did find a few for parts and diagrams that have been helpful.

I pulled the valve cover off this past weekend. I was surprised to see the upgraded cam towers, but a "00" stamp on my camshaft. I didn't think those would work together based off of the service manual describing only the "08 and 05" camshafts had an increased bearing diameter by 2.5mm. But maybe its just a short run set before they settled on the complete upgrade? I did have the upgraded yellow-yellow springs though, I believe the caps are of the upgraded type, and all my ZXN bolts are 12mm for the cam towers. So, this swap should be pretty straight forward in a few weeks from now when I have all the parts.

Anything I'm missing I'm all ears. Thank you all again!
1979 300SD

UTn_boy

Quote from: ptashek on 21 January 2024, 07:01 PM
Quote from: UTn_boy on 20 January 2024, 01:49 AMRegarding getting your engine number from the VIN, if you have access to EPC, typing in the VIN will reveal the engine and transmission number on the cars data sheet.

W116 data cards are not digitised. You won't find any of that data there.

Also, there's no EPC since 2018, if not earlier.
It's called Xentry now, and only available to MB dealers, and members of approved MB clubs.
The annual subscription available to private users was killed off with EPC.

Not entirely correct. This is how I got his engine number.....I typed his VIN in, hit enter, and a data sheet icon on the top right, when opened, shows the engine number, transmission number, date of delivery, and country code.  The very late W116 cars, especially U.S. models, were somehow included in the stored data card databases.  Granted, they don't show option codes or SA option codes, nor does it show pain color or interior trim code. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

revilla