ISP Problems and Clarification
 

I have had a lot of problem with my ISP and was not able to add info and edit my first post. Please re-read my post as I hope to have clarified and completed it.

All I can say about the MB engine manual that I own is that I have found info in it that does not directly apply to my 300D (see my post about injector nozzles and whether to use the nozzle plates/sealing washers). I do know that most Honda service manuals available when I was associated with Honda did not contain all the info that was available to the dealership - much less the info American Honda had. I am fairly certain that MB service departments have 1,000's of pages and/or CD-ROMS with much more info than what the public can buy. I am not inferring that the MB manual is misleading and/or wrong - I am saying that we may not have all the info available. I have also found info about MB vehicles in service manuals at my library that is not in my MB service manuals, especially the Mitchell service manuals. However, these other manuals do not have info contained in the MB manual.

The method that anyone uses to attach their timing chain is up to them. I am only providing my opinion on the method I know will work - endless chains are far stronger than chains using a master link (the e-type or c-type clip). However, I do know that some/many will take exception to my suggestion/knowledge/opinion since my background is on less-well engineered vehicles than the engineering used in MB vehicles and my actual experience on MB vehicles is limited to my personal 300D and some with one medium-duty MB truck (GVW 40,000 lbs.) - so be it.

Good Luck!

Tom

Last comment and suggestions
 

One observation about timing chains using master link vs. making it an endless chain. Did your original timing chain have a master link? If not, then that fact speaks volumes about making a replacement chain endless and not use a master link.

However, if someone is going to use a master link then in addition to making sure the open end of the clip is facing in the opposite direction of engine rotation the sharp edge of the clip MUST face outwards. These clips (both the e-type and c-type) are stamped out when made and there is a round edge (this is the side that was struck by the cutter) and a sharp edge. The sharp edge will provide a larger more sure contact area on the grooves cut into the pin. The sharp edge of the clip can be easily found by fealing it with your finger.

Last, do not twist, deform, or in any manner damage the clip so that it will have its original shape and best chance of staying on the pin grooves.

I am curious about whether or not anyone's MB engine manual goes into the details of using a master link similar to my suggestions? My MB engine manual does not contain any of this info.

Good Luck!

Tom

The reason the manufacturer uses the endless chain in the original installation is simple; the engine cover is off and during assembly it is easy to put on the cheaper endless chain. The manufacture of a master link costs more since it must be machined for the clips. It has nothing to do with strength.:)

Larry, I would like to know if there are, in your experience, some name brands made in Germany from which one would be wise to steer clear or is this just an idle statement?

I've a couple of questions about my chain that broke.

Each link is stamped I believed with "JWIS". The chain has 96 pins.

Is this a MB chain?

It was not the "Master" link that snapped. The link that was used to connect this chain together is chamfered or beaten along the whole edge of each rivet while all other rivets on the chain is beveled only on two opposite sides.

Note by the attachment that the pin that pulled out of the link does not have the roller or spacer. Where could it have gone, or was it never there? I can't believe that it came off. No other pin has a roller that has any kind of indication that it is biginning to separate.

Had to buy the "triple square" socket to get at the head bolts. Will have it off tomorrow. I am waiting for my parts. My brother who has a German auto shop in Arizona is sending them out, but who knows when a plane can have them here?

I went to the machine shop that has my Harley heads to find out when they will be done and look into them doing the work on this head when to my suprise they were closed and apparently in bankrupcy. Mayfair has been doing great work for 30-40 years. I hope I am wrong. How do I go about finding out about getting my heads back?

Southern Son,

I apologize for not putting a question mark on the end of my original question. I will say again for the third time, I am asking a question here. I don't know which brand is a good brand and which one is a bad brand, that is why I am seeking the experience of others with aftermarket chains to see if there is one to stay away from, or one that is known to be high quality. Call my statement an idle statement if you want. I was merely seeking the benefit of the experience(s) of others.

Additionally, it is not the STRENGTH of a clipped master link that is in question. It is the possibility of the clip coming off. If you wish to debate whether or not the clip can come off or not, that would be what you should debate, not the STRENGTH of the closing link. Many people continue to use the term master link interchangably for a clipped master link as well as a peened master link. In the case of a factory chain, every link is the same, they are all peened together. The only difference in a peened master link and a clipped master link is the means of holding the plate in place. When replacing a chain, using the crimping tool properly, you will probably not be able to recognize the closing (master) link.

Have a great day,

Michael,

I am sorry to hear about your machine shop closing down. I hope you can find out how to get your Harley heads back. I have put lots of hours into cylinder heads before in the form of port work and other tedious time spent, it would have been a loss greater than the value of the heads had I run into what you are experiencing.

I thank you again for continuing to supply information and photographs of your failed chain. I very much expect that the pin and roller are in the bottom of the pan. It wouldn't be too much trouble to remove the lower oil pan, or maybe you've already done that.

Best of luck with the project,

I was thinking that my chain was intact and that the end of the chain that you see in pic with the exposed pin was the pin that was pulled out. I wonder if there ever was a roller on that pin. I will look in the pan but I can't see how the roller could have come off.

I haven't removed the pan. You have to lift the engine to do this don't you? That is not something I wanted to do. However, if I do remove the pan, how much more trouble if it to do some bottom end work? I expect that is where most of my oil pressure is dissapearing.

Michael,

Yes, I forgot, this engine has a one piece pan. I expect that it wouldn't be too bad to raise the engine enough to remove it.

I expect that there was a roller in place at one time. The way the chain is made, the rollers are in place before you put in the connecting link.

Good luck,

Do yo think I can do enough to the bottom without too much trouble? It's one of those "While I am at it..." things.


I was wondering if the chain was missing that roller when it was installed. That would extra stress on the link, especially when about to enter or exit the sprocket. Over time this could wear out the holes the pin goes through to the oint is cannot hold the tension and pulls through the remaining metal.

Just thinking out loud (per se).

Michael,

Do you mean in the form of replacing bearings and such? There was a very good article in the Star magazine about six months or so ago about the fact that the bottom of these engines far outlast the top. When my cylinder head demanded attention at 170K miles, I found the bottom to be in excellent shape. These engines typically respond extremely well to cylinder head work. Mine has gone about 30K miles now since I did the top and it has great oil pressure and no oil consumption problems at all.

I expect that missing roller is in the pan, but there is just no way to be sure without some disassembly. Most likely it would stay in the bottom of the pan and not cause any problems, but there are no guarantees of this. If you had a magnet small enough to fit through the drain plug hole and move around in the sump, you very possibly could get lucky and fish it out. The drain plug hole is large enough that it would be worth investigating.

Best of luck,

Yes, I meant bearings and such. The bottom end has 220k on it and I have absolutely no oil pressure reading at idle while hot. Increasing rpm by about 200 can increase it to about 1000. It has not been confirmed via a true pressure gauge though. I can only attribute this to bearings and journals. If I do decide to, what can be replaced without too much trouble?

Michael,

Wow, if the oil pressure is really totally gone, you would expect some serious clearance problem somewhere. Since you're working on the top end anyway, examine cam bearing surfaces and journals to see if there is obvious wear at that area, if so that might be where your oil pressure is going.

I think we both know, however, that the most likely area would be the main bearings and journals. You won't know until you mic the crank journals and the mains can't be measured properly without at least partially removing the crankshaft. If the engine is this bad, do you have facilities to just pull the motor and do it all? With the exhaust loose, which it has to be for the head to come off anyway, the rest of the work involved with pulling the engine would not be much more than raising the motor. You will just need to be careful with connections and mark them well.

With the engine out, you can then more easily remove the crankshaft for grinding if necessary. I'm sure you know that when you start down this road, one thing often leads to another.

Another thing that may help you decide is the bore condition which you will, of course, know after the head is off. If you find the bores have a heavy ridge, then your crankshaft is more likely to need attention, and the engine would best come out at that time anyway.

It's really difficult sometimes to know where to draw the line. It almost always turns out to take more time and money than your original plan.

Good luck,

I just returned from the MB dealership here in San Antone. I picked-up some bolts special ordered from Germany to rebuild the mechanical governor that controls the amount of advance of the injection pump on my 300D (believe it or not, MB only replaces mechanical governors and not rebuild them, cost $504 to $580 to replace versus about $30 to rebuild, I used grade 8.8 bolts bought locally to temporarily assemble the mechanical governor and get my car on the road until the special bolts came in).

The asst. parts manager confirmed that his technicians/mechanics use master links that are crimped with a special tool and that they do not use clip type master links. To aid our discussion the asst. parts mngr. got a timing chain for my 300D and we inspected the master link - it is the crimp type to make an endless chain. I asked him why the MB engine manual I have shows the clip type master link - he did not know why, only that the crimp type master link is stronger than the clip type.

Also, the MB timing chain for the 300D is made by JWIS and these initials/service mark are stamped on the timing chain's side plates. The replacement chain for my 300D purchased from Performance Products is also made by JWIS and comes with a master link that has to be crimped with a special tool that I discussed in an earlier reply. The PP timing chain has a 24 month transferable warranty - the MB replacement chain a 12 month warranty. I have used JWIS chain in the past and they were all equal to the OE chain or better.

Neither the MB timing chain nor the PP timing chain come with a clip type master link - only the crimp type master link requiring a special tool to perform the crimp operation. PP rents the tool for $35 for a two week period plus S&H.

Larry your observation that the clip type master link is used for replacing the old chain by attaching the old chain to the new chain is probably correct (since the MB manual does not say). Like you, I cannot see MB using a clip type master link for continuous service and the clip type link is only used for assisting with the replacement of the old chain to ensure the chains do not become separated and turning a straight forward job into a much more time-consuming repair. I can see the clip type master link being a MB special tool to assist with replacing an old chain.

Michael, your pictures of the timing chain indicate a major failure probably in the oil reaching the chain. The oil lubrication path diagram for my 300D shows that this timing chain is lubricated from outflow from the first bearing journal (the closest bearing journal to the front of the engine) and when I replaced my front crankshaft seal I did not see an oil pipe or oil passage that would directly oil the timing chain. Meaning the timing chain on my engine is lubricated indirectly - which is a method that I have seen on numerous engines Your engine probably uses the same or similar way to lubricate the timing chain - indirect. Your comments about low oil pressure indicates a major failure of some kind (oil pump, failed main journal bearing, cam bearing, some crack or break or blockage in one of the oil passageways, failed oil filter with pieces clogging an oil line/passage, etc., etc.) and will have to be found when you disassemble the engine - as Larry wrote about. I would suggest being very observant as you disassemble your engine and look for the cause of the failure. Finding the real cause of the failure is very important because the cause must be found and corrected before rebuilding your engine - simply replacing broken parts with new ones and then running your engine may/probably lead to the same failure again.

Finding the cause may require more extensive disassembly of your engine than you may want to do or have planned for, but I think you and Larry will agree the cause must be found to avoid a repeat failure costing lots of $. As I recall, you wrote that this engine had been overhauled not too long ago (correct me if I am wrong) leading me to believe that the cause leading to the first overhaul was not found and fixed, or was not fixed completely/correctly.

Your picture of the timing chain shows a chain made with split rollers that fit onto the pin and the picture shows one pin missing a roller. Split rollers do come apart far more easily than non-split rollers. The lack of a split roller coupled with the torn side plate show a probable loss of oil pressure leading to a failure (perhaps stopping the crankshaft or cam from turning) causing damage to the timing chain- as you and Larry have written about. I am sure the chain had the roller when it was replaced (provided it was replaced) and the failure caused damage to the roller and that is why it is missing. One would hope that the people who did the overhaul did not re-use a timing chain that was missing a roller.

An inspection of the pan and the debris (if any) in it will tell a lot. As Larry said, you should remove the pan to see what's in it.

When you rebuild the engine I know you will lubricate the various moving parts that are usually done (pistons/rings/pins, cylinder walls, rods, bearings, cam, valve guides, etc., etc.) - I suggest that the new timing chain be lubricated with engine oil. Simply rotate the engine and pour some oil on the top of the chain, rotate it a bit more and pour more oil on it until the entire chain has been oiled. I have not read any recommendation to oil the timing chain like this before initial start-up, but I believe pre-oiling the chain will extend its life since it is indirectly lubricated. This is how I lubricated my 300D's timing chain before start-up as well as other timing chains on the numerous engines that I have rebuilt - none ever failed.

Michael, I will read with interest as you write about your engine and the cause of the failure.

Good luck!

Tom

I have a couple of comments to add.

I don't believe that the clip-type master link reduces the strength of the chain. The strength is determined by the pin and side plate strentgh. This is a question of reliability and I firmly agree that the crimp-type master link is more reliable than a clip-type.

There is another mode of failure for the e-type clips that wasn't discussed. The clips can actually spin on the pins due to vibration and wear the pin away. I have never used e-clips on a timing chain, but I have had this failure mode with other applications of e-clips.

Finally, there is a type of chain known as a "true roller" where the rollers are machined bearing surfaces, not the split rollers like shown in the picture. True rollers are quieter and roll on the chain wheels, which reduces friction and wear. I am familiar with them from small block Chevys, but is there a choice for a "true roller" versus split roller for MBZ? If so, the choice is obvious. I didn't even think to check which type of chain it was when I replaced the one in the 300E.

Your missing roller could be smashed on either the crank or cam gear. It's worth a look.

mplafleur, before tearing down the bottom end you may want to ask a mechanic familiar with the 190 to confirm the existence of a bypass valve in the oil pump/filter. If there is one and the spring or seat is messed up, you can experience low pressure. Hopefully this will be the case.