S65 timing chain information needed.
07-28-2018, 04:20 PM
#1
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S65 timing chain information needed.
Guys... Two days ago I'm driving the S65 and hear screechy noises at idle and just above idle... Hmmmm...
I look at accessory drive... Meh-- could be better so I give it a serp belt + all the bearings; none of which looked or felt bad enough to obviously be the issue and of course don't just jump in there! Light it up... Sounds great. Headed toward the road and she dies. Cranks as though it has a six under the hood and is firing into the exhaust. Code for cam position sensor.
$127.00 later the tow truck has her back in my shop and on the hoist. Next up is pulling charge coolers and coils to peek into cylinders and see if there are tell-tale marks in pistons which will confirm that this is a really really unpleasant disaster vs merely an really unpleasant disaster.
Point in all of this being that I'm having difficulties locating real information about where timing marks for timing chains are supposed to be ect. AllData has voluminous data about paint colors for bearing shells, how to properly inspect the bore, phases of the moon in which to torque oil pan bolts ect but thus far absolutely no mention of chains or how that is set up. Four hours of going through AllData including using the search functions and here we are.
Also.... Any of you MB techs who are familiar with known 275 gotchas in timing chains, gears, guides ect please speak up!
edit: borescope image makes clear what we knew. The lump comes out.
Many thanks. John
I look at accessory drive... Meh-- could be better so I give it a serp belt + all the bearings; none of which looked or felt bad enough to obviously be the issue and of course don't just jump in there! Light it up... Sounds great. Headed toward the road and she dies. Cranks as though it has a six under the hood and is firing into the exhaust. Code for cam position sensor.
$127.00 later the tow truck has her back in my shop and on the hoist. Next up is pulling charge coolers and coils to peek into cylinders and see if there are tell-tale marks in pistons which will confirm that this is a really really unpleasant disaster vs merely an really unpleasant disaster.
Point in all of this being that I'm having difficulties locating real information about where timing marks for timing chains are supposed to be ect. AllData has voluminous data about paint colors for bearing shells, how to properly inspect the bore, phases of the moon in which to torque oil pan bolts ect but thus far absolutely no mention of chains or how that is set up. Four hours of going through AllData including using the search functions and here we are.
Also.... Any of you MB techs who are familiar with known 275 gotchas in timing chains, gears, guides ect please speak up!
edit: borescope image makes clear what we knew. The lump comes out.
Many thanks. John
Last edited by JohnLane; 07-28-2018 at 10:38 PM.
07-30-2018, 08:26 PM
#2
The timing for the m275 is done using a special tool set that locks the cam in place at 30 degrees ATDC. The reason you need the tool is that the mark on the cam is not exact and depends on the angle you view that mark from. With the tool, you guarantee that you have locked the cam at 30 degrees ATDC. Basically, if you are thinking of checking chain stretch or removing the cams or chain then you absolutely positively need the special timing tool set. Once you have the tool, you rotate the crankshaft until you are at 30 degrees ATDC and check to see if the tool can be mounted free of tension (the mark on the cam tower kind of should be near the mark on the front camshaft barrel to make sure you are not 180 degrees out). If the too cannot be mounted free of tension then timing is off. You can then get the tools to mount free of tension and look down at crank position to see how much stretch (but this is very unlikely given your miles on that engine-for example I had 0 stretch at 89k miles.
Guides are buried under front timing cover and are very difficult to get to. At your mileage, it would be very unusual to have a chain issue on that engine. If you remove the valve cover on passenger side, you can see if chain tensioner is tight (should be very solid feeling).
With cam sensor code, perhaps you actually have a bad cam sensor? But given issues and the price of the engine, at this point if you are capable, why not open valve covers and take a look at everything. If your noise went away after replacing belt system, then that probably was the sound you heard.
As far as "gotchas", I will speak to one part that I really did not like the looks of and have verification from another tech that this occured on another m275. The front oil separator on the front of the drivers side cam is plastic and was cracked on my car and on the tech's car (luckily had not broken apart yet). If you have the valve covers off, you might consider replacing this. You need to remove the front cover on the driver head (small cover on front). Part number for the separator is A2750100762
Let us know
Guides are buried under front timing cover and are very difficult to get to. At your mileage, it would be very unusual to have a chain issue on that engine. If you remove the valve cover on passenger side, you can see if chain tensioner is tight (should be very solid feeling).
With cam sensor code, perhaps you actually have a bad cam sensor? But given issues and the price of the engine, at this point if you are capable, why not open valve covers and take a look at everything. If your noise went away after replacing belt system, then that probably was the sound you heard.
As far as "gotchas", I will speak to one part that I really did not like the looks of and have verification from another tech that this occured on another m275. The front oil separator on the front of the drivers side cam is plastic and was cracked on my car and on the tech's car (luckily had not broken apart yet). If you have the valve covers off, you might consider replacing this. You need to remove the front cover on the driver head (small cover on front). Part number for the separator is A2750100762
Let us know
Last edited by MooksM275; 07-30-2018 at 08:33 PM.
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AllPhonesAretap (07-25-2022),
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07-30-2018, 09:58 PM
#3
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Thanks for the response.
I have pulled the driver's side coil pack, a spark plug and threaded the borescope into the cylinder. There is no missing the mark in the top of the piston where it contacted an exhaust valve. I will pull the cam cover and look for tell tale loose valves. I'm in the process of extracting the lump. She's on a hoist so the pain is in my getting to do this for the first time in my car. Many photos taken. Carefully made selections of fasteners laid out on the stainless steel bench with a sharpie pen describing how many that do what. Patience. Persistence. Once she's out we shall learn of what failed.
I have pulled the driver's side coil pack, a spark plug and threaded the borescope into the cylinder. There is no missing the mark in the top of the piston where it contacted an exhaust valve. I will pull the cam cover and look for tell tale loose valves. I'm in the process of extracting the lump. She's on a hoist so the pain is in my getting to do this for the first time in my car. Many photos taken. Carefully made selections of fasteners laid out on the stainless steel bench with a sharpie pen describing how many that do what. Patience. Persistence. Once she's out we shall learn of what failed.
07-31-2018, 12:01 AM
#4
Thanks for the response.
I have pulled the driver's side coil pack, a spark plug and threaded the borescope into the cylinder. There is no missing the mark in the top of the piston where it contacted an exhaust valve. I will pull the cam cover and look for tell tale loose valves. I'm in the process of extracting the lump. She's on a hoist so the pain is in my getting to do this for the first time in my car. Many photos taken. Carefully made selections of fasteners laid out on the stainless steel bench with a sharpie pen describing how many that do what. Patience. Persistence. Once she's out we shall learn of what failed.
I have pulled the driver's side coil pack, a spark plug and threaded the borescope into the cylinder. There is no missing the mark in the top of the piston where it contacted an exhaust valve. I will pull the cam cover and look for tell tale loose valves. I'm in the process of extracting the lump. She's on a hoist so the pain is in my getting to do this for the first time in my car. Many photos taken. Carefully made selections of fasteners laid out on the stainless steel bench with a sharpie pen describing how many that do what. Patience. Persistence. Once she's out we shall learn of what failed.
As a suggestion, get a subscription at https://epc.startekinfo.com/epc/. Official mercedes parts diagrams and will tell you how many bolts go where and the zies including length. I do not sort bolts at all anymore due to EPC. The car doesn't use many different sizes so as long as you measure the length and size, you are good to go. Saves me lots of time.
One word on rebuilding it if you are looking into it, there is no supply anywhere for replacement piston rings which means you either have to buy pistons (like 600 bucks a piece) which includes the rings or custom pistons. Just so you would know before taking anything out. Cylinder walls can be lapped but without replacement rings, we have an issue on rebuilds for the m275.
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JohnLane (07-31-2018)
07-31-2018, 01:33 AM
#5
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So I am the lucky one! I will have to purchase a lottery ticket as perhaps lightning will strike twice.
Thank you for the link to startek. I will sign up straight away.
I will take photos of what happened.
We have an evil plan for this engine once real internals are made up. Brabus K-8 becomes EV12.
if needed perhaps it can be sleeved. Will know once it is apart.
Thank you for the link to startek. I will sign up straight away.
I will take photos of what happened.
We have an evil plan for this engine once real internals are made up. Brabus K-8 becomes EV12.
if needed perhaps it can be sleeved. Will know once it is apart.
07-31-2018, 09:23 AM
#6
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This morning I pulled the driver's side cam cover to have a look.
Six bent exhaust valves.
$600 each for pistons says it will get custom forged Pistons and H-beam rods.
Startek is quite helpful with pics, part numbers and such once we figure out secret handshakes.
Six bent exhaust valves.
$600 each for pistons says it will get custom forged Pistons and H-beam rods.
Startek is quite helpful with pics, part numbers and such once we figure out secret handshakes.
Last edited by JohnLane; 07-31-2018 at 06:17 PM.
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AllPhonesAretap (07-25-2022)
07-31-2018, 10:40 PM
#7
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Pulled passenger side cam cover. Shone a light into the darkness... Parts of a plastic chain guide are on top of the crank gear. Timing chain is as tight as I have ever seen one. Pretty clear that a chain guide failed and got involved with the cank gear. When it managed to roll under it the chain jumped. Have not figured out how many teeth it is off but is clearly at the crank as 12 bent exhaust valves.
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AllPhonesAretap (07-25-2022)
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08-01-2018, 06:12 AM
#8
Pulled passenger side cam cover. Shone a light into the darkness... Parts of a plastic chain guide are on top of the crank gear. Timing chain is as tight as I have ever seen one. Pretty clear that a chain guide failed and got involved with the cank gear. When it managed to roll under it the chain jumped. Have not figured out how many teeth it is off but is clearly at the crank as 12 bent exhaust valves.
Makes me glad I changed all my guides when I had the heads off. The one guide I saw that was suspect was the oil pump chain guide (mine already had a crack). Take photos as it will help the group know what to look for.
One item I struggled getting was the spring tensioner for the oil pump chain guide. These are known on the m113 to wear down and lose tension. Mercedes USA no longer sells these (multiple dealers could not get). I ordered from a vendor located in Germany who went to dealer and ordered. He thought it was weird cause the spring is like $2 and no issue getting it in Germany. I can send you his info if you need it.
08-01-2018, 10:14 AM
#9
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Car has 70,000 miles. It had been running perfectly.... Until it wasn't running at all.
I will get pics once the lump drops to the floor.
Replacement is en route as are assorted sundries from MB to reassemble.
I'm curious as to color of fresh timing chain guides. I have seen many plastic chain guides that start white and turn to a dark yellow to red/brown as they age and get brittle. My buddy believes this may be related to a certain drive we took with the cars which included some..... Savagery. I always keep a close eye on engine and oil temp. She had fresh Mobil-1 and always has. Coolant always right at normal, oil temp got as high as 110C. None of which seems out of line. Naturally with plenty of cool-off time.
I will get pics once the lump drops to the floor.
Replacement is en route as are assorted sundries from MB to reassemble.
I'm curious as to color of fresh timing chain guides. I have seen many plastic chain guides that start white and turn to a dark yellow to red/brown as they age and get brittle. My buddy believes this may be related to a certain drive we took with the cars which included some..... Savagery. I always keep a close eye on engine and oil temp. She had fresh Mobil-1 and always has. Coolant always right at normal, oil temp got as high as 110C. None of which seems out of line. Naturally with plenty of cool-off time.
08-07-2018, 02:13 PM
#11
Please post some pictures. Knowing how the chain and tensioners are designed, it is incredibly hard to understand how a tenionser got caught under the crank gear. Curious whether it was the tensioner or whether it was something else.
Best,
Best,
08-07-2018, 06:14 PM
#12
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It is coming out. Taking my time and many photos so that my failing memory will get appropriately jogged via visual aids to reassemble.
Shining a light into the timing cover I can see pieces of chain guide; broken up atop the crank drive gear for chains.
1/4" of slop at rocker arms and valves visibly shorter then they should be + how it felt cranking it by hand to get torque converter bolts out says all for now.
Engine arrives Thursday. Transfer all to it and put Humpty back together. This will go faster next time if within the next few months but would much prefer to not ever need to repeat the learning experience.
The damaged lump will get a timing cover pulled straight away. I want to know what happened. I DRIVE my cars and if there is something cheesy about how chain drive happens the replacement will get a Re-think to solve it. I'm the lottery winner for this one. Not happening again.
Shining a light into the timing cover I can see pieces of chain guide; broken up atop the crank drive gear for chains.
1/4" of slop at rocker arms and valves visibly shorter then they should be + how it felt cranking it by hand to get torque converter bolts out says all for now.
Engine arrives Thursday. Transfer all to it and put Humpty back together. This will go faster next time if within the next few months but would much prefer to not ever need to repeat the learning experience.
The damaged lump will get a timing cover pulled straight away. I want to know what happened. I DRIVE my cars and if there is something cheesy about how chain drive happens the replacement will get a Re-think to solve it. I'm the lottery winner for this one. Not happening again.
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AllPhonesAretap (07-25-2022)
08-08-2018, 10:35 AM
#15
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Yes; a six liter 275. Replacement is coming from Chicago. 30,000 miles on it.
Transmission got pulled on the hoist so I wouldn't have that awkward lump hanging from the rear of the engine as it sits on the stand I made of 4X4" lumber.
On the hoist pulling the trans is not bad to do.
Transmission got pulled on the hoist so I wouldn't have that awkward lump hanging from the rear of the engine as it sits on the stand I made of 4X4" lumber.
On the hoist pulling the trans is not bad to do.
08-08-2018, 11:06 AM
#16
Ouch. A 30k 65 engine must've been tough on the wallet. Should be real healthy though. That's a good feeling.
Pulling the transmission is definitely the way to go. Easy to pull and out of the way. Engines well balanced in the car with the trans out. Fairly easy to lift right out.
Pulling the transmission is definitely the way to go. Easy to pull and out of the way. Engines well balanced in the car with the trans out. Fairly easy to lift right out.
08-08-2018, 02:17 PM
#17
It is coming out. Taking my time and many photos so that my failing memory will get appropriately jogged via visual aids to reassemble.
Shining a light into the timing cover I can see pieces of chain guide; broken up atop the crank drive gear for chains.
1/4" of slop at rocker arms and valves visibly shorter then they should be + how it felt cranking it by hand to get torque converter bolts out says all for now.
Engine arrives Thursday. Transfer all to it and put Humpty back together. This will go faster next time if within the next few months but would much prefer to not ever need to repeat the learning experience.
The damaged lump will get a timing cover pulled straight away. I want to know what happened. I DRIVE my cars and if there is something cheesy about how chain drive happens the replacement will get a Re-think to solve it. I'm the lottery winner for this one. Not happening again.
Shining a light into the timing cover I can see pieces of chain guide; broken up atop the crank drive gear for chains.
1/4" of slop at rocker arms and valves visibly shorter then they should be + how it felt cranking it by hand to get torque converter bolts out says all for now.
Engine arrives Thursday. Transfer all to it and put Humpty back together. This will go faster next time if within the next few months but would much prefer to not ever need to repeat the learning experience.
The damaged lump will get a timing cover pulled straight away. I want to know what happened. I DRIVE my cars and if there is something cheesy about how chain drive happens the replacement will get a Re-think to solve it. I'm the lottery winner for this one. Not happening again.
Best,
08-09-2018, 10:05 AM
#19
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Ouch. A 30k 65 engine must've been tough on the wallet. Should be real healthy though. That's a good feeling.
Pulling the transmission is definitely the way to go. Easy to pull and out of the way. Engines well balanced in the car with the trans out. Fairly easy to lift right out.
Pulling the transmission is definitely the way to go. Easy to pull and out of the way. Engines well balanced in the car with the trans out. Fairly easy to lift right out.
or
Wait a LOT longer for custom pistons and rods....
or
Toss the car.
i enjoy driving the car so the quick route happens. Internals will get ordered for the EV12
08-09-2018, 10:30 AM
#20
I'd like to know what route you take with the build. Brand of pistons and rods, availability, block mods, etc...
I've had many cp.pistons and crower rods built for custom applications but that was over a decade ago and never any mercedes stuff.
Also really anxious to see pictures of the failure. Mine has 100k on it. Need to know if some preventative parts replacement is in order.
08-09-2018, 12:05 PM
#21
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On the replacement engine, mileage is not the enemy but age is of course. I would inspect thee guides to see if they look brittle. The one guide that I noticed as having problems was the oil pump chain guide (mine had a crack). Also, replace the oil separator attached to the drivers side camshaft as they get brittle and crack. I also highly recommend getting yourself a copy of Mercedes WIS. It will give you all tightening torques and procedures. Impossible to do without it in my opinion.
Best,
Best,
For what reason did you get into the timing case of your 275 that you managed to catch a cracked oil pump chain guide? We don't exactly venture in there as part of a valve adjustment as in an MB straight six from 1970.
Also.... How best to procure WIS? That may be a godsend.
08-09-2018, 12:22 PM
#22
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I get it. If you go through the other engine at least you'll have a spare.
I'd like to know what route you take with the build. Brand of pistons and rods, availability, block mods, etc...
I've had many cp.pistons and crower rods built for custom applications but that was over a decade ago and never any mercedes stuff.
Also really anxious to see pictures of the failure. Mine has 100k on it. Need to know if some preventative parts replacement is in order.
I'd like to know what route you take with the build. Brand of pistons and rods, availability, block mods, etc...
I've had many cp.pistons and crower rods built for custom applications but that was over a decade ago and never any mercedes stuff.
Also really anxious to see pictures of the failure. Mine has 100k on it. Need to know if some preventative parts replacement is in order.
Custom pistons get ordered bespoke. Rods we prefer to be close to off the shelf parts for several machine steps performed... Presto! H-Beams for more strength, reduced rotating and reciprocating weight.
Engine is supposed to arrive today. Once bits are transplanted to the fresh lump the timing cover comes off. Wx is supposed to be cooler for the week-end which will help a lot.
08-09-2018, 03:18 PM
#23
Pray tell....
For what reason did you get into the timing case of your 275 that you managed to catch a cracked oil pump chain guide? We don't exactly venture in there as part of a valve adjustment as in an MB straight six from 1970.
Also.... How best to procure WIS? That may be a godsend.
WIS can be purchased on many many sites around
Do not do anything internal without it. The camshaft sprockets for example are torque to yield.Btw, I am not positive that you want to remove timing cover without heads off? the front of the head rests on the cover so be careful if this is something you plan.
08-09-2018, 08:44 PM
#24
No reading comprehension fail here. I simply meant that I can relate to the three choices you outlined and I agree as I like to drive my cars also. I also read your earlier post and understand that you will be building the engine youre taking out now. Once that one is built and back in it will surely be a nice feeling to know you have a healthy spare sitting there in case it's ever needed. As far as I'm concerned owning these cars is made much easier with spares lying around. I have various Mercedes at my shop being parted out at all times. It is very nice to just be able to grab something when you need it. Especially the random small parts, nuts and bolts etc.. that are just a pain in the butt to get when you want them right then.
08-09-2018, 09:46 PM
#25
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No reading comprehension fail here. I simply meant that I can relate to the three choices you outlined and I agree as I like to drive my cars also. I also read your earlier post and understand that you will be building the engine youre taking out now. Once that one is built and back in it will surely be a nice feeling to know you have a healthy spare sitting there in case it's ever needed. As far as I'm concerned owning these cars is made much easier with spares lying around. I have various Mercedes at my shop being parted out at all times. It is very nice to just be able to grab something when you need it. Especially the random small parts, nuts and bolts etc.. that are just a pain in the butt to get when you want them right then.
1). Intar-webs do not infer tone and inflection. You're getting razzed just a bit about reading comprehension.
2). Are you familiar with the Brabus K-8? It is that car in 211 chassis form which will be fitted with my damaged bent-12 once it is made to be fresh and naughty. Thus; EV12. Look around on the web for them. Fine car **** that is.
3). When doing a project like this I take many photos. Parts are laid out on the stainless bench which gets marked up with the sharpie pen to make the whole thing as dummy-proof as we can manage. Lord knows I need all the help I can muster.
Replacement looks nice. Newer then what my car had fitted per serial number. Now if it would just cool down! Much prefer to do tasks like this during the winter. Easier to heat the shop then cool it.
