I have a 1990 300 SEL which recently blew the head gasket. I have had the head reworked through the Berg Works and I am ready to re-install.

I ahve read on this shop forum that head gasket failure on the M103 is inevitable which makes me wonder how well the stock fasteners maintain the clamping load necessary for proper operation or if there are inherent weaknesses in the head gasket design. Since I am considering the Mosselman twin turbo setup I'm worried that I will only make this situation worse.

I happen to live in the same town as ARP who are well known for their high strength fasterners. I brought them one of my head bolts and they came up with a 12 mm stud that will work on the M103 head.

I was recommended to me that, before I swtich fasteners, I look into the concept of angle torquing. I would appreciate as explanantion of why this is more effective than using a series of increasing torque adjustments using the settings on the torque wrench. Can you tell me what the ultimate torque spec is when you start at 55 Nm and then turn 90 degrees twice after that? My understanding is that head studs are much more forgiving on the block threads since the stud is fully engaged in the block before torque is applied. The stud I'm looking at has a 220,000 psi tensile strength and is commonly used in high perfromance applications.

Any input on this would be greatly appreciated. I tried attaching a picture of a mock-up using one of the head studs but the server says the file size is too big even though the picture is only 140K. I'll try to attach it to a seperate post.

Thanks,
Motorhead

Here is the picture.

Attached Thumbnails

 

Leak on the M103 engine isn't related to "fastener" problems!
The OE head bolts are stretch bolts & require angle torquing.

With a turbo, the gasket will let loose before the bolts will, but why not go with new fasteners either way.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

MB Doc,

Thanks for the reply. Can you elaborate on what the weak link is in the M103 that causes the head gasket to fail? Is there anything I can do to mitigate the problem especially if I install the turbos?

Just for clarification, it sounded like you didn't see a problem using the head studs. Is this correct?

Thanks,
Motor Head

Quick Question.......

Will The Cylinder Head CLEAR the studs when Installing the Head?
As The Studs are VERY Tall...I Have done several Headgaskits on the 103/104 engines and The clearance when Installing is Tight!

I had no trouble getting the head on and off when I was test fitting the studs and the rocker assembies install with plenty of room.

Motorhead:

I am currently getting ready to have the head reworked on my 190E, 2.6 and I am interested in the studs in the pic.

Can you tell me where you obtained them? Also you mentioned that you had your head reworked from the berg works, would you share in the cost of the work and what you did to your head to bring it back to within specs?

Thanks,

I use a stock head gasket and the studs as pictured by you.

The way I see it, in case of problems, I want a fuse. In my case the fuse is the head gasket. If I have detonation to the point of desctruction, the head gasket will most likely fail instead of costly parts.

Just my theory.

BTW. I blew a stock head gasket at 15psi of boost, then I studded and had no more problems!

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Scripley,

I got the head studs from Automotive Racing Products.

http://www.arp-bolts.com/

They don't have any mercedes applications on the shelf. I had to bring them one of my head bolts along with a number of measurements off the motor. Luckily they had an application on the shelf that was compatible with the dimensions required. If you have to get a set custom made the cost won't be worth the benefit. If you email me I can send you a pdf of the measurement form they use. If you call them they can walk you through it.

As for the head, it depends what the condition of the head and its components dictate (as well as your wallet). In my case, the car was burning a lot of oil and finally I blew the head gasket. As a result, I had the valve guides and valve stem seals replaced. I reused the valves as they are very expensive and mine were in good shape. The valve springs were going soft (150,000 miles) so they were replaced and a light surfacing was done on the head. Total cost was $500 for the parts and machine work.

Good luck on your project

Benzmac,

Thanks for the feedback. Sounds like I'm headed down the same path as you. I was intending to run 10 pounds of boost. How much can I safely run with the stock bottm end on the M103?

Thanks,
Motor Head

It depends on how big the intercooler is and how much fuel and timing you run.

If you run a large intercooler and can adjust timing down under big boost, 12-14 is no problem.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

I installed ARP studs in my 2.3-16. The ARP head studs for a Ford Pinto 2300cc (part number 151-4202) are perfect for a 16 valve. The "Ford price" was $95 while the Mercedes price on another web site was $190. Go figure. I believe that these are the correct studs for most older Mercedes engines. This "kit" came with 10 studs, you will need 14 studs for a six cylinder engine.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

Jim,

Thanks for the info. I'll give ARP a call and see what the dimensions are of the stud you are using.

Motor Head

Hello Motor Head:

Did you get your bolts and were they a match of the 2300cc pinto engine? The head is coming off and I would like to go back with studs if possible.

Thanks,

scripley,

Unfortunately, that irritating thing called WORK has gotten in the way the last few weeks so I have not made any progress on the head. I do intend to check out the tip on the pinto studs before I buy the ones I worked with ARP to use for the 103. Bottom line is I know they have studs that will work. It's just more convenient to use something off the shelf instead of putting your own parts together. I'll let you know how it turns out.

Motor Head