Head bolts snapping

[spock500]

Spock
How did you go about timing the pump?

I used the 'notch' that MB dealers use with their electronic timing tool (or locking tool) no 17 on diagram, but instead of locking it I used a torch and mirror to see when aligned with the inspection hole in the side of the IP -

This should then be exactly 14 degree's ATDC, mine was, but on the exhaust stroke -

Btw, are you on the veg forum as well?

 

[spock500]

And the finished article

Mmm maybe not, can you post youtubes vids on here??

http://www.youtube.com/watch?v=v2H0sjQqZNI

 

[television]

And the finished article

Mmm maybe not, can you post youtubes vids on here??

http://www.youtube.com/watch?v=v2H0sjQqZNI

That sounds good and looks good. congratulations

 

[spock500]

That sounds good and looks good. congratulations

Thanks, I am not sure who was more relieved to see it start, me or the neighbours

 

[Dieselman]

I used the 'notch' that MB dealers use with their electronic timing tool (or locking tool) no 17 on diagram, but instead of locking it I used a torch and mirror to see when aligned with the inspection hole in the side of the IP -

This should then be exactly 14 degree's ATDC, mine was, but on the exhaust stroke -

Btw, are you on the veg forum as well?

Yep.

The reason I asked about the timing was that I have an MB tool for setting static timing that you can use if you need it.

As long as the pointer was dead central in the hole you will be alright assuming it fired up Ok and sounds alright.

I still notice some holding back at full load when cold but have made a heat exchanger today and need some fittings before I can install it. I suspect the fuel filter is restricting flow when cold.

Also if your car had electric fans in front of the radiator try taking the viscous fan off as a diesel can't normally overheat anyway due to not wasting enough heat.

 

[spock500]

Yep.

The reason I asked about the timing was that I have an MB tool for setting static timing that you can use if you need it.

As long as the pointer was dead central in the hole you will be alright assuming it fired up Ok and sounds alright.

I still notice soem holding back at full load when cold but have made a heat exchanger today and need some fittings before I can install it. I suspect the fuel filter is restricting flow when cold.

Also if your car had electric fans in front of the radiator try taking the viscous fan off as a diesel can't normally overheat anyway due to not wasting enough heat.

Thanks, thats very kind of you -

The timing seems ok, a big veggie sewing machine

Once I have recond injectors fitted may try experimenting by advancing the timing a couple of degree's, will mark it first as a ref point.

6.5mm ID pipes are going to be far too small, the ally stuff looks great if you can get hold of some coils - I used the cheap push fit fittings from Wickes, do not be put off by the fact they are a push fit - they are held together extremely well and have not leaked yet depsite a good few knocks (see saddle tank thread)

My advice would always be a twin tank even though the engine will run, this one's similar to yours ?

http://forums.mercedesclub.org.uk/showthread.php?t=38035

Sorry folks for the O/T

 

[williarg]

The technical name is "hydraulic jacking". I would have thought the threads in the engine block would have stripped first rather than the bolts shearing even if the torque wrench was faulty. There again the bolts may have been faulty.

 

[Dieselman]

My advice would always be a twin tank even though the engine will run, this one's similar to yours ?

http://forums.mercedesclub.org.uk/showthread.php?t=38035

Sorry folks for the O/T

Thanks. I've already seen that and it does bother me but I wonder if it's a broken ring or a blocked breather.
Also wonder how oftent he oil was changed.

 

[Number_Cruncher]

>>I would have thought the threads in the engine block would have stripped first rather than the bolts shearing

A well designed bolted joint [and in this case, I credit MB with exactly that] will allways fail in the shank of the bolt, or as in this case, the root of the un-engaged male thread. For more, see a copy of VDI-2230, and this, albeit rather technical, paper which describes how to engineer thread engagement to ensure bolt breakage rather than thread shearing.

http://www.hexagon.de/dose/dose-1e.pdf

 

[davidjpowell]

Yep.

Also if your car had electric fans in front of the radiator try taking the viscous fan off as a diesel can't normally overheat anyway due to not wasting enough heat.

Mine tried very hard to do so when the viscous fan died.

David

 

[fredfloggle]

Mine tried very hard to do so when the viscous fan died.

David

I've also had no trouble overheating diesels. I'd be very careful of this. Heat soak after a hard run is a very real danger.

 

[Dieselman]

I am aware of heat soak but I have tried giving the car a good thrashing then allow to idle and not excess heat built up. Obviously I will be aware on hot days.
The car has twin electric fans as well but they rarely come on.

 

[spock500]

Its very hard to improve on the original Mercedes design, sometimes their use is not so obvious but they are there for a reason.

Dieselman, in you post you mentioned fuel starvation under full load when cold I would avoid putting the engine under strain until fully warmed up, this is when its most vulnerable.

 

[Dieselman]

Cold Veg-oil, not cold engine.

 

[spock500]

Cold Veg-oil, not cold engine.

Ok, you had me worried there for a moment

I took me a while to put my setup together but from the various trial and error development that I did the net result was don't let cold veg anywhere near your engine, its just not worth it -

You have many people on the forums who claim to have no problems doing this or that and then 6 months down the road (literally) you see the inevitable post or none at all.

For the sake of a few quid do it properly and minimise the risk, you are going to uprgrade the pipe work so why not stick another filter and switch in at the same time - all you need then is a tank for the diesel or svo/wvo.

A lot of the MB users from the Biotuning web site are sent my way which has lead to quite a bit of background being built up on various models - all twin tanked

 

[spock500]

Well Paypal have come down on my side against the seller

the-aviators and offered a full refund -

I just looked at the other items for sale, all claim to be used in the aircraft industry?

Time for a banana I feel :bannana:

 

[OzC36]

A lot of discussion here about tools...

...but not much about Mercedes stretch head bolts. I was under the impression that stretch bolts were designed for single use only?

The fact that the bolt is stretched under tightening torque means that the metal has started to yield. And if re-torqued in a second use, another yield would seriously weaken or cause failure (Hookes law and Youngs Modulus?).

I have already bought a new set of head bolts for the inevitable head gasket leak on my M104 engine (so far so good). The bolts were as cheap as chips from Autohaus online.

 

[Number_Cruncher]

>>I was under the impression that stretch bolts were designed for single use only?

You can safely re-use them providing that they haven't already stretched too far. In the FSM, there are limiting values for the bolt length. I wouldn't be surprised if some helpful fellow hasn't posted these values higher up in this thread.

The bolts can be re-used, because there is an amount of strain (stretch) between the yield point and the ultimate stress - in other words, there is significant post-yield response.

If you consider a stress/strain graph, when you release a tightened bolt, you go back down a line which is parallel to the original elastic line, and so, when you have no stress in the bolt, there is some residual strain.

If you then re-tighten this strained bolt, you go back up the unloading line until you reach the yield point (which is probably a higher stress value than originally), and from there, follow the material's post yield response again.

It's only when you have used too much of this strain, and the margin between the operating point of the bolt and the ultimate stress is too close.

 

[spock500]

I rang MB dealer and they said it wasnt always necassary to change the bolts. From memory the tolerance limits from lower to upp range, 3mm, mine were within this.

The torque setting is quite low so not a great deal of stress until you go for the two 90o turns.

Heres an interesting question;

Does grinding the outer surface of a socket to enable it to fit into a smaller hole reduce the size of the actual socket?

I already know the answer but the tool supplier/manufaturer got it wrong

 

[skymaster]

Just found this forum. Looks like a good place to be. I am getting ready to pull the head on my '86 300E 3.0L. My 'Bible' seems to have everything but the head bolt torque values. Does anyone have that info available? Much appreciate it.