M70 Rebuild Thread.

[Mikekugel]

If the bolt is ended, the new ones must be better? Those bearings like the Goetz rings are both Federal Mogel products. I'm pretty sure you won't go wrong there. Make sure you check your bearing clearances!!

[dragon850]

So the two current bolts look very different... this is: 11247589671


And this is 11241713342 :


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You think it is necessary to go as far as checking clearances on the new bearings, I do not believe Glyco makes undersized/over sized bearing halves, just BMW at $21 a halve

If the bolt is ended, the new ones must be better? Those bearings like the Goetz rings are both Federal Mogel products. I'm pretty sure you won't go wrong there. Make sure you check your bearing clearances!!

[Mikekugel]

So the two current bolts look very different... this is: 11247589671


And this is 11241713342 :


- - - Updated - - -

You think it is necessary to go as far as checking clearances on the new bearings, I do not believe Glyco makes undersized/over sized bearing halves, just BMW at $21 a halve

The new bolt almost looks like it could be a torque to yield bolt. It might be wise to consult with a BMW ENGINE BUILDER, or BMW parts dept. My thoughts are you might be ok not checking clearances, but plastigauge is cheap, or you could use micrometers, or have a machine shop check a few of them. It would be a real bitch to get it all together, fire it up, and have it come unglued.

[Mikekugel]

Some interesting information about bolts, http://www.enginebuildermag.com/2001...rque-to-angle/

[dragon850]

Called 2 BMW dealers so far including Gault, both were puzzled about these 2 bolts and why there are 2 options and which one to use..
One of the parts guys said, "go with more expensive one" LOL... ughhh

[Mikekugel]

After looking at the newer bolt, it seems like BMW was trying to increase the contact area with the rod cap. I myself would go with the newer style bolts, but would also buy about 4 more, and torque a couple of rods, and check clearances.

[cartoonz]

umm... isnt 11241713342 a full 6mm longer than 11247589671

uh huh.....

[dragon850]

After looking at the newer bolt, it seems like BMW was trying to increase the contact area with the rod cap. I myself would go with the newer style bolts, but would also buy about 4 more, and torque a couple of rods, and check clearances.

So from my understanding, there were 2 styles originally, the 11241713342 stayed the same though out the years, the 11247589671 is an update to the older bolt of the same style.
It seems that the 11247589671 is designed to eat into the rod caps??
My original bolts look like 11241713342.
It's just weird that BMW put two options for the same application, I am sure there is an explanation to this...

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umm... isnt 11241713342 a full 6mm longer than 11247589671

uh huh.....

Indeed...

[Mikekugel]

This is truly a mystery that needs to be solved. Buy a new bolt and compare it.

[Mikekugel]

Contact Wolf Wokke.. He has rebuilt a few engines.

[cartoonz]

...My original bolts look like 11241713342...

Then that's the part you buy. No brainer, really... you don't replace them with a shorter bolt!

[Mikekugel]

Then that's the part you buy. No brainer, really... you don't replace them with a shorter bolt!

Agree absolutely! I have never replaced rod bolts on any American V8 engines when rebuilding them, but BMW? Then again better safe than sorry. Buy 4 extras, to check a couple of clearances on a couple of rods, Autohauz has them http://www.autohausaz.com/pn/11241713342

[dragon850]

Agree absolutely! I have never replaced rod bolts on any American V8 engines when rebuilding them, but BMW? Then again better safe than sorry. Buy 4 extras, to check a couple of clearances on a couple of rods, Autohauz has them http://www.autohausaz.com/pn/11241713342

Yeah I know... Problem is these freaking rod bolts are more expensive than head bolts! Man... soon enough I will be over my 1.5 k budget in parts to rebuild this thing!

[bmw528e11]

soon enough I will be over my 1.5 k budget in parts to rebuild this thing!

If you would have a 6-speed manual, you would spend 1k more, for flywheel and clutch kit

[dragon850]

If you would have a 6-speed manual, you would spend 1k more, for flywheel and clutch kit

I will be sending off my torque converter to get rebuilt and strengthened. $$$

[cartoonz]

I will be sending off my torque converter to get rebuilt and strengthened. $$$

Yeah, but we already dealt with your impetuousness on that one.. .saved you what, a grand? haha

[John in DC]

Some of this was covered years ago.

http://forum.roadfly.com/archive/ind...11749574.html?

[Mikekugel]

Some of this was covered years ago.

http://forum.roadfly.com/archive/ind...11749574.html?

Good read, but Ed is looking at Rod bolts.

[dragon850]

Purchased x 24 longer rod bolts more expensive option.$$$ Still don't know what is the difference between the two or which one is better. But I guess we know that Original longer bolt held just fine...

[John in DC]

Good read, but Ed is looking at Rod bolts.

Can you elaborate what is the advantage of using studs over head bolts?

Are you sure???

[dragon850]

I dont know if you believe this ,, but i had to pay,, with the highest discount possible ,, over 800€ for the rod bearings,,,,,, holy shxx,,,,,,, at the Icelandic BMW dealer

For the future reference, connecting rod bearings available for under $100 for a set: https://www.ecstuning.com/BMW-E31-85...cal/ES2626371/

[dragon850]

A whole bunch of parts is coming so now its just a waiting game. Here is the piston deringed and cleaned and the block after prepping with block 600 grit sanding and cleaning.


ForumRunner_20151019_200912.png



ForumRunner_20151019_200925.png

[Mikekugel]

Just love naked pictures! Keep them coming.

[B10 BITURBO]

For the future reference, connecting rod bearings available for under $100 for a set: https://www.ecstuning.com/BMW-E31-85...cal/ES2626371/

Fantastic !!!!!!!!!

[cartoonz]

just don't be taking any grit sandpaper to those pistons...