616 flywheel bolt specs. 240D
 

I decided to start a new thread specifically in regards the flywheel attachment for 616 engines. The topic had been discussed previously in a thread I started previously on a 240D auto tranny to manual tranny swap.

Does any one have the specs. for the minimum diameter of the neck down portion of the flywheel attachment bolts for the 616 engines. I do not have the FSM for that engine so I looked in my 617.95 FSM. Those attachmnet bolts have a new neck diameter of 7.3mm and a min. of 7mm.
However, when I miked the bolts from the flywheel I am going to use in my tranny swap the necks measured around 8.25mm. So I don't know if these are O.K. or if they will need to be replaced.

Thanks

On the 617 engine at least the bolts are a different length. If you use the automatic bolts to secure a flywheel they are too long and the motor will seem to be locked up.

I believe the recommended proceedure on them is to install new ones.

Tom W

FSM says bolts can be reused if they are within spec.
 

Tom

The FSM for the 617.95 engines give a minimum of the neck portion of the bolts. It states that if the neck portion reduces below the specified min. diameter they need to be replaced. If diameter is above the minimum they can be reused. The tightening specifications require the bolts to tightened to a specified torque and then turned an additional 90-100 degrees. I assume after being fully tightened the bolts undergo some plastic deformation which reduces the neck diameters. If the bolts are still within spec I see no reason not to reuse them. Problem is I do not know what that spec is as the 616 bolts are a different diameter than the 617 bolts(8.25 mm as compared to 7). Maybe they are thicker because they are a lower grade bolt. They do however have a necked portion so I am assuming the tightening process is similar.

Thanks

OK. It is clear that you understand the concept of stretch bolts. My Haynes manual specifies how to tighten them but does not tell about measuring the neck.

My comment about using new ones is from memory so it may not actuallly be correct. Of course new ones cannot be wrong , just wasteful of your $.

Tom W

I found the bolt spec
 

I just got a copy of the FSM for the 615, 616, 617.912 engines in the mail today. The bolt specs. to the necked down portion of the bolts for the manual flywheel are: 8.5mm -.2mm new, 8.1 is the lower limit where they need to be replaced.

The FSM also has the procedure for static balancing the new flywheel to the old one. There is a special tool that links the two together. You attach them at 180 degrees opposed to how they will mount to the crank flange, and them put them in a balancing cradle that allows them to turn freely. If they have a tendancy to turn at all you drill the heavy side of the new flywheel until they will not move at all when placed on the cradle.

Cool.

Thanks for posting the info.

Tom W

I resurrected this thread
 

Everybody is doing auto to manual conversions and so I understand why it's easy to get the specs for the flywheel bolts for that BUT I need to know the specs for the auto flywheel bolts and can't seem to find that. It is possible that I missed it combing through countless threads so please forgive me if I have. Does anyone have a FSM that would be willing to share the flywheel bolt specs for an automatic flywheel for a 616 engine. I would appreciate that very much. Thanks!

Kevin

I don`t have a FSM for the 616 but do have the one for the 617.95 engine,

Tightening torques:

Initial torque 30 - 40 nm

Angle of rotation torque 90 - 100 deg


Charlie

oilslick:

Thread-- M10x1
Underhead length-- 31mm
New neck diam.-- 7.7-7.5mm
Min. neck diam.-- 7.3mm

Thanks!
 

Yes! This is what I desperately needed. I am also appreciative for the torque specs too! I love this forum!!! You guys are great.

you are supposed to buy new ones--from the pelican.

Uh?
 

Is that directly from the FSM? The pelican parts part I mean. LOL!

Its supposed to be sound advice and buy new bolts--just like head bolts. BTY i could supply used ones if you dont believe that.:)