Big End and Main Bearing bolts

[nidgester]

Can anyone advise me if these are stretch bolts and should be replaced when removed. I cannot find any listed on th GSF site and they list the shells so i would assume they are not stretch bolts and can be re-used.
Any help will be appreciated

[E30cabalan]

Can be re-used
Its the head bolts which hve to be binned and a new set fitted

[nidgester]

That's what i thought. Autodata states that mains and big ends can be re-used. Threads on this forum lean towards replacing but with no data to back this up. My local motor factors, who have the latest vesrion of autodata, also agree that replacement is not neccessary.

[B7]

WHOA!!!! ANY stretch bolt should be renewed full stop. Therefore the big end bolts should be renewed but the mains bolts can be reused and they are not stretch (on an M20 anyway).

You want to throw that auto data away mate. It's wrong.

[nidgester]

That's what confused me. The mains look like standard bolts but the big end bolts are necked like stretch bolts.
I don't want to bodge the rebuild, but i'm not replacing bolts just to line BMW's pockets with my hard earned cash.

[Simon13]

i can state 140% the big end bolts are stretch on all bmw engines!

[gooner1]

Bit of a thread revival, just to make absolutely sure.

These are the Main Bearing Bolts and can be reused.

Part No 2 on Diagram http://www.realoem.com/bmw/showparts.do ... fg=10&hl=9

These are the Big End Bolts and must be replaced Part No 4 on Diagram

http://www.realoem.com/bmw/showparts.do ... g=11&fg=20

Have I got that correct

While i'm here, i've finished cleaning up my Pistons, and went to great length to keep
all parts separate from each other. However, i now find that i 'm having some difficulty getting
the Connecting Rod Bush, Part No2 in the bottom Diagram, to go through the Piston itself.
Have not tried forcing them in as i don't want to damage the Pistons.
This isn't happening with every Piston, just 2 of them.
Is this normal and would i be better off replacing all the Bushes

[daimlerman]

Try warming the pistons in the oven.

Either get permission first,or wait untill she goes shopping!(and remove all traces )

[gooner1]

Will try that, Malc....... and blame you for any mishaps to the Oven.

[daimlerman]

Will try that, Malc....... and blame you for any mishaps to the Oven.

It's more the oven mitts that are likely to suffer....

'You've had WHAT in my mitts....'

[HairyScreech]

the bmw bolts are actually rather well designed stretch bolts.
in fact you wont find a piston held in with anything other than stretch bolts (very good engineering reason for this ill explain later)

you will need new bolts if you want to do it properly.

[gooner1]

you will need new bolts if you want to do it properly.

Already got the Big end bolts, Simon, wasn't 100% sure
re the Mains.
Still interested in your explanation though.

[HairyScreech]

well with the rod cap, theres funny illogical forces going on.

the bearing needs to remain crushed at all times, ill go look up my notes as i cant be sure im right from the top of my head.

[gooner1]

No rush mate.
When i do fit the new bearings to the Cap, am i right in thinking the tangs should
all be on the same side?

[HairyScreech]

the tangs fit the indents, which iirc are on the same side provided the cap is on the right way around.
*limps across room to check rod*

yep, both on same side.

and yes i have spare rods in the living room.

[gooner1]

the tangs fit the indents, which iirc are on the same side provided the cap is on the right way around.
*limps across room to check rod*

yep, both on same side.

and yes i have spare rods in the living room.

Doesn't everybody
Thanks, btw.