Champ engine torque settings

[philb]

Could someone please tell me the torque settings for the B40 big-end nuts, main bearing cap nuts and the flywheel stud nuts?

As far as we can see (maybe not far enough?) the manual does not mention them.

Cheers, Phil

[fv1609]

Phil but what manual are you looking in?

EMER POWER S 528 Inspection Standards B40

Crankshaft main bearing nuts

High 425 lb in

Low 400 lb in

It also lists the torques for 3/8 & 5/16 set screws if you want them

Flywheel bolts

High 475 lb in

Low 450 lb in

I remember once snapping a stud on a flywheel forgetting it was inches not pounds!

 

[philb]

Thanks Clive. Any mention of the big end figures?

The manual we have is a disorganised reprint of a cocktail of EMERs, very descriptive but short on useful info.

You seriously tried to apply 450 ft lbs? Report to the headmaster's office for a good whacking.

[Richard Farrant]

32 minutes ago, philb said:

Thanks Clive. Any mention of the big end figures?

 

Hi Phil,

You have to measure the length of the big end bolts to achieve the correct tightness. First measure the bolt then tighten until the length increases by 0.006" to 0.009", then fit the split pins in the nut. You can measure the bolts insitu with a caliper.

regards, Richard

[philb]

Thanks Richard.

That's the first time I've come across a sensible way to accurately pre-stress bolts in small engine construction.

[Richard Farrant]

17 minutes ago, philb said:

Thanks Richard.

That's the first time I've come across a sensible way to accurately pre-stress bolts in small engine construction.

Phil,

You gotta love Rolls engines!

The REME Inspection Standards for the B40 engine, dated 1953, has no mention of torques, just tighten big end nuts using a 6" Tommy bar of 3% Nickel Steel ....................

[philb]

but what size Ape do you attach to the Tommy bar?

[Richard Farrant]

Stick to the bolt stretch method, it came from a much later EMER instruction - No Apes required !!!