Torque spec/tightness of nuts securing intake stub pipes?

[shiny_car]

Hey

I can't find torque specs for the nuts that hold the intake stub pipes to the heads. They are 8mm nuts, pipes are cast aluminium; in case someone can recommend a generic spec.

There was no reference in the workshop manual that I could see. Anyone know?

Thanks

[colcol]

For holding nuts on steel products, i usually torque to 15lbs, for holding nuts on aluminium products, go for about 8lbs, if you don't have a torque wrench OR you cannot get it near the nut, use a ring open end stubby spanner, use one finger to push on spanner, that will give you about 8lbs, for 15lbs, use normal spanner with one finger to push on spanner, and when it hurts your finger you have reached the correct torque, don't ask me about newton metres, because i have an old torque wrench that is still imperial, Colin.

[shiny_car]

Thanks Chokerboy. Just as well you have all the common sense in the world. I find it just so hard to work out what I'm doing. I think I should ask my wife to help.

You're right, I shouldn't ask dumb questions. Though strangely, all the newer Alfas have specs for virtually all bolts. And the 75 does have specs for things like the groundwires on the cam covers; must be critical.

However, it was a simple question, so a simple answer would have been helpful: 'just snug them up' would suffice if that's what you recommend.

[alfagtv58]

Yup, agreed Shiny.

While it may be common sense to you Choderboy, and I know that you have the ability to 'feel' before destroying a bolt or the thread, dont forget you work on these cars regularly, not everyone does.

Had a new guy at work recently tell me he had never heard the term 'imperial thread'....kind of highlighted to me that information that may be second nature to me may not be the case with other people.

Shiny - not trying to imply you are a novice or anything, given the work you are doing on that 75 I am sure its quite the opposite!

[gergory]

shiny-car
I think I have the torque settings for a lot of the ancillaries at home............will look them up for you

I have attached a chart with some of the more common settings for you

rgds

[gergory]

shiny-car

intake runners  19-23 Nm

[shiny_car]

Awesome, thanks. 

That's reassuring. I refitted them today, and tightened them to 180 in-lbs (had to use the small torque wrench with a thin-walled socket), which equates to 20Nm. Spot-on.

I tightened the injector retaining flanges to 88 in-lbs (10Nm).

@ alfagtv58: I'm definitely not an 'expert' or 'professional', and far more towards the 'novice/amateur' end of the scale! As a self-taught backyarder, maybe I'm no mug. But I've not had training unlike some people here. I appreciate the support.

[Duk]

The feel for tightening smaller bolts into aluminium threads tends to be acquired from painful lessons.
Another thing to help give a little extra leeway with tapped aluminium holes is to have some never seize compound on the threads. This adds lubrication and helps to prevent the tearing of the thread that precedes the stripping of the thread. It doesn't make them any stronger but the transition from 'tight enough' to 'heli-coil' is noticeably bigger.
It also stops that lovely Alfa engine habit of hanging on indefinitely to studs and bolts screwed into the engine  .

[colcol]

And a old mechanic told me once, if you are unsure of the torque, then LISTEN, two clicks and you are in business, i have always found that things like sumps, where you have lots of little bolts holding a large part on, doing it up to the factory specs, causes the gasket to swell out, just torque it until the gasket flattens out, and make sure the torque is even on all the bolts, Colin