2GM20 exhaust mixing elbow bolts - how tight ?

[edante]

Since ruining the thread on my fuel lift pump by over tightening a banjo bolt I am now very cautious about other bolts.

I have removed the exhaust mixing elbow to clean and check for corrosion and am now about to replace it.

It has 3 bolts , each one has a number 7 on the end which i think means a stronger bolt than normal.

I have bought a torque wrench - the question is how much torque do i need to use?

Can anyone help ?

Jeff

 

[earlybird]

Guessing that they're M8, like my Beta elbow, into an alloy h/e, the figure recommended by Beta is ~25Nm.
The marking 7 or 7T is not common AFAIK but seems to denote a medium strength. Markings such as 8.8 or 10.9 are more usual.
Hope that helps, but I wouldn't worry too much about a precise figure. My torque wrench is very cobwebby.

 

[RichardS]

Guessing that they're M8, like my Beta elbow, into an alloy h/e, the figure recommended by Beta is ~25Nm.
The marking 7 or 7T is not common AFAIK but seems to denote a medium strength. Markings such as 8.8 or 10.9 are more usual.
Hope that helps, but I wouldn't worry too much about a precise figure. My torque wrench is very cobwebby.

25Nm would be a little bit too righty-tighty for me for an M8, particularly into alloy. Even if that is the manufacturers recommendation, for a non-critical part which can be easily checked I would err towards 15 - 20 Nm. Personally, I wouldn't use a torque wrench for that operation but 15 - 20 is where I would end up.

Richard

 

[richardabeattie]

Just done the same job and certainly did not use a torque wrench. Just tightened it up without using excessive force. Then when the new gasket has had time to consider its position I might nip it up a touch more.

 

[MagicalArmchair]

Just done the same job and certainly did not use a torque wrench. Just tightened it up without using excessive force. Then when the new gasket has had time to consider its position I might nip it up a touch more.

I did the same with mine last year - I used to be more twitchy about torque! These Yanmar bolts are made of cheese too so go gently.

Edit - Ha, forgot I wrote this: http://www.albinballad.co.uk/how-tos/remove-a-sheared-off-exhaust-elbow-bolt/
Edit 2 - Also, note I applied copper grease to the bolts so they came out again, this can skew your torque settings and you can end up over-tightening stuff as the bolt is more slippery...