What torque settings do I use?

[MulletMan]

I have to replace the manifolds and exhaust risers on my 5.8 L OMC Cobra V8 inboard ($3,000 :'( :'( :'() and am having trouble finding out what the torque settings should be. I think this donk equates to the old 357 Chevvy motor ..............?

It was thanks to Ausfish guys that I found the problem under a post "What's wrong with this motor" after all the experts of the industry (and three grand later) could not find the problem! The hint to look for clean spark plugs (washed in salt water!!) led me to the fix. :D

I don't think the risers are all that critical in terms of the torque but would like to get the manifolds right.

Should I also pull the head and have a look as it got salt water in it due a corroded riser twelve months that I "repaired".
They are now completely eaten out with corrosion and ready for the bin! :-[ :-[

It is presently running like an absolute dream i.e. if it ain't broke don't fix it!

I will do a compression test on it during the repairs but they were all up about the 150 to 160 mark last time I checked.

She has only done 500 hours and I look after her better than my wife! ::) ::)

[blaze]

Hi PP
If you look at the tops of the bolts they will have markings on them
3 marks for grade 5 etc
Let me know the diameter of the bolts and how many marks?
If they are studs, let me know the diameter

I can then supply you with the standard torque setting for that bolt (hope I still got the data)
Also when torquing something up do it in stages and work from the centre out to the ends
cheers
blaze

[MulletMan]

Is that right Blaze? :-? :-?
Geeez, never knew such a thing existed. :-/ :-/
I won't be doing it for a week or two but will have a squiz and see what I can see!
Thanks
TPP

[SO70]

as a mechanic i wouldn't worry about it.
the torque wrench only gets used on bolts that hold more important things like cylinder heads, cranks and conrods.
did you consider buying stainless steel manifolds.
i put stainless steel manifolds on a 460ci OMC Cobra
they were cheaper than buying genuine manifolds and the riser is part of the manifoild.
will last a life time and have no corrosion problems.

[blaze]

Hi s070
Being a mechanic I would have thought your advice to a probmatic area with a motor you would have done all in your power to eliminate a source of a possible problem.
AS a mechanic also is why I offered the advice I have, PP has asked for torque setting to do the job the correct way.
cheers
blaze

[flyingfish]

Hi Guys

Just got to watch those standard torque settings especially when the internal thread is within some kind of softer alloys. ;)

[blaze]

speaking on torque setting of bolts
I would hate to count the times I have seen bolts/nuts come undone from someone doing them up to tight. Wheel nuts is a classic example. What happens is the stud streches and in extreme cases cause a wine glass effect on the thread and the nut or bolt can never be tightened to the correct torque, so if you have a nut/bolt that comes loose all the time, odds are that it has been over tensioned.
cheers
blaze