I am hoping to do the precats at the weekend and would like to replace the manifold to block and cat to manifold nuts with something of a better quality than standard.
Does anyone know the specification of the nuts and what material would be best, from memory manifold nuts always used to be Brass.
Don't look like brass to me, but I renewed mine with new MrT parts 2 years ago and they're fine, and the Man nuts have been used again on the C2 install - they don't seem any the worse for it.
Manifold nuts have a spinning washer face and relatively low torque setting (37Nm/27ftlb).
Man to Cat are locknuts to between 62Nm/46ftlb, the man-cat stud bolts should be re-usable, but if you replace the old ones, the new ones go in at 43Nm/32ftlb.
If you really want to be thorough (and unecessary!), you might be replacing the two bolts on the Manifold - engine block bracket. If you do, don't forget they're different size heads (12mm/13mm or 13mm/14mm - can't remember s:? :? s:? ). The bigger one is hard to get 'cos its a 10mm thread but finer pitched than your average hardware store will stock. A friendly chat with a MRT mechanic will get you these - they have buckets of them in the workshop s:wink: :wink: s:wink: (they're painted green)
Quote from: "stevewarbs"I am hoping to do the precats at the weekend and would like to replace the manifold to block and cat to manifold nuts with something of a better quality than standard.
Does anyone know the specification of the nuts and what material would be best, from memory manifold nuts always used to be Brass.
Steve, FWIW I wouldn't bother replacing the nuts - on the Mk1 and Mk2 MR2s (from bitter experience) they're specials costing £1.50 each or so from Toyota. They're high grade metal that can be heat cycled without becomming brittle, and they're usually nipped in at the top a little to 'grip' the stud and stop them shaking loose.
If you put standard M sized nuts on there I'd guarantee they'll shake loose in less than 1,000 miles of driving.
At the end of the day, "if it ain't broke, don't fix it" applies s:) :) s:)
Yep, they are certainly a funky shape - I can attest to that.
They also appear to be made of butter s:? :? s:? (Certainly couldn't accuse them of being brittle s;) ;) s;) )
You could do it the old style way I suppose - thick brass nut tightens the manifold on, and a thin brass nut is wound on tight to the back of the first to lock it on. That might work..
I'm now desperately trying to remember what the nuts are - M8, I think..