7 replies to this topic

[AlasdairM]

Hi folks

I fitted a stage 1 kit to my 1990 1275cc cooper in the summer, and since then, I’ve had to tighten the manifold nuts/studs a few times. I hear a slight blowing coming from the engine, and that’s when I know they need a tighten up.

I say studs/nuts, as some of the nuts are seized into the studs, whereas some aren’t.

Has anyone else had this problem? Why is this happening? I can try using locktite?

[Dusky]

A spring washer was usually everything I needed. Now I fit stage 8 fasteners in most locations. https://youtu.be/U15OxrX_NBc

[Spider]

On the Exhaust System, anywhere where the fasteners are going to get quite hot, like the Manifold, and Clamps, I use Brass Nuts on these, they are adequately strong enough and if the stud or bolt gets rusty, these will still undo easily enough. For the Manifold, I actually fit a long nut, the original Cooper S Had these, I find them easier to land spanners and sockets on to.

 

If your nuts are coming loose or as it seems you are getting an Exhaust Leak at the Manifold Face, it could well be that a flange is not landing flat on to the head and / or a difference in thickness between the flanges of the Inlet and Exhaust Manifold, I'd suggest checking these before going too far. The Flanges you can measure the thickness of easy enough and to check for flatness, one way is to nip the manifolds up to the head without a gasket and look at them from all angles , to look under, use a dentist's mirror.

[sonscar]

In addition to the above I would remove the stuck nuts from the studs and refit the studs with brass nuts.Steve..

[AlasdairM]

Thanks all.

Yes I noticed there was a slight difference in thickness between the inlet manifold and the exhaust manifold.
I’ll try the brass nut idea, and buy a new set of studs too. That’ll be a winter job though!

[Mini Manannán]

File/mill/grind one side of each of the washers down to remove the discrepancy in the heights while you're at it. 

[Spider]

Thanks all.

Yes I noticed there was a slight difference in thickness between the inlet manifold and the exhaust manifold.
I’ll try the brass nut idea, and buy a new set of studs too. That’ll be a winter job though!

 

I either bend the washers a little or have brazed 2 strips of 3 mm steel wire to one side of the washers, then when doing them up, they'll automatically put equal pressure on to both flanges, like a see-saw 

[Cooperman]

If I have manifolds with unequal flange thicknesses, which is not unusual when 'mixing & matching' performance parts, I file a flat on the washers to ensure equal clamping.

I use 1.25" long x 5/16" UNF bolts instead of studs and nuts. This enables removal of the head easily and quickly. 1/4" sq. drive sockets make it not difficult to do up and undo the bolts.