Rocker cover thread type/size?

[Lexie]

As above lads, 1 bolt has came loose and wont tighten up so lookin a thread size to get a helicoil kit

 

[Chris]

Quite a bit of work and expense. You could thread lock a stud in there and put a nut and washer on instead.

 

[StarCruiser]

I'm pretty sure they are M6 Lexie, they take a 10mm spanner iirc. Best to unscrew one and try it in an M6 not to be sure it's not a fine thread or such like, which I very much doubt.

 

[frank rabbets]

If the thread is deep enough the bottom part will be undamaged so Chris's method may well be better than helicoil.

 

[Lexie]

Thanks lads good advice chris. Il remove 1 and go from there.

Changing oil the other night and noticed oil on head gasket well i nearly had a stroke lol. Washed all up and inspected closely onli to later discover bolt on rocker cover was doing nothing.

Out curiousity how n the hell do these go slack i see a few posts on different forums

 

[StarCruiser]

It's very easy to overtighten them. Some folks see a leaky rocker cover gasket and tighten the bolt a bit. Thing is once a rocker cover gasket starts leaking, it's probably so hardened it won't seal too well anyway. I got me a new one from Roughtrax and it's on my list to do.

 

[Chris]

True, after this length of time they go go very hard and brittle. I changed one recently and it was in a very poor state. If you are going to 'glue' it in there to start with, I'd spray some brake or carb cleaner in first then blow out with an airline. If it's all oily then threadlock probably won't work.

 

[Towpack]

If the stud idea doesn't work you might just get away with re tapping it M7.

 

[Chris]

Depending on where the thread has gone of course there might be some better thread deeper down where the end of the bolt doesn't reach. Putting a stud (sawn off bolt maybe) here might just bite

 

[frank rabbets]

An m6 threaded bar might do the job if screwed in with 2 lock nuts on and then cut off to length. Care must be taken not to over tighten though as there will be no protective shoulder to stop this as per the original shouldered bolt. Over tightening could lead to a bent or cracked rocker cover. If it were mine I'd make a sleeve the same as the shoulder as on the bolt but not many people have a lathe.

 

[Chris]

Indeed Frank. I once screwed a bolt into a threaded hole and split a piece of the casing off. There was liquid in the hole and the bolt acted like a hydraulic piston and the pressure was sufficient to crack the edge of the block

 

[Lexie]

On further inspection the head of the bolt came off in my hand