Page 1 of 2

Rocker problem

Posted: Sun Jan 29, 2012 5:28 pm
by lee_rob
Hey guys

Just had my head professionally rebuilt only to find my rocker cover won't now fit on. This is because newer type rocker arms have been fitted which have clamp bolts on them and these foul on the tapered cover. Anyone else had this problem and know how to get around it??

Lee

Re: Rocker problem

Posted: Sun Jan 29, 2012 8:38 pm
by ian judd
How about fitting a really thick cam cover gasket to lift it up a bit? (You could experiment with some card first)

Re: Rocker problem

Posted: Sun Jan 29, 2012 8:43 pm
by lee_rob
The cover fouls far too low down for a thick gasket to be of any use, we are talking the cover being about a good inch from the head face

Re: Rocker problem

Posted: Sun Jan 29, 2012 9:34 pm
by lee_rob
Another thought, as I have a later 31 engine fitted to my car, which I think is the engine from the Family 8, did the rocker covers differ as from some pictures I have found the earlier OHC minor covers look different from the later family 8 ones.

Re: Rocker problem

Posted: Sun Jan 29, 2012 9:34 pm
by Ian Grace
Lee,

This is a known problem with J2 rocker fingers which your rebuilder has fitted because new M Type/Minor fingers are not available. They fit inside the MG alloy rocker covers, but no t the Minor one. You can grind metal off the clamp bolt heads or bend the cam cover out a bit, or fit an alloy cover. The first option usually works.

Re: Rocker problem

Posted: Sun Jan 29, 2012 9:40 pm
by lee_rob
Ian,

Hmm I guess they will have to be ground back then, not sure if I do it myself I will disturb the valve timing that has been set up by removing the bolt for grinding or if they can be put back easily??

Lee

Re: Rocker problem

Posted: Sun Jan 29, 2012 9:45 pm
by Ian Grace
You should be OK as long as you don't rotate the eccentric bush in the finger while the bolt is out.

Re: Rocker problem

Posted: Sun Jan 29, 2012 10:15 pm
by Sam Christie
Why not use an MG M-type/J2 cover if you can find one?

Re: Rocker problem

Posted: Sun Jan 29, 2012 10:16 pm
by lee_rob
Ok am I also right in thinking that these should still be set up with the eccentric bush towards the cam or is this not as critical on the J type fingers?

Re: Rocker problem

Posted: Sun Jan 29, 2012 10:17 pm
by lee_rob
Sam Christie wrote:Why not use an MG M-type/J2 cover if you can find one?
That is an option I guess but I would have to find one and also I guess they would be expensive being M type bits

Re: Rocker problem

Posted: Sun Jan 29, 2012 11:07 pm
by Ian Grace
lee_rob wrote:Ok am I also right in thinking that these should still be set up with the eccentric bush towards the cam or is this not as critical on the J type fingers?
Yes, as with the Minor fingers, you need the thick part of the bush towards the cam, otherwise the oilways don't connect. This has the effect of offsetting the finger inboard, actually helping the clearance with respect to the cam cover.

Check out the Tech Topics in M 103, which you can find in the Members' Area.

Re: Rocker problem

Posted: Mon Jan 30, 2012 8:25 am
by ian judd
Actually, it's only with the J type followers that the position is critical. With Minor and M the follower is fully enclosed so the oil will always find its way round. The J has a gap where the pinch bolt is. I think the MG cover can be bought new but I don't know how much they are. S + V probably do them.

Re: Rocker problem

Posted: Mon Jan 30, 2012 3:01 pm
by Ian Grace
Here's the Minor rocker finger arrangement from the handbook, showing the arc within which the eccentric must be positioned in order to maintain oil to the finger.

Image

Re: Rocker problem

Posted: Mon Jan 30, 2012 10:44 pm
by Ronald
We have these new type fingers on MT now, and the engine came back with a minor cover fitted.... so i can only assume he ground the bolts back to gain clearance....... although, knowing him he most likely sourced shallower headed bolts!

Re: Rocker problem

Posted: Mon Jan 30, 2012 10:51 pm
by lee_rob
Ronald wrote:We have these new type fingers on MT now, and the engine came back with a minor cover fitted.... so i can only assume he ground the bolts back to gain clearance....... although, knowing him he most likely sourced shallower headed bolts!
Who did your head?