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MG Midget and Sprite Technical - hi-lift rockers and rocker covers

Another silly basic question I'm afraid. I'm about to fit some Minispares 1.5 roller tipped rockers (the purple ones). I seem to recall that some of you have had clearance problems with the rockers catching the rocker cover. I've searched the archives but can't find any info on this. Is this a common problem and how can I establish there is enough clearance? I don't know the make of my alloy cover.
Chris Hasluck

Its a trial and error fix

If I did it agian, id spray the inside with white paint and run a it for a few minutes and see if any scratches appear

I used a 4inch angle grinder

Remember to adjust the valves from the side, not the front with the feeler gauge

Good luck

Prop
Prop and the Blackhole Midget

Also.. a little trick

Use silicone on the cork gasket between the cork and the valve cover to nake a permenate seal....then use a smear of white liethen grease between the cork and the cly head..this makes it reusable by many times

Prop
Prop and the Blackhole Midget

Chris,

If you have the Common ally type of rocker cover (like the one on my profile pic) you will probably need to remove a bit of material all along the pushrod side of the cover. A bit more around the radii internally where 1 and 8 rockers are closest as well. I've got the purple mini spares rockers, excellent bit of kit.

John
john payne

There are no silly 'technical' questions - just a knowledge gap to be filled!

I suspect that since even head castings vary slightly as will rocker covers you can't be sure if the rocker cover will need some relieving until you do a test fit.

What's perhaps more likely is that the push rods will rub in the head and they almost certainly will need to be relieved, slightly enlarged for 1.5 rockers, at least in my experience.
Daniel Stapleton

Anyone else with 1.5 rockers relieved their push rods?
Chris Hasluck

No, mine were fine. They do rub though! They have a very slight polish to them where they must slightly catch the sides at high revs. There was clearance when I built it but they must flex a bit.

I've had it apart a few times over the years but never bothered opening them out - I must remember to do it next time!

Of course your cam lift and rocker geometry will effect the clearance. The mini spares rockers were just a straight fit onto my engine (Kent 286 and a fairly well skimmed head) without any need to alter push rod length or pedestal height.

john payne

I opened mine up, but im using stainlees steel tubular in (3/16th) pushrods.

When I built the head, I used a rat tail file attachment on my milwaulki recipicating saw... the holes oveled out nicely and fairly fast.

Prop
Prop and the Blackhole Midget

Mmm I added a correction that seems to have vanished!

What I meant to make clear was that it's the push rod holes in the head that need to be relieved not the push rods themelves + what John says.
Daniel Stapleton

X2 all the way danial...

Prop
Prop and the Blackhole Midget

This thread was discussed between 13/12/2013 and 15/12/2013

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