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MG Midget and Sprite Technical - hg questions

so here is one for you

i had to remove my rocker gear (sliding the shaft out did not work)so i had to undo my head nuts.

i loosend them in the reverse order from tightening them in smal steps
the was no water on the block at the time and it had not been run for over 24 hours so it was cold

now do i just retighten to the correct torque and retorque when hot

or am i screwed?

there is a payen HG in there now and i do have other hg's lying around but no payen

i will probaly try it anny way but your views would be nice
Onno Könemann

Onno,

as long as you didn't disturb the head then you should be fine just retorquing the head.
Deborah Evans

Onno. Have not tried it myself. Others claim to have loosened the nuts associated with the rocker arm system, then retightened them back with no problems. Thus, I would agree with your thought of trying it and seeing what happens. Please report back with your results and we will have one more data point to support the theory that all is ok with this procedure, or one data point to show that it does not always work. Several test drives, of increasing length, before a long trip might be a good idea.

Les
Les Bengtson

Onno,

I have replaced the rockers twice without any noticable problems. First time I even got water in the cilinders and could't rotate the engine to set the valve clearance. removed spark plugs and sprayed the water out. That was back when MGWS was still in the bleekerstraat.

There is one sidenote I must make; when I removed the head to replace it with my flowed head there was "water damage" in cil no3. Not to bad, but still. Still have to investigate that head for cracks.

Anyways just do it, and DO NOT give the nuts some extra torque "just to be sure".
This could split the fire rings and cuase a leak. (Calver's corner...)
Alex G Matla

At the end of the 2007 race season we had to return the 1.5:1 roller rockers we had borrowed from Peter May. Accordingly I had to detorque the head. Later that winter we sourced our own roller rockers and, accordingly, I fitted them and retorqued the head.

The car then carried a full race season (2008), ie 10 15-20 minute sprint races as well as over an hour racing in the Birkett 6 hour relay race, with no problems. Bear in mind this is a high compression (11.75:1 engine).

So I reiterate, as long as the head has not been disturbed, then retorquing it is fine.
Deborah Evans

The great thing about the payne HG is its made out of a composit of some type kind of a plastic teflon, so shouldnt tear apart like a fel-pro. Plus I think its got a SS core.

Prop
Prop

well i am happy to hear these comments

seems like i am in the green
Onno Könemann

Yeah go baby, go baby
Alex G Matla

Torque up cold, warm the engine, allow to cool overnight and re-torque again when cold. Don't forget to check and adjust tappet clearances again.

I agree with Debbie, I have never had H/G problems as a result of swapping a rocker shaft.

Mark.
M T Boldry

I must have been unlucky (or ham fisted!). I changed my rockers and was as careful as I could but had a hg failure afterwards.
Dean Smith ('73 RWA)

well i am unlucky to

broke a head stud while pulling it to torque

so now the head has to come off to replace the stud
and i do not have a payen hg on stock only the copper like thingys (peter may sells them as competition so can't be to bad)

no time to order a payen and wait i need to drive the midget to a family gathering

me and my cousin have the thing where we both come in a diffrent car each year
and this midget has not been there
Onno Könemann

Onno,

I think all the gaskets I used were Payen, be they the Metro turbo silver coloured, competition copper coloured as supplied by my big bore engine machinist. I've never had a failure attributable to the gasket. I haven't needed one recently enough to comment on the black composite as IIRC they hadn't been invented at that time.
David Billington

Onno, are you saying you broke a high tensile stud or are you saying you don't have high tensile studs? By that I mean STD)

Either way, shouldn't you fit a complete new set of studs then?

How much torque where you pulling them?

Alex "finally, engine is ready!!!" Matla
Alex G Matla

Excuse Me!!!

You "Broke" a 3/8" head stud!...Grade 8 or ARP?

There has to be a back story to this...please do tell,

The copper will do fine for the trip there and back, probably dont want it for an indefintae period time, as its made more for racing where the head needs to come on and off, if any thing order the Payen HG and have it sent to your destination.

Prop
Prop

i used the std studs (so they should be high tensile)and used the std torque of 68NM

i was stuned as well
and i hope that bart has a complete new set lying around
Onno Könemann

Well that is classic

need the midget sunday
can pick up new head studs tomorow

so frantic tinkering on saturday!
Onno Könemann

This thread was discussed between 19/05/2009 and 22/05/2009

MG Midget and Sprite Technical index

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