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Re: Hot head

Posted: Wed Feb 15, 2012 9:23 am
by bmcecosse
And the sparks etc go everywhere - possibly in your eye..........or it slips and takes a finger off...........take care.

Re: Hot head

Posted: Wed Feb 15, 2012 3:26 pm
by Trog
Checked the face to valve clearance and some are a shade under 7.9mm :( the worst is 0.2mm under. I can probably lap that away if you think it's worth it??[frame]Image[/frame]

Re: Hot head

Posted: Wed Feb 15, 2012 4:59 pm
by bmcecosse
You will be fine at that - the 320 thou clearance includes an element of 'safety' - and ignores the thickness of the gasket.

Re: Hot head

Posted: Wed Feb 15, 2012 5:05 pm
by chrisryder
you do appear to be measuring the inlet in the picture though... did you measure the exhausts as well?

Re: Hot head

Posted: Wed Feb 15, 2012 7:12 pm
by Trog
I measured all of them and came to an average of 7.6 to 7.9mm :D I haven't sourced the rockers yet (solid type) ......I'm sure I'v seen on hear that different ration rockers are around? I'd be in trouble with any higher lift but how do I tell when I come across a set :roll:

Re: Hot head

Posted: Wed Feb 15, 2012 9:19 pm
by bmcecosse
Don't worry about daft 'high ratio' rockers - the standard rockers are fine. Actually - the earlier 'pressed steel' rockers are the ones to use - but then you must spend time re-aligning them on the shaft so they act directly over the valve tips........ satisfying to do - but does take a bit of time. MG/Rover cheated by producing wide faced 'sintered' rockers which cover the off-set valves - but they are far from ideal - and certainly NOT to be used with high lift cam or silly strong valve springs.

Re: Hot head

Posted: Thu Feb 16, 2012 8:46 am
by chrisryder
these are the sintered ones you need:

Image

i think all sintered ones like them are the standard ratio.

Mini-spares high ratio rockers look like this:

Image

and have 1.5:1 written on them, as you can possibly make out.

or these, which are high ratio 'roller rockers'

Image

Basically, you want the first ones!

Re: Hot head

Posted: Thu Feb 16, 2012 9:16 am
by bmcecosse
The sintered rockers are cr@p - but they will do the job on a standardish engine with no high lift cam or silly strong valve springs......

Re: Hot head

Posted: Thu Feb 16, 2012 8:51 pm
by linearaudio
The sintered rockers are sooo rubbish that BL only fitted them to every A-series made after about 1980.... still a few of those going around OK!!
They are fine for what you are doing, and by far the simplest option!

Re: Hot head

Posted: Thu Feb 16, 2012 9:37 pm
by bmcecosse
Hahahahah - but - they do put a side force on the valves in the guides. So for a more elegant engineering solution - it is better to overhaul a set of pressed steel rockers and carefully align them to operate directly over the valve stem tips. But as you say la - it's not essential, and they will do the job, for a while........