Well, here's a can of worm to open: lots of subjective thoughts available on
this one.. so heres my $.02 worth
First, anything you do to increase head efficiancy, compression, breathing
(cam) or anything else will affect other worn parts. How long your rings and
bearings will last is impossible to guess. Obviously how hard you drive the
car and how much you change the oil are the biggest issues. But I'd assume
that you have a problem NOW that you need to fix regardless or you'd be doing
the rebuild in the prefered manner, all together at once.
With that in mind... on the MGB Breathing Is King! Always do a good 3 angle
valve job! It's not much more expensive to do the head right if you're doing
it at all. Get Sil-bronze valve guides. Make sure they are properly de-burred
and clearanced! (there's a story there....)
Clean up the chambers, match the manifolds, and get a decent large diameter
exhaust on the car. Use a set of matched valve springs, at least check to see
if you have a weak one or two. Don't get into heavier springs unless you plan
to get into a higher lift cam, the stock springs (pre-18V) are fine for the
stock cam. IMHO the copper gasket is a waste of money. It was designed to
survive repeated installations and retorques in racing situations. Better
sealing is said to be available from the good composite gaskets available. (
But DON't buy a cheapo!!)
Worry about lifters when you do the cam. Do the cam when you do the motor...
and replace the cam bearings while you're in there. Why put new lifters on
old lobes, and why put new cam into old bearings??
I strongly recommend the Peter Burgess book "How to power tune your MGB"
available from Moss. This will give detailed guidence, backed by dyno
testing, as to which mods are worth the money.
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>From: "kcmgb" <kcmgb@kc.rr.com>
Subject: Valve Job on 70 B
>I need advice on having a valve job done on a 70 B. My first Question is
this ...If I have the valve job done ONLY will the added compression gain
blow out the rings and the bottom end say a year from now or sooner? I
have asked a number of people this and got a number of yes'es and no's
Question
Two...Should I do the little extras like a 3 angle grind , port and
polishing, heaver springs, lifters, comp.copper head gasket now? This car
will be a daily driver for now with the possability of a street cam and
other HP goodys down the road. Should I invest in the long haul now or wait
til I do the whole thing I have a limited budget to the basics but I would
be willing to pay for the extras now IF it will pay off NOW. Any advice
>would be helpful......thanks
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